Anesthesia and analgesia
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Anesthesia and analgesia · Mar 2006
Comparative StudyVasotrac arterial blood pressure and direct arterial blood pressure monitoring during liver transplantation.
During liver transplantation two arterial catheters are often placed. The Vasotrac is a noninvasive monitor that provides radial arterial blood pressures by a tonometric method. We investigated whether the Vasotrac would be an accurate substitute for an arterial catheter by comparing Vasotrac blood pressures with simultaneous direct radial blood pressures recorded from the contralateral arm in 14 patients undergoing liver transplantation. ⋯ Correlation was 0.82. Vasotrac bias was +3.3 mm Hg and limits of agreement +/-15 mm Hg. We conclude that the Vasotrac is not adequately accurate to substitute for direct arterial blood pressure monitoring in liver transplantation.
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Anesthesia and analgesia · Mar 2006
Comparative StudyPostoperative upper airway obstruction after recovery of the train of four ratio of the adductor pollicis muscle from neuromuscular blockade.
Anesthetics, and even minimal residual neuromuscular blockade, may lead to upper airway obstruction (UAO). In this study we assessed by spirometry in patients with a train-of-four (TOF) ratio >0.9 the incidence of UAO (i.e., the ratio of maximal expiratory flow and maximal inspiratory flow at 50% of vital capacity [MEF50/MIF50] >1) and determined if UAO is induced by neuromuscular blockade (defined by a forced vital capacity [FVC] fade, i.e., a decrease in values of FVC from the first to the second consecutive spirometric maneuver of > or =10%). Patients received propofol and opioids for anesthesia. ⋯ The mean maximal expiratory flow and maximal inspiratory flow at 50% of vital capacity ratio after tracheal extubation was significantly increased from baseline (by 20%; 1.39 +/- 1.01 versus 1.73 +/- 1.02; P < 0.01), and subsequently decreased significantly to values observed at baseline (1.49 +/- 0.93). A statistically significant FVC fade was not present, and a FVC fade of > or =10% was observed in only 2 patients after extubation. Thus, recovery of the TOF ratio to 0.9 predicts with high probability an absence of neuromuscular blocking drug-induced UAO, but outliers, i.e., persistent effects of neuromuscular blockade on upper airway integrity despite recovery of the TOF ratio, may still occur.
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Anesthesia and analgesia · Mar 2006
Randomized Controlled Trial Comparative StudyUpper airway collapsibility in anesthetized children.
We sought to establish the feasibility of measuring upper airway narrowing in spontaneously breathing, anesthetized children using dynamic application of negative airway pressure. A secondary aim was to compare differences in upper airway collapsibility after the administration of sevoflurane or halothane. Subjects were randomized to either drug for inhaled anesthetic induction. ⋯ Pcrit for sevoflurane ranged from -6.7 to -11.6 (mean +/- sd, -9.8 +/- 1.9) cm H2O. Pcrit for halothane ranged from -8.1 to -33 (mean +/- sd, -19.4 +/- 9.3) cm H2O (sevoflurane versus halothane, P = 0.048). We conclude that when using dynamic application of negative airway pressure, halothane appears to cause less upper airway obstruction than sevoflurane at equipotent concentrations.
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Anesthesia and analgesia · Mar 2006
Comparative StudyResidents' and program directors' attitudes toward research during anesthesiology training: a Canadian perspective.
We assessed the attitudes of residents and program directors (PD) toward research training in Canadian anesthesiology residency programs. Questionnaires were sent to all 476 anesthesiology residents in Canada and a modified questionnaire was sent to the PD of each of the 16 anesthesiology programs between November 2003 and April 2004. There was a 60% response rate to the resident questionnaire and 95% from the PDs. ⋯ Residents regard the time needed to learn clinical anesthesia, schedule conflicts, inadequate faculty support, and a lack of protected research time as the top barriers to undertaking a research project. PDs do not consider schedule conflicts or a lack of time as important barriers for resident research. Seventy-five percent of residents would prefer to do another academic activity, such as learning transesophageal echocardiography or taking postgraduate programs in education, rather than completing a research project during their residency.
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Anesthesia and analgesia · Mar 2006
Comparative StudyDeterminants of volatile general anesthetic potency: a preliminary three-dimensional pharmacophore for halogenated anesthetics.
We investigated the molecular basis for the immobilizing activity of halogenated volatile anesthetics using comparative molecular field analysis. In vivo potency data (expressed as minimum alveolar concentrations) for 69 structurally diverse anesthetics were obtained from the literature. The drugs were randomly divided into a training set (n = 52) used to derive the activity model and a test set (n = 17) used to independently assess the model's predictive power. ⋯ The final model explained 94.2% of the variance in the observed activities of the training set compounds. The model showed good predictive capability for both the training set (cross-validated r2 = 0.705) and randomly excluded test set anesthetics (r2 = 0.837). Three-dimensional pharmacophoric maps were derived to identify the spatial distribution of key areas where steric and electrostatic interactions are important in determining immobilizing activity of the halogenated drugs and were compared with our previously published maps obtained for nonhalogenated volatile anesthetics.