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Using Amsorb to detect dehydration of CO2 absorbents containing strong base

Background: Because Amsorb changes color when it dries, the authors investigated whether Amsorb combined with different strong base-containing carbon dioxide absorbents signals dehydration of such absorbents. Methods: Five different carbon dioxide absorbents (1,330 g) each topped with 70 g of Amsorb were dried in an anesthesia machine (Modulus CD, Datex-Ohmeda, Madison, WI) with oxygen (Amsorb layer at the fresh gas inflow site). As soon as a color change was detected in the Amsorb, the authors tested the samples for a change in weight and carbon monoxide formation from 7.5% desflurane or 4% isoflurane. In a different experiment with the five absorbents, Amsorb was layered at the drying gas outflow site. In further experiments, the authors tested for a color change in Amsorb from drying and rehydrating and from drying with nitrogen. Finally, they dried a mixture of Amsorb and 1% NaOH and examined it for color change. Results: In the experiments with Amsorb layered at the inflow, the Amsorb changed color when the water content of the samples was only marginally reduced (to a mean 13.6%), and no carbon monoxide formed. With Amsorb layered at the outflow, it changed color when the mean water content of the samples was reduced to 8.8%, and carbon monoxide formation was detected to varying degrees. The color change was independent of the drying gas and could be reversed by rehydrating. Adding NaOH to Amsorb prevented a color change. Conclusions: Dehydration in strong base-containing absorbents can reliably be indicated before carbon monoxide is formed when Amsorb is layered at the fresh gas inflow. The authors assume that the indicator dye in Amsorb changes color on drying because of the absence of strong base in this absorbent.

Changing anesthesiologists' practice patterns: Can it be done?

Background: Because the ultimate purpose of new medical knowledge is to achieve improved health outcomes, physicians need to possess and use this knowledge in their practice. The authors introduced enhanced education and individualized feedback to reduce postoperative nausea and vomiting (PONY). The primary objective was to increase anesthesiologists' use of preventive measures to reduce PONV, and the secondary objective was to determine whether patient outcomes were improve. Methods: After obtaining hospital ethics committee approval, the effect of education and feedback on anesthesiologist performance and the rate of PONV in major surgery elective inpatients during a 2-yr period was assessed. After baseline data collection (6 months), anesthesiologists at the study hospital received enhanced education (8 months) and individualized feedback (10 months). Parallel data collection was performed at a control hospital at which practice was continued as usual. The education promoted preventive measures (antiemetic premedication, nasogastric tubes, droperidol, metoclopramide). Individualized feedback provided the number of patients receiving promoted measures and the rate of PONV. The mean percentage of anesthesiologists' patients receiving at least one promoted measure and the rate of PONY were compared with baseline levels. Results: At the study hospital, there was a significant increase in the mean percentage of the anesthesiologists' female patients receiving a preventive measure as well as a significant increase in the use of droperidol ≤ 1 mg (P < 0.05) for all patients. The use of other promoted measures was unaffected. Absolute rates of PONV were unaffected at the study hospital until the post feedback period (decrease of 8.8% between baseline and postfeedback (P - 0.015)). Conclusion: It was demonstrated that enhanced education and individualized feedback can change anesthesiologists' practice patterns. The actual benefit to patients from use of preventive measures was limited when used in the everyday clinical situation. Therefore, only modest decreases in PONV were achieved, despite the use of preventive measures.

Anesthesiologist board certification and patient outcomes

Background: Board certification is often used as a surrogate indicator of provider competence, although few outcome studies have demonstrated its validity. The aim of this study was to compare the outcomes of patients who underwent surgical procedures under the care of an anesthesiologist with or without board certification. Methods: Medicare claims records for 144,883 patients in Pennsylvania who underwent general surgical or orthopedic procedures between 1991 and 1994 were used to determine provider-specific outcome rates adjusted to account for patient severity and case mix, and hospital characteristics. Outcomes of 8,894 cases involving midcareer anesthesiologists, 11-25 yr from medical school graduation, who lacked board certification were compared with all other cases. Midcareer anesthesiologist cases were studied because this group had sufficient time to become certified during an era when obtaining certification was already considered important, and consequently had the highest rate of board certification. Mortality within 30 days of admission and the failure-torescue rate (defined as the rate of death after an in-hospital complication) were the two primary outcome measures. Results: Adjusted odds ratios for death and failure to rescue were greater when care was delivered by noncertified midcareer anesthesiologists (death = 1.13 [95% confidence interval, 1.00, 1.26], P < 0.04; failure to rescue = 1.13 [95% confidence interval, 1.01, 1.27], P < 0.04). Adjusting for international medical school graduates did not change these results. Conclusions: When anesthesiology board certification is very common, as in midcareer practitioners, the lack of board certification is associated with worse outcomes. However, the poor outcomes associated with noncertified providers may be a result of the hospitals at which they practice and not necessarily their manner of practice.

Neuroprotective effects of dexmedetomidine against glutamate agonist-induced neuronal cell death are related to increased astrocyte brain-derived neurotrophic factor expression

Background: Brain-derived neurotrophic factor (BDNF) plays a prominent role in neuroprotection against perinatal brain injury. Dexmedetomidine, a selective agonist of α2-adrenergic receptors, also provides neuroprotection against glutamate-induced damage. Because adrenergic receptor agonists can modulate BDNF expression, our goal was to examine whether dexmedetomidine's neuroprotective effects are mediated by BDNF modulation in mouse perinatal brain injury. Methods: The protective effects against glutamate-induced injury of BDNF and dexmedetomidine alone or in combination with either a neutralizing BDNF antibody or an inhibitor of the extracellular signal-regulated kinase pathway (PD098059) were compared in perinatal ibotenate-induced cortical lesions (n = 10-20 pups/groups) and in mouse neuronal cultures (300 μM of ibotenate for 6 h). The effect of dexmedetomidine on BDNF expression was examined in vivo and in vitro with cortical neuronal and astrocyte isolated cultures. Results: Both BDNF and dexmedetomidine produced a significant neuroprotective effect in vivo and in vitro. Dexmedetomidine enhanced Bdnf4 and Bdnf5 transcription and BDNF protein cortical expression in vivo. Dexmedetomidine also enhanced Bdnf4 and Bdnf5 transcription and increased BDNF media concentration in isolated astrocyte cultures but not in neuronal cultures. Dexmedetomidine's protective effect was inhibited with BDNF antibody (mean lesion size ± SD: 577 ± 148 μm vs. 1028 ± 213 μm, n = 14-20, P < 0.001) and PD098059 in vivo but not in isolated neuron cultures. Finally, PD098059 inhibited the increased release of BDNF induced by dexmedetomidine in astrocyte cultures. Conclusion: These results suggest that dexmedetomidine increased astrocyte expression of BDNF through an extracellular signal-regulated kinase-dependent pathway, inducing subsequent neuroprotective effects. © 2013 the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

Buprenorphine disrupts sleep and decreases adenosine concentrations in sleep-regulating brain regions of sprague dawley rat

Background: Buprenorphine, a partial μ-opioid receptor agonist and κ-opioid receptor antagonist, is an effective analgesic. The effects of buprenorphine on sleep have not been well characterized. This study tested the hypothesis that an antinociceptive dose of buprenorphine decreases sleep and decreases adenosine concentrations in regions of the basal forebrain and pontine brainstem that regulate sleep. Methods: Male Sprague Dawley rats were implanted with intravenous catheters and electrodes for recording states of wakefulness and sleep. Buprenorphine (1 mg/kg) was administered systemically via an indwelling catheter and sleep-wake states were recorded for 24 h. In additional rats, buprenorphine was delivered by microdialysis to the pontine reticular formation and substantia innominata of the basal forebrain while adenosine was simultaneously measured. Results: An antinociceptive dose of buprenorphine caused a significant increase in wakefulness (25.2%) and a decrease in nonrapid eye movement sleep (-22.1%) and rapid eye movement sleep (-3.1%). Buprenorphine also increased electroencephalographic delta power during nonrapid eye movement sleep. Coadministration of the sedative-hypnotic eszopiclone diminished the buprenorphine-induced decrease in sleep. Dialysis delivery of buprenorphine significantly decreased adenosine concentrations in the pontine reticular formation (-14.6%) and substantia innominata (-36.7%). Intravenous administration of buprenorphine significantly decreased (-20%) adenosine in the substantia innominata. Conclusions: Buprenorphine significantly increased time spent awake, decreased nonrapid eye movement sleep, and increased latency to sleep onset. These disruptions in sleep architecture were mitigated by coadministration of the nonbenzodiazepine sedative-hypnotic eszopiclone. The buprenorphine-induced decrease in adenosine concentrations in basal forebrain and pontine reticular formation is consistent with the interpretation that decreasing adenosine in sleep-regulating brain regions is one mechanism by which opioids disrupt sleep. © 2011, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

High incidence of burnout in academic chairpersons of anesthesiology: Should we be taking better care of our leaders?

Background: Burnout is a work-related psychologic syndrome characterized by emotional exhaustion, low personal accomplishment, and depersonalization. Methods: By using an instrument that included the MBI-HHS Burnout Inventory, we surveyed academic anesthesiology chairpersons in the United States. Current level of job satisfaction compared with 1 and 5 yr before the survey, likelihood of stepping down as chair in the next 2 yr, and a high risk of burnout were the primary outcomes. Results: Of the 117 chairs surveyed, 102 (87%) responded. Nine surveys had insufficient responses for assessment of burnout. Of 93 chairs, 32 (34%) reported high current job satisfaction, which represented a significant decline compared with that reported for 1 yr (P = 0.009) and 5 yr (P = 0.001) before the survey. Of 93 chairs, 26 (28%) reported extreme likelihood of stepping down as a chair in 1-2 yr. There was no association of age (P = 0.16), sex (P = 0.82), or self-reported effectiveness (P = 0.63) with anticipated likelihood of stepping down, but there was a negative association between the modified efficacy scale scoρrgr; = -0.303, P = 0.003) and likelihood of stepping down. Of 93 chairs, 26 (28%) met the criteria for high burnout and an additional 29 (31%) met the criteria for moderately high burnout. Decreased current job satisfaction and low self-reported spousal/significant other support were independent predictors of high burnout risk. Conclusion: Fifty-one percent of academic anesthesiology chairs exhibit a high incidence/risk of burnout. Age, sex, time as a chair, hours worked, and perceived effectiveness were not associated with high burnout; however, low job satisfaction and reduced self-reported spousal/significant other support significantly increased the risk. © 2010, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins.

Adora2b signaling on bone marrow derived cells dampens myocardial ischemia-reperfusion injury

Background: Cardiac ischemia-reperfusion (I-R) injury represents a major cause of cardiac tissue injury. Adenosine signaling dampens inflammation during cardiac I-R. The authors investigated the role of the adenosine A2b-receptor (Adora2b) on inflammatory cells during cardiac I-R. Methods: To study Adora2b signaling on inflammatory cells, the authors transplanted wild-type (WT) bone marrow (BM) into Adora2 b-/- mice or Adora2b b-/- BM into WT mice. To study the role of polymorphonuclear leukocytes (PMNs), neutrophil-depleted WT mice were treated with an Adora2b b-/- agonist. After treatments, mice were exposed to 60 min of myocardial ischemia and 120 min of reperfusion. Infarct sizes and troponin I concentrations were determined by triphenyltetrazolium chloride staining and enzyme-linked immunosorbent assay, respectively. Results: Transplantation of WT BM into Adora2b mice decreased infarct sizes by 19 ± 4% and troponin I by 87.5 ± 25.3 ng/ml (mean ± SD, n = 6). Transplantation of Adora2b BM into WT mice increased infarct sizes by 20 ± 3% and troponin I concentrations by 69.7 ± 17.9 ng/ml (mean ± SD, n = 6). Studies on the reperfused myocardium revealed PMNs as the dominant cell type. PMN depletion or Adora2b agonist treatment reduced infarct sizes by 30 ± 11% or 26 ± 13% (mean ± SD, n = 4); however, the combination of both did not produce additional cardioprotection. Cytokine profiling showed significantly higher cardiac tumor necrosis factor α concentrations in Adora2b compared with WT mice (39.3 ± 5.3 vs. 7.5 ± 1.0 pg/mg protein, mean ± SD, n = 4). Pharmacologic studies on human-activated PMNs revealed an Adora2b-dependent tumor necrosis factor α release. Conclusion: Adora2b signaling on BM-derived cells such as PMNs represents an endogenous cardioprotective mechanism during cardiac I-R. The authors' findings suggest that Adora2b agonist treatment during cardiac I-R reduces tumor necrosis factor α release of PMNs, thereby dampening tissue injury. © 2012 the American Society of Anesthesiologists, Inc. Lippincott Williams &amp; Wilkins. Anesthesiology.

Role of the o-linked β-N-acetylglucosamine in the cardioprotection induced by isoflurane

Background: Cardiac protection by volatile anesthetic-induced preconditioning and ischemic preconditioning have similar signaling pathways. Recently, it was reported that augmentation of protein modified with O-linked β-N-acetylglucosamine (O-GlcNAc) contributes to cardiac protection. This study investigated the role of O-GlcNAc in cardiac protection induced by anesthetic-induced preconditioning. Methods: O-GlcNAc-modified proteins were visualized by immunoblotting. Tolerance against ischemia or reperfusion was tested in vivo (n = 8) and in vitro (n = 6). The opening of the mitochondrial permeability transition pore (mPTP) upon oxidative stress was examined in myocytes treated with calcein AM (n = 5). Coimmunoprecipitation and enzymatic labeling were performed to detect the mitochondrial protein responsible for the mPTP opening. RESULTS:: Isoflurane treatment and the consequent augmentation of O-GlcNAc concentrations reduced the infarct size (26 ± 5% [mean ± SD], P < 0.001) compared with the control. The protective effect of O-GlcNAc was eliminated in the group pretreated with the O-GlcNAc transferase inhibitor alloxan (39 ± 5%, P < 0.001). Myocyte survival also showed the same result in vitro. Formation of the mPTP was abrogated in the isoflurane-treated cells (86 ± 4%, P < 0.001) compared with the control and alloxan-plus-isoflurane-treated cells (57 ± 7%, P < 0.001). Coimmunoprecipitation and enzymatic labeling studies revealed that the O-GlcNAc-modified, voltage-dependent anion channel restained the mPTP opening. Conclusions: Isoflurane induced O-GlcNAc modification of mitochondrial voltage-dependent anion channel. This modification inhibited the opening of the mPTP and conferred resistance to ischemia-reperfusion stress. © 2011 the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

Anesthesiology trainees face ethical, practical, and relational challenges in obtaining informed consent

BACKGROUND: Categorizing difficulties anesthesiologists have in obtaining informed consent may influence education, performance, and research. This study investigated the trainees perspectives and educational needs through a qualitative analysis of narratives. METHODS: The Program to Enhance Relational and Communication Skills-Anesthesia used professional actors to teach communication skills and relational abilities associated with informed consent. Before attending the program, participants wrote about a challenging informed consent experience. Narratives were analyzed by two researchers following the principles of grounded theory. The researchers independently read the narratives and marked key words and phrases to identify reoccurring challenges described by anesthesiologists. Through rereading of the narratives and discussion, the two researchers reached consensus on the challenges that arose and calculated their frequency. RESULTS: Analysis of the 39 narratives led to the identification of three types of challenges facing anesthesiologists in obtaining informed consent. Ethical challenges included patient wishes not honored, conflict between patient and family wishes and medical judgment, patient decision-making capacity, and upholding professional standards. Practical challenges included the amount of information to provide, communication barriers, and time limitations. Relational challenges included questions about trainee competence, mistrust associated with previous negative experiences, and misunderstandings between physician and patient or family. CONCLUSIONS: The ethical, practical, and relational challenges in obtaining informed consent colored trainees views of patient care and affected their interactions with patients. Using participant narratives personalizes education and motivates participants. The richness of narratives may help anesthesiologists to appreciate the qualitative aspects of informed consent.

Celecoxib impairs heart development via inhibiting cyclooxygenase-2 activity in zebrafish embryos

Background: Celecoxib, a cyclooxygenase-2 inhibitor, is a commonly ingested drug that is used by some women during pregnancy. Although use of celecoxib is associated with increased cardiovascular risk in adults, its effect on fetal heart development remains unknown. Methods: Zebrafish embryos were exposed to celecoxib or other relevant drugs from tailbud stage (10.3-72 h postfertilization). Heart looping and valve formation were examined at different developmental stages by in vivo confocal imaging. In addition, whole mount in situ hybridization was performed to examine drug-induced changes in the expression of heart valve marker genes. Results: In celecoxib-treated zebrafish embryos, the heart failed to undergo normal looping and the heart valve was absent, causing serious blood regurgitation. Furthermore, celecoxib treatment disturbed the restricted expression of the heart valve markers bone morphogenetic protein 4 and versican-but not the cardiac chamber markers cardiac myosin light chain 2, ventricular myosin heavy chain, and atrial myosin heavy chain. These defects in heart development were markedly relieved by treatment with the cyclooxygenase-2 downstream product prostaglandin E2, and mimicked by the cyclooxygenase-2 inhibitor NS398, implying that celecoxib-induced heart defects were caused by the inhibition of cyclooxygenase-2 activity. Conclusions: These findings provide the first in vivo evidence that celecoxib exposure impairs heart development in zebrafish embryos by inhibiting cyclooxygenase-2 activity. © 2011, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

Do they understand? (Part I): Parental consent for children participating in clinical anesthesia and surgery research

Background: Central to the tenet of informed consent is the quality of disclosure of information by the investigator and the understanding thereof by the research subject or his or her surrogate. This study was designed to measure parents' understanding of the elements of informed consent for clinical studies in which their children had been approached to participate. Methods: The study sample consisted of 505 parents who had been approached for permission to allow their child to participate in a clinical anesthesia or surgery study. Regardless of whether the parent consented (consenters, n = 411) or declined (nonconsenters, n = 94) to their child's participation in a study, they were interviewed to determine their understanding of 11 elements of consent. Two independent assessors who were familiar with the study protocols scored the parents' levels of understanding. Results: Parents perceived their overall understanding of the elements of consent as high (8.7 ± 1.6; 0-10 scale); however, this represented a significant overestimation compared with the assessors' measures of parental understanding (7.3 ± 1.8; P < 0.0001). Furthermore, consenters had greater understanding than nonconsenters (7.6 ± 1.6 vs. 6.1 ± 1.9; P < 0.001). Several predictors of understanding were identified, including whether the parent consented, education level, clarity of disclosure, child in previous study, age of parent, parent listened to disclosure, and degree to which parent read the consent document. The day on which consent was sought had no impact on the level of understanding. Conclusions: Parents approached for permission to allow their child to participate in a research study had less than optimal understanding of the elements of consent. As such, investigators must make every effort to enhance understanding and ensure that parents have sufficient information to make informed decisions regarding their child's participation in research studies.

A single subanesthetic dose of ketamine relieves depression-like behaviors induced by neuropathic pain in rats

Background: Chronic pain is associated with depression. In rodents, pain is often assessed by sensory hypersensitivity, which does not sufficiently measure affective responses. Low-dose ketamine has been used to treat both pain and depression, but it is not clear whether ketamine can relieve depression associated with chronic pain and whether this antidepressant effect depends on its antinociceptive properties. Methods: The authors examined whether the spared nerve injury model of neuropathic pain induces depressive behavior in rats, using sucrose preference test and forced swim test, and tested whether a subanesthetic dose of ketamine treats spared nerve injury-induced depression. Results: Spared nerve injury-treated rats, compared with control rats, showed decreased sucrose preference (0.719 ± 0.068 (mean ± SEM) vs. 0.946 ± 0.010) and enhanced immobility in the forced swim test (107.3 ± 14.6s vs. 56.2 ± 12.5s). Further, sham-operated rats demonstrated depressive behaviors in the acute postoperative period (0.790 ± 0.062 on postoperative day 2). A single subanesthetic dose of ketamine (10 mg/kg) did not alter spared nerve injury-induced hypersensitivity; however, it treated spared nerve injury-associated depression-like behaviors (0.896 ± 0.020 for ketamine vs. 0.663 ± 0.080 for control rats 1 day after administration; 0.858 ± 0.017 for ketamine vs. 0.683 ± 0.077 for control rats 5 days after administration). Conclusions: Chronic neuropathic pain leads to depression-like behaviors. The postoperative period also confers vulnerability to depression, possibly due to acute pain. Sucrose preference test and forced swim test may be used to compliment sensory tests for assessment of pain in animal studies. Low-dose ketamine can treat depression-like behaviors induced by chronic neuropathic pain. © 2011, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

Resident characterization of better-than- and worse-than-average clinical teaching

Background: Clinical teachers and trainees share a common view of what constitutes excellent clinical teaching, but associations between these behaviors and high teaching scores have not been established. This study used residents' written feedback to their clinical teachers, to identify themes associated with above- or below-average teaching scores.Methods: All resident evaluations of their clinical supervisors in a single department were collected from January 1, 2007 until December 31, 2008. A mean teaching score assigned by each resident was calculated. Evaluations that were 20% higher or 15% lower than the resident's mean score were used. A subset of these evaluations was reviewed, generating a list of 28 themes for further study. Two researchers then, independently coded the presence or absence of these themes in each evaluation. Interrater reliability of the themes and logistic regression were used to evaluate the predictive associations of the themes with above- or below-average evaluations.Results: Five hundred twenty-seven above-average and 285 below-average evaluations were evaluated for the presence or absence of 15 positive themes and 13 negative themes, which were divided into four categories: teaching, supervision, interpersonal, and feedback. Thirteen of 15 positive themes correlated with above-average evaluations and nine had high interrater reliability (Intraclass Correlation Coefficient >0.6). Twelve of 13 negative themes correlated with below-average evaluations, and all had high interrater reliability. On the basis of these findings, the authors developed 13 recommendations for clinical educators.Conclusions: The authors developed 13 recommendations for clinical teachers using the themes identified from the aboveand below-average clinical teaching evaluations submitted by anesthesia residents. © 2013, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins.

