bluuebunny/crossref_metadata_2025_split huggingface dataset:
Positioning in Anesthesiology
Authors: Coppieters Michel W. , Van De Velde Marc , Stappaerts Karel H. 
Published: November 2003

Background
Stretch-induced neuropathy of the brachial plexus and median nerve in conventional perioperative care remains a relatively frequent and poorly understood complication. Guidelines for positioning have been formulated, although the protective effect of most recommendations remains unexamined. The similarity between the stipulated potentially dangerous positions and the components of the brachial plexus tension test (BPTT) justified the analysis of the BPTT to quantify the impact of various arm and neck positions on the peripheral nervous system.

Methods
Four variations of the BPTT in three different shoulder positions were performed in 25 asymptomatic male participants. The impact of arm and neck positions on the peripheral nervous system was evaluated by analyzing the maximal available range of motion, pain intensity, and type of elicited symptoms during the BPTT.

Results
Cervical contralateral lateral flexion, lateral rotation of the shoulder and fixation of the shoulder girdle in a neutral position in combination with shoulder abduction, and wrist extension all significantly reduced the available range of motion. Elbow extension also challenged the nervous system substantially. A cumulative impact could be observed when different components were simultaneously added, and a neutralizing effect was noted when an adjacent region allowed for unloading of the nervous system.

Conclusions
The experimental findings support the experientially based guidelines for positioning. Especially when simultaneously applied, submaximal joint positions easily load the nervous system, which may substantially compromise vital physiologic processes in and around the nerve. Therefore, even when the positioning of all upper limb joints is carefully considered, complete prevention of perioperative neuropathy seems almost inconceivable.
Effects of Subhypnotic Doses of Propofol on Gastric Emptying in Volunteers
Authors: Chassard Dominique , Lansiaux Sabine , Duflo Frédéric , Mion François , Bleyzac Nathalie , Debon Richard , Allaouchiche Bernard 
Published: November 2003

Background
Drugs which accelerate gastric emptying (GE) decrease nausea and vomiting. This could contribute to the antiemetic potential of subhypnotic doses of propofol. On the contrary, subhypnotic doses of propofol used for sedation could decrease GE and thus favor regurgitation and pulmonary inhalation. Therefore, the aim of this study was to assess the effect of low-dose propofol infusion on GE.

Methods
On three separate occasions, 10 volunteers received either a propofol infusion at a rate set to achieve a target plasma concentration of 0.5 microg/ml or equivalent volumes of 10% Intralipid(R) or 0.9% saline. GE for solids was measured by using the octanoic acid breath test. An acetaminophen absorption technique measured the GE rate for liquids. Blood samples were assayed for acetaminophen and propofol. Breath samples were analyzed for (13)CO(2) concentration by isotope-ratio mass spectrometry. Carbon dioxide production (VCO(2)) was measured instead of calculated by indirect calorimetry. Sedation was evaluated by the Bispectral Index of the electroencephalogram.

Results
Propofol blood concentrations were 0.32 +/- 0.20 and 0.45 +/- 0.18 microg/ml at 60 and 165 min, respectively. These concentrations were not sedative. Propofol or its solvent did not modify GE for solids or liquids. In all groups, differences in GE were obtained if measured VCO(2) was integrated in the formula instead of calculated VCO(2) (P < 0.002).

Conclusions
Subhypnotic doses of propofol known to be antiemetic do not inhibit GE. These results suggest that the antiemetic properties of propofol are not peripheral and that propofol cannot be considered as a prokinetic agent. V(13)CO(2) must be measured instead of calculated to accurately determine GE.
Gabapentin Suppresses Cutaneous Hyperalgesia following Heat-Capsaicin Sensitization
Authors: Dirks Jesper , Petersen Karin L. , Rowbotham Michael C. , Dahl Jørgen B. 
Published: November 2003

Background
The anticonvulsant gabapentin, proven effective for neuropathic pain in two large, placebo-controlled clinical trials, is widely used for treatment of chronic pain. Preclinical studies have demonstrated analgesic and antiallodynic effects in models involving neuronal sensitization and nerve injury, without affecting acute pain transmission. The aim of the present study was to link data from animal models and clinical trials for chronic pain by investigating the effect of gabapentin on acute nociception and experimentally induced cutaneous hyperalgesia in healthy volunteers.

