bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prospective study on Incidence and Functional Impact of Transient Neurologic Symptoms Associated with 1%Versus 5% Hyperbaric Lidocaine in Short Urologic Procedures
Authors: Tong Doris , Wong Jean , Chung Frances , Friedlander Mark , Bremang Joseph , Mezei Gabor , Streiner David 
Published: November 2003

Background
The objectives of this study were to compare the incidence, onset, duration and pain scores of transient neurologic symptoms (TNS) with 1% versus 5% hyperbaric lidocaine in spinal anesthesia for short urological procedures in a large prospective study. This study would also evaluate patient satisfaction, and impact of TNS on functional recovery to assess the clinical significance of TNS.

Methods
This was a multicenter, double-blind, randomized controlled trial. Four hundred fifty-three patients undergoing short transurethral procedures were randomized to receive 1% or 5% hyperbaric lidocaine. Eighty milligrams of 1% or 5% hyperbaric lidocaine was administered. During the first 3 days after surgery, the presence of TNS, its intensity and duration, and patient functional level were recorded. An intention-to-treat analysis was used.

Results
There was no difference in the incidence of TNS (21% vs. 18%) between 1% versus 5% lidocaine. Patients with TNS had significantly higher pain scores (5.3 +/- 3 vs. 2.3 +/- 3) than patients without TNS during the first 24 h. This difference in pain scores persisted until 72 h postoperatively. There was a significant difference in the daily activities functional scores (2.2 +/- 1 vs. 1.4 +/- 0.8) of TNS non-TNS patients during the first 24 h postoperatively.

Conclusions
There was no difference in the incidence of TNS between the 1% versus 5% spinal lidocaine groups. Pain scores were higher in patients with TNS than those who did not have TNS. During the first 48 h postop, a small proportion of patients who had TNS experienced functional impairment of walking, sitting, and sleeping.
Spinal Anesthesia
Authors: Imarengiaye Charles O. , Song Dajun , Prabhu Atul J. , Chung Frances 
Published: November 2003

Background
The ability of patients to walk without assistance after spinal anesthesia is a determining factor in the time to discharge following ambulatory surgery. The authors compared clinical markers of gross motor recovery with objective data of functional balance after spinal anesthesia.

Methods
Twenty-two male patients with American Society of Anesthesiology physical status I or II who were scheduled for perineal surgery were studied during recovery from spinal anesthesia to compare the predictive accuracy of clinical markers of ambulatory readiness (e.g., full knee flexion and extension) with that of an objective method of measurement focused on functional balance. Lumbar puncture was performed at the L2-L3 or L3-L4 interspace using a 25-gauge Whitacre needle, with patients in the sitting position. A 3-ml mixture of 5 mg bupivacaine (heavy) and 10 microg fentanyl was injected. Block regression and restoration of motor function were assessed and recorded. Functional balance was measured using a computerized force platform method.

Results
The majority of patients maintained motor function and proprioception sensation at the onset of surgical anesthesia, as indicated by performance on clinical tests of function: 96% were able to perform the straight leg increase; 82, 77, and 91%, respectively, were able to perform full knee flexion and extension, perform heel-to-shin maneuvers, and identify joint position in the supine position. Postoperatively, clinical return of motor function occurred much earlier than recovery of functional balance. At 60 min after onset of spinal anesthesia, 22 patients (100%) had recovered sensory and gross motor function, but only 36% could stand, and 8% could walk without assistance (P < 0.01). At 150-180 min after onset, 96-100% of patients achieved the levels of functional balance that permitted adequate ambulation.

Conclusions
The results suggest that the recovery time to unassisted ambulation is longer than has been assumed, and that the standard clinical markers of gross motor function are poor predictors of functional balance following ambulatory surgery.
Do They Understand? (Part I)
Authors: Tait Alan R. , Voepel-Lewis Terri , Malviya Shobha 
Published: November 2003

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.
Teaching with a Video System Improves the Training Period but Not Subsequent Success of Tracheal Intubation with the Bullard Laryngoscope
Authors: Shulman G. Brent , Nordin Ned G. , Connelly Neil Roy 
Published: November 2003

Background
The Bullard laryngoscope is useful for the management of a variety of airway management scenarios. Without the aid of a video system, teaching laryngoscopy skills occurs with indirect feedback to the instructor. The purpose of this study was to determine if use of a video system would speed the process of learning the Bullard laryngoscope or improve the performance (speed or success) of its use.