General anesthesia causes long-term impairment of mitochondrial morphogenesis and synaptic transmission in developing rat brain

Background: Clinically used general anesthetics, alone or in combination, are damaging to the developing mammalian brain. In addition to causing widespread apoptotic neurodegeneration in vulnerable brain regions, exposure to general anesthesia at the peak of synaptogenesis causes learning and memory deficiencies later in life. In vivo rodent studies have suggested that activation of the intrinsic (mitochondria-dependent) apoptotic pathway is the earliest warning sign of neuronal damage, suggesting that a disturbance in mitochondrial integrity and function could be the earliest triggering events. Methods: Because proper and timely mitochondrial morphogenesis is critical for brain development, the authors examined the long-term effects of a commonly used anesthesia combination (isoflurane, nitrous oxide, and midazolam) on the regional distribution, ultrastructural properties, and electron transport chain function of mitochondria, as well as synaptic neurotransmission, in the subiculum of rat pups. RESULTS:: This anesthesia, administered at the peak of synaptogenesis, causes protracted injury to mitochondria, including significant enlargement of mitochondria (more than 30%, P < 0.05), impairment of their structural integrity, an approximately 28% increase in their complex IV activity (P < 0.05), and a twofold decrease in their regional distribution in presynaptic neuronal profiles (P < 0.05), where their presence is important for the normal development and functioning of synapses. Consequently, the authors showed that impaired mitochondrial morphogenesis is accompanied by heightened autophagic activity, decrease in mitochondrial density (approximately 27%, P < 0.05), and long-lasting disturbances in inhibitory synaptic neurotransmission. The interrelation of these phenomena remains to be established. Conclusion: Developing mitochondria are exquisitely vulnerable to general anesthesia and may be important early target of anesthesia-induced developmental neurodegeneration. © 2011 the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

Strategy-dependent dissociation of the neural correlates involved in pain modulation

Background: Cognitive strategies are a set of psychologic behaviors used to modulate one's perception or interpretation of a sensation or situation. Although the effectiveness of each cognitive strategy seems to differ between individuals, they are commonly used clinically to help patients with chronic pain cope with their condition. The neural basis of commonly used cognitive strategies is not well understood. Understanding the neural correlates that underlie these strategies will enhance understanding of the analgesic network of the brain and the cognitive modulation of pain. Methods: The current study examines patterns of brain activation during two common cognitive strategies, external focus of attention and reappraisal, in patients with chronic pain using functional magnetic resonance imaging. Results: Behavioral results revealed interindividual variability in the effectiveness of one strategy versus another in the patients. Functional magnetic resonance imaging revealed distinct patterns of activity when the two strategies were used. During external focus of attention, activity was observed mainly in cortical areas including the postcentral gyrus, inferior parietal lobule, middle occipital gyrus, and precentral gyrus. The use of reappraisal evoked activity in the thalamus and amygdala in addition to cortical regions. Only one area, the postcentral gyrus, was observed to be active during both strategies. Conclusions: The results of this study suggest that different cognitive behavioral strategies recruit different brain regions to perform the same task: pain modulation. © 2011, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

New Setting of Neurally Adjusted Ventilatory Assist during Noninvasive Ventilation through a Helmet

Background: Compared to pneumatically controlled pressure support (PSP), neurally adjusted ventilatory assist (NAVA) was proved to improve patient-ventilator interactions, while not affecting comfort, diaphragm electrical activity (EAdi), and arterial blood gases (ABGs). This study compares neurally controlled pressure support (PSN) with PSP and NAVA, delivered through two different helmets, in hypoxemic patients receiving noninvasive ventilation for prevention of extubation failure. Methods: Fifteen patients underwent three (PSP, NAVA, and PSN) 30-min trials in random order with both helmets. Positive end-expiratory pressure was always set at 10 cm H2O. In PSP, the inspiratory support was set at 10 cm H2O above positive end-expiratory pressure. NAVA was adjusted to match peak EAdi (EAdipeak) during PSP. In PSN, the NAVA level was set at maximum matching the pressure delivered during PSP by limiting the upper pressure. The authors assessed patient comfort, EAdipeak, rates of pressurization (i.e., airway pressure-time product [PTP] of the first 300 and 500 ms after the initiation of patient effort, indexed to the ideal pressure-time products), and measured ABGs. Results: PSN significantly increased comfort to (median [25 to 75% interquartile range]) 8 [7 to 8] and 9 [8 to 9] with standard and new helmets, respectively, as opposed to both PSP (5 [5 to 6] and 7 [6 to 7]) and NAVA (6 [5 to 7] and 7 [6 to 8]; P &lt; 0.01 for all comparisons). Regardless of the interface, PSN also decreased EAdipeak (P &lt; 0.01), while increasing PTP of the first 300 ms from the onset of patient effort, indexed to the ideal PTP (P &lt; 0.01) and PTP of the first 500 ms from the onset of patient effort, indexed to the ideal PTP (P &lt; 0.001). ABGs were not different among trials. Conclusions: When delivering noninvasive ventilation by helmet, compared to PSP and NAVA, PSN improves comfort and patient-ventilator interactions, while not ABGs. (Anesthesiology 2016; 125:1181-9). Copyright © 2016, the American Society of Anesthesiologists, Inc. Wolters Kluwer Health, Inc. All Rights Reserved.

Compassionate and Clinical Behavior of Residents in a Simulated Informed Consent Encounter

BACKGROUND: Compassionate behavior in clinicians is described as seeking to understand patients' psychosocial, physical and medical needs, timely attending to these needs, and involving patients as they desire. The goal of our study was to evaluate compassionate behavior in patient interactions, pain management, and the informed consent process of anesthesia residents in a simulated preoperative evaluation of a patient in pain scheduled for urgent surgery. METHODS: Forty-nine Clinical Anesthesia residents in year 1 and 16 Clinical Anesthesia residents in year 3 from three residency programs individually obtained informed consent for anesthesia for an urgent laparotomy from a standardized patient complaining of pain. Encounters were assessed for ordering pain medication, for patient-resident interactions by using the Empathic Communication Coding System to code responses to pain and nausea cues, and for the content of the informed consent discussion. RESULTS: Of the 65 residents, 56 (86%) ordered pain medication, at an average of 4.2 min (95% CI, 3.2 to 5.1) into the encounter; 9 (14%) did not order pain medication. Resident responses to the cues averaged between perfunctory recognition and implicit recognition (mean, 1.7 [95% CI, 1.6 to 1.9]) in the 0 (less empathic) to 6 (more empathic) system. Responses were lower for residents who did not order pain medication (mean, 1.2 [95% CI, 0.8 to 1.6]) and similar for those who ordered medication before informed consent signing (mean, 1.9 [95% CI, 1.6 to 2.1]) and after signing (mean, 1.9 [95% CI, 1.6 to 2.0]; F (2, 62) = 4.21; P = 0.019; partial η = 0.120). There were significant differences between residents who ordered pain medication before informed consent and those who did not order pain medication and between residents who ordered pain medication after informed consent signing and those who did not. CONCLUSIONS: In a simulated preoperative evaluation, anesthesia residents have variable and, at times, flawed recognition of patient cues, responsiveness to patient cues, pain management, and patient interactions.

Regional and gender differences and trends in the anesthesiologist workforce

Background: Concerns have long existed about potential shortages in the anesthesiologist workforce. In addition, many changes have occurred in the economy, demographics, and the healthcare sector in the last few years, which may impact the workforce. The authors documented workforce trends by region of the United States and gender, trends that may have implications for the supply and demand of anesthesiologists. Methods: The authors conducted a national survey of American Society of Anesthesiologists members (accounting for >80% of all practicing anesthesiologists in the United States) in 2007 and repeated it in 2013. The authors used logistic regression analysis and Seemingly Unrelated Regression to test across several indicators under an overarching hypothesis. Results: Anesthesiologists in Western states had markedly different patterns of practice relative to anesthesiologists in other regions in 2007 and 2013, including differences in employer type, the composition of anesthesia teams, and the time spent on monitored anesthesia care. The number and proportion of female anesthesiologists in the workforce increased between 2007 and 2013, and females differed from males in employment arrangements, compensation, and work hours. Conclusions: Regional differences remained stable during this time period although the reasons for these differences are speculative. Similarly, how and whether the gender difference in work hours and shift to younger anesthesiologists during this period will impact workforce needs is uncertain. Copyright © 2015, the American Society of Anesthesiologists, Inc.

Sites Related to Crawford Williamson Long in Georgia

Background: Crawford Williamson Long (1815 to 1878) was the first to use ether as an inhaled anesthetic for surgical operations. By not publishing his discovery for 7 yr, his pioneering work was largely overshadowed by that of Horace Wells (1815 to 1848), Charles Thomas Jackson (1805 to 1880), and William Thomas Green Morton (1819 to 1868). As a result, sites commemorating Long's discovery are not offered the same recognition as those affiliated with Wells or Morton. Methods: We highlight sites in Athens, Danielsville, and Jefferson, Georgia, that honor the first man to regularly use ether as an anesthetic agent. Extensive site visits, examination of museum artifacts, and genealogical research were used to obtain information being presented. Results: Historic Oconee Hill Cemetery in Athens is where Long and members of his family are buried. Established in 1856, it is closely linked to the history of Athens and the University of Georgia (Athens, Georgia). The main site we describe is the Crawford W. Long Museum, located in Jefferson, Georgia, which opened to the public in 1957. It has undergone extensive renovations and holds an expansive collection of Long's family heirlooms and personal artifacts. In addition, it displays an impressive art collection, depicting Long, surgical procedures, members of Long's family, and homes associated with him. Visitors to the museum may also enjoy a walking audio tour that highlights the life of Long and his contribution to medicine. Conclusions: We provide information on sites and artifacts that honor Georgia's most celebrated physician. Much of this has not been published before, and it is our hope that Crawford Williamson Long's legacy receives the attention it richly deserves. Copyright © 2016, the American Society of Anesthesiologists, Inc. Wolters Kluwer Health, Inc. All Rights Reserved.

Standard Setting for Clinical Performance of Basic Perioperative Transesophageal Echocardiography: Moving beyond the Written Test

Background: Credible methods for assessing competency in basic perioperative transesophageal echocardiography examinations have not been reported. The authors' objective was to demonstrate the collection of real-world basic perioperative transesophageal examination performance data and establish passing scores for each component of the basic perioperative transesophageal examination, as well as a global passing score for clinical performance of the basic perioperative transesophageal examination using the Angoff method. Methods: National Board of Echocardiography (Raleigh, North Carolina) advanced perioperative transesophageal echocardiography-certified anesthesiologists (n = 7) served as subject matter experts for two Angoff standard-setting sessions. The first session was held before data analysis, and the second session for calibration of passing scores was held 9 months later. The performance of 12 anesthesiology residents was assessed via the new passing score grading system. Results: The first standard-setting procedure resulted in a global passing score of 63 ± 13% on a basic perioperative transesophageal examination. The global passing score from the second standard-setting session was 73 ± 9%. Three hundred seventy-one basic perioperative transesophageal examinations from 12 anesthesiology residents were included in the analysis and used to guide the second standard-setting session. All residents scored higher than the global passing score from both standard-setting sessions. Conclusions: To the authors' knowledge, this is the first demonstration that the collection of real-world anesthesia resident basic perioperative transesophageal examination clinical performance data is possible and that automated grading for competency assessment is feasible. The authors' findings demonstrate at least minimal basic perioperative transesophageal examination clinical competency of the 12 residents. © 2016, the American Society of Anesthesiologists, Inc. Wolters Kluwer Health, Inc. All Rights Reserved.

Propofol restores transient receptor potential vanilloid receptor subtype-1 sensitivity via activation of transient receptor potential ankyrin receptor subtype-1 in sensory neurons

Background: Cross talk between peripheral nociceptors belonging to the transient receptor potential vanilloid receptor subtype-1 (TRPV1) and ankyrin subtype-1 (TRPA1) family has been demonstrated recently. Moreover, the intravenous anesthetic propofol has directly activates TRPA1 receptors and indirectly restores sensitivity of TRPV1 receptors in dorsal root ganglion (DRG) sensory neurons. Our objective was to determine the extent to which TRPA1 activation is involved in mediating the propofol-induced restoration of TRPV1 sensitivity. Methods: Mouse DRG neurons were isolated by enzymatic dissociation and grown for 24 h. F-11 cells were transfected with complementary DNA for both TRPV1 and TRPA1 or TRPV1 only. The intracellular Ca2+ concentration was measured in individual cells via fluorescence microscopy. After TRPV1 desensitization with capsaicin (100 nM), cells were treated with propofol (1, 5, and 10 μM) alone or with propofol in the presence of the TRPA1 antagonist, HC-030031 (0.5 μM), or the TRPA1 agonist, allyl isothiocyanate (AITC; 100 μM); capsaicin was then reapplied. Results: In DRG neurons that contain both TRPV1 and TRPA1, propofol and AITC restored TRPV1 sensitivity. However, in DRG neurons containing only TRPV1 receptors, exposure to propofol or AITC after desensitization did not restore capsaicin-induced TRPV1 sensitivity. Similarly, in F-11 cells transfected with both TRPV1 and TRPA1, propofol and AITC restored TRPV1 sensitivity. However, in F-11 cells transfected with TRPV1 only, neither propofol nor AITC was capable of restoring TRPV1 sensitivity. Conclusions: These data demonstrate that propofol restores TRPV1 sensitivity in primary DRG neurons and in cultured F-11 cells transfected with both the TRPV1 and TRPA1 receptors via a TRPA1-dependent process. Propofol's effects on sensory neurons may be clinically important and may contribute to peripheral sensitization to nociceptive stimuli in traumatized tissue. Copyright © 2011, the American Society of Anesthesiologists, Inc. Lippincott Williams &amp; Wilkins. Anesthesiology.

Predicting success on the certification examinations of the american board of anesthesiology

Background: Currently, residency programs lack objective predictors for passing the sequenced American Board of Anesthesiology (ABA) certification examinations on the first attempt. Our hypothesis was that performance on the ABA/American Society of Anesthesiologists In-Training Examination (ITE) and other variables can predict combined success on the ABA Part 1 and Part 2 examinations. METHOD: The authors studied 2,458 subjects who took the ITE immediately after completing the first year of clinical anesthesia training and took the ABA Part 1 examination for primary certification immediately after completing residency training 2 yr later. ITE scores and other variables were used to predict which residents would complete the certification process (passing the ABA Part 1 and Part 2 exam-inations) in the shortest possible time after graduation. Results: ITE scores alone accounted for most of the explained variation in the desired outcome of certification in the shortest possible time. In addition, almost half of the observed variation and most of the explained variance in ABA Part 1 scores was accounted for by ITE scores. A combined model using ITE scores, residency program accreditation cycle length, country of medical school, and gender best predicted which residents would complete the certification examinations in the shortest possible time. Conclusions: The principal implication of this study is that higher ABA/ American Society of Anesthesiologists ITE scores taken at the end of the first clinical anesthesia year serve as a significant and moderately strong predictor of high performance on the ABA Part 1 (written) examination, and a significant predictor of success in completing both the Part 1 and Part 2 examinations within the calendar year after the year of graduation from residency. Future studies may identify other predictors, and it would be helpful to identify factors that predict clinical performance as well. © 2010 American Society of Anesthesiologists, Inc.

Midazolam suppresses maturation of murine dendritic cells and priming of lipopolysaccharide-induced t helper 1-type immune response

Background: Dendritic cells (DCs), as antigen-presenting cells, play a key role in the induction and regulation of adaptive immune response. Midazolam is reported to have immunomodulatory properties that affect immune cells. However, the effect of midazolam on DCs has not been characterized. We examined the immunomodulatory properties of midazolam on DC-mediated immune response. Methods: After allowing murine bone marrow-derived DCs induced by granulocyte macrophage colony stimulating factor to mature, we analyzed their expression of costimulatory molecules (CD80 and CD86), major histocompatibility complex class II molecules, and the secretion of interleukin-12 p40. In vitro, we evaluated the effect of midazolam on maturing DCs in mixed cell cultures containing DCs and T cells. In vivo, we investigated the contact-hypersensitivity response. Results: Midazolam suppressed the expression of CD80, CD86, and major histocompatibility complex class II molecules from murine DCs. Treated with midazolam, DCs also secreted less interleukin-12 p40. In mixed cell cultures with CD3-positive T cells, midazolam-treated DCs showed less propensity to stimulate the proliferation of CD3-positive T cells and the secretion of interferon-γ from CD4-positive T cells. Midazolam-treated DCs impaired the induction of contact-hypersensitivity response. Treatment with ligands for peripheral benzodiazepine receptor inhibited the up-regulation of CD80 during DC maturation. Conclusion: Midazolam inhibits the functional maturation of murine DCs and interferes with DC induction of T helper 1 immunity in the whole mouse. In addition, it appears that the immunomodulatory effect of midazolam is mediated via the action of midazolam on the peripheral benzodiazepine receptor. © 2011, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

Adding Examples to the ASA-Physical Status Classification Improves Correct Assignment to Patients

Background: Despite its widespread use, the American Society of Anesthesiologists (ASA)-Physical Status Classification System has been shown to result in inconsistent assignments among anesthesiologists. The ASA-Physical Status Classification System is also used by nonanesthesia-trained clinicians and others. In 2014, the ASA developed and approved examples to assist clinicians in determining the correct ASA-Physical Status Classification System assignment. The effect of these examples by anesthesia-trained and nonanesthesia-trained clinicians on appropriate ASA-Physical Status Classification System assignment in hypothetical cases was examined. Methods: Anesthesia-trained and nonanesthesia-trained clinicians were recruited via email to participate in a web-based questionnaire study. The questionnaire consisted of 10 hypothetical cases, for which respondents were first asked to assign ASA-Physical Status using only the ASA-Physical Status Classification System definitions and a second time using the newly ASA-approved examples. Results: With ASA-approved examples, both anesthesia-trained and nonanesthesia-trained clinicians improved in mean number of correct answers (out of possible 10) compared to ASA-Physical Status Classification System definitions alone (P < 0.001 for all). However, with examples, nonanesthesia-trained clinicians improved more compared to anesthesia-trained clinicians. With definitions only, anesthesia-trained clinicians (5.8 ± 1.6) scored higher than nonanesthesia-trained clinicians (5.4 ± 1.7; P = 0.041). With examples, anesthesia-trained (7.7 ± 1.8) and nonanesthesia-trained (8.0 ± 1.7) groups were not significantly different (P = 0.100). Conclusions: The addition of examples to the definitions of the ASA-Physical Status Classification System increases the correct assignment of patients by anesthesia-trained and nonanesthesia-trained clinicians. © 2016, the American Society of Anesthesiologists, Inc. Wolters Kluwer Health, Inc. All Rights Reserved.

Establishing obstetric anesthesiology practice guidelines in the Republic of Armenia: A global health collaboration

Background: Disparity exists in anesthesia practices between high- and low-to-middle income countries, and awareness has been raised within the global health community to improve the standards of anesthesia care and patient safety. The establishment of international collaborations and appropriate practice guidelines may help address clinical care deficiencies. This report's aim was to assess the impact of a multiyear collaboration on obstetric anesthesia practices in the Republic of Armenia. Methods: An invited multinational team of physicians conducted six visits to Armenia between 2006 and 2015 to observe current practice and establish standards of obstetric anesthesia care. The Armenian Society of Anaesthesiologists and Intensive Care specialists collected data on the numbers of vaginal delivery, cesarean delivery, and neuraxial anesthesia use in maternity units during the period. Data were analyzed with the Fisher exact or chi-square test, as appropriate. Results: Neuraxial anesthesia use for cesarean delivery increased significantly (P < 0.0001) in all 10 maternity hospitals within the capital city of Yerevan. For epidural labor analgesia, there was sustained or increased use in only two hospitals. For hospitals located outside the capital city, there was a similar increase in the use of neuraxial anesthesia for cesarean delivery that was greater in hospitals that were visited by an external team (P < 0.0001); however, use of epidural labor analgesia was not increased significantly. Over the course of the collaboration, guidelines for obstetric anesthesia were drafted and approved by the Armenian Ministry of Health. Conclusions: Collaboration between Armenian anesthesiologists and dedicated visiting physicians to update and standardize obstetric anesthesia practices led to national practice guidelines and sustained improvements in clinical care in the Republic of Armenia. © 2017, the American Society of Anesthesiologists, Inc. Wolters Kluwer Health, Inc.