Methods
The human experimental hyperalgesia model, the heat-capsaicin sensitization model, was induced in 25 healthy male volunteers. Subjects received oral gabapentin (1,200 mg) or placebo after heat-capsaicin sensitization was established on the forearm. The primary outcome measures were the sizes of the areas of secondary hyperalgesia to von Frey hair and brush stimulation on the forearm. Secondary outcome measures were as follows: (1) size of secondary hyperalgesia area in response to brief thermal sensitization procedure on the thigh; (2) heat pain detection thresholds in normal and sensitized skin; and (3) painfulness of 1 min of 45 degrees C stimulation in normal skin.

Results
Oral gabapentin profoundly suppressed established cutaneous sensitization on the forearm and prevented development of cutaneous sensitization on the thigh. Thermal nociception in normal skin was unchanged. Side effects were modest.

Conclusion
The results link preclinical findings with results from clinical trials of neuropathic pain. The results further suggest that gabapentin may prove effective in acute pain disorders involving neuronal sensitization, such as postoperative pain and acute herpetic pain, and could prove effective in prevention of chronic pain.
Differences in Systemic Opioid Use Do Not Explain Increased Fever Incidence in Parturients Receiving Epidural Analgesia
Authors: Gross Jeffrey B. , Cohen Amy P. , Lang Janet M. , Frigoletto Fredric D. , Lieberman Ellice S. 
Published: November 2003

Background
It has been hypothesized that an increased incidence of fever in patients receiving epidural analgesia might result not from epidural per se, but rather from the antipyretic effect of opioids preferentially administered to women in the no-epidural group. If this were the case, then one would expect the incidence of fever in parturients who did not receive systemic opioids to be independent of whether they received epidural analgesia.

Methods
Using a cohort study design, the authors evaluated the records of 1,233 nulliparous patients whose labor analgesia was managed with (1) no medication (N = 170); (2) 10 mg intravenous systemic nalbuphine plus 10 mg intramuscular every 3 to 4 h as required (N = 327); (3) epidural analgesia with continuous infusion of 0.125% bupivacaine with 2 microg/ml fentanyl (N = 278); or (4) patients who received both systemic nalbuphine and epidural analgesia (N = 458). Fever was diagnosed if the maximum temperature during labor exceeded 100.4 degrees F (38 degrees C).

Results
The incidence of fever did not differ according to nalbuphine administration for women not receiving epidural analgesia (1% no nalbuphine, 0.3% with nalbuphine, P = 0.27) or for women receiving epidural analgesia (17% no nalbuphine, 17% with nalbuphine, P = 1.0). However, the incidence of fever differed significantly between patients who received no analgesia as compared to those who received epidural analgesia alone (1% vs. 17%, P = 10(-6)). Controlling for confounding did not alter these associations.

Conclusions
Our findings suggest that an antipyretic effect of nalbuphine in patients who do not receive an epidural does not explain the greater incidence of fever observed in women who receive epidural analgesia for labor.
Efficacy and Safety of Intravenous Parecoxib Sodium in Relieving Acute Postoperative Pain following Gynecologic Laparotomy Surgery
Authors: Barton Scott F. , Langeland Fred F. , Snabes Michael C. , LeComte Diane , Kuss Michael E. , Dhadda Shobha S. , Hubbard Richard C. 
Published: November 2003

Background
This study tested the hypothesis that an injectable cyclooxygenase (COX)-2-specific inhibitor will be at least as effective and well tolerated as a COX-nonspecific conventional nonsteroidal antiinflammatory drug (NSAID) by comparing the analgesic efficacy and tolerability of one intravenous dose of parecoxib sodium, an injectable prodrug of the novel COX-2-specific inhibitor, valdecoxib, with ketorolac and placebo in postoperative laparotomy surgery patients. Intravenous morphine, 4 mg, was studied as a positive analgesic control.

Methods
In this multicenter, double-blinded, placebo-controlled study, women experiencing moderate-to-severe pain on the first day after abdominal hysterectomy or myomectomy received one intravenous dose of parecoxib sodium, 20 or 40 mg, ketorolac, 30 mg, morphine, 4 mg, or placebo. Analgesic efficacy and tolerability were evaluated for 24 h postdose or until patients, whose pain was not adequately controlled, opted to receive rescue analgesia.

Results
Two hundred two patients were enrolled. All treatment groups had comparable demographics and baseline pain status. All active treatments had an equally rapid time to onset of analgesia (10-23 min). Overall, each parecoxib sodium dose and ketorolac were significantly superior to morphine and placebo for most measures of analgesic efficacy at most time points, including a significantly longer (two- to threefold) time to rescue analgesia (P </= 0.05). All treatments were well tolerated.

