Anesthesiology
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Comment Letter
Valve leaks with new disposable extraglottic airway devices.
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Patient simulators possess features for performance assessment. However, the concurrent validity and the "added value" of simulator-based examinations over traditional examinations have not been adequately addressed. The current study compared a simulator-based examination with an oral examination for assessing the management skills of senior anesthesia residents. ⋯ Variance in participant scores suggests that the examination is able to perform as expected in terms of discriminating among test takers. The rather large participant-by-modality interaction, along with the pattern of correlations, suggests that an examinee's performance varies based on the testing modality and a trainee who "knows how" in an oral examination may not necessarily be able to "show how" in a simulation laboratory. Simulation may therefore be considered a useful adjunct to the oral examination.
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To support safe and effective use of propofol in nonventilated children after major surgery, a model for propofol pharmacokinetics and pharmacodynamics is described. ⋯ Propofol clearance is two times higher in nonventilated healthy children than reported in the literature for ventilated children and adults. Based on the model, the authors advise a propofol dose of 30 mg/h in a 10-kg infant to achieve values of 12-14 on the COMFORT-Behavior scale and 70-75 on the Bispectral Index during the night. Wide pharmacodynamic variability emphasizes the importance of dose titration.
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On the basis of electroencephalographic analysis, several parameters have been proposed as a measure of the hypnotic component of anesthesia. All currently available indices have different time lags to react to a change in the level of anesthesia. The aim of this study was to determine the latency of three frequently used indices: the Cerebral State Index (Danmeter, Odense, Denmark), the Bispectral Index (Aspect Medical Systems Inc., Newton, MA), and the Narcotrend Index (MonitorTechnik, Bad Bramstedt, Germany). ⋯ The time delays of the tested indices may limit their value in prevention of recall of intraoperative events. Furthermore, different latencies for decreasing and increasing values may indicate a limitation of these monitors for pharmacodynamic studies.
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The early memory of anesthetic-induced preconditioning (APC) is a period when myocardial protection continues even after removal of the anesthetic. Because adenosine triphosphate-sensitive potassium (KATP) channels are important mediators of APC, the authors investigated the hypothesis that the memory involves channel priming by isoflurane via a long-term modulation of the sensitivity to intracellular adenosine nucleotides. ⋯ In vivo APC by isoflurane decreases sensitivity of the sarcolemmal KATP channel to inhibition by adenosine 5'-triphosphate and decreases adenosine 5'-diphosphate sensitivity. These effects persist even after discontinuation of the anesthetic, suggesting a possible novel factor that may contribute to the mechanism of early memory of APC.