Acquisition of critical intraoperative event management skills in novice anesthesiology residents by using high-fidelity simulation-based training

Background: Early acquisition of critical competencies by novice anesthesiology residents is essential for patient safety, but traditional training Methods may be insufficient. The purpose of this study was to determine the effectiveness of high-fidelity simulation training of novice residents in the initial management of critical intraoperative events. Methods: Twenty-one novice residents participated in this 6-week study. Three hypoxemia and three hypotension scenarios were developed and corresponding checklists were validated. Residents were tested in all scenarios at baseline (0 weeks) and divided into two groups, using a randomized crossover study design. Group 1 received simulation-based training in hypoxemic events, whereas Group 2 was trained in hypotensive events. After intermediate (3 weeks) testing in all scenarios, the groups switched to receive training in the other critical event. Final testing occurred at 6 weeks. Raters blinded to subject identity, group assignment, and test date scored videotaped performances by using checklists. The primary outcome measure was composite scores for hypoxemia and hypotension scenarios, which were compared within and between groups. Results: Baseline performance between groups was similar. At the intermediate evaluation, the mean hypoxemia score was higher in Group 1 compared with Group 2 (65.5% vs. 52.4%, 95% CI of difference 6.3-19.9, P < 0.003). Conversely, Group 2 had a higher mean hypotension score (67.4% vs. 45.5%, 95% CI of difference 14.6-29.2, P < 0.003). At Week 6, the scores between groups did not differ. Conclusions: Event-specific, simulation-based training resulted in superior performance in scenarios compared with traditional training and simulation-based training in an alternate event. © 2010 American Society of Anesthesiologists, Inc.

Building the evidence on simulation validity: Comparison of anesthesiologists' communication patterns in real and simulated cases

Background: Effective teamwork is important for patient safety, and verbal communication underpins many dimensions of teamwork. The validity of the simulated environment would be supported if it elicited similar verbal communications to the real setting. The authors hypothesized that anesthesiologists would exhibit similar verbal communication patterns in routine operating room (OR) cases and routine simulated cases. The authors further hypothesized that anesthesiologists would exhibit different communication patterns in routine cases (real or simulated) and simulated cases involving a crisis. © 2013, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins.

Impact of entropy monitoring on volatile anesthetic uptake

Background: Electroencephalogram-derived monitoring to assess anesthetic depth may allow more accurate hypnotic drug administration, resulting in decreased anesthetic drug consumption. The authors hypothesized that the use of M-Entropy monitoring (Datex-Ohmeda, Helsinki, Finland) is associated with reduced sevoflurane uptake (primary outcome) in patients undergoing major abdominal surgery. Methods: A total of 50 patients with an American Society of Anesthesiology score of II-III, scheduled for elective laparoscopic rectosigmoidectomy were randomized into two groups in this randomized controlled trial. In the control group, the target expiratory fraction of sevoflurane was adapted according to standard clinical practice. In the study group, the target expiratory fraction of sevoflurane was adapted to maintain state entropy values between 40 and 60. State entropy values were continuously recorded in both groups but were not available to the anesthesiologist in the control group. In both groups, patients were ventilated using the auto-control mode of the Zeus (Dräger, Lübeck, Germany) respirator, which allows precise measurements of sevoflurane uptake. Sufentanil was administered using a target-controlled infusion system. Results: Demographics did not differ between groups. During the anesthesia maintenance phase, state entropy values were lower in the control group than the study group (P < 0.0001). Sevoflurane uptake was higher in the control group than the study group (5.2 ± 1.4 ml/h vs. 3.8 ± 1.5 ml/h; P = 0.0012). Three patients in the control group developed intraoperative hypotension compared with none in the study group (P = 0.03). Conclusions: Monitoring the depth of anesthesia using M-Entropy was associated with a significant reduction in sevoflurane uptake. © 2013, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins.

The effect of electronic record keeping and transesophageal echocardiography on task distribution, workload, and vigilance during cardiac anesthesia

Background: Electronic anesthesia record keeping (EARK) systems increasingly are used in the operating room, but studies have only recently begun to investigate their effect on anesthesia task performance. Task analysis, workload assessment, and vigilance assessment techniques were used to study senior residents providing anesthesia for coronary artery bypass graft (CABG) procedures. The impact on anesthesia residents workload of the routine use of transesophageal echocardiography (TEE) also was examined. Methods: Before each case, the record keeping system was randomly selected as either electronic (Diatek ARKIVE(TM); EARK) or traditional manual recording (MAN). Twenty CABG procedures (10 EARK and 10 MAN) were examined, with observation commencing with anesthetic induction and terminating on initiation of cardiopulmonary bypass. The activities of each resident, divided into 32 task categories (e.g., 'laryngoscopy,' 'observe monitors,' etc.), were recorded by a trained observer using a computer. The response latency to a randomly activated alarm light was used to as a measure of vigilance ('vigilance latency'). Workload was rated by subject and observer at random 10- to 15-min intervals throughout the case. Data analysis included calculation of workload density (number of tasks/min multiplied by task- specific workload values) and task-links (relationship between sequential tasks). Results: The two groups had a similar distribution of tasks before induction. In only 4 of the 20 cases studied did any manual record keeping occur before intubation. After intubation, the EARK group spent less time record keeping and using the TEE but more time observing the monitors and conversing with the attending physician than the MAN group did. All subjects reported significantly higher workload scores before intubation compared with after intubation. Similarly, vigilance latency was greater before intubation compared with after intubation (57 vs. 31 s; P < 0.001). There were no significant differences in between the two record keeping groups in subjective workload scores, workload density, or vigilance latency. During TEE use, vigilance latency was significantly longer, and workload density was greater than during other monitoring or recording tasks. Conclusions: This study provides an objective description of the task distribution and workload during the administration of anesthesia for cardiac surgery. Under the conditions of this study, EARK use modestly decreased the time spent record keeping during the postintubation prebypass period. However, there was no effect of EARK either on vigilance or several measures of workload. TEE use was associated with increased workload and possibly decreased vigilance.

Simulation-based assessment and retraining for the anesthesiologist seeking reentry to clinical practice a case series

Background: Established models for assessment and maintenance of competency in anesthesiology may not be adequate for anesthesiologists wishing to reenter practice. The authors describe a program developed in their institution incorporating simulator-based education, to help determine competency in licensed and previously licensed anesthesiologists before return to practice. Methods: The authors have used simulation for assessment and retraining at their institution since 2002. Physicians evaluated by the authors' center undergo an adaptable 2-day simulation-based assessment conducted by two board-certified anesthesiologists. A minimum of three cases are presented on each day, with specific core competencies assessed, and participants complete a standard Clinical Anesthesia Year 3 level anesthesia knowledge test. Participants are debriefed extensively and retraining regimens are designed, where indicated, consisting of a combination of simulation and operating-room observership. Results: Twenty anesthesiologists were referred to the authors' institution between 2002 and 2012. Fourteen participants (70%) were in active clinical practice 1 yr after participation in the authors' program, five (25%) were in supervised positions, and nine (45%) had resumed independent clinical practice. The reasons of participants not in practice were personal (1 participant) and medico-legal (3 participants); two participants were lost to follow-up. Two of 14 physicians, who were formally assessed in the authors' program, were deemed likely unfit for safe return to practice, irrespective of further training. These physicians were unavailable for contact 1 yr after assessment. Conclusion: Anesthesiologists seeking to return to active clinical status are a heterogeneous group. The simulated environment provides an effective means by which to assess baseline competency and also a way to retrain physicians. Copyright © 2013, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins.

Reporting of Ethical Approval and Informed Consent in Clinical Research Published in Leading Anesthesia Journals

Background: Ethical conduct in human research in anesthesia includes approval by an institutional review board (IRB) or ethics committee and informed consent. Evidence of these is sometimes lacking in journal publications. Methods: The authors reviewed all publications involving human subjects in six leading anesthesia journals for the year 2001 (n = 1189). Rates of IRB approval and informed consent were examined and compared with potential predictors that included journal, type of publication, and patient demographics (age, sex, elective or emergency status). Rates were compared by use of chi-square and logistic regression. Results: The authors found that IRB approval was documented in 71% of publications and consent was obtained in 66% of publications. Significant variation in IRB approval and consent was found among journals (P < 0.0005) and according to type of publication (P < 0.0005). Because publication type affected rates of IRB approval and consent (trials > mechanistic studies > observational studies > case reports), an analysis restricted to prospective studies also found a significant difference in IRB approval and consent among journals (P < 0.0005). Conclusions: This study suggests that rates of IRB approval and informed consent vary among publications in anesthesia journals. Clearer guidelines (and author adherence) for all types of publication are needed, both as a protection for research subjects and to maintain public trust in the process.

Two etomidate sites in α1β2γ2 γ-aminobutyric acid type a receptors contribute equally and noncooperatively to modulation of channel gating

Background: Etomidate is a potent hypnotic agent that acts via γ-aminobutyric acid receptor type A (GABAA) receptors. Evidence supports the presence of two etomidate sites per GABAA receptor, and current models assume that each site contributes equally and noncooperatively to drug effects. These assumptions remain untested. Methods: We used concatenated dimer (β2-α1) and trimer (γ2-β2-α1) GABAA subunit assemblies that form functional α1β2γ2 channels, and inserted α1M236W etomidate site mutations into both dimers (β2-α1M236W) and trimers (γ2-β2-α1M236W). Wild-type or mutant dimers (D wt or Dαm236w) and trimers (T wt or T αm236w) were coexpressed in Xenopus oocytes to produce four types of channels: DT wt, DT wt, D αm236wT wt, and D αm236wT. For each channel type, two-electrode voltage clamp was performed to quantitatively assess GABA EC 50, etomidate modulation (left shift), etomidate direct activation, and other functional parameters affected by αM236W mutations. Results: Concatenated wild-type DT channels displayed etomidate modulation and direct activation similar to α1β2γ2 receptors formed with free subunits. DT receptors also displayed altered GABA sensitivity and etomidate modulation similar to mutated channels formed with free subunits. Both single-site mutant receptors (DT and DT) displayed indistinguishable functional properties and equal gating energy changes for GABA activation (-4.9 ± 0.48 vs.-4.7 ± 0.48 kJ/mol, respectively) and etomidate modulation (-3.4 ± 0.49 vs.-3.7 ± 0.38 kJ/mol, respectively), which together accounted for the differences between DT and DT channels. Conclusions: These results support the hypothesis that the two etomidate sites on α1β2γ2 GABAA receptors contribute equally and noncooperatively to drug interactions and gating effects. © 2012 the American Society of Anesthesiologists, Inc. Lippincott Williams &amp; Wilkins. Anesthesiology.

Closed-loop continuous infusions of etomidate and etomidate analogs in rats: A comparative study of dosing and the impact on adrenocortical function

Background: Etomidate is a sedative-hypnotic that is often given as a single intravenous bolus but rarely as an infusion because it suppresses adrenocortical function. Methoxycarbonyl etomidate and (R)-ethyl 1-(1-phenylethyl)-1H-pyrrole-2-carboxylate (carboetomidate) are etomidate analogs that do not produce significant adrenocortical suppression when given as a single bolus. However, the effects of continuous infusions on adrenocortical function are unknown. In this study, we compared the effects of continuous infusions of etomidate, methoxycarbonyl etomidate, and carboetomidate on adrenocortical function in a rat model. Methods: A closed-loop system using the electroencephalographic burst suppression ratio as the feedback was used to administer continuous infusions of etomidate, methoxycarbonyl etomidate, or carboetomidate to Sprague-Dawley rats. Adrenocortical function was assessed during and after infusion by repetitively administering adrenocorticotropic hormone 1-24 and measuring serum corticosterone concentrations every 30 min. Results: The sedative-hypnotic doses required to maintain a 40% burst suppression ratio in the presence of isoflurane, 1%, and the rate of burst suppression ratio recovery on infusion termination varied (methoxycarbonyl etomidate > carboetomidate > etomidate). Serum corticosterone concentrations were reduced by 85% and 56% during 30-min infusions of etomidate and methoxycarbonyl etomidate, respectively. On infusion termination, serum corticosterone concentrations recovered within 30 min with methoxycarbonyl etomidate but persisted beyond an hour with etomidate. Carboetomidate had no effect on serum corticosterone concentrations during or after continuous infusion. Conclusions: Our results suggest that methoxycarbonyl etomidate and carboetomidate may have clinical utility as sedative-hypnotic maintenance agents when hemodynamic stability is desirable. © 2011, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

Does Iso-mechanical Power Lead to Iso-lung Damage? An Experimental Study in a Porcine Model

Background: Excessive tidal volume, respiratory rate, and positive end-expiratory pressure (PEEP) are all potential causes of ventilator-induced lung injury, and all contribute to a single variable: The mechanical power. The authors aimed to determine whether high tidal volume or high respiratory rate or high PEEP at iso-mechanical power produce similar or different ventilator-induced lung injury. Methods: Three ventilatory strategies-high tidal volume (twice baseline functional residual capacity), high respiratory rate (40 bpm), and high PEEP (25 cm H2O)-were each applied at two levels of mechanical power (15 and 30 J/min) for 48 h in six groups of seven healthy female piglets (weight: 24.2 ± 2.0 kg, mean ± SD). Results: At iso-mechanical power, the high tidal volume groups immediately and sharply increased plateau, driving pressure, stress, and strain, which all further deteriorated with time. In high respiratory rate groups, they changed minimally at the beginning, but steadily increased during the 48 h. In contrast, after a sudden huge increase, they decreased with time in the high PEEP groups. End-experiment specific lung elastance was 6.5 ± 1.7 cm H2O in high tidal volume groups, 10.1 ± 3.9 cm H2O in high respiratory rate groups, and 4.5 ± 0.9 cm H2O in high PEEP groups. Functional residual capacity decreased and extravascular lung water increased similarly in these three categories. Lung weight, wet-to-dry ratio, and histologic scores were similar, regardless of ventilatory strategies and power levels. However, the alveolar edema score was higher in the low power groups. High PEEP had the greatest impact on hemodynamics, leading to increased need for fluids. Adverse events (early mortality and pneumothorax) also occurred more frequently in the high PEEP groups. Conclusions: Different ventilatory strategies, delivered at iso-power, led to similar anatomical lung injury. The different systemic consequences of high PEEP underline that ventilator-induced lung injury must be evaluated in the context of the whole body. (ANESTHESIOLOGY 2020; 132:1126-37). © 2020, the American Society of Anesthesiologists, Inc. All Rights Reserved.

ARA290, a peptide derived from the tertiary structure of erythropoietin, produces long-term relief of neuropathic pain: An experimental study in rats and β-common receptor knockout mice

Background: Exogenous erythropoietin inhibits development of allodynia in experimental painful neuropathy because of its antiinflammatory and neuroprotective properties at spinal, supraspinal, and possibly peripheral sites. The authors assess the effect of a nonhematopoietic erythropoietin analog, ARA290, on tactile and cold allodynia in a model of neuropathic pain (spared nerve injury) in rats and mice lacking the β-common receptor (βcR mice), a component of the receptor complex mediating tissue protection. Methods: Twenty-four hours after peripheral nerve injury, rats and mice were injected with ARA290 or vehicle (five 30-μg/kg intraperitoneal injections at 2-day intervals, followed by once/week, n = 8/group). In a separate group of eight rats, ARA290 treatment was restricted to five doses during the initial 2 weeks after surgery. RESULTS:: In rats, irrespective of treatment paradigm, ARA290 produced effective, long-term (as long as 15 weeks) relief of tactile and cold allodynia (P < 0.001 vs. vehicle-treated animals). ARA290 was effective in wild-type mice, producing significant relief of allodynia. In contrast, in βcR mice no effect of ARA290 was observed. Conclusions: ARA290 produces long-term relief of allodynia because of activation of the β-common receptor. It is argued that relief of neuropathic pain attributable to ARA290 treatment is related to its antiinflammatory properties, possibly within the central nervous system. Because ARA290, in contrast to erythropoietin, is devoid of hematopoietic and cardiovascular side effects, ARA290 is a promising new drug in the prevention of peripheral nerve injury-induced neuropathic pain in humans. © 2011 the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

Deleterious impact of a γ-aminobutyric acid type a receptor preferring general anesthetic when used in the presence of persistent inflammation

Background: Experimental data suggest general anesthetics preferring γ-aminobutyric acid receptor type A may increase postoperative pain in patients with persistent inflammation. The current study was designed to begin to test this hypothesis. Methods: Groups of rats were defined by the presence of inflammation, surgical intervention, and/or the type of general anesthetic used for a 3-h period of anesthesia. Persistent inflammation was induced with complete Freund adjuvant. The surgical intervention was a plantar incision. Three mechanistically distinct general anesthetics were used: pentobarbital, ketamine/xylazine, and isoflurane. Ongoing pain and hypersensitivity were assessed with guarding behavior analysis and the von Frey test, respectively. Results: There was no influence of general anesthetic type on the magnitude or time course of recovery from postoperative hypersensitivity in the absence of persistent inflammation. However, in the presence of persistent inflammation, recovery from hypersensitivity was significantly slower in the pentobarbital group than in the ketamine/xylazine or isoflurane groups. The pentobarbital effect was significant within 3 days of surgery and persisted through the remainder of the testing period. A comparable delay in recovery was observed in pentobarbital-anesthetized inflamed rats not subjected to hind paw incision. The time to 50% recovery in the pentobarbital-treated inflamed groups was almost double that in the other groups. No differences were observed between ketamine/xylazine and isoflurane. Pentobarbital exposure did not increase guarding scores. Conclusions: These results suggest that general anesthetics preferring γ-aminobutyric acid receptor type A may have deleterious consequences when used in the presence of persistent inflammation. © 2011, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

Variation in expert opinion in medical malpractice review

Background: Expert opinion in medical malpractice is a form of implicit assessment, based on unstated individual opinion. This contrasts with explicit assessment processes, which are characterized by criteria specified and stated before the assessment. Although sources of bias that might hinder the objectivity of expert witnesses have been identified, the effect of the implicit nature of expert review has not been firmly established. Methods: Pairs of anesthesiologist-reviewers independently assessed the appropriateness of care in anesthesia malpractice claims. With potential sources of bias eliminated or held constant, the level of agreement was measured. Results: Thirty anesthesiologists reviewed 103 claims. Reviewers agreed on 62% of claims and disagreed on 38%. They agreed that care was appropriate in 27% and less than appropriate in 32%. Chance-corrected levels of agreement were in the poor-good range (kappa = 0.37; 95% CI = 0.23 to 0.51). Conclusions: Divergent opinion stemming from the implicit nature of expert review may be common among objective medical experts reviewing malpractice claims.

Facilitation of resident scholarly activity: Strategy and outcome analyses using historical resident cohorts and a rank-to-match population

Background: Facilitation of residents' scholarly activities is indispensable to the future of medical specialties. Research education initiatives and their outcomes, however, have rarely been reported.Methods: Since academic year 2006, research education initiatives, including research lectures, research problem-based learning discussions, and an elective research rotation under a new research director's supervision, have been used. The effectiveness of the initiatives was evaluated by comparing the number of residents and faculty mentors involved in residents' research activity (Preinitiative [2003-2006] vs. Postinitiative [2007-2011]). The residents' current postgraduation practices were also compared. To minimize potential historical confounding factors, peer-reviewed publications based on work performed during residency, which were written by residents who graduated from the program in academic year 2009 to academic year 2011, were further compared with those of rank-to-match residents, who were on the residency ranking list during the same academic years, and could have been matched with the program of the authors had the residents ranked it high enough on their list.Results: The Postinitiative group showed greater resident research involvement compared with the Preinitiative group (89.2% [58 in 65 residents] vs. 64.8% [35 in 54]; P = 0.0013) and greater faculty involvement (23.9% [161 in 673 faculty per year] vs. 9.2% [55 in 595]; P < 0.0001). Choice of academic practice did not increase (50.8% [Post] vs. 40.7% [Pre]; P = 0.36). Graduated residents (n = 38) published more often than the rank-to-match residents (n = 220) (55.3% [21 residents] vs. 13.2% [29]; P < 0.0001, odds ratio 8.1 with 95% CI of 3.9 to 17.2).Conclusions: Research education initiatives increased residents' research involvement. © 2013, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins.

Analysis of dynamic intratidal compliance in a lung collapse model

Background: For mechanical ventilation to be lung-protective, an accepted suggestion is to place the tidal volume (VT) between the lower and upper inflection point of the airway pressure-volume relation. The drawback of this approach is, however, that the pressure-volume relation is assessed under quasistatic, no-flow conditions, which the lungs never experience during ventilation. Intratidal nonlinearity must be assessed under real (i.e., dynamic) conditions. With the dynamic gliding-SLICE technique that generates a high-resolution description of intratidal mechanics, the current study analyzed the profile of the compliance of the respiratory system (CRS). Methods: In 12 anesthetized piglets with lung collapse, the pressure-volume relation was acquired at different levels of positive end-expiratory pressure (PEEP: 0, 5, 10, and 15 cm H2O). Lung collapse was assessed by computed tomography and the intratidal course of CRS using the gliding-SLICE method. Results: Depending on PEEP, CRS showed characteristic profiles. With low PEEP, CRS increased up to 20% above the compliance at early inspiration, suggesting intratidal recruitment; whereas a profile of decreasing CRS, signaling overdistension, occurred with VT > 5 ml/kg and high PEEP levels. At the highest volume range, CRS was up to 60% less than the maximum. With PEEP 10 cm H2O, CRS was high and did not decrease before 5 ml/kg VT was delivered. Conclusions: The profile of dynamic CRS reflects nonlinear intratidal mechanics of the respiratory system. The SLICE analysis has the potential to detect intratidal recruitment and overdistension. This might help in finding a combination of PEEP and VT level that is protective from a lung-mechanics perspective. Copyright © 2011, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

Adverse events with medical devices in anesthesia and intensive care unit patients recorded in the french safety database in 2005-2006

Background: French regulations require that adverse events involving medical devices be reported to the national healthcare safety agency. The authors evaluated reports made in 2005-2006 for patients in anesthesiology and critical care. Methods: For each type of device, the authors recorded the severity and cause of the event and the manufacturer's response where relevant. The authors compared the results with those obtained previously from the reports (n = 1,004) sent in 1998 to the same database. Results: The authors identified 4,188 events, of which 91% were minor, 7% severe, and 2% fatal. The cause was available for 1,935 events (46%). Faulty manufacturing was the main cause of minor events. Inappropriate use was the cause in a significantly larger proportion of severe events than minor events (P < 0.001) and was usually considered preventable via improved knowledge or device verification before use. Compared to with that in 1998, the annual number of reported events doubled and the rate of severe events decreased slightly (12-10%, P = 0.03). The rate of events related to manufacturing problems remained stable (59-60%, P = nonsignificant), and the rate of events caused by human errors was 32-42% (P = 0.01). There were no changes in the mortality rate (2% in both studies). Conclusions: The number of adverse events related to medical devices indicates a need for greater attention to these complex pieces of equipment that can suffer from faulty design and manufacturing and from inappropriate use. Improvements in clinician knowledge of medical devices, and to a lesser extent improvement in manufacturing practices, should improve safety. Copyright © 2010, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins.