Methods
Thirty-six anesthesia providers with no previous Bullard laryngoscope experience were randomly divided into two groups: initial training (first 15 intubations) with looking directly through the eyepiece (n = 20), or with the display of the scope on a video monitor (n = 16). The subjects each then performed 15 Bullard intubations by looking directly through the eyepiece.

Results
There was not an overall significant difference in laryngoscopy or intubation times between the groups. When only the first 15 intubations were considered, the laryngoscopy time was shorter in the video group (26 +/- 24) than in the nonvideo group (32 +/- 34; P< 0.04). In the first 15 patients, there were fewer single attempts at intubation (67.9% vs 80.3%; P< 0.002) and more failed intubations (17.2% vs 6.0%; P< 0.0001) in the nonvideo group.

Conclusions
In conclusion, the authors have shown that use of a video camera decreases time for laryngoscopic view and improves success rate when the Bullard laryngoscope is first being taught to experienced clinicians. However, these benefits are not evident as more experience with the Bullard laryngoscope is achieved, such that no difference in skill with the Bullard laryngoscope is discernible after 15 intubations whether a video system was used to teach this technique.
Redistribution of Microcirculatory Blood Flow within the Intestinal Wall during Sepsis and General Anesthesia
Authors: Hiltebrand Luzius B. , Krejci Vladimir , tenHoevel Marcus E. , Banic Andrej , Sigurdsson Gisli H. 
Published: November 2003

Background
Hypoperfusion of the intestinal mucosa remains an important clinical problem during sepsis. Impairment of the autoregulation of microcirculatory blood flow in the intestinal tract has been suggested to play an important role in the development of multiple organ failure during sepsis and surgery. The authors studied microcirculatory blood flow in the gastrointestinal tract in anesthetized subjects during early septic shock.

Methods
Eighteen pigs were intravenously anesthetized and mechanically ventilated. Regional blood flow in the superior mesenteric artery was measured with ultrasound transit time flowmetry. Microcirculatory blood flow was continuously measured with a six-channel laser Doppler flowmetry system in the mucosa and the muscularis of the stomach, jejunum, and colon. Eleven pigs were assigned to the sepsis group, while seven animal served as sham controls. Sepsis was induced with fecal peritonitis, and intravenous fluids were administered after 240 min of sepsis to alter hypodynamic sepsis to hyperdynamic sepsis.

Results
In the control group, all monitored flow data remained stable throughout the study. During the hypodynamic phase of sepsis, cardiac output, superior mesenteric artery flow, and microcirculatory blood flow in the gastric mucosa decreased by 45%, 51%, and 40%, respectively, compared to baseline (P < 0.01 in all). Microcirculatory blood flow in the muscularis of the stomach, jejunum, and colon decreased by 55%, 64%, and 70%, respectively (P < 0.001 in all). In contrast, flow in the jejunal and colonic mucosa remained virtually unchanged. During the hyperdynamic phase of sepsis, there was a threefold increase in cardiac output and superior mesenteric artery flow. Blood flow in the gastric, jejunal, and colonic mucosa also increased (22%, 24%, and 31% above baseline, respectively). Flow in the muscularis of the stomach returned to baseline, while in the jejunum and colon, flow in the muscularis remained significantly below baseline (55% and 45%, respectively, P< 0.01).