Conclusions
Single intravenous doses of parecoxib sodium, 20 mg and 40 mg, have comparable analgesic effects and are well tolerated after laparotomy surgery. Parecoxib sodium appears to be as effective as intravenous ketorolac, 30 mg, and superior to intravenous morphine, 4 mg.
Low Complication Rate Associated with Cesarean Section under Spinal Anesthesia for HIV-1–Infected Women on Antiretroviral Therapy
Authors: Avidan Michael S. , Groves Philippa , Blott Margaret , Welch Jan , Leung Theresa , Pozniak Anton , Davies Edward , Ball Colin , Zuckerman Mark 
Published: November 2003

Background
Elective cesarean section decreases the likelihood of vertical human immunodeficiency virus (HIV) transmission from mother to infant. This study aimed to determine whether cesarean section done with spinal anesthesia on HIV-1-infected pregnant women taking antiretroviral therapy is associated with intraoperative hemodynamic instability, postoperative complications, or changes in immune function or HIV-1 viral load.

Methods
A case-controlled study was conducted over a 3-year period in a London academic hospital. Forty-four women infected with HIV-1 and a control group of 45 HIV-negative women undergoing cesarean sections were included. The main outcome measures included intraoperative blood pressure, heart rate, blood loss, and ephedrine requirements, and postoperative infective complications, blood transfusion, changes in blood HIV-1 viral load and lymphocyte subsets, and time to hospital discharge.

Results
There were no differences in hemodynamic stability and postoperative complications between the HIV-infected group and the controls. There was an acute postoperative increase in the CD4T lymphocyte count (P = 0.01), but the CD4T:CD8T ratio and viral load did not change.

Conclusions
Elective cesarean section under spinal anesthesia for women infected with HIV-1 taking antiretroviral therapy was not associated with intraoperative or postoperative complications.
Comparison of Conventional Averaged and Rapid Averaged, Autoregressive-based Extracted Auditory Evoked Potentials for Monitoring the Hypnotic Level during Propofol Induction
Authors: Litvan Héctor , Jensen Erik W. , Galan Josefina , Lund Jeppe , Rodriguez Bernardo E. , Henneberg Steen W. , Caminal Pere , Villar Landeira Juan M. 
Published: November 2003

Background
The extraction of the middle latency auditory evoked potentials (MLAEP) is usually done by moving time averaging (MTA) over many sweeps (often 250-1,000), which could produce a delay of more than 1 min. This problem was addressed by applying an autoregressive model with exogenous input (ARX) that enables extraction of the auditory evoked potentials (AEP) within 15 sweeps. The objective of this study was to show that an AEP could be extracted faster by ARX than by MTA and with the same reliability.

Methods
The MTA and ARX methods were compared with the Modified Observer's Assessment of Alertness and Sedation Scale (MOAAS) in 15 patients scheduled for cardiac surgery and anesthetized with propofol. The peak amplitudes and latencies were recorded continuously for the MTA- and ARX-extracted AEP. An index, AAI, was derived from the ARX-extracted AEP as well.

Results
The best predictors of the awake and anesthetized states, in terms of the prediction probability, Pk, were the AAI (Pk [SE] = 0.93 [0.01]) and Na-Pa amplitude (MTA, Pk [SE] = 0.89 [0.02]; ARX, Pk [SE] = 0.87[0.02]). When comparing the AAI at the MOAAS levels 5-3 versus 2-0, significant differences were achieved. During the transitions from awake to asleep, the ARX-extracted AEP were obtained with significantly less delay than the MTA-extracted AEP (28.4 s vs. 6 s).

Conclusion
The authors conclude that the MLAEP peaks and the AAI correlate well to the MOAAS, whether extracted by MTA or ARX, but the ARX method produced a significantly shorter delay than the MTA.
Intraoperative Low-volume Acute Normovolemic Hemodilution in Adult Open-heart Surgery
Authors: Casati Valter , Speziali Giovanni , D'Alessandro Cesare , Cianchi Clara , Antonietta Grasso Maria , Spagnolo Salvatore , Sandrelli Luca 
Published: November 2003

Background
Recently, various studies have questioned the efficacy of intraoperative acute normovolemic hemodilution (ANH) in reducing bleeding and the need for allogeneic transfusions in cardiac surgery. The aim of the present study was to reevaluate the effects of a low-volume ANH in elective, adult open-heart surgery.