Gabapentin inhibits γ-amino butyric acid release in the locus coeruleus but not in the spinal dorsal horn after peripheral nerve injury in rats

Background: Gabapentin reduces acute postoperative and chronic neuropathic pain, but its sites and mechanisms of action are unclear. Based on previous electrophysiologic studies, the authors tested whether gabapentin reduced γ-amino butyric acid (GABA) release in the locus coeruleus (LC), a major site of descending inhibition, rather than in the spinal cord. Methods: Male Sprague-Dawley rats with or without L5-L6 spinal nerve ligation (SNL) were used. Immunostaining for glutamic acid decarboxylase and GABA release in synaptosomes and microdialysates were examined in the LC and spinal dorsal horn. Results: Basal GABA release and expression of glutamic acid decarboxylase increased in the LC but decreased in the spinal dorsal horn after SNL. In microdialysates from the LC, intravenously administered gabapentin decreased extracellular GABA concentration in normal and SNL rats. In synaptosomes prepared from the LC, gabapentin and other α2δ ligands inhibited KCl-evoked GABA release in normal and SNL rats. In microdialysates from the spinal dorsal horn, intravenous gabapentin did not alter GABA concentrations in normal rats but slightly increased them in SNL rats. In synaptosomes from the spinal dorsal horn, neither gabapentin nor other α2δ ligands affected KCl-evoked GABA release in normal and SNL rats. Discussion: These results suggest that peripheral nerve injury induces plasticity of GABAergic neurons differently in the LC and spinal dorsal horn and that gabapentin reduces presynaptic GABA release in the LC but not in the spinal dorsal horn. The current study supports the idea that gabapentin activates descending noradrenergic inhibition via disinhibition of LC neurons. © 2012 the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

An International, Multicenter, Observational Study of Cerebral Oxygenation during Infant and Neonatal Anesthesia

Background: General anesthesia during infancy is associated with neurocognitive abnormalities. Potential mechanisms include anesthetic neurotoxicity, surgical disease, and cerebral hypoxia-ischemia. This study aimed to determine the incidence of low cerebral oxygenation and associated factors during general anesthesia in infants. Methods: This multicenter study enrolled 453 infants aged less than 6 months having general anesthesia for 30 min or more. Regional cerebral oxygenation was measured by near-infrared spectroscopy. We defined events (more than 3 min) for low cerebral oxygenation as mild (60 to 69% or 11 to 20% below baseline), moderate (50 to 59% or 21 to 30% below baseline), or severe (less than 50% or more than 30% below baseline); for low mean arterial pressure as mild (36 to 45 mmHg), moderate (26 to 35 mmHg), or severe (less than 25 mmHg); and low pulse oximetry saturation as mild (80 to 89%), moderate (70 to 79%), or severe (less than 70%). Results: The incidences of mild, moderate, and severe low cerebral oxygenation were 43%, 11%, and 2%, respectively; mild, moderate, and severe low mean arterial pressure were 62%, 36%, and 13%, respectively; and mild, moderate, and severe low arterial saturation were 15%, 4%, and 2%, respectively. Severe low oxygen saturation measured by pulse oximetry was associated with mild and moderate cerebral desaturation; American Society of Anesthesiology Physical Status III or IV versus I was associated with moderate cerebral desaturation. Severe low cerebral saturation events were too infrequent to analyze. Conclusions: Mild and moderate low cerebral saturation occurred frequently, whereas severe low cerebral saturation was uncommon. Low mean arterial pressure was common and not well associated with low cerebral saturation. Unrecognized severe desaturation lasting 3 min or longer in infants seems unlikely to explain the subsequent development of neurocognitive abnormalities. Copyright © 2017, the American Society of Anesthesiologists, Inc. Wolters Kluwer Health, Inc. All Rights Reserved.

Rapid eye movement sleep debt accrues in mice exposed to volatile anesthetics

Background: General anesthesia has been likened to a state in which anesthetized subjects are locked out of access to both rapid eye movement (REM) sleep and wakefulness. Were this true for all anesthetics, a significant REM rebound after anesthetic exposure might be expected. However, for the intravenous anesthetic propofol, studies demonstrate that no sleep debt accrues. Moreover, preexisting sleep debts dissipate during propofol anesthesia. To determine whether these effects are specific to propofol or are typical of volatile anesthetics, the authors tested the hypothesis that REM sleep debt would accrue in rodents anesthetized with volatile anesthetics. Methods: Electroencephalographic and electromyographic electrodes were implanted in 10 mice. After 9-11 days of recovery and habituation to a 12 h:12 h light-dark cycle, baseline states of wakefulness, nonrapid eye movement sleep, and REM sleep were recorded in mice exposed to 6 h of an oxygen control and on separate days to 6 h of isoflurane, sevoflurane, or halothane in oxygen. All exposures were conducted at the onset of light. Results: Mice in all three anesthetized groups exhibited a significant doubling of REM sleep during the first 6 h of the dark phase of the circadian schedule, whereas only mice exposed to halothane displayed a significant increase in nonrapid eye movement sleep that peaked at 152% of baseline. Conclusion: REM sleep rebound after exposure to volatile anesthetics suggests that these volatile anesthetics do not fully substitute for natural sleep. This result contrasts with the published actions of propofol for which no REM sleep rebound occurred. © 2011, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

Early exposure to general anesthesia disturbs mitochondrial fission and fusion in the developing rat brain

Background: General anesthetics induce apoptotic neurodegeneration in the developing mammalian brain. General anesthesia (GA) also causes significant disturbances in mitochondrial morphogenesis during intense synaptogenesis. Mitochondria are dynamic organelles that undergo remodeling via fusion and fission. The fine balance between these two opposing processes determines mitochondrial morphometric properties, allowing for their regeneration and enabling normal functioning. As mitochondria are exquisitely sensitive to anesthesia-induced damage, we examined how GA affects mitochondrial fusion/fission. Methods: Seven-day-old rat pups received anesthesia containing a sedative dose of midazolam followed by a combined nitrous oxide and isoflurane anesthesia for 6 h. Results: GA causes 30% upregulation of reactive oxygen species (n = 3-5 pups/group), accompanied by a 2-fold downregulation of an important scavenging enzyme, superoxide dismutase (n = 6 pups/group). Reactive oxygen species upregulation is associated with impaired mitochondrial fission/fusion balance, leading to excessive mitochondrial fission. The imbalance between fission and fusion is due to acute sequestration of the main fission protein, dynamin-related protein 1, from the cytoplasm to mitochondria, and its oligomerization on the outer mitochondrial membrane. These are necessary steps in the formation of the ring-like structures that are required for mitochondrial fission. The fission is further promoted by GA-induced 40% downregulation of cytosolic mitofusin-2, a protein necessary for maintaining the opposing process, mitochondrial fusion (n = 6 pups/group). Conclusions: Early exposure to GA causes acute reactive oxygen species upregulation and disturbs the fine balance between mitochondrial fission and fusion, leading to excessive fission and disturbed mitochondrial morphogenesis. These effects may play a causal role in GA-induced developmental neuroapoptosis. © 2013 the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

Sevoflurane and Parkinson's Disease Subthalamic Nucleus Neuronal Activity and Clinical Outcome of Deep Brain Stimulation

Background: General anesthetics-induced changes of electrical oscillations in the basal ganglia may render the identification of the stimulation targets difficult. The authors hypothesized that while sevoflurane anesthesia entrains coherent lower frequency oscillations, it does not affect the identification of the subthalamic nucleus and clinical outcome. Methods: A cohort of 19 patients with Parkinson's disease with comparable disability underwent placement of electrodes under either sevoflurane general anesthesia (n = 10) or local anesthesia (n = 9). Microelectrode recordings during targeting were compared for neuronal spiking characteristics and oscillatory dynamics. Clinical outcomes were compared at 5-yr follow-up. Results: Under sevoflurane anesthesia, subbeta frequency oscillations predominated (general vs. local anesthesia, mean ± SD; delta: 13 ± 7.3% vs. 7.8 ± 4.8%; theta: 8.4 ± 4.1% vs. 3.9 ± 1.6%; alpha: 8.1 ± 4.1% vs. 4.8 ± 1.5%; all P < 0.001). In addition, distinct dorsolateral beta and ventromedial gamma oscillations were detected in the subthalamic nucleus solely in awake surgery (mean ± SD; dorsal vs. ventral beta band power: 20.5 ± 6.6% vs. 15.4 ± 4.3%; P < 0.001). Firing properties of subthalamic neurons did not show significant difference between groups. Clinical outcomes with regard to improvement in motor and psychiatric symptoms and adverse effects were comparable for both groups. Tract numbers of microelectrode recording, active contact coordinates, and stimulation parameters were also equivalent. Conclusions: Sevoflurane general anesthesia decreased beta-frequency oscillations by inducing coherent lower frequency oscillations, comparable to the pattern seen in the scalp electroencephalogram. Nevertheless, sevoflurane-induced changes in electrical activity patterns did not reduce electrode placement accuracy and clinical effect. These observations suggest that microelectrode-guided deep brain stimulation under sevoflurane anesthesia is a feasible clinical option. (ANESTHESIOLOGY 2020; 132:1034-44). © 2020, the American Society of Anesthesiologists, Inc. All Rights Reserved.

Redesign of the System for Evaluation of Teaching Qualities in Anesthesiology Residency Training (SETQ Smart)

Background: Given the increasing international recognition of clinical teaching as a competency and regulation of residency training, evaluation of anesthesiology faculty teaching is needed. The System for Evaluating Teaching Qualities (SETQ) Smart questionnaires were developed for assessing teaching performance of faculty in residency training programs in different countries. This study investigated (1) the structure, (2) the psychometric qualities of the new tools, and (3) the number of residents' evaluations needed per anesthesiology faculty to use the instruments reliably. Methods: Two SETQ Smart questionnaires - for faculty self-evaluation and for resident evaluation of faculty - were developed. A multicenter survey was conducted among 399 anesthesiology faculty and 430 residents in six countries. Statistical analyses included exploratory factor analysis, reliability analysis using Cronbach α, item-total scale correlations, interscale correlations, comparison of composite scales to global ratings, and generalizability analysis to assess residents' evaluations needed per faculty. Results: In total, 240 residents completed 1,622 evaluations of 247 faculty. The SETQ Smart questionnaires revealed six teaching qualities consisting of 25 items. Cronbach α's were very high (greater than 0.95) for the overall SETQ Smart questionnaires and high (greater than 0.80) for the separate teaching qualities. Interscale correlations were all within the acceptable range of moderate correlation. Overall, questionnaire and scale scores correlated moderately to highly with the global ratings. For reliable feedback to individual faculty, three to five resident evaluations are needed. Conclusions: The first internationally piloted questionnaires for evaluating individual anesthesiology faculty teaching performance can be reliably, validly, and feasibly used for formative purposes in residency training. Copyright © 2016, the American Society of Anesthesiologists, Inc. Wolters Kluwer Health, Inc. All Rights Reserved.

Pharmacokinetics and clinical pharmacodynamics of the new propofol prodrug GPI 15715 in volunteers (Retraction in: Anesthesiology (2010) 112:4 (1056-1057))

Background: GPI 15715 (AQUAVAN injection) is a new water-soluble prodrug which is hydrolyzed to release propofol. The objectives of this first study in humans were to investigate the safety, tolerability, pharmacokinetics, and clinical pharmacodynamics of GPI 15715. Methods: Three groups of three healthy male volunteers (aged 19-35 y, 67-102 kg) received 290, 580, and 1,160 mg GPI 15715 as a constant rate infusion over 10 min. The plasma concentrations of GPI 15715 and propofol were measured from arterial and venous blood samples up to 24 h. Pharmacokinetics were analyzed with compartment models. Pharmacodynamics were assessed by clinical signs. Results: GPI 15715 was well tolerated without pain on injection. Two subjects reported a transient unpleasant sensation of burning or tingling at start of infusion. Loss of consciousness was achieved in none with 290 mg and in one subject with 580 mg. After 1,160 mg, all subjects experienced loss of consciousness at propofol concentrations of 2.1 ± 0.6 μg/ml. A two-compartment model for GPI 15715 (central volume of distribution, 0.07 1/kg; clearance, 7 ml · kg-1 min-1; terminal half-life, 46 min) and a three-compartment model for propofol (half-lives: 2.2, 20, 477 min) best described the data. The maximum decrease of blood pressure was 25%; the heart rate increased by approximately 35%. There were no significant laboratory abnormalities. Conclusions: Compared with propofol lipid emulsion, the potency seemed to be higher with respect to plasma concentration but was apparently less with respect to dose. Pharmacokinetic simulations showed a longer time to peak propofol concentration after a bolus dose and a longer context-sensitive half-time.

Comparative pharmacokinetics and pharmacodynamics of the new propofol prodrug GPI 15715 and propofol emulsion (Retraction in: Anesthesiology (2010) 112:4 (1056-1057))

Background: GPI 15715 is a new water-soluble prodrug that is hydrolyzed to release propofol. The objectives of this crossover study in volunteers were to investigate the pharmacokinetics and pharmacodynamics of GPI 15715 in comparison with propofol emulsion. Methods: In two separate sessions, nine healthy male volunteers (19-35 yr, 70-86 kg) received GPI 15715 and propofol emulsion as a target controlled infusion over 60 min. In the first 20 min, the propofol target concentration increased linearly to 5 μg/ml. Subsequently, the targets were reduced to 3 μg/ml and 1.5 μg/ml for 20 min each. The plasma concentrations of GPI 15715 and propofol were measured from arterial and venous blood samples up to 24 h and pharmacokinetics were analyzed. The pharmacodynamic effect was measured by the median frequency of the power spectrum of the electroencephalogram, and a sigmoid model with effect compartment was fitted to the data. Results: Compared with propofol emulsion, propofol from GPI 15715 showed a different disposition function and especially larger volumes of distribution. The propofol effect site concentration for half maximum effect was 2.0 ± 0.5 μg/ml for GPI 15715 and 3.0 ± 0.7 μg/ml for propofol emulsion (P < 0.05). Propofol from GPI 15715 did not show a hysteresis between plasma concentration and effect. Conclusions: Compared with propofol emulsion, propofol front GPI 15715 showed different pharmacokinetics and pharmacodynamics, particularly a higher potency with respect to concentration. These differences may indicate an influence of the formulation.

A Feedback and Evaluation System That Provokes Minimal Retaliation by Trainees

Background: Grade inflation is pervasive in educational settings in the United States. One driver of grade inflation may be faculty concern that assigning lower clinical performance scores to trainees will cause them to retaliate and assign lower teaching scores to the faculty member. The finding of near-zero retaliation would be important to faculty members who evaluate trainees. Methods: The authors used a bidirectional confidential evaluation and feedback system to test the hypothesis that faculty members who assign lower clinical performance scores to residents subsequently receive lower clinical teaching scores. From September 1, 2008, to February 15, 2013, 177 faculty members evaluated 188 anesthesia residents (n = 27,561 evaluations), and 188 anesthesia residents evaluated 204 faculty members (n = 25,058 evaluations). The authors analyzed the relationship between clinical performance scores assigned by faculty members and the clinical teaching scores received using linear regression. The authors used complete dyads between faculty members and resident pairs to conduct a mixed effects model analysis. All analyses were repeated for three different epochs, each with different administrative attributes that might influence retaliation. Results: There was no relationship between mean clinical performance scores assigned by faculty members and mean clinical teaching scores received in any epoch (P ≥ 0.45). Using only complete dyads, the authors' mixed effects model analysis demonstrated a very small retaliation effect in each epoch (effect sizes of 0.10, 0.06, and 0.12; P ≤ 0.01). Conclusions: These results imply that faculty members can provide confidential evaluations and written feedback to trainees with near-zero impact on their mean teaching scores.

Local administration of morphine for analgesia after iliac bone graft harvest (Retraction in: Anesthesiology (2009) 110:3 (689))

Background: Harvesting autogenous bone grafts from the ilium may cause considerable pain and may represent a significant source of postoperative morbidity. The local application of morphine can reduce pain in a rat model of bone damage. We evaluated the analgesic efficacy of administering morphine to the donor bone graft site for spinal fusion surgery. Methods: Sixty patients undergoing cervical spinal fusion surgery using autogenous bone harvested from the ilium were randomly assigned to one of three groups: Group 1 was given saline infiltrated into the harvest site, group 2 was given 5 mg intramuscular morphine; group 3 was given 5 mg morphine infiltrated into the harvest site. After surgery, all patients were given morphine through a patient-controlled analgesia pump. Pain scores both from the harvest and the incision sites, as well as morphine use, were recorded at 2, 4, 6, 8, 12, and 24 h after surgery. At 1 yr after surgery the presence and subjective characteristics of donor site pain were recorded. Results: Total 24-h morphine use (milligrams) was significantly lower (P < 0.0001) in group 3 (33.7 ± 8.3 mg, mean ± SD), compared with either group 1 (64.3 ± 6.6 mg) or group 2 (59.6 ± 9.3 mg). Pain from the graft site was scored the same at 2 h but remained significantly lower (P < 0.0001) for group 3 at all later time intervals. Pain scores from the incision site were similar among the three study groups. One year after surgery, 25% of patients reported having chronic donor site pain. The association of chronic donor site pain was significantly higher (P < 0.05) in groups 1 (33%) and 2 (37%) compared with group 3 (5%). Conclusion: Low-dose morphine applied to the harvest graft site can reduce local pain, morphine use, and chronic donor site pain after cervical spine fusion surgery.

Massive hemorrhage : A report from the anesthesia closed claims project

Background: Hemorrhage is a potentially preventable cause of adverse outcomes in surgical and obstetric patients. New understanding of the pathophysiology of hemorrhagic shock, including development of coagulopathy, has led to evolution of recommendations for treatment. However, no recent study has examined the legal outcomes of these claims. The authors reviewed closed anesthesia malpractice claims related to hemorrhage, seeking common factors to guide future management strategies. Methods: The authors analyzed 3,211 closed surgical or obstetric anesthesia malpractice claims from 1995 to 2011 in the Anesthesia Closed Claims Project. Claims where patient injury was attributed to hemorrhage were compared with all other surgical and obstetric claims. Risk factors for hemorrhage and coagulopathy, clinical factors, management, and communication issues were abstracted from claim narratives to identify recurrent patterns. Results: Hemorrhage occurred in 141 (4%) claims. Obstetrics accounted for 30% of hemorrhage claims compared with 13% of nonhemorrhage claims (P < 0.001); thoracic or lumbar spine surgery was similarly overrepresented (24 vs. 6%, P < 0.001). Mortality was higher in hemorrhage than nonhemorrhage claims (77 vs. 27%, P < 0.001), and anesthesia care was more often judged to be less than appropriate (55 vs. 38%, P < 0.001). Median payments were higher in hemorrhage versus nonhemorrhage claims ($607,750 vs. $276,000, P < 0.001). Risk factors for hemorrhage and coagulopathy were common, and initiation of transfusion therapy was commonly delayed. Conclusions: Hemorrhage is a rare, but serious, cause of anesthesia malpractice claims. Understanding which patients are at risk can aid in patient referral decisions, design of institutional systems for responding to hemorrhage, and education of surgeons, obstetricians, and anesthesiologists. Copyright © 2014, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins.

Stress management training improves overall performance during critical simulated situations: A prospective randomized controlled trial

Background: High-fidelity simulation improves participant learning through immersive participation in a stressful situation. Stress management training might help participants to improve performance. The hypothesis of this work was that Tactics to Optimize the Potential, a stress management program, could improve resident performance during simulation. Methods: Residents participating in high-fidelity simulation were randomized into two parallel arms (Tactics to Optimize the Potential or control) and actively participated in one scenario. Only residents from the Tactics to Optimize the Potential group received specific training a few weeks before simulation and a 5-min reactivation just before beginning the scenario. The primary endpoint was the overall performance during simulation measured as a composite score (from 0 to 100) combining a specific clinical score with two nontechnical scores (the Ottawa Global Rating Scale and the Team Emergency Assessment Measure scores) rated for each resident by four blinded independent investigators. Secondary endpoints included stress level, as assessed by the Visual Analogue Scale during simulation. Results: Of the 134 residents randomized, 128 were included in the analysis. The overall performance (mean ± SD) was higher in the Tactics to Optimize the Potential group (59 ± 10) as compared with controls ([54 ± 10], difference, 5 [95% CI, 1 to 9]; P = 0.010; effect size, 0.50 [95% CI, 0.16 to 0.91]). After specific preparation, the median Visual Analogue Scale was 17% lower in the Tactics to Optimize the Potential group (52 [42 to 64]) than in the control group (63 [50 to 73]; difference, -10 [95% CI, -16 to -3]; P = 0.005; effect size, 0.44 [95% CI, 0.26 to 0.59]. Conclusions: Residents coping with simulated critical situations who have been trained with Tactics to Optimize the Potential showed better overall performance and a decrease in stress level during high-fidelity simulation. The benefits of this stress management training may be explored in actual clinical settings, where a 5-min Tactics to Optimize the Potential reactivation is feasible prior to delivering a specific intervention. © 2020 Wolters Kluwer Health, Inc. All rights reserved.

