Anesthesiology
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Comparative Study Clinical Trial Controlled Clinical Trial
Awakening propofol concentration with and without blood-effect site equilibration after short-term and long-term administration of propofol and fentanyl anesthesia.
The propofol awakening concentration can vary. However, the effect site awakening propofol concentration will be a fixed value. The purpose of this study was to determine the awakening propofol concentrations obtained from infusion Schede using abrupt discontinuation of propofol (half-maximal effective concentration [EC50]) or a descending decrease in concentration to allow blood-effect site equilibration (EC50eq). ⋯ The EC50eq was independent of propofol infusion length, compared with the EC50. Thus the potential for hysteresis during emergence from propofol anesthesia was confirmed.
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Comparative Study Clinical Trial
Changing from isoflurane to desflurane toward the end of anesthesia does not accelerate recovery in humans.
In an attempt to combine the advantage of the lower solubilities of new inhaled anesthetics with the lesser cost of older anesthetics, some clinicians substitute the former for the latter toward the end of anesthesia. The authors tried to determine whether substituting desflurane for isoflurane in the last 30 min of a 120-min anesthetic would accelerate recovery. ⋯ Substituting desflurane for isoflurane during the latter part of anesthesia does not improve recovery, in part because partial rebreathing through a semiclosed circuit limits elimination of isoflurane during the crossover period. Although higher fresh gas flow during the crossover period would speed isoflurane elimination, the amount of desflurane used and, therefore, the cost would increase.
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Comparative Study Clinical Trial
The pharmacokinetics and steady state pharmacodynamics of mivacurium in children.
The authors previously showed that children require larger infusion rates of mivacurium than adults to maintain target twitch depression. Here, they determined whether there are differences between children and adults in mivacurium's pharmacokinetic and pharmacodynamic properties. ⋯ Clearance of mivacurium's potent isomers is larger in younger patients, consistent with the larger mivacurium infusion requirement in children than in adults reported previously.
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Comparative Study Clinical Trial
The relation between the platelet-activated clotting test (HemoSTATUS) and blood loss after cardiopulmonary bypass.
Platelet dysfunction is one of several major causes of bleeding after cardiopulmonary bypass. A timely, simple, point-of-care determinant of platelet function recently became available for clinical use. Adding platelet-activating factor to conventional activated clotting time methods (platelet-activated clotting test [PACT]) produces rapid results (<15 min) and may yield a measure of platelet responsiveness and whole-blood procoagulant activity. ⋯ The PT correlated with blood loss and transfusion requirements and was superior to PACT, aPTT, and platelet count for predicting excessive blood loss after cardiopulmonary bypass.
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Comparative Study
Effect of subarachnoid bupivacaine block on anesthetic requirements for thiopental in rats.
Subarachnoid bupivacaine blockade has been reported to reduce thiopental and midazolam hypnotic requirements in patients. The purpose of this study was to examine if local anesthetically induced lumbar intrathecal blockade would reduce thiopental requirements for blockade of motor responses to noxious and nonnoxious stimuli in rats. ⋯ This study demonstrates that lumbar intrathecally administered local anesthetic blockade decreases anesthetic requirements for thiopental for a spectrum of end points tested. This effect is due neither to altered pharmacokinetics nor to a direct action of the local anesthetic on the brain; rather, it is most likely due to decreased afferent input.