Anesthesiology
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The lungs have been mentioned as a possible site contributing to the extrahepatic clearance of propofol. The objective of the present study was to clarify the pulmonary disposition of propofol directly in human lungs by investigating both the first-pass uptake and pulmonary extraction at pseudo-steady state. ⋯ Most of the propofol that undergoes pulmonary uptake during the first pass was released back to the circulation by back diffusion. Metabolism was not involved in the pulmonary uptake in human lungs.
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Previously, mathematical theory was developed for determining when a patient should be ready for surgery on the day of surgery. To apply this theory, a method is needed to predict the earliest start time of the case. ⋯ The earliest start time of a case can be estimated using the 0.05 prediction bound for the duration of the preceding case. The authors show 0.05 prediction bounds can be estimated accurately assuming that case durations follow log-normal distributions.
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A rigorous study of the dose-response relation of rapacuronium has, to our knowledge, yet to be performed. In addition, there is little information available regarding the onset or offset profile of rapacuronium when administered in subparalyzing doses. These issues necessitate further study. ⋯ The authors found the ED95 of rapacuronium to be substantially less than suggested by previous estimates. Rapacuronium has an onset profile that is not different from that previously reported for succinylcholine. The rate of spontaneous recovery was faster after rapacuronium than the authors previously observed after mivacurium administration but was slower than after succinylcholine, using an identical protocol.
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Comparative Study
Addition of sodium bicarbonate to lidocaine decreases the duration of peripheral nerve block in the rat.
Adding sodium bicarbonate to lidocaine to enhance its efficacy during peripheral nerve block is controversial. The authors studied the effect of adding sodium bicarbonate to lidocaine with and without epinephrine versus equivalent alkalinization by sodium hydroxide (NaOH) on onset, degree, and duration of peripheral nerve block. ⋯ With 1% commercial lidocaine without epinephrine, sodium bicarbonate decreases the degree and duration of block. However, in solutions with epinephrine, sodium bicarbonate hastens onset, without effecting degree or duration.