Distribution of epidural saline upon injection and the epidural volume effect in pregnant women

Background: How injected epidural solution is distributed and affects the epidural volume in pregnant women are unclear. Methods: Lumbar epidural catheters were placed using the loss-of-resistance technique with saline in eight full-term (39 weeks gestation) parturients for labor and eight volunteer nonpregnant women. Lumbosacral cerebrospinal fluid volume was measured on thoracic and lumbosacral axial magnetic resonance images. Another image series was obtained after injecting 10 ml saline into the epidural space through the catheter to compare the saline distribution (dural sac coating and exit from foramina) and cerebrospinal fluid volume before and after epidural injection. Dural sac coating was based on observation of epidural saline in the anterior epidural space after injection in axial magnetic resonance images at the pedicle levels from T12 to L5. Saline leakage from the foramina was determined by the same method at six disc levels from T11-T12 to L4-L5. Results: Significantly fewer images of pregnant women than nonpregnant women showed saline surrounding the dural sac (0 [0-0] vs. 3 [1-4], median [interquartile range]; P < 0.01) and saline leakage from the foramina (0 [0-1] vs. 6 [4-6]; P < 0.01). The mean reduction in cerebrospinal fluid volume was significantly greater in pregnant (8.4 ± 1.4 ml; mean ± SD) than in nonpregnant women (4.6 ± 1.1 ml; P < 0.001). Conclusion: Limited dural sac coating and decreased leakage from the foramina of saline injected into the epidural space may account for the facilitation of longitudinal spread of epidural analgesia in pregnant women. The epidural volume effect is greater in pregnant than in nonpregnant women. Copyright © 2011, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

Degrees of reality: Airway anatomy of high-fidelity human patient simulators and airway trainers

Background: Human patient simulators and airway training manikins are widely used to train airway management skills to medical professionals. Furthermore, these patient simulators are employed as standardized patients to evaluate airway devices. However, little is known about how realistic these patient simulators and airway-training manikins really are. This trial aimed to evaluate the upper airway anatomy of four high-fidelity patient simulators and two airway trainers in comparison with actual patients by means of radiographic measurements. The volume of the pharyngeal airspace was the primary outcome parameter. Methods: Computed tomography scans of 20 adult trauma patients without head or neck injuries were compared with computed tomography scans of four high-fidelity patient simulators and two airway trainers. By using 14 predefined distances, two cross-sectional areas and three volume parameters of the upper airway, the manikins' similarity to a human patient was assessed. Results: The pharyngeal airspace of all manikins differed significantly from the patients' pharyngeal airspace. The HPS Human Patient Simulator (METI®, Sarasota, FL) was the most realistic high-fidelity patient simulator (6/19 [32%] of all parameters were within the 95% CI of human airway measurements). Conclusion: The airway anatomy of four high-fidelity patient simulators and two airway trainers does not reflect the upper airway anatomy of actual patients. This finding may impact airway training and confound comparative airway device studies. © 2012 the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

Supervised Machine-learning Predictive Analytics for Prediction of Postinduction Hypotension

Background: Hypotension is a risk factor for adverse perioperative outcomes. Machine-learning methods allow large amounts of data for development of robust predictive analytics. The authors hypothesized that machine-learning methods can provide prediction for the risk of postinduction hypotension. Methods: Data was extracted from the electronic health record of a single quaternary care center from November 2015 to May 2016 for patients over age 12 that underwent general anesthesia, without procedure exclusions. Multiple supervised machine-learning classification techniques were attempted, with postinduction hypotension (mean arterial pressure less than 55 mmHg within 10 min of induction by any measurement) as primary outcome, and preoperative medications, medical comorbidities, induction medications, and intraoperative vital signs as features. Discrimination was assessed using cross-validated area under the receiver operating characteristic curve. The best performing model was tuned and final performance assessed using split-set validation. Results: Out of 13,323 cases, 1,185 (8.9%) experienced postinduction hypotension. Area under the receiver operating characteristic curve using logistic regression was 0.71 (95% CI, 0.70 to 0.72), support vector machines was 0.63 (95% CI, 0.58 to 0.60), naive Bayes was 0.69 (95% CI, 0.67 to 0.69), k-nearest neighbor was 0.64 (95% CI, 0.63 to 0.65), linear discriminant analysis was 0.72 (95% CI, 0.71 to 0.73), random forest was 0.74 (95% CI, 0.73 to 0.75), neural nets 0.71 (95% CI, 0.69 to 0.71), and gradient boosting machine 0.76 (95% CI, 0.75 to 0.77). Test set area for the gradient boosting machine was 0.74 (95% CI, 0.72 to 0.77). Conclusions: The success of this technique in predicting postinduction hypotension demonstrates feasibility of machine-learning models for predictive analytics in the field of anesthesiology, with performance dependent on model selection and appropriate tuning. Copyright © 2018, the American Society of Anesthesiologists, Inc. Wolters Kluwer Health, Inc. All Rights Reserved. Anesthesiology 2018; 129:675-88

Obstetric anesthesia work force survey, 1981 versus 1992

Background: In 1981, with support from the American Society of Anesthesiologists and the American College of Obstetricians and Gynecologists, anesthesia and obstetric providers were surveyed to identify the personnel and methods used to provide obstetric anesthesia in the United States. The survey was expanded and repeated in 1992 with support from the same organizations. Methods: Comments and questions from the American Society of anesthesiologists Committee on Obstetrical Anesthesia and the American College of Obstetricians and Gynecologists Committee on Obstetric Practice were added to the original survey instrument to include newer issues while allowing comparison with data from 1981. Using the American Hospital Association registry of hospitals, hospitals were differentiated by number of births per year (stratum I, ≤ 1,500 births; stratum II, 500-1,499 births; stratum III, <500 births) and by U.S. census region. A stratified random sample of hospitals was selected. Two copies of the survey were sent to the administrator of each hospital, one for the chief of obstetrics and one for the chief of anesthesiology. Results: Compared with 1981 data, there was an overall reduction in the number of hospitals providing obstetric care (from 4,163 to 3,545), with the decrease occurring in the smallest units (56% of stratum III hospitals in 1981 compared with 45% in 1992). More women received some type of labor analgesia, and there was a 100% increase in the use of epidural analgesia. However, regional analgesia was unavailable in 20% of the smallest hospitals. Spinal analgesia for labor was used in 4% of parturients. In 1981, obstetricians provided 30% of epidural analgesia for labor; they provided only 2% in 1992. Regional anesthesia was used for 78-85% (depending on strata) of patients undergoing cesarean section, resulting in a marked decrease in the use of general anesthesia. Anesthesia for cesarean section was provided by nurse anesthetists without the medical direction of an anesthesiologist in only 4% of stratum I hospitals but in 59% of stratum III hospitals. Anesthesia personnel provided neonatal resuscitation in 10% of cesarean deliveries compared with 23% in 1981. Conclusions: Compared with 1981, analgesia is more often used by parturients during labor, and general anesthesia is used less often in patients having cesarean section deliveries. In the smallest hospitals, regional analgesia for labor is still unavailable to many parturients, and more than one half of anesthetics for cesarean section are provided by nurse anesthetics without medical direction by an anesthesiologist. Obstetricians are less likely to personally provide epidural analgesia for their patients. Anesthesia personnel are less involved in newborn resuscitation.

Financial impact if payers use medicare rates: Anesthesiology versus other specialties

Background: In 1992, Medicare changed its method for calculating physician payments. The resulting fee schedules have contained low payments for anesthesiologists. Now, other third-party (insurance) payers are using these schedules. The financial impact on anesthesiologists if all payers pay Medicare rates is unknown. Methods: Payments from Medicare were compared with payments from other third parties in each clinical procedural terminology (CPT) grouping Used by the West Virginia University Department of AnesthesiOlogy during 1998. Changes in total Department of Anesthesiology receipts were determined if non-Medicare third-party payers paid Medicare rates. Then, the effect of adding payments at Medicare rates from patients without insurance was determined. Finally, potential changes in receipts of the Departments of Anesthesiology, Radiology, Surgery, and Medicine were compared by considering only patients with insurance and recalculating total payments to the departments using Medicare rates. Results: Medicare paid less than other third-party payers in every clinical procedural terminology group. Total Department of Anesthesiology payments would decrease by 31% if all non-Medicare third-parties paid Medicare rates. Adding payments at Medicare rates from patients without insurance still leads to a 21% decrease in total Department of Anesthesiology receipts. Considering only patients with third-party coverage, Medicare-rate payments would decrease total Department of Anesthesiology payments by 37%, whereas radiology, surgery, and medicine payments would decrease by 26, 22, and 13% respectively. Conclusions: Universal payments at Medicare rates would substantially reduce revenue to anesthesiologists, proportionally more than to radiologists, surgeons, or internists.

Association between performance in a maintenance of certification program and disciplinary actions against the medical licenses of anesthesiologists

Background: In 2000, the American Board of Anesthesiology (Raleigh, North Carolina) began issuing time-limited certificates requiring renewal every 10 yr through a maintenance of certification program. This study investigated the association between performance in this program and disciplinary actions against medical licenses. Methods: The incidence of postcertification prejudicial license actions was compared (1) between anesthesiologists certified between 1994 and 1999 (non-time-limited certificates not requiring maintenance of certification) and those certified between 2000 and 2005 (time-limited certificates requiring maintenance of certification); (2) within the non-time-limited cohort, between those who did and did not voluntarily participate in maintenance of certification; and (3) within the time-limited cohort, between those who did and did not complete maintenance of certification requirements within 10 yr. Results: The cumulative incidence of license actions was 3.8% (587 of 15,486). The incidence did not significantly differ after time-limited certificates were introduced (hazard ratio = 1.15; 95% CI, 0.95 to 1.39; for non-time-limited cohort compared with time-limited cohort). In the non-time-limited cohort, 10% (n = 953) voluntarily participated in maintenance of certification. Maintenance of certification participation was associated with a lower incidence of license actions (hazard ratio = 0.60; 95% CI, 0.38 to 0.94). In the time-limited cohort, 90% (n = 5,329) completed maintenance of certification requirements within 10 yr of certificate issuance. Not completing maintenance of certification requirements (n = 588) was associated with a higher incidence of license actions (hazard ratio = 4.61; 95% CI, 3.27 to 6.51). Conclusions: These findings suggest that meeting maintenance of certification requirements is associated with a lower likelihood of being disciplined by a state licensing agency. The introduction of time-limited certificates in 2000 was not associated with a significant change in the rate of license actions. Copyright © 2018, the American Society of Anesthesiologists, Inc. Wolters Kluwer Health, Inc. All Rights Reserved.

Drug Enforcement Agency 2014 Hydrocodone Rescheduling Rule and Opioid Dispensing after Surgery

Background: In 2014, the U.S. Drug Enforcement Agency reclassified hydrocodone from Schedule III to Schedule II of the Controlled Substances Act, resulting in new restrictions on refills. The authors hypothesized that hydrocodone rescheduling led to decreases in total opioid dispensing within 30 days of surgery and reduced new long-term opioid dispensing among surgical patients. Methods: The authors studied privately insured, opioid-naïve adults undergoing 10 general or orthopedic surgeries between 2011 and 2015. The authors conducted a differences-in-differences analysis that compared overall opioid dispensing before versus after the rescheduling rule for patients treated by surgeons who frequently prescribed hydrocodone before rescheduling (i.e., patients who were functionally exposed to rescheduling's impact) while adjusting for secular trends via a comparison group of patients treated by surgeons who rarely prescribed hydrocodone (i.e., unexposed patients). The primary outcome was any filled opioid prescription between 90 and 180 days after surgery; secondary outcomes included the 30-day refill rate and the amount of opioids dispensed initially and at 30 days postoperatively. Results: The sample included 65,136 patients. The percentage of patients filling a prescription beyond 90 days was similar after versus before rescheduling (absolute risk difference,-1.1%; 95% CI,-2.3% to 0.1%; P = 0.084). The authors estimated the rescheduling rule to be associated with a 45.4-mg oral morphine equivalent increase (difference-in-differences estimate; 95% CI, 34.2-56.7 mg; P < 0.001) in initial opioid dispensing, a 4.1% absolute decrease (95% CI,-5.5% to-2.7%; P < 0.001) in refills within 30 days, and a 37.7-mg oral morphine equivalent increase (95% CI, 20.6-54.8 mg; P = 0.008) in opioids dispensed within 30 days. Conclusions: Among patients treated by surgeons who frequently prescribed hydrocodone before the Drug Enforcement Agency 2014 hydrocodone rescheduling rule, rescheduling did not impact long-term opioid receipt, although it was associated with an increase in opioid dispensing within 30 days of surgery. (ANESTHESIOLOGY 2020; 132:1151-64). © 2020, the American Society of Anesthesiologists, Inc. All Rights Reserved.

Availability of Inpatient Pediatric Surgery in the United States

Background: In 2015, the American College of Surgeons began its Children's Surgery Verification Quality Improvement Program, promulgating standards intended to promote regionalization and improve pediatric surgical care. It was hypothesized that pediatric surgical care was already highly regionalized and concentrated before implementation of the program. This study aimed to demonstrate this by describing the sites and volume of nonambulatory pediatric surgery. Methods: A two-part, retrospective, cross-sectional analysis was performed. First, six all-encounter state inpatient data sets (Arkansas, Florida, Kentucky, Maryland, and New York from the Healthcare Cost and Utilization Project and Massachusetts from the Center for Health Information) were used to evaluate all procedures performed within specific hospitals in 2014. Next, a national sample data set (2016 Kids' Inpatient Database) was used to determine the generalizability of the single state results. All acute care hospital admissions for patients less than 18 yr of age were included to describe the nature and location of all surgical procedures therein by patient age, surgical specialty, procedure type, and hospital service breadth. Results: Within the six study states, there were 713 hospitals, of which 635 (89.1%) admitted patients less than 18 yr old, and 516 (72.4%) reported pediatric procedures. Among these, there were 9 specialty hospitals and 39 hospitals with services comparable to independent children's hospitals. Of 153,587 procedures among 1,065,655 pediatric admissions, 127,869 (83.3%) took place within these 48 centers. This fraction decreased with age (89.9% of patients less than 2 yr old and 68.5% of 15- to 17-yr-olds), varied slightly by specialty, and was similar across states. Outside of specialized centers, teenagers accounted for 47.4% of all procedures. Within the national data sample, the concentration was similar: 8.7% (328 of 3,777) of all hospitals admitting children were responsible for 90.1% (793,905 of 881,049) of all procedures, with little regional variation. Conclusions: Before the American College of Surgeons Children's Surgery Verification Quality Improvement Program, the vast majority of pediatric nonambulatory surgeries were already confined to a small subset of high-capability and specialty centers. © 2021 Lippincott Williams and Wilkins. All rights reserved.

Trends in Direct Hospital Payments to Anesthesia Groups: A Retrospective Cohort Study of Nonacademic Hospitals in California

BACKGROUND: In addition to payments for services, anesthesia groups in the United States often receive revenue from direct hospital payments. Understanding the magnitude of these payments and their association with the hospitals' payer mixes has important policy implications. METHODS: Using a dataset of financial reports from 240 nonacademic California hospitals between 2002 and 2014, the authors characterized the prevalence and magnitude of direct hospital payments to anesthesia groups, and analyzed the association between these payments and the fraction of anesthesia revenue derived from public payers (e.g., Medicaid). RESULTS: Of hospitals analyzed, 69% (124 of 180) made direct payments to an anesthesia group in 2014, compared to 52% (76 of 147) in 2002; the median payment increased from $242,351 (mean, $578,322; interquartile range, $72,753 to $523,861; all dollar values in 2018 U.S. dollars) to $765,128 (mean, $1,295,369; interquartile range, $267,006 to $1,503,163) during this time period. After adjusting for relevant covariates, hospitals where public insurers accounted for a larger fraction of anesthesia revenues were more likely to make direct payments to anesthesia groups (β = 0.45; 95% CI, 0.10 to 0.81; P = 0.013), so that a 10-percentage point increase in the fraction of anesthesia revenue derived from public payers would be associated with a 4.5-percentage point increase in the probability of receiving any payment. Among hospitals making payments, our results (β = 2.10; 95% CI, 0.74 to 3.45; P = 0.003) suggest that a 1-percentage point increase in the fraction of anesthesia revenue derived from public payers would be associated with a 2% relative increase in the amount paid. CONCLUSIONS: Direct payments from hospitals are becoming a larger financial consideration for anesthesia groups in California serving nonacademic hospitals, and are larger for groups working at hospitals serving publicly insured patients.

Neonatal desflurane exposure induces more robust neuroapoptosis than do isoflurane and sevoflurane and impairs working memory

Background: In animal models, neonatal exposure to volatile anesthetics induces neuroapoptosis, leading to memory deficits in adulthood. However, effects of neonatal exposure to desflurane are largely unknown. Methods: Six-day-old C57BL/6 mice were exposed to equivalent doses of desflurane, sevoflurane, or isoflurane for 3 or 6 h. Minimum alveolar concentration was determined by the tail-clamp method as a function of anesthesia duration. Apoptosis was evaluated by immunohistochemical staining for activated caspase-3, and by TUNEL. Western blot analysis for cleaved poly-(adenosine diphosphate-ribose) polymerase was performed to examine apoptosis comparatively. The open-field, elevated plus-maze, Y-maze, and fear conditioning tests were performed to evaluate general activity, anxiety-related behavior, working memory, and long-term memory, respectively. RESULTS:: Minimum alveolar concentrations at 1 h were determined to be 11.5% for desflurane, 3.8% for sevoflurane, and 2.7% for isoflurane in 6-day-old mice. Neonatal exposure to desflurane (8%) induced neuroapoptosis with an anatomic pattern similar to that of sevoflurane or isoflurane; however, desflurane induced significantly greater levels of neuroapoptosis than almost equivalent doses of sevoflurane (3%) or isoflurane (2%). In adulthood, mice treated with these anesthetics had impaired long-term memory, whereas no significant anomalies were detected in the open-field and the elevated plus-maze tests. Although performance in a working memory task was normal in mice exposed neonatally to sevoflurane or isoflurane, mice exposed to desflurane had significantly impaired working memory. Conclusions: In an animal model, neonatal desflurane exposure induced more neuroapoptosis than did sevoflurane or isoflurane and impaired working memory, suggesting that desflurane is more neurotoxic than sevoflurane or isoflurane. © 2011 the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

Isoflurane decreases self-renewal capacity of rat cultured neural stem cells

Background: In models, isoflurane produces neural and behavioral deficits in vitro and in vivo. This study tested the hypothesis that neural stem cells are adversely affected by isoflurane such that it inhibits proliferation and kills these cells. Methods: Sprague-Dawley rat embryonic neural stem cells were plated onto 96-well plates and treated with isoflurane, 0.7, 1.4, or 2.8%, in 21% oxygen for 6 h and fixed either at the end of treatment or 6 or 24 h later. Control plates received 21% oxygen under identical conditions. Cell proliferation was assessed immunocytochemically using 5-ethynyl-2′- deoxyuridine incorporation and death by propidium iodide staining, lactate dehydrogenase release, and nuclear expression of cleaved caspase 3. Data were analyzed at each concentration using an ANOVA; P < 0.05 was considered significant. Results: Isoflurane did not kill neural stem cells by any measure at any time. Isoflurane, 1.4 and 2.8%, reduced cell proliferation based upon 5-ethynyl-2′-deoxyuridine incorporation, whereas isoflurane, 0.7%, had no effect. At 24 h after treatment, the net effect was a 20-30% decrease in the number of cells in culture. Conclusions: Isoflurane does not kill neural stem cells in vitro. At concentrations at and above the minimum alveolar concentrations required for general anesthesia (1.4 and 2.8%), isoflurane inhibits proliferation of these cells but has no such effect at a subminimum alveolar concentration (0.7%). These data imply that dosages of isoflurane at and above minimum alveolar concentrations may reduce the pool of neural stem cells in vivo but that lower dosages may be devoid of such effects. © 2011, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

Dexmedetomidine prevents cognitive decline by enhancing resolution of high mobility group box 1 protein-induced inflammation through a vagomimetic action in mice

Background: Inflammation initiated by damage-Associated molecular patterns has been implicated for the cognitive decline associated with surgical trauma and serious illness. We determined whether resolution of inflammation mediates dexmedetomidine-induced reduction of damage-Associated molecular pattern-induced cognitive decline. Methods: Cognitive decline (assessed by trace fear conditioning) was induced with high molecular group box 1 protein, a damage-Associated molecular pattern, in mice that also received blockers of neural (vagal) and humoral inflammation-resolving pathways. Systemic and neuroinflammation was assessed by proinflammatory cytokines. Results: Damage-Associated molecular pattern-induced cognitive decline and inflammation (mean ± SD) was reversed by dexmedetomidine (trace fear conditioning: 58.77 ± 8.69% vs. 41.45 ± 7.64%, P &lt; 0.0001; plasma interleukin [IL]-1β: 7.0 ± 2.2 pg/ml vs. 49.8 ± 6.0 pg/ml, P &lt; 0.0001; plasma IL-6: 3.2 ± 1.6 pg/ml vs. 19.5 ± 1.7 pg/ml, P &lt; 0.0001; hippocampal IL-1β: 4.1 ± 3.0 pg/mg vs. 41.6 ± 8.0 pg/mg, P &lt; 0.0001; hippocampal IL-6: 3.4 ± 1.3 pg/mg vs. 16.2 ± 2.7 pg/mg, P &lt; 0.0001). Reversal by dexmedetomidine was prevented by blockade of vagomimetic imidazoline and α7 nicotinic acetylcholine receptors but not by α2 adrenoceptor blockade. Netrin-1, the orchestrator of inflammation-resolution, was upregulated (fold-change) by dexmedetomidine (lung: 1.5 ± 0.1 vs. 0.7 ± 0.1, P &lt; 0.0001; spleen: 1.5 ± 0.2 vs. 0.6 ± 0.2, P &lt; 0.0001), resulting in upregulation of proresolving (lipoxin-A4: 1.7 ± 0.2 vs. 0.9 ± 0.2, P &lt; 0.0001) and downregulation of proinflammatory (leukotriene-B4: 1.0 ± 0.2 vs. 3.0 ± 0.3, P &lt; 0.0001) humoral mediators that was prevented by α7 nicotinic acetylcholine receptor blockade. Conclusions: Dexmedetomidine resolves inflammation through vagomimetic (neural) and humoral pathways, thereby preventing damage-Associated molecular pattern-mediated cognitive decline. (Anesthesiology 2018; 128:921-31). © 2018, the American Society of Anesthesiologists, Inc. Wolters Kluwer Health, Inc. All Rights Reserved.