Methods
Two hundred four consecutive adult patients undergoing cardiac surgery were prospectively randomized in a nonblinded manner into two groups: ANH group (103 patients), where 5-8 ml/kg of blood was withdrawn before systemic heparinization and replaced with colloid solutions, and a control group, where no hemodilution was performed (101 patients). Procedures included single and multiple valve surgery, aortic root surgery, coronary surgery combined with valve surgery, or partial left ventriculectomy. The purpose of the study was to evaluate the efficacy of ANH in reducing the need for allogeneic blood components. Routine hematochemical evaluations, perioperative blood loss, major complications, and outcomes were also recorded.

Results
No differences were found between the groups regarding demographics, baseline hematochemical data, and operative characteristics. There was no difference in the amount of transfusions of packed red cells, fresh frozen plasma, platelet concentrates, total number of patients transfused (control group, 36% vs. ANH group, 34.3%; P = 0.88), and amount of postoperative bleeding (control group, 412 ml [313-552 ml] vs. ANH group, 374 ml [255-704 ml]) (median [25th-75th percentiles]); P = 0.94. Further, perioperative complications, postoperative hematochemical data, and outcomes were not different.

Conclusions
In patients undergoing elective open-heart surgery, low-volume ANH showed lack of efficacy in reducing the need for allogeneic transfusions and postoperative bleeding.
Epidural Blockade Modifies Perioperative Glucose Production without Affecting Protein Catabolism
Authors: Lattermann Ralph , Carli Franco , Wykes Linda , Schricker Thomas 
Published: November 2003

Background
Epidural blockade with local anesthetic has been shown to blunt the increase in plasma glucose concentration during and after abdominal surgery. The aim of the study was to test the hypothesis that epidural blockade inhibits this hyperglycemic response by attenuating endogenous glucose production. The authors further examined if the modification of glucose production by epidural blockade has an impact on perioperative protein catabolism.

Methods
Sixteen patients undergoing colorectal surgery received either general anesthesia and epidural blockade with local anesthetic (n = 8) or general anesthesia alone (control, n = 8). Glucose and protein kinetics were assessed by stable isotope tracer technique ([6,6-2H2]glucose, L-[1-13C]leucine) during and 2 h after surgery. Plasma concentrations of glucose, lactate, free fatty acids (FFA), cortisol, glucagon, and insulin were also determined.

Results
Epidural blockade blunted the perioperative increase in the plasma concentration of glucose, cortisol, and glucagon when compared with the control group (P < 0.05). Plasma concentrations of lactate, FFA, and insulin did not change. Intra- and postoperative glucose production was lower in patients with epidural blockade than in control subjects (intraoperative, epidural blockade 8.2 +/- 1.9 vs. control 10.7 +/- 1.4 micromol x kg(-1) x min(-1), P < 0.05; postoperative, epidural blockade 8.5 +/- 1.8 vs. control 10.5 +/- 1.2 micromol x kg(-1) x min(-1), P < 0.05), whereas glucose clearance decreased to a comparable extent in both groups (P < 0.05). Protein breakdown (P < 0.05), protein synthesis (P < 0.05), and amino acid oxidation (P > 0.05) decreased with both anesthetic techniques.

Conclusions
Epidural blockade attenuates the hyperglycemic response to surgery through modification of glucose production. The perioperative suppression of protein metabolism was not influenced by epidural blockade.
Effect of a Nonsedative Dose of Propofol on Memory for Aversively Loaded Information in Rats
Authors: Pain Laure , Angst Marie-Josée , LeGourrier Laurence , Oberling Philippe 
Published: November 2003

Background
The effects of propofol on memory for aversive information are not well determined. The authors evaluated the effects of a minimal nonsedative dose of propofol or midazolam on memory in rats, using an apparatus composed of two compartments: a large bright anxiogenic one and a small dark neutral one.

Methods
Groups of rat received propofol (9 mg/kg, intraperitoneally) or midazolam (3 mg/kg). Anxiety was assessed in rats placed in the anxiogenic compartment as the time before the animals entered the neutral compartment. Memory for an aversive event was assessed in rats placed in the anxiogenic compartment as the time to enter the neutral one where they previously experienced foot shocks (fear conditioning). To assess the memory for a nonaversive event, rats were placed in the neutral compartment with no shocks (preexposure). The following day, rats were placed in it and they experienced foot shocks. As a result of the preexposure, rats exhibit less fear to enter it.