Conclusions
It appears that in early septic shock, autoregulation of microcirculatory blood flow is largely intact in the intestinal mucosa in anesthetized pigs, explaining why microcirculatory blood flow remained virtually unchanged. This may be facilitated through redistribution of flow within the intestinal wall, from the muscularis toward the mucosa.
Neutrophils Pretreated with Volatile Anesthetics Lose Ability to Cause Cardiac Dysfunction
Authors: Hu Guochang , Vasiliauskas Tomas , Salem M. Ramez , Rhone Douglas P. , Crystal George J. 
Published: November 2003

Background
Volatile anesthetics can precondition the myocardium against functional depression and infarction following ischemia-reperfusion. Neutrophil activation, adherence, and release of superoxide play major roles in reperfusion injury. The authors tested the hypothesis that pretreatment of neutrophils with a volatile anesthetic, i.e., simulated preconditioning, can blunt their ability to cause cardiac dysfunction.

Methods
Studies were performed in 60 buffer-perfused and paced isolated rat hearts. Left ventricular developed pressure served as an index of myocardial contractility. Polymorphonuclear neutrophils and/or drugs were added to coronary perfusate for 10 min, followed by 30 min of recovery. Platelet-activating factor was used to stimulate neutrophils. Pretreatment of neutrophils consisted of incubation with 1.0 minimum alveolar concentration (MAC) isoflurane or sevoflurane for 15 min, followed by washout. Additional studies were performed with 0.25 MAC isoflurane. Effects of superoxide dismutase were compared to those of volatile anesthetics. Superoxide production was measured by spectrophotometry. Neutrophil adherence to coronary vascular endothelium was estimated from the difference between neutrophils administered and recovered in coronary venous effluent.

Results
Activated neutrophils caused marked, persistent reduction (> 50%) in left ventricular developed pressure. Isoflurane and sevoflurane at 1.0 MAC and superoxide dismutase abolished this effect. Isoflurane and sevoflurane reduced superoxide production of activated neutrophils by 29% and 33%, respectively, and completely prevented the platelet-activating factor-induced increases in neutrophil adherence. Isoflurane at 0.25 MAC blunted, but did not abolish, the neutrophil-induced decreases in left ventricular developed pressure.

Conclusion
Neutrophils pretreated with 1.0 MAC isoflurane or sevoflurane lost their ability to cause cardiac dysfunction, while those pretreated with a concentration of isoflurane as low as 0.25 MAC were partially inhibited. This action of the volatile anesthetics was associated with reductions in superoxide production and neutrophil adherence to the coronary vascular endothelium. Our findings suggest that inhibitory actions on neutrophil activation and neutrophil-endothelium interaction may contribute to the preconditioning effects of volatile anesthetics observed in vivo during myocardial ischemia-reperfusion.
Assessment of the Lower Limit for Cerebral Perfusion Pressure in Severe Head Injuries by Bedside Monitoring of Regional Energy Metabolism
Authors: Nordström Carl-Henrik , Reinstrup Peter , Xu Wangbin , Gärdenfors Anna , Ungerstedt Urban 
Published: November 2003

Background
In patients with severe traumatic brain lesions, the lower limit for cerebral perfusion pressure (CPP) is controversial. The aim of this prospective study was to assess this limit from bedside measurements of cerebral energy metabolism and to clarify whether the penumbra zone surrounding a focal lesion is more sensitive to a decrease in CPP than less-injured areas.

Methods
Fifty patients with severe head injury were included after evacuation of an intracranial hematoma and/or focal brain contusion. They were treated according to intensive care routine (Lund concept), including continuous monitoring of intracranial pressure. One microdialysis catheter was inserted in less-injured brain tissue ("better" position), and one or two catheters were inserted into the boundary of injured cerebral cortex ("worse" position). Concentrations of glucose, pyruvate, and lactate were analyzed and displayed bedside and were related to CPP (n = 29,495).

Results
Mean interstitial glucose concentration was unaffected by the level of the CPP within the studied ranges. Increases in lactate concentration (P = 0.0008) and lactate-pyruvate ratio (P = 0.01) were obtained in the "worse" but not in the "better" position at CPP less than 50 mmHg compared with the same positions at CPP greater than 50 mmHg.