Comparing clinical productivity of anesthesiology groups

Background: Intergroup comparisons of clinical productivity are important for strategic planning and evaluation of clinical and business operations. However, in a preliminary study, comparisons of two anesthesiology groups using "per full-time equivalent" measurements were confounded by different concurrencies or staffing ratios, whereas measurements based on "per operating room (OR) site," "per case," and "billed American Society of Anesthesiologists (ASA) units per hour of care" permitted meaningful comparisons despite differing concurrencies. The purpose of this study was to determine whether these measurements would allow for meaningful comparisons when applied to multiple groups. Methods: Annual totals of total ASA units (tASA), 15-min time units, and the number of cases billed, as well as the average number of daily anesthetizing sites (OR sites) staffed and the average number of anesthesiologists required to the staff sites, were collected from each group that participated. All anesthesia care billed with ASA units was included, except for obstetric care. Any clinical service not billed using ASA units was excluded. Productivity measurements (concurrency, tASA/OR site, hours billed per OR site per day, hours billed per case, tASA billed per hour of anesthesia care, and base units per case) were calculated. Median and range for all groups and for private-practice and academic groups were determined. Results: Eleven private-practice and nine academic groups from 12 states participated in the study. Productivity measurements that are influenced by duration of surgery (hours billed per case, tASA billed per hour of anesthesia care) differed significantly between groups, with private-practice groups having shorter duration than academic groups (median hours billed per case, 1.5 vs. 2.6, respectively). Although tASA/OR site measurements were similar in private- practice and academic groups, academic groups worked significantly longer hours billed per OR site per day (median, 6.0 h vs. 7.8, respectively) to achieve the same level of tASA/OR site. Hourly billing productivity (tASA billed per hour of anesthesia care) correlated highly with surgical duration (hours billed per case). Conclusion: This study demonstrates a method of comparing departmental clinical productivity between anesthesiology groups. Private-practice groups provided care for cases of shorter duration than academic groups. This difference was evident in several productivity measurements.

Predicting acute pain after cesarean delivery using three simple questions

Background: Interindividual variability in postoperative pain presents a clinical challenge. Preoperative quantitative sensory testing is useful but time consuming in predicting postoperative pain intensity. The current study was conducted to develop and validate a predictive model of acute postcesarean pain using a simple three-item preoperative questionnaire. Methods: A total of 200 women scheduled for elective cesarean delivery under subarachnoid anesthesia were enrolled (192 subjects analyzed). Patients were asked to rate the intensity of loudness of audio tones, their level of anxiety and anticipated pain, and analgesic need from surgery. Postoperatively, patients reported the intensity of evoked pain. Regression analysis was performed to generate a predictive model for pain from these measures. A validation cohort of 151 women was enrolled to test the reliability of the model (131 subjects analyzed). Results: Responses from each of the three preoperative questions correlated moderately with 24-h evoked pain intensity (r = 0.24-0.33, P < 0.001). Audio tone rating added uniquely, but minimally, to the model and was not included in the predictive model. The multiple regression analysis yielded a statistically significant model (R = 0.20, P < 0.001), whereas the validation cohort showed reliably a very similar regression line (R = 0.18). In predicting the upper 20th percentile of evoked pain scores, the optimal cut point was 46.9 (z =0.24) such that sensitivity of 0.68 and specificity of 0.67 were as balanced as possible. Conclusions: This simple three-item questionnaire is useful to help predict postcesarean evoked pain intensity, and could be applied to further research and clinical application to tailor analgesic therapy to those who need it most. © 2013 the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

An algorithm for assessing intraoperative mean arterial pressure lability

Background: Intraoperative blood pressure liability may be related to risk factors, hypovolemia, light anesthesia, and morbid outcomes, but the measurements of lability in previous studies have been limited by imprecise and infrequent data collection methods. Computerized intraoperative data acquisition systems have provided an opportunity to readdress the issue of intraoperative blood pressure lability with more abundant and precise data. This study sought to derive and validate an algorithm (expert system) to measure mean arterial pressure (MAP) lability. Methods: Two hundred thirty- nine computerized anesthesia records were reviewed retrospectively. Three anesthesiologists separately rated MAP as very stable, average, or very labile. The parameters of a computer algorithm that measured the change of median MAP between consecutive 2-min epochs were optimized to achieve the best possible agreement among the anesthesiologists. The algorithm was then validated on 229 additional anesthesia records. Results: The proportion of consecutive 2-min epochs in which the absolute value of the fractional change of median MAP exceeded 0.06 (i.e., 6%) correlated strongly with the anesthesiologists' ratings (r = 0.78; P < 0.0001). The optimal sensitivity and specificity of the algorithm for detecting MAP lability were 98% and 59%, respectively. Conclusions: One potential application of expert systems to anesthesia practice is a 'smart alarm' to detect blood pressure lability. It may also provide a better tool to assess the relation between lability and outcome than has been available previously.

Transient Receptor Potential Vanilloid 1 Antagonists Prevent Anesthesia-induced Hypothermia and Decrease Postincisional Opioid Dose Requirements in Rodents

Background: Intraoperative hypothermia and postoperative pain control are two important clinical challenges in anesthesiology. Transient receptor potential vanilloid 1 has been implicated both in thermoregulation and pain. Transient receptor potential vanilloid 1 antagonists were not advanced as analgesics in humans in part due to a side effect of hyperthermia. This study tested the hypothesis that a single, preincision injection of a transient receptor potential vanilloid 1 antagonist could prevent anesthesia-induced hypothermia and decrease the opioid requirement for postsurgical hypersensitivity. Methods: General anesthesia was induced in rats and mice with either isoflurane or ketamine, and animals were treated with transient receptor potential vanilloid 1 antagonists (AMG 517 or ABT-102). The core body temperature and oxygen consumption were monitored during anesthesia and the postanesthesia period. The effect of preincision AMG 517 on morphine-induced reversal of postincision hyperalgesia was evaluated in rats. Results: AMG 517 and ABT-102 dose-dependently prevented general anesthesia-induced hypothermia (mean ± SD; from 1.5° ± 0.1°C to 0.1° ± 0.1°C decrease; P < 0.001) without causing hyperthermia in the postanesthesia phase. Isoflurane-induced hypothermia was prevented by AMG 517 in wild-type but not in transient receptor potential vanilloid 1 knockout mice (n = 7 to 11 per group). The prevention of anesthesia-induced hypothermia by AMG 517 involved activation of brown fat thermogenesis with a possible contribution from changes in vasomotor tone. A single preincision dose of AMG 517 decreased the morphine dose requirement for the reduction of postincision thermal (12.6 ± 3.0 vs. 15.6 ± 1.0 s) and mechanical (6.8 ± 3.0 vs. 9.5 ± 3.0 g) withdrawal latencies. Conclusions: These studies demonstrate that transient receptor potential vanilloid 1 antagonists prevent anesthesia-induced hypothermia and decrease opioid dose requirements for the reduction of postincisional hypersensitivity in rodents. © 2017, the American Society of Anesthesiologists, Inc. Wolters Kluwer Health, Inc. All Rights Reserved.

S(+)-ketamine suppresses desensitization of γ-aminobutyric acid type B receptor-mediated signaling by inhibition of the interaction of γ-aminobutyric acid type B receptors with G protein-coupled receptor kinase 4 or 5

Background: Intrathecal baclofen therapy is an established treatment for severe spasticity. However, long-term management occasionally results in the development of tolerance. One of the mechanisms of tolerance is desensitization of γ-aminobutyric acid type B receptor (GABABR) because of the complex formation of the GABAB2 subunit (GB2R) and G protein-coupled receptor kinase (GRK) 4 or 5. The current study focused on S(+)-ketamine, which reduces the development of morphine tolerance. This study was designed to investigate whether S(+)-ketamine affects the GABABR desensitization processes by baclofen. Methods: The G protein-activated inwardly rectifying K channel currents induced by baclofen were recorded using Xenopus oocytes coexpressing G protein-activated inwardly rectifying K+ channel 1/2, GABAB1a receptor subunit, GB2R, and GRK. Translocation of GRKs 4 and 5 and protein complex formation of GB2R with GRKs were analyzed by confocal microscopy and fluorescence resonance energy transfer analysis in baby hamster kidney cells coexpressing GABAB1a receptor subunit, fluorescent protein-tagged GB2R, and GRKs. The formation of protein complexes of GB2R with GRKs was also determined by coimmunoprecipitation and Western blot analysis. Results: Desensitization of GABABR-mediated signaling was suppressed by S(+)-ketamine in a concentration-dependent manner in the electrophysiologic assay. Confocal microscopy revealed that S(+)-ketamine inhibited translocation of GRKs 4 and 5 to the plasma membranes and protein complex formation of GB2R with the GRKs. Western blot analysis also showed that S(+)-ketamine inhibited the protein complex formation of GB2R with the GRKs. Conclusion: S(+)-Ketamine suppressed the desensitization of GABABR-mediated signaling at least in part through inhibition of formation of protein complexes of GB2R with GRK 4 or 5. © 2011, the American Society of Anesthesiologists, Inc. Lippincott Williams &amp; Wilkins. Anesthesiology.

Source-level Cortical Power Changes for Xenon and Nitrous Oxide-induced Reductions in Consciousness in Healthy Male Volunteers

Background: Investigations of the electrophysiology of gaseous anesthetics xenon and nitrous oxide are limited revealing inconsistent frequencydependent alterations in spectral power and functional connectivity. Here, the authors describe the effects of sedative, equivalent, stepwise levels of xenon and nitrous oxide administration on oscillatory source power using a crossover design to investigate shared and disparate mechanisms of gaseous xenon and nitrous oxide anesthesia. Methods: Twenty-one healthy males underwent simultaneous magnetoencephalography and electroencephalography recordings. In separate sessions, sedative, equivalent subanesthetic doses of gaseous anesthetic agents nitrous oxide and xenon (0.25, 0.50, and 0.75 equivalent minimum alveolar concentration-awake [MACawake]) and 1.30 MACawake xenon (for loss of responsiveness) were administered. Source power in various frequency bands were computed and statistically assessed relative to a conscious/pre-gas baseline. Results: Observed changes in spectral-band power (P &lt; 0.005) were found to depend not only on the gas delivered, but also on the recording modality. While xenon was found to increase low-frequency band power only at loss of responsiveness in both source-reconstructed magnetoencephalographic (delta, 208.3%, 95% CI [135.7, 281.0%]; theta, 107.4%, 95% CI [63.5, 151.4%]) and electroencephalographic recordings (delta, 260.3%, 95% CI [225.7, 294.9%]; theta, 116.3%, 95% CI [72.6, 160.0%]), nitrous oxide only produced significant magnetoencephalographic high-frequency band increases (low gamma, 46.3%, 95% CI [34.6, 57.9%]; high gamma, 45.7%, 95% CI [34.5, 56.8%]). Nitrous oxide-not xenon-produced consistent topologic (frontal) magnetoencephalographic reductions in alpha power at 0.75 MACawake doses (44.4%; 95% CI [-50.1,-38.6%]), whereas electroencephalographically nitrous oxide produced maximal reductions in alpha power at submaximal levels (0.50 MACawake,-44.0%; 95% CI [-48.1,-40.0%]). Conclusions: Electromagnetic source-level imaging revealed widespread power changes in xenon and nitrous oxide anesthesia, but failed to reveal clear universal features of action for these two gaseous anesthetics. Magnetoencephalographic and electroencephalographic power changes showed notable differences which will need to be taken into account to ensure the accurate monitoring of brain state during anaesthesia. (ANESTHESIOLOGY 2020; 132:1017-33). © 2020, the American Society of Anesthesiologists, Inc. All Rights Reserved.

TASK channel deletion reduces sensitivity to local anesthetic-induced seizures

Background: Local anesthetics (LAs) are typically used for regional anesthesia but can be given systemically to mitigate postoperative pain, supplement general anesthesia, or prevent cardiac arrhythmias. However, systemic application or inadvertent intravenous injection can be associated with substantial toxicity, including seizure induction. The molecular basis for this toxic action remains unclear. Methods: We characterized inhibition by different LAs of homomeric and heteromeric K channels containing TASK-1 (K2P3.1, KCNK3) and TASK-3 (K2P9.1, KCNK9) subunits in a mammalian expression system. In addition, we used TASK-1/TASK-3 knockout mice to test the possibility that TASK channels contribute to LA-evoked seizures. RESULTS:: LAs inhibited homomeric and heteromeric TASK channels in a range relevant for seizure induction; channels containing TASK-1 subunits were most sensitive and IC50 values indicated a rank order potency of bupivacaine > ropivacaine lidocaine. LAs induced tonic-clonic seizures in mice with the same rank order potency, but higher LA doses were required to evoke seizures in TASK knockout mice. For bupivacaine, which produced the longest seizure times, seizure duration was significantly shorter in TASK knockout mice; bupivacaine-induced seizures were associated with an increase in electroencephalogram power at frequencies less than 5 Hz in both wild-type and TASK knockout mice. Conclusions: These data suggest that increased neuronal excitability associated with TASK channel inhibition by LAs contributes to seizure induction. Because all LAs were capable of evoking seizures in TASK channel deleted mice, albeit at higher doses, the results imply that other molecular targets must also be involved in this toxic action. © 2011 the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

Hospital stay and mortality are increased in patients having a triple low of low blood pressure, low bispectral index, and low minimum alveolar concentration of volatile anesthesia

Background: Low mean arterial pressure (MAP) and deep hypnosis have been associated with complications and mortality. The normal response to high minimum alveolar concentration (MAC) fraction of anesthetics is hypotension and low Bispectral Index (BIS) scores. Low MAP and/or BIS at lower MAC fractions may represent anesthetic sensitivity. The authors sought to characterize the effect of the triple low state (low MAP and low BIS during a low MAC fraction) on duration of hospitalization and 30-day all-cause mortality. Methods: Mean intraoperative MAP, BIS, and MAC were determined for 24,120 noncardiac surgery patients at the Cleveland Clinic, Cleveland, Ohio. The hazard ratios associated with combinations of MAP, BIS, and MAC values greater or less than a reference value were determined. The authors also evaluated the association between cumulative triple low minutes, and excess length-of-stay and 30-day mortality. RESULTS:: Means (±SD) defining the reference, low, and high states were 87 ± 5 mmHg (MAP), 46 ± 4 (BIS), and 0.56 ± 0.11 (MAC). Triple lows were associated with prolonged length of stay (hazard ratio 1.5, 95% CI 1.3-1.7). Thirty-day mortality was doubled in double low combinations and quadrupled in the triple low group. Triple low duration 60 min quadrupled 30-day mortality compared with ≤15 min. Excess length of stay increased progressively from ≤15 min to 60 min of triple low. Conclusions: The occurrence of low MAP during low MAC fraction was a strong and highly significant predictor for mortality. When these occurrences were combined with low BIS, mortality risk was even greater. The values defining the triple low state were well within the range that many anesthesiologists tolerate routinely. © 2012 the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

Influence of low tidal volume ventilation on time to extubation in cardiac surgical patients

Background: Low tidal volumes have been associated with improved outcomes in patients with established acute lung injury. The role of low tidal volume ventilation in patients without lung injury is still unresolved. We hypothesized that such a strategy in patients undergoing elective surgery would reduce ventilator-associated lung injury and that this improvement would lead to a shortened time to extubation Methods: A single-center randomized controlled trial was undertaken in 149 patients undergoing elective cardiac surgery. Ventilation with 6 versus 10 ml/kg tidal volume was compared. Ventilator settings were applied immediately after anesthesia induction and continued throughout surgery and the subsequent intensive care unit stay. The primary endpoint of the study was time to extubation. Secondary endpoints included the proportion of patients extubated at 6 h and indices of lung mechanics and gas exchange as well as patient clinical outcomes. Results: Median ventilation time was not significantly different in the low tidal volume group; a median (interquartile range) of 450 (264-1,044) min was achieved compared with 643 (417-1,032) min in the control group (P = 0.10). However, a higher proportion of patients in the low tidal volume group was free of any ventilation at 6 h: 37.3% compared with 20.3% in the control group (P = 0.02). In addition, fewer patients in the low tidal volume group required reintubation (1.3 vs. 9.5%; P = 0.03). Conclusions: Although reduction of tidal volume in mechanically ventilated patients undergoing elective cardiac surgery did not significantly shorten time to extubation, several improvements were observed in secondary outcomes. When these data are combined with a lack of observed complications, a strategy of reduced tidal volume could still be beneficial in this patient population. Copyright © 2011, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

Double epidural catheter with ropivacaine versus intravenous morphine: A comparison for postoperative analgesia after scoliosis correction surgery

Background: Major spine surgery with a dorsal or ventrodorsal approach causes severe postoperative pain. The use of continuous epidural analgesia through one or two epidural catheters placed intraoperatively by the surgeon has been shown to provide efficient postoperative pain control. In this prospective unblinded study, the authors compared the efficacy of continuous intravenous morphine with a continuous double epidural catheter technique with ropivacaine after scoliosis correction. Methods: Thirty patients with American Society of Anesthesiology physical status I-III were prospectively randomized to either the morphine group or the epidural group. At the end of surgery, patients in the epidural group received two epidural catheters placed by the surgeon, one directed cephalad and one caudally. Correct placement was checked radiographically. Postoperative analgesia until the first postoperative morning was performed with remifentanil target-control infusion for all patients. From that time remifentanil was stopped and continuous intravenous analgesia with morphine or double epidural analgesia with ropivacaine 0.3% was initiated (T0 = beginning of study). Pain at rest and pain in motion (using a visual analog scale from 0-100), the amount of rescue analgesics, sensory level, motor blockade, postoperative nausea and vomiting, and pruritus were assessed every 6 h and bowel function was assessed every 12 h until T72 (end of study). Two days later, patient satisfaction was assessed. Results: Pain scores at rest were significantly decreased in the epidural group at all time points except at T12, T60, and T72. Pain scores in motion were significantly decreased in the epidural group at T24, T48, and T72. Bowel activity was significantly better in the epidural group at T24, T36, T48, and T 60. Postoperative nausea and vomiting and pruritus occurred significantly less frequently in the epidural group. No complications related to the epidural catheter occurred. Conclusions: Both methods provide efficient postoperative analgesia. However, double epidural catheter technique provides better postoperative analgesia, earlier recovery of bowel function, fewer side effects, and a higher patient satisfaction.

Initial experience of an anesthesiology-based service for perioperative management of pacemakers and implantable cardioverter defibrillators

Background: Management of cardiovascular implantable electronic devices (CIEDs), including pacemakers and implantable cardioverter defibrillators, for surgical procedures is challenging due to the increasing number of patients with CIEDs and limited availability of trained providers. At the authors' institution, a small group of anesthesiologists were trained to interrogate CIEDs, devise a management plan, and perform preoperative and postoperative programming and device testing whenever necessary. Methods: Patients undergoing surgery between October 1, 2009 and June 30, 2013 at the University of Washington Medical Center were included in a retrospective chart review to determine the number of devices actively managed by the Electrophysiology/Cardiology Service (EPCS) versus the Anesthesiology Device Service (ADS), changes in workload over time, surgical case delays due to device management, and errors and problems encountered in device programming. Results: The EPCS managed 254 CIEDs, the ADS managed 548, and 227 by neither service. Over time, the ADS providers managed an increasing percentage of devices with decreasing supervision from the EPCS. Only two CIEDs managed by the ADS required immediate assistance from the EPCS. Patients who were unstable postoperatively were referred to the EPCS. Although numerous issues in programming were encountered, primarily when restoring demand pacing after programming asynchronous pacing for surgery, no patient harm resulted from ADS or EPCS management of CIEDs. Conclusions: An ADS can provide safe CIED management for surgery, but it requires specialized provider training and strong support from the EPCS. Due to the complexity of CIED management, an ADS will likely only be feasible in high-volume settings. Copyright © 2015, the American Society of Anesthesiologists, Inc.