Results
Propofol and midazolam increased the time to enter the neutral compartment. Propofol or midazolam was given to rats before experiencing foot shocks in the neutral compartment. When later tested, the time to enter it was decreased. Propofol or midazolam was given to rats before the preexposure to the neutral compartment. When later tested, the latency to enter it was not modified by the preexposure.

Conclusions
Propofol and midazolam impaired memory for aversive and for nonaversive experiences at equianxiolytic doses that do not produce locomotor impairment in rats.
Modulation of Rat Pial Arteriolar Responses to Flow by Glucose
Authors: Ward Michael E. , Yan Lu , Angle Mark R. 
Published: November 2003

Background
Pial arteriolar responses to flow contribute to regulation of cerebral perfusion and vary according to the transmural pressure to which the vessel is exposed. This study determined the effect of increased glucose concentration on the flow responses of pial arterioles at low and high levels of transmural pressure.

Methods
Pial arterioles from Sprague-Dawley rats were mounted in a perfusion myograph. In some arterioles, the endothelium was removed by perfusion with air. Diameters were recorded at transmural pressures of 60 and 120 mmHg during superfusion with physiologic saline containing 5 mm D-glucose, 20 mm D-glucose, or 5 mm D-glucose and 15 mm L-glucose. Diameters during superfusion with saline containing 44 mm D-glucose were measured at an intraluminal pressure of 60 mmHg. Flow-diameter relationships (5-30 microl/min) were recorded during perfusion with the same solutions.

Results
Increasing D-glucose concentration caused constriction (P < 0.05) in endothelium-denuded but not in endothelium-intact arterioles. Addition of L-glucose caused constriction in endothelium-intact and -denuded vessels (P < 0.05 for both). At a D-glucose concentration of 5 mm and at low intraluminal pressure, flow elicits endothelium-dependent dilation such that shear stress remains constant. At a D-glucose concentration of 20 or 44 mm, after addition of L-glucose (15 mm), and at high intraluminal pressures, flow elicits constriction and shear stress is unregulated.

Conclusions
High glucose concentrations elicit increased basal arteriolar smooth muscle tone that is counteracted by release of endothelium-derived relaxing factors. Endothelium-dependent relaxation to flow (shear stress) is inhibited at high glucose concentrations.
Different Mechanisms of Development and Maintenance of Experimental Incision-induced Hyperalgesia in Human Skin
Authors: Kawamata Mikito , Watanabe Hiroaki , Nishikawa Kohki , Takahashi Toshiyuki , Kozuka Yuji , Kawamata Tomoyuki , Omote Keiichi , Namiki Akiyoshi 
Published: November 2003

Background
To determine the mechanisms of postoperative pain, the effects of local anesthesia on development and maintenance of surgical incision-induced hyperalgesia were evaluated in a crossover, double-blinded, placebo-controlled human study using 17 subjects.

Methods
An experimental 4-mm-long incision through skin, fascia, and muscle was made in the volar forearm of each subject. In experiment 1, 1% lidocaine or saline in a volume of 0.2 ml was subcutaneously injected into the incision site pretraumatically and posttraumatically. In experiment 2, a 5-cm-long strip of skin was subcutaneously injected with 0.2 ml of 1% lidocaine near the incision site pretraumatically and posttraumatically. Flare, spontaneous pain, and primary and secondary hyperalgesia to punctate mechanical stimuli were assessed after the incision had been made.

Results
Pretraumatic lidocaine injection prevented the occurrence of spontaneous pain and development of flare formation that was found surrounding the incision site immediately (1 min) after the incision had been made. The lidocaine suppressed primary hyperalgesia more effectively than did posttraumatic block, but only for the first 4 h after the incision. The preincision block prevented development of secondary hyperalgesia, whereas posttraumatic block did not significantly affect the fully developed secondary hyperalgesia. The area of flare formation and the area of secondary hyperalgesia did not extend over the strip of the skin that had been pretraumatically anesthetized, whereas the posttraumatic block did not significantly reduce the area of fully developed secondary hyperalgesia.

Conclusions
Pretraumatic injection of lidocaine reduces primary hyperalgesia more effectively than does posttraumatic injection, but only for a short period after incision. The spread of secondary hyperalgesia is mediated peripheral nerve fibers, but when secondary hyperalgesia has fully developed, it becomes less dependent on or even independent of peripheral neural activity originating from the injured site.