Conclusions
The study results support the view that CPP may be reduced to 50 mmHg in patients with severe traumatic brain lesions, provided that the physiologic and pharmacologic principles of the Lund concept are recognized. In the individual patient, preservation of normal concentrations of energy metabolites within cerebral areas at risk can be guaranteed by intracerebral microdialysis and bedside biochemical analyses.
Influence of Erythrocyte Concentrate Storage Time on Postsurgical Morbidity in Cardiac Surgery Patients
Authors: Leal-Noval Santiago R. , Jara-López Irene , García-Garmendia José L. , Marín-Niebla Ana , Herruzo-Avilés Angel , Camacho-Laraña Pedro , Loscertales Jesús 
Published: November 2003

Background
The transfusion of erythrocytes that have been stored for long periods of time can produce visceral ischemia and favor the acquisition of postsurgical infections. To estimate the role of the duration of storage of erythrocytes on morbidity in cardiac surgery, we performed an observational study.

Methods
All patients (n = 897) undergoing cardiac surgery during three consecutive years were included. Morbidity (main outcome measure) was evaluated by means of four surrogate measures: duration of stay in the intensive care unit longer than 4 days, mechanical ventilation time longer than 1 day, perioperative myocardial infarction rate, and severe postoperative infection rate. The mean duration of storage of all erythrocytes transfused and the duration of storage of the oldest unit transfused were used as storage variables.

Results
After considering multiple confounding variables related to patient severity, illness, and surgical difficulty, the duration of storage of erythrocytes was found to be associated neither with a more prolonged stay in the intensive care unit or mechanical ventilation time nor with increased rates of perioperative infarction, mediastinitis, or sepsis. However, each day of storage of the oldest unit was associated with an increment of the risk of pneumonia of 6% (95% confidence interval, 1-11; P = 0.018). The cutoff point of maximum sensitivity and specificity (54.8 and 66.9%) associated with a greater risk for pneumonia corresponded to 28 days of storage for the oldest unit (odds ratio, 2.74; 95% confidence interval, 1.18-6.36; P = 0.019).

Conclusions
Prolonged storage of erythrocytes does not increase morbidity in cardiac surgery. However, storage for longer than 28 days could be a risk factor for the acquisition of nosocomial pneumonia.
The Effects of Hydration on Core Temperature in Pediatric Surgical Patients
Authors: Ezri Tiberiu , Szmuk Peter , Weisenberg Marian , Serour Francis , Gorenstein Arcadi , Sessler Daniel I. 
Published: November 2003

Background
Reduced vascular volume might influence body temperature by diverting heat flow from peripheral tissues to the central organs. We therefore tested the hypothesis that mild hypovolemia helps to prevent intraoperative hypothermia in pediatric patients.

Methods
Twenty-two pediatric patients (aged 1-3 yr) undergoing prolonged minor surgery were randomly assigned to conservative (n = 12) or aggressive (n = 10) perioperative fluid management. The conservative group fasted 8 h before surgery and received a crystalloid at 1 ml. kg-1. h-1 during surgery. The aggressive group was allowed to drink liquids until 3 h before surgery and was given a maintenance crystalloid at 8 ml. kg-1. h-1. Anesthesia was induced and maintained with halothane in nitrous oxide. Ambient temperature was kept near 25 degrees C, but the patients were not actively warmed. During recovery from anesthesia, additional fluid was given to the conservative group so that perioperative fluid totaled 9.5 ml. kg-1. h-1 in both groups.

Results
Intraoperative body weight remained unchanged in the aggressive group and decreased only 1% in patients managed conservatively. Heart rate was slightly greater in the conservative group (107 +/- 9 vs. 95 +/- 4 beats/min, P = 0.002), but blood pressure was similar. Esophageal temperature in patients whose fluid was managed conservatively increased significantly, by 0.4 +/- 0.3 degrees C, to 37.1 degrees C; in contrast, temperature in the aggressive group decreased significantly, by 0.4 +/- 0.2 degrees C, to 36.4 degrees C (P < 0.001 between groups). Temperatures remained significantly different 1 h after surgery.