Where are the costs in perioperative care?: Analysis of hospital costs and charges for inpatient surgical care

Background: Many health-care institutions are emphasizing cost reduction programs as a primary tool for managing profitability. The goal of this study was to elucidate the proportion of anesthesia costs relative to perioperative costs as determined by charges and actual costs. Methods: Costs and charges for 715 inpatients undergoing either discectomy (n = 234), prostatectomy (n = 152), appendectomy (n = 122) or laparoscopic cholecystectomy (n = 207) were retrospectively analyzed at Stanford University Medical Center from September 1993 to September 1994. Total hospital costs were separated into 11 hospital departments. Cost-to-charge ratios were calculated for each surgical procedure and hospital department. Hospitalization costs were also divided into variable and fixed costs (costs that do and do not change with patient volume). Costs were further partitioned into direct and indirect costs (costs that can and cannot be linked directly to a patient). Results: Forty-nine (49%) percent of total hospital costs were variable costs. Fifty-seven (57%) percent were direct costs. The largest hospital cost category was the operating room (33%) followed by the patient ward (31%). Intraoperative anesthesia costs were 5.6% of the total hospital cost. The overall cost-to- charge ratio (0.42) was constant between operations. Cost-to-charge ratios varied threefold among hospital departments. Patient charges overestimated resource consumption in some hospital departments (anesthesia) and underestimated resource consumption in others (ward). Conclusions: Anesthesia comprises 5.6% of perioperative costs. The influence of anesthesia practice patterns on 'downstream' events that influence costs of hospitalization requires further study.

Laryngoscopic intubation: Learning and performance

Background: Many healthcare professionals are trained in direct laryngoscopic tracheal intubation (LEI), which is a potentially lifesaving procedure. This study attempts to determine the number of successful LEI exposures required during training to assure competent performance, with special emphasis on defining competence itself. Methods: Analyses were based on a longitudinal study of novices under training conditions in the operating room. The progress of 438 LEIs performed by the 20 nonanesthesia trainees was monitored by observation and videotape analysis. Eighteen additional LEIs were performed by experienced anesthesiologists to define the standard. A generalized linear, mixed-modelling approach was used to identify key aspects of effective training and performance. The number of tracheal intubations that the trainees were required to perform before acquiring expertise in LEI was estimated. Results: Subjects performed between 18 and 35 laryngoscopic intubations. However, statistical modeling indicates that a 90% probability of a "good intubation" required 47 attempts. Proper insertion and lifting of the laryngoscope were crucial to "good" or "competent" performance of LEI. Traditional features, such as proper head and neck positions, were found to be less important under the study conditions. Conclusions: This study determined that traditional LEI teaching for nonanesthesia personnel using manikin alone is inadequate. A reevaluation of current standards in LEI teaching for nonanesthesia is required.

Patterns of preoperative consultation and surgical specialty in an integrated healthcare system

Background: Many patients scheduled for elective surgery are referred for a preoperative medical consultation. Only limited data are available on factors associated with preoperative consultations. The authors hypothesized that surgical specialty contributes to variation in referrals for preoperative consultations. Methods: This is a cohort study using data from Group Health Cooperative, an integrated healthcare system. The authors included 13,673 patients undergoing a variety of common procedures-primarily low-risk surgeries-representing six surgical specialties, in 2005-2006. The authors identified consultations by family physicians, general internists, pulmonologists, or cardiologists in the 42 days preceding surgery. Multivariable logistic regression was used to estimate the association between surgical specialty and consultation, adjusting for potential confounders including the revised cardiac risk index, age, gender, Deyo comorbidity index, number of prescription medications, and 11 medication classes. Results: The authors found that 3,063 (22%) of all patients had preoperative consultations, with significant variation by surgical specialty. Patients having ophthalmologic, orthopedic, or urologic surgery were more likely to have consultations compared with those having general surgery-adjusted odds ratios (95% CI) of 3.8 (3.3-4.2), 1.5 (1.3-1.7), and 2.3 (1.8-2.8), respectively. Preoperative consultations were more common in patients with lower revised cardiac risk scores. Conclusion: There is substantial practice variation among surgical specialties with regard to the use of preoperative consultations in this integrated healthcare system. Given the large number of consultations provided for patients with low cardiac risk and for patients presenting for low-risk surgeries, their indications, the financial burden, and cost-effectiveness of consultations deserve further study. © 2013 the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

Influence of patient comorbidities on the risk of near-miss maternal morbidity or mortality

Background: Maternal morbidity and mortality are increased in the United States compared with that of other developed countries. The objective of this investigation is to determine the extent to which it is possible to predict which patients will experience near-miss morbidity or mortality. Methods: The authors defined near-miss morbidity as end-organ injury associated with length of stay greater than the 99 percentile or discharge to a second medical facility, and identified all cases of near-miss morbidity or death from admissions for delivery in the 2003-2006 Nationwide Inpatient Sample. Logistic regression was used to examine the effect of maternal characteristics on rates of near-miss morbidity/mortality. RESULTS:: Approximately 1.3 per 1,000 hospitalizations for delivery was complicated by near-miss morbidity/mortality as defined in this study (95% CI 1.3-1.4). Most of these events (58.3%) occurred in 11.8% of the delivering population-in those women with important medical comorbidities or obstetric complications identified before admission for delivery. The highest rates were noted among women with pulmonary hypertension (98.0 cases per 1,000 deliveries), malignancy (23.4 per 1,000), and systemic lupus erythematosus (21.1 per 1,000). Conclusions: Risk for near-miss morbidity or mortality is substantially increased among an identifiable subset of pregnant women. To the extent that antepartum multidisciplinary coordination and high-quality intrapartum care improve delivery outcomes for women with significant antepartum medical and obstetric disease, then public health investments to reduce the national burden of delivery-related near-miss morbidity and mortality will have the greatest effect by focusing resources on identifying and serving these high-risk groups. © 2011 the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

A series of anesthesia-related maternal deaths in Michigan, 1985-2003

BACKGROUND: Maternal Mortality Surveillance has been conducted by the State of Michigan since 1950, and anesthesia-related maternal deaths were most recently reviewed for the years 1972-1984. METHODS: Records for pregnancy-associated deaths between 1985 and 2003 were reviewed to identify 25 cases associated with a perioperative arrest or major anesthetic complication. Four obstetric anesthesiologists independently classified these cases, and disagreements were resolved by discussion. Precise definitions of anesthesia-related and anesthesia-contributing maternal death were constructed. Anesthesia-related deaths were reviewed to identify the chain of medical errors or care management problems that contributed to each patient death. RESULTS: Of 855 pregnancy-associated deaths, 8 were anesthesia-related and 7 were anesthesia-contributing. There were no deaths during induction of general anesthesia. Five resulted from hypoventilation or airway obstruction during emergence, extubation, or recovery. Lapses in either postoperative monitoring or anesthesiology supervision seemed to contribute to 5 of the 8 anesthesia-related deaths. Other characteristics common to these cases included obesity (n = 6) and African-American race (n = 6). CONCLUSIONS: The 8 anesthesia-related and seven anesthesia-contributing maternal deaths in Michigan between 1985 and 2003 illustrate three key points. First, all anesthesia-related deaths from airway obstruction or hypoventilation took place during emergence and recovery, not during the induction of general anesthesia. Second, system errors played a role in the majority of cases. Of concern, lapses in postoperative monitoring and inadequate supervision by an anesthesiologist seemed to contribute to more than half of the deaths. Finally, this report confirms previous work that obesity and African-American race are important risk factors for anesthesia-related maternal mortality. © 2007 American Society of Anesthesiologists, Inc.

Myocardial Function during Low versus Intermediate Tidal Volume Ventilation in Patients without Acute Respiratory Distress Syndrome

Background: Mechanical ventilation with low tidal volumes has the potential to mitigate ventilation-induced lung injury, yet the clinical effect of tidal volume size on myocardial function has not been clarified. This cross-sectional study investigated whether low tidal volume ventilation has beneficial effects on myocardial systolic and diastolic function compared to intermediate tidal volume ventilation. Methods: Forty-two mechanically ventilated patients without acute respiratory distress syndrome (ARDS) underwent transthoracic echocardiography after more than 24 h of mechanical ventilation according to the Protective Ventilation in Patients without ARDS (PReVENT) trial comparing a low versus intermediate tidal volume strategy. The primary outcome was left ventricular and right ventricular myocardial performance index as measure for combined systolic and diastolic function, with lower values indicating better myocardial function and a right ventricular myocardial performance index greater than 0.54 regarded as the abnormality threshold. Secondary outcomes included specific systolic and diastolic parameters. Results: One patient was excluded due to insufficient acoustic windows, leaving 21 patients receiving low tidal volumes with a tidal volume size (mean ± SD) of 6.5 ± 1.8 ml/kg predicted body weight, while 20 patients were subjected to intermediate tidal volumes receiving a tidal volume size of 9.5 ± 1.6 ml/kg predicted body weight (mean difference,-3.0 ml/kg; 95% CI,-4.1 to-2.0; P < 0.001). Right ventricular dysfunction was reduced in the low tidal volume group compared to the intermediate tidal volume group (myocardial performance index, 0.41 ± 0.13 vs. 0.64 ± 0.15; mean difference,-0.23; 95% CI,-0.32 to-0.14; P < 0.001) as was left ventricular dysfunction (myocardial performance index, 0.50 ± 0.17 vs. 0.63 ± 0.19; mean difference,-0.13; 95% CI,-0.24 to-0.01; P = 0.030). Similarly, most systolic parameters were superior in the low tidal volume group compared to the intermediate tidal volume group, yet diastolic parameters did not differ between both groups. Conclusions: In patients without ARDS, intermediate tidal volume ventilation decreased left ventricular and right ventricular systolic function compared to low tidal volume ventilation, although without an effect on diastolic function. (ANESTHESIOLOGY 2020; 132:1102-13). © 2020, the American Society of Anesthesiologists, Inc. All Rights Reserved.

Using an anesthesia information management system as a cost containment tool: Description and validation

Background: Medical informatics provide a new way to evaluate the practice of medicine. Anesthesia automated record keepers have introduced anesthesiologists to computerized medical records. To derive useful information from the stored data requires programming that is not currently commercially available. The authors describe how they custom-programmed an automated record keeper's database to perform cost calculations, how they validated the programming, and how they used the data in a successful pharmaceutical cost-containment program. Methods: The Arkive® (San Diego, CA) automated record keeper database was programmed at Duke University Medical Center as an independent noncommercial project to calculate costs according to standard formulae and to follow adherence to Duke University Department of Anesthesiology's prescribing guidelines for anesthetic drugs. Validation of that programming (including analysis of discarded drugs) was accomplished by comparing database calculated costs with actual pharmacy distribution of drugs during a 1-month period. Results: Validation data demonstrated a 99% accuracy rate for total costs of the drugs studied (atracurium, vecuronium, rocuronium, propofol, midazolam, fentanyl, and isoflurane). The study drugs represented approximately 67% of all drug costs for the period studied. Conclusions: Programming of an anesthesia automated record keeper's database yields essential information for management of an anesthetic practice. Accurate economic evaluation of anesthetic drug use is now possible. In the future, as definitive identification of best anesthetic practices that yield optimal patient outcomes and higher measures of patient satisfaction is pursued, large numbers of patients should be studied. This is only possible through database analysis and complete computerization of the perioperative medical record.

Malpractice claims associated with medication management for chronic pain

Background: Medication management is an integral part of chronic pain management. Prompted by an increase in the role of medication management in anesthesia chronic pain liability, we investigated the characteristics of malpractice claims collected from 2005 to 2008. METHODS:: After Institutional Review Board approval, we compared medication management claims with other chronic pain claims from the American Society of Anesthesiologists Closed Claims Database of 8,954 claims. Claims for death underwent in-depth analysis. Results:Medication management represented 17% of 295 chronic non-cancer pain claims. Compared with other chronic pain claims, medication management patients tended to be younger men (P < 0.01) with back pain. Most patients were prescribed opioids (94%) and also additional psychoactive medications (58%). Eighty percent of patients had at least one factor commonly associated with medication misuse and 24% had ? 3 factors. Most claims (82%) involved patients who did not cooperate in their care (69%) or inappropriate medication management by physicians (59%). Death was the most common outcome in medication management claims (57% vs. 9% in other chronic pain claims, P < 0.01). Factors associated with death included long-acting opioids, additional psychoactive medications, and ? 3 factors commonly associated with medication misuse. Alleged addiction from prescribed opioids was the complaint in 24%. Appropriateness of care and payments was similar for medication management versus other chronic pain claims. Conclusions: Most anesthesia malpractice claims for medication management problems involved patients with a history of risk behaviors commonly associated with medication misuse. Malpractice claims arising from medication management had a high proportion of deaths with both patient and physician contributions to the outcome.

New insights into the mechanism of methoxyflurane nephrotoxicity and implications for anesthetic development (Part 2): Identification of nephrotoxic metabolites

BACKGROUND: Methoxyflurane nephrotoxicity results from its metabolism, which occurs by both dechlorination (to methoxydifluoroacetic acid [MDFA]) and O-demethylation (to fluoride and dichloroacetic acid [DCAA]). Inorganic fluoride can be toxic, but it remains unknown why other anesthetics, commensurately increasing systemic fluoride concentrations, are not toxic. Fluoride is one of many methoxyflurane metabolites and may itself cause toxicity and/or reflect formation of other toxic metabolite(s). This investigation evaluated the disposition and renal effects of known methoxyflurane metabolites. METHODS: Rats were given by intraperitoneal injection the methoxyflurane metabolites MDFA, DCAA, or sodium fluoride (0.22, 0.45, 0.9, or 1.8 mmol/kg followed by 0.11, 0.22, 0.45, or 0.9 mmol/kg on the next 3 days) at doses relevant to metabolite exposure after methoxyflurane anesthesia, or DCAA and fluoride in combination. Renal histology and function (blood urea nitrogen, urine volume, urine osmolality) and metabolite excretion in urine were assessed. RESULTS: Methoxyflurane metabolite excretion in urine after injection approximated that after methoxyflurane anesthesia, confirming the appropriateness of metabolite doses. Neither MDFA nor DCAA alone had any effects on renal function parameters or necrosis. Fluoride at low doses (0.22, then 0.11 mmol/kg) decreased osmolality, whereas higher doses (0.45, then 0.22 mmol/kg) also caused diuresis but not significant necrosis. Fluoride and DCAA together caused significantly greater tubular cell necrosis than fluoride alone. CONCLUSIONS: Methoxyflurane nephrotoxicity seems to result from O-demethylation, which forms both fluoride and DCAA. Because their coformation is unique to methoxyflurane compared with other volatile anesthetics and they are more toxic than fluoride alone, this suggests a new hypothesis of methoxyflurane nephrotoxicity. This may explain why increased fluoride formation from methoxyflurane, but not other anesthetics, is associated with toxicity. These results may have implications for the interpretation of clinical anesthetic defluorination, use of volatile anesthetics, and the laboratory methods used to evaluate potential anesthetic toxicity. Copyright © 2006, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins, Inc.

TT-301 inhibits microglial activation and improves outcome after central nervous system injury in adult mice

Background: Microglial inhibition may reduce secondary tissue injury and improve functional outcome following acute brain injury. Utilizing clinically relevant murine models of traumatic brain injury and intracerebral hemorrhage, neuroinflammatory responses and functional outcome were examined in the presence of a potential microglial inhibitor, TT-301. Methods: TT-301 or saline was administered following traumatic brain injury or intracerebral hemorrhage, and then for four subsequent days. The effect of TT-301 on neuroinflammatory responses and neuronal viability was assessed, as well as short-term vestibulomotor deficit (Rotorod) and long-term neurocognitive impairment (Morris water maze). Finally differential gene expression profiles of mice treated with TT-301 were compared with those of vehicle. Results: Reduction in F4/80+ staining was demonstrated at 1 and 10 days, but not 28 days, after injury in mice treated with TT-301 (n = 6). These histologic findings were associated with improved neurologic function as assessed by Rotorod, which improved by 52.7% in the treated group by day 7, and Morris water maze latencies, which improved by 232.5% as a function of treatment (n = 12; P < 0.05). Similar benefit was demonstrated following intracerebral hemorrhage, in which treatment with TT-301 was associated with functional neurologic improvement of 39.6% improvement in Rotorod and a reduction in cerebral edema that was independent of hematoma volume (n = 12; P < 0.05). Differential gene expression was evaluated following treatment with TT-301, and hierarchical cluster analysis implicated involvement of the Janus kinase-Signal Transducer and Activator of Transcription pathway after administration of TT-301 (n = 3/group). Conclusions: Modulation of neuroinflammatory responses through TT-301 administration improved histologic and functional parameters in murine models of acute neurologic injury. © 2012 the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

Flexible interaction model for complex interactions of multiple anesthetics

BACKGROUND: Minto et al. (Anesthesiology 2000) described a mathematical approach based on response surface methods for characterizing drug-drug interactions between several intravenous anesthetic drugs. To extend this effort, the authors developed a flexible interaction model based on the general Hill dose-response relation that includes a set of parameters that can be statistically assessed for interaction significance. METHODS: This new model was developed to identify pharmacologically meaningful interaction-related parameters and address mathematical limitations in previous models. The flexible interaction model and the model of Minto et al. were compared in their assessment of additivity using simulated sample data sets. The flexible interaction model was also compared with the Minto model in describing drug interactions using data from several other clinical studies of propofol, opioids, and benzodiazepines from Short et al. (Anesthesiology 2002) and Kern et al. (Anesthesiology 2004). RESULTS: The flexible interaction model was able to accurately classify an additive interaction based on the classic definition proposed by Loewe, with at most an 8% difference between the two surfaces. Also, the proposed model fit the clinical interaction data as well or slightly better than that of Minto et al. CONCLUSIONS: The new model can accurately classify additive and synergistic drug interactions. It also can classify antagonistic interactions with biologically rational surfaces. This has been a problem for other interaction models in the past. The statistically assessable interaction parameters provide a quantitative manner to assess the interaction significance. © 2006 American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins, Inc.

Evaluation of MP4OX for prevention of perioperative hypotension in patients undergoing primary hip arthroplasty with spinal anesthesia: A randomized, double-blind, multicenter study

Background: MP4OX (oxygenated polyethylene glycol-modified hemoglobin) is an oxygen therapeutic agent with potential applications in clinical settings where targeted delivery of oxygen to ischemic tissues is required. The primary goal of this study was to investigate MP4OX for preventing hypotensive episodes. An additional goal was to establish the safety profile of MP4OX in a large surgical population. Methods: Patients (n = 367) from 18 active study sites in six countries, undergoing elective primary hip arthroplasty with spinal anesthesia, were randomized to receive MP4OX or hydroxyethyl starch 130/0.4. Patients received a 250-ml dose at induction of spinal anesthesia and a second 250-ml dose if the protocol-specified trigger (predefined decrease in systolic blood pressure) was reached. The primary end point was the proportion of patients who developed one or more hypotensive episodes. Results: The proportion of patients with one or more hypotensive episodes was significantly lower (P < 0.0001) in the MP4OX group (66.1%) versus controls receiving hydroxyethyl starch 130/0.4 (90.2%). More MP4OX-treated patients experienced adverse events compared with controls (72.7% vs. 61.4%; P = 0.026). Transient elevations in laboratory values (e.g., alanine aminotransferase, aspartate aminotransferase, lipase, and troponin concentrations) occurred more frequently in the MP4OX group. There were no significant differences in the incidence of serious adverse events or in the composite morbidity and ischemia outcome end points, but nausea and hypertension were reported more often in MP4OX-treated patients. Conclusion: MP4OX significantly reduced the incidence of hypotensive episodes in patients undergoing hip arthroplasty, but the adverse event profile does not support use in routine low-risk surgical patients for the indication evaluated in this study. Copyright © 2011, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

Identical de novo mutation in the type 1 ryanodine receptor gene associated with fatal, stress-induced malignant hyperthermia in two unrelated families

Background: Mutations in the type 1 ryanodine receptor gene (RYR1) result in malignant hyperthermia, a pharmacogenetic disorder typically triggered by administration of anesthetics. However, cases of sudden death during exertion, heat challenge, and febrile illness in the absence of triggering drugs have been reported. The underlying causes of such drug-free fatal "awake" episodes are unknown. Methods: De novo R3983C variant in RYR1 was identified in two unrelated children who experienced fatal, nonanesthetic awake episodes associated with febrile illness and heat stress. One of the children also had a second novel, maternally inherited D4505H variant located on a separate haplotype. Effects of all possible heterotypic expression conditions on RYR1 sensitivity to caffeine-induced Ca2+ release were determined in expressing RYR1-null myotubes. RESULTS:: Compared with wild-type RYR1 alone (EC50 = 2.85 ± 0.49 mM), average (±SEM) caffeine sensitivity of Ca release was modestly increased after coexpression with either R3983C (EC50 = 2.00 ± 0.39 mM) or D4505H (EC50 = 1.64 ± 0.24 mM). Remarkably, coexpression of wild-type RYR1 with the double mutant in cis (R3983C-D4505H) produced a significantly stronger sensitization of caffeine-induced Ca release (EC50 = 0.64 ± 0.17 mM) compared with that observed after coexpression of the two variants on separate subunits (EC50 = 1.53 ± 0.18 mM). Conclusions: The R3983C mutation potentiates D4505H-mediated sensitization of caffeine-induced RYR1 Ca release when the mutations are in cis (on the same subunit) but not when present on separate subunits. Nevertheless, coexpression of the two variants on separate subunits still resulted in a ∼2-fold increase in caffeine sensitivity, consistent with the observed awake episodes and heat sensitivity. © 2011 the American Society of Anesthesiologists, Inc. Lippincott Williams &amp; Wilkins. Anesthesiology.

Desflurane Anesthesia Alters Cortical Layer-specific Hierarchical Interactions in Rat Cerebral Cortex

Background: Neurocognitive investigations suggest that conscious sensory perception depends on recurrent neuronal interactions among sensory, parietal, and frontal cortical regions, which are suppressed by general anesthetics. The purpose of this work was to investigate if local interactions in sensory cortex are also altered by anesthetics. The authors hypothesized that desflurane would reduce recurrent neuronal interactions in cortical layer-specific manner consistent with the anatomical disposition of feedforward and feedback pathways. Methods: Single-unit neuronal activity was measured in freely moving adult male rats (268 units; 10 animals) using microelectrode arrays chronically implanted in primary and secondary visual cortex. Layer-specific directional interactions were estimated by mutual information and transfer entropy of multineuron spike patterns within and between cortical layers three and five. The effect of incrementally increasing and decreasing steady-state concentrations of desflurane (0 to 8% to 0%) was tested for statistically significant quadratic trend across the successive anesthetic states. Results: Desflurane produced robust, state-dependent reduction (P = 0.001) of neuronal interactions between primary and secondary visual areas and between layers three and five, as indicated by mutual information (37 and 41% decrease at 8% desflurane from wakeful baseline at [mean ± SD] 0.52 ± 0.51 and 0.53 ± 0.51 a.u., respectively) and transfer entropy (77 and 78% decrease at 8% desflurane from wakeful baseline at 1.86 ± 1.56 a.u. and 1.87 ± 1.67 a.u., respectively). In addition, a preferential suppression of feedback between secondary and primary visual cortex was suggested by the reduction of directional index of transfer entropy overall (P = 0.001; 89% decrease at 8% desflurane from 0.11 ± 0.18 a.u. at baseline) and specifically, in layer five (P = 0.001; 108% decrease at 8% desflurane from 0.12 ± 0.19 a.u. at baseline). Conclusions: Desflurane anesthesia reduces neuronal interactions in visual cortex with a preferential effect on feedback. The findings suggest that neuronal disconnection occurs locally, among hierarchical sensory regions, which may contribute to global functional disconnection underlying anestheticinduced unconsciousness. (ANESTHESIOLOGY 2020; 132:1080-90). © 2020, the American Society of Anesthesiologists, Inc. All Rights Reserved.

A 18F-fluorodeoxyglucose MicroPET imaging study to assess changes in brain glucose metabolism in a rat model of surgery-induced latent pain sensitization

Background: Neuroplastic changes involved in latent pain sensitization after surgery are poorly defined. We assessed temporal changes in glucose brain metabolism in a postoperative rat model using positron emission tomography. We also investigated brain metabolism after naloxone administration. Methods: Rats were given remifentanil anesthetic and underwent a plantar incision, with 1 mg/kg of (-)-naloxone subcutaneously administered on postoperative days 20 and 21. Using the von Frey test, mechanical thresholds were measured pre-and postoperatively at different time points in awake animals during F-fluorodeoxyglucose (F-FDG) uptake. Brain images were also obtained the day before mechanical testing, using a positron emission tomography R4 scanner (Concorde Microsystems, Siemens, Knoxville, TN). Differences in brain activity were assessed utilizing a statistical parametric mapping. RESULTS:: Surgery induced minor changes in F-FDG uptake in the cerebellum, hippocampus, and posterior cortex, which extended to the thalamus, hypothalamus, and brainstem on days 6 and 7. Changes were still present on day 21. Maximal postoperative hypersensitivity was observed on day 2. The administration of (-)-naloxone on day 21 induced significant hypersensitivity, greatly enhancing the effect on F-FDG uptake. In sham-operated rats, naloxone induced changes limited to the striatum and the cerebellum. Nonnociceptive stimulation with von Frey filaments had no effect on F-FDG uptake. Conclusions: Surgery, remifentanil, and their combination induced long-lasting and significant metabolic changes in the pain brain matrix, with a positive correlation with hypersensitivity after naloxone. Changes in brain F-FDG precipitated by naloxone suggest that surgery under remifentanil anesthetic induces the greatest neuroplastic brain adaptations in opioid-related pathways involved in nociceptive processing and long-lasting pain sensitization. © 2011 the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

The glottic aperture seal airway: A new ventilatory device

Background: None of the presently used airway devices are ideal regarding ease of insertion, alignment with the laryngeal inlet, and provision of a high-pressure seal from the environment. The purpose of this study was to determine, in awake volunteers, the performance of a new ventilatory device, the glottic aperture seal airway, regarding ease of insertion, alignment with the laryngeal inlet, and forced exhalation seal pressure (PFES). Methods: The glottic aperture seal airway consists of a curved tubular component that ends in the middle of an elliptical foam cushion glottic component. The posterior surface of the foam has a curved flexible plastic backing, which imparts a 60°angle between the proximal haft and the distal haft of the foam cushion. When the glottic aperture seal airway is properly in situ in a supine patient, the proximal half of the foam cushion is opposite the laryngeal inlet. The posterior surface of the plastic backing has a balloon attached to it. Inflation of the balloon presses the ventilation hole and foam cushion up against the laryngeal inlet, thereby creating a seal from the environment. Using the laryngeal mask airway as a control device, the glottic aperture seal airway was tested for time and ease of insertion, fiberoptic alignment with the laryngeal inlet, and PFES in 18 lightly sedated and locally anesthetized volunteers. Results: The glottic aperture seal and laryngeal mask airways were inserted with equal ease and speed. The fiberoptic alignment with the larynx was excellent for both the glottic aperture seal and laryngeal mask airways. In all volunteers, the mean ± SD PFES values at 0-, 10-, 20-, 30-, and 40-ml balloon inflation volumes of the glottic aperture seal airway were 23.4 ± 11.8, 29.6 ± 12.4, 42.7 ± 12.5, 56.9 ± 5.6, and 60 ± 0 cm H2O, respectively; the PFES at ≤20 ml balloon inflation volume of the glottic aperture seal airway was significantly greater than with the laryngeal mask airway (19.4 ± 6.7 cm H2O, P &lt; 0.01). A PFES of ≤60 cm H2O was achieved with the glottic aperture seal airway in all volunteers (n = 2 at 10 ml, n = 3 at 20 ml, n = 9 at 30 ml, and n = 4 at 40 ml). The glottic aperture seal airway did not cause any trauma. Conclusion: In awake volunteers, the glottic aperture seal and laryngeal mask airways were equally easy to insert and position. The glottic aperture seal airway was capable of achieving a higher PFES than the laryngeal mask airway.

Invasive and concomitant noninvasive intraoperative blood pressure monitoring: Observed differences in measurements and associated therapeutic interventions

Background: Noninvasive (NIBP) and intraarterial (ABP) blood pressure monitoring are used under different circumstances and may yield different values. The authors endeavored to characterize these differences and hypothesized that there could be differences in interventions associated with the use of ABP alone ([ABP]) versus ABP in combination with NIBP ([ABP+NIBP]). Methods: Simultaneous measurements of ABP and NIBP made during noncardiac cases were extracted from electronic anesthesia records; the differences were subjected to regression analysis. Records of blood products, vasopressors, and antihypertensives administered were also extracted, and associations between the use of these therapies and monitoring strategy ([ABP] vs. [ABP+NIBP]) were tested using univariate, multivariate, and propensity score matched analyses. RESULTS:: Among 24,225 cases, 63% and 37% used [ABP+NIBP] and [ABP], respectively. Systolic NIBP was likely to be higher than ABP when ABP was less than 111 mmHg and lower than ABP otherwise. Among patients with hypotension, transfusion occurred in 27% versus 43% of patients in the [ABP+NIBP] versus [ABP] group, respectively (odds ratio = 0.4; 95% CI 0.35-0.46), and 7% versus 18% of patients in the [ABP+NIBP] versus [ABP] group received vasopressor infusions, respectively (P < 0.01). Among hypertensive patients, 12% versus 44% of those in the [ABP+NIBP] versus [ABP] group received antihypertensive agents, respectively (P < 0.01). Conclusions: NIBP was generally higher than ABP during periods of hypotension and lower than ABP during periods of hypertension. The use of NIBP measurements to supplement ABP measurements was associated with decreased use of blood transfusions, vasopressor infusions, and antihypertensive medications compared with the use of ABP alone. © 2011 the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

α2-Adrenergic receptors in human dorsal root ganglia: Predominance of α(2b) and α(2c) subtype mRNAs

Background: Nonselective α2-adrenergic receptor (α2AR) agonists (e.g., clonidine) mediate antinociception in part through α2ARs in spinal cord dorsal horn; however, use of these agents for analgesia in humans is limited by unwanted sedation and hypotension. The authors previously demonstrated α(2a) ≃ α(2b) &gt; &gt; &gt; α(2c) mRNA in human spinal cord dorsal horn cell bodies. However, because 20% of dorsal horn α2ARs derive from cell bodies that reside in the associated dorsal root ganglion (DRG), it is important to evaluate α2AR expression in this tissue as well. Therefore, the authors evaluated the hypothesis that α(2b) mRNA, α(2c) mRNA, or both are present in human DRG. Methods: Molecular approaches were used to determine α2AR expression in 28 human DRGs because of low overall receptor mRNA expression and small sample size. After creation of synthetic competitor cDNA and establishment of amplification conditions with parallel efficiencies, competitive reverse transcription polymerase chain reaction was performed using RNA isolated from human DRG. Results: Overall expression of α2AR mRNA in DRG is low but reproducible at all spinal levels. α(2b) and α(2c)AR subtype mRNAs predominate (α(2b) ≃ α(2c)), accounting for more than 95% of the total α2AR mRNA in DRG at all human spinal nerve root levels. Conclusions: Predominance of α(2b) and α(2c)AR mRNA in human DRG is distinct from α2AR mRNA expression in cell bodies originating in human spinal cord dorsal horn, where α(2a) and α(2b) predominate with little or absent α(2c) expression. These findings also highlight species heterogeneity in α2AR expression in DRG. If confirmed at a protein level, these findings provide an additional step in unraveling mechanisms involved in complex neural pathways such as those for pain.

Liability associated with obstetric anesthesia: A closed claims analysis

BACKGROUND: Obstetrics carries high medical liability risk. Maternal death and newborn death/brain damage were the most common complications in obstetric anesthesia malpractice claims before 1990. As the liability profile may have changed over the past two decades, the authors reviewed recent obstetric claims in the American Society of Anesthesiologists Closed Claims database. METHODS: Obstetric anesthesia claims for injuries from 1990 to 2003 (1990 or later claims; n = 426) were compared to obstetric claims for injuries before 1990 (n = 190). Chi-square and z tests compared categorical variables; payment amounts were compared using the Kolmogorov-Smirnov test. RESULTS: Compared to pre-1990 obstetric claims, the proportion of maternal death (P = 0.002) and newborn death/brain damage (P = 0.048) decreased, whereas maternal nerve injury (P < 0.001) and maternal back pain (P = 0.012) increased in 1990 or later claims. In 1990 or later claims, payment was made on behalf of the anesthesiologist in only 21% of newborn death/brain damage claims compared to 60% of maternal death/brain damage claims (P < 0.001). These payments in both groups were associated with an anesthesia contribution to the injury (P < 0.001) and substandard anesthesia care (P < 0.001). Anesthesia-related newborn death/brain damage claims had an increased proportion of delays in anesthetic care (P = 0.001) and poor communication (P = 0.007) compared to claims unrelated to anesthesia. CONCLUSION: Newborn death/brain damage has decreased, yet it remains a leading cause of obstetric anesthesia malpractice claims over time. Potentially preventable anesthetic causes of newborn injury included delays in anesthesia care and poor communication between the obstetrician and anesthesiologist. © 2008, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins, Inc.

Simulation-based Assessment to Reliably Identify Key Resident Performance Attributes

Background: Obtaining reliable and valid information on resident performance is critical to patient safety and training program improvement. The goals were to characterize important anesthesia resident performance gaps that are not typically evaluated, and to further validate scores from a multiscenario simulation-based assessment. Methods: Seven high-fidelity scenarios reflecting core anesthesiology skills were administered to 51 first-year residents (CA-1s) and 16 third-year residents (CA-3s) from three residency programs. Twenty trained attending anesthesiologists rated resident performances using a seven-point behaviorally anchored rating scale for five domains: (1) formulate a clear plan, (2) modify the plan under changing conditions, (3) communicate effectively, (4) identify performance improvement opportunities, and (5) recognize limits. A second rater assessed 10% of encounters. Scores and variances for each domain, each scenario, and the total were compared. Low domain ratings (1, 2) were examined in detail. Results: Interrater agreement was 0.76; reliability of the seven-scenario assessment was r = 0.70. CA-3s had a significantly higher average total score (4.9 ± 1.1 vs. 4.6 ± 1.1, P = 0.01, effect size = 0.33). CA-3s significantly outscored CA-1s for five of seven scenarios and domains 1, 2, and 3. CA-1s had a significantly higher proportion of worrisome ratings than CA-3s (chi-square = 24.1, P < 0.01, effect size = 1.50). Ninety-eight percent of residents rated the simulations more educational than an average day in the operating room. Conclusions: Sensitivity of the assessment to CA-1 versus CA-3 performance differences for most scenarios and domains supports validity. No differences, by experience level, were detected for two domains associated with reflective practice. Smaller score variances for CA-3s likely reflect a training effect; however, worrisome performance scores for both CA-1s and CA-3s suggest room for improvement. © 2018, the American Society of Anesthesiologists, Inc. Wolters Kluwer Health, Inc. All Rights Reserved.

Prevalence of latex allergy among anesthesiologists: Identification of sensitized but asymptomatic individuals

Background: Occupational exposure to natural rubber latex has led to sensitization of health-care workers. However, the prevalence of latex allergy among occupationally exposed workers in American hospitals has not been reproducibly determined. The objectives of the current study were to determine the prevalence of and risk factors for latex sensitization among a cohort of highly exposed health-care workers. Methods: Participants were 168 of 171 eligible anesthesiologists and nurse anesthetists working in the Department of Anesthesiology and Critical Care Medicine. A clinical questionnaire was administered, and testing was performed using a characterized nonammoniated latex reagent for puncture skin testing, a Food and Drug Administration-approved assay to quantify latex-specific immunoglobulin E antibody in serum, and, when required for clarification, a validated two-stage (contact-inhalation) latex glove provocation procedure. Results: The prevalence of latex allergy with clinical symptoms and latex sensitization without clinical symptoms was 2.4% and 10.1%, respectively. The prevalence of irritant or contact dermatitis was 24%. The risk factors identified for latex sensitization were atopy (odds ratio, 14.1; 95% CI, 1.8112.1; P = 0.012); history of allergy to selected fruits, such as bananas, avocados, or kiwis (odds ratio, 9.8; 95% CI, 1.6-61.9; P = 0.015); and history of skin symptoms with latex glove use (odds ratio, 4.6; 95% CI, 1.6- 13.4; P = 0.006). Conclusions: The prevalence of latex sensitization among anesthesiologists is high (12.50%). Of these, 10.1% had occult (asymptomatic) latex allergy. Hospital employees may be sensitized to latex even in the absence of perceived latex allergy symptoms. These data support the need to transform the health-care environment into a latex-safe one that minimizes latex exposure to patients and hospital staff.

The psychological and physiological effects of acute occupational stress in new anesthesiology residents: A pilot trial

Background: Occupational stress in resident physicians has profound implications for wellness, professionalism, and patient care. This observational pilot trial measured psychological and physiological stress biomarkers before, during, and after the start of anesthesia residency.Methods: Eighteen physician interns scheduled to begin anesthesia residency were recruited for evaluation at three time points: baseline (collected remotely before residency in June 2013); first-month visit 1 (July); and follow-up visit 2 (residency months 3 to 5, September-November). Validated scales were used to measure stress, anxiety, resilience, and wellness at all three time points. During visits 1 and 2, the authors measured resting heart-rate variability, responses to laboratory mental stress (hemodynamic, catecholamine, cortisol, and interleukin-6), and chronic stress indices (C-reactive protein, 24-h ambulatory heart rate and blood pressure, 24-h urinary cortisol and catecholamines, overnight heart-rate variability ).Results:Thirteen interns agreed to participate (72% enrollment). There were seven men and six women, aged 27 to 33 yr. The mean ± SD of all study variables are reported.Conclusion: The novelty of this report is the prospective design in a defined cohort of residents newly exposed to the similar occupational stress of the operating environment. Because of the paucity of literature specific to the measures and stress conditions in this investigation, no data were available to generate a priori definition of primary outcomes and a data analytic plan. These findings will allow power analysis for future design of trials examining occupational stress and stress-reducing interventions. Given the importance of physician burnout in our country, the impact of chronic stress on resident wellness requires further study. Copyright © 2014, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins.

Offset analgesia in neuropathic pain patients and effect of treatment with morphine and ketamine

Background: Offset analgesia, in which a disproportionally large amount of analgesia becomes apparent upon a slight decrease in noxious heat stimulation, has not been described previously in patients with chronic pain. Methods: Offset analgesia responses in 10 patients with neuropathic pain (in both legs) were compared with 10 matched healthy controls and volunteers from a convenience sample (n = 110) with an age range of 6-80 yr. Offset analgesia was defined by the reduction in electronic pain score upon the 1°C decrease in noxious heat stimulus relative to the peak pain score where pain was administered at the volar side of the arm. RESULTS:: Offset analgesia was present in healthy volunteers irrespective of age and sex (pain score decrease = 97 ± 1% [mean ± SEM]). In contrast, a reduced or absent offset analgesia response was observed in patients with neuropathic pain (pain score decrease = 56 ± 9% vs. controls 98 ± 1%, P < 0.001). Intravenous treatment with ketamine, morphine, and placebo had no effect on offset analgesia in patients, despite sharp reductions in spontaneous pain scores. Conclusions: These data indicate that offset analgesia is fully developed at the age of 6 yr and does not undergo additional maturation. The reduced or absent responses observed in patients with chronic neuropathic pain indicate the inability to modulate changes in pain stimulation, with perseverance of pain perception in situations in which healthy subjects display signs of strong analgesia. Both central and peripheral sites may be involved in the altered offset analgesia responses in these patients. © 2011 the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins. Anesthesiology.

Prolonged Operative Time to Extubation Is Not a Useful Metric for Comparing the Performance of Individual Anesthesia Providers

Background: One anesthesiologist performance metric is the incidence of "prolonged" (15 min or longer after dressing complete) times to extubation. The authors used several methods to identify the performance outliers and assess whether targeting these outliers for reduction could improve operating room workflow. Methods: Time to extubation data were retrieved for 27,757 anesthetics and 81 faculty anesthesiologists. Provider-specific incidences of prolonged extubation were assessed by using unadjusted frequentist statistics and a Bayesian model adjusted for prone positioning, American Society of Anesthesiologist's base units, and case duration. Results: 20.31% of extubations were "prolonged," and 40% of anesthesiologists were identified as outliers using a frequentist approach, that is, incidence greater than upper 95% CI (20.71%). With an adjusted Bayesian model, only one anesthesiologist was deemed an outlier. If an average anesthesiologist performed all extubations, the incidence of prolonged extubations would change negligibly (to 20.67%). If the anesthesiologist with the highest incidence of prolonged extubations was replaced with an average anesthesiologist, the change was also negligible (20.01%). Variability among anesthesiologists in the incidence of prolonged extubations was significantly less than among other providers. Conclusions: Bayesian methodology with covariate adjustment is better suited to performance monitoring than an unadjusted, nonhierarchical frequentist approach because it is less likely to identify individuals spuriously as outliers. Targeting outliers in an effort to alter operating room activities is unlikely to have an operational impact (although monitoring may serve other purposes). If change is deemed necessary, it must be made by improving the average behavior of everyone and by focusing on anesthesia providers rather than on faculty. © 2015 the American Society of Anesthesiologists, Inc.

Introduction of anesthesia resident trainees to the operating room does not lead to changes in anesthesia-controlled times for efficiency measures

Background: Operating room efficiency is an important concern in most hospitals today. Little work has been reported to evaluate the contribution of anesthesia residents to changes in anesthesia-controlled time-related efficiencies in the operating room. The goal of this study was to measure the impact of the initiation of new residents to the operating room on anesthesia-related time measures of operating room efficiency. Methods: Using the computerized operating room information systems, specific data regarding anesthesia-controlled times were extracted over three distinct 2-week periods over the course of 1 academic year. These included the first 2 weeks of July, when most of the operating rooms were staffed by attending physicians working alone; 2 weeks in September when new anesthesia residents were working in a 2:1 ratio with staff; and 2 weeks in May. The induction times, emergence times, and room turnover times were compared over these three periods for first-year anesthesia residents. Standard descriptive statistics were computed. Analysis of variance testing was then conducted comparing each of these time periods. Significance was set at P < 0.05. Results: A total of 3,004 surgical procedures were performed during the 2-week study periods in July, September, and May, respectively. For the July, September, and May groups, the mean anesthesia induction times were 17.3, 19.0, and 20.8 min (P = 0.047); the emergence times were 8.7, 9.7, and 10.0 min, (P = 0.024); and the corresponding mean room turnover times were 47.6, 48.5, and 48.6 min (P = 0.907), respectively. Conclusion: Although statistically significant time differences were found, these data strongly suggest that the initiation of anesthesia trainees to the operating room has no clinically or economically meaningful adverse effect on the anesthesia-controlled time component of operating room efficiency.