Conclusions
Conservative fluid management, which decreased body weight by only 1%, prevented reduction in core body temperature, presumably by reducing dissipation of metabolic heat from the core thermal compartment to peripheral tissues.
Neuraxial Morphine May Trigger Transient Motor Dysfunction after a Noninjurious Interval of Spinal Cord Ischemia
Authors: Kakinohana Manabu , Marsala Martin , Carter Christopher , Davison J. Kenneth , Yaksh Tony L. 
Published: November 2003

Background
A patient underwent repair of a thoracoabdominal aortic aneurysm. Epidural morphine, 4 mg, was given for pain relief. After anesthesia, the patient displayed lower extremity paraparesis. This effect was reversed by naloxone. The authors sought to confirm these observations using a rat spinal ischemia model to define the effects of intrathecal morphine administered at various times after reflow on behavior and spinal histopathology.

Methods
Spinal cord ischemia was induced for 6 min using an intraaortic balloon. Morphine or saline, 30 microg, was injected intrathecally at 0.5, 2, or 24 h after reflow. In a separate group, spinal cord temperature was decreased to 27 degrees C before ischemia. After ischemia, recovery of motor function was assessed periodically using the motor deficit index (0 = complete recovery; 6 = complete paraplegia).

Results
After ischemia, all rats showed near-complete recovery of function by 4-6 h. Intrathecal injection of morphine at 0.5 or 2 h of reflow (but not at 24 h) but not saline caused a development of hind limb dysfunction and lasted for 4.5 h (motor deficit index score = 4-6). This effect was reversed by intrathecal naloxone (30 microg). Intrathecal morphine administered after hypothermic ischemia was without effect. Histopathological analysis in animals that received intrathecal morphine at 0.5 or 2 h after ischemia (but not at 24 h) revealed dark-staining alpha motoneurons and interneurons. Intrathecal saline or spinal hypothermia plus morphine was without effect.

Conclusions
These data indicate that during the immediate reflow following a noninjurious interval of spinal ischemia, intrathecal morphine potentiates motor dysfunction. Reversal by naloxone suggests that this effect results from an opioid receptor-mediated potentiation of a transient block of inhibitory neurons initiated by spinal ischemia.
Sources of Error in Noninvasive Pulmonary Blood Flow Measurements by Partial Rebreathing
Authors: Yem Johnny S. , Tang Yongquan , Turner Martin J. , Baker A. Barry 
Published: November 2003

Background
Partial rebreathing is a noninvasive method for measuring pulmonary blood flow (PBF). This study examines the systematic errors produced by the partial rebreathing technique utilizing a comprehensive mathematical model of the cardiorespiratory system of a healthy, 70-kg adult male.

Methods
The model simulates tidal breathing through a branched respiratory tree and incorporates the effects on carbon dioxide dynamics of lung tissue mass, vascular transport delays, multiple body compartments, and realistic blood-gas dissociation curves. Four studies were performed: (1) errors produced under standard conditions, (2) effects of recirculation, (3) effects of alveolar-proximal airway partial pressure of carbon dioxide (Pco(2)) differences, and (4) effects of rebreathing time.

Results
Systematic errors are less than 10% when the simulated PBF is between 3 and 6 l/min. At 2 l/min, PBF is overestimated by approximately 35%. At 14 l/min, PBF is underestimated by approximately 40%. At PBF of greater than 6 l/min, recirculation causes approximately 60% of the systematic error, alveolar-proximal airway differences cause approximately 20%, and alveolar-arterial differences cause approximately 20%. The standard rebreathing time of 50 s is shown to be excessive for PBF of greater than 6 l/min. At PBF of less than 3 l/min, errors are caused by inadequate rebreathing time and alveolar-arterial gradients.

Conclusions
Systematic errors in partial rebreathing cardiac output measurements have multiple causes. Our simulations suggest that errors can be reduced by using a variable rebreathing time, which should be increased at low PBF so that quasi-equilibrium in the alveoli can be achieved and decreased at high PBF to reduce the effects of recirculation.