Anesthesiology
-
Comment Letter Comparative Study
Useful information about the pharmacokinetics and pharmacodynamics of midazolam and lorazepam.
-
Randomized Controlled Trial Clinical Trial
Effect of N2O on sevoflurane vaporizer settings during minimal- and low-flow anesthesia.
Uptake of a second gas of a delivered gas mixture decreases the amount of carrier gas and potent inhaled anesthetic leaving the circle system through the pop-off valve. The authors hypothesized that the vaporizer settings required to maintain constant end-expired sevoflurane concentration (Etsevo) during minimal-flow anesthesia (MFA, fresh gas flow of 0.5 l/min) or low-flow anesthesia (LFA, fresh gas flow of 1 l/min) would be lower when sevoflurane is used in oxygen-nitrous oxide than in oxygen. ⋯ When using oxygen-nitrous oxide as the carrier gas, less gas and vapor are wasted through the pop-off valve than when 100% oxygen is used. During MFA with an oxygen-nitrous oxide mixture, when almost all of the delivered oxygen and nitrous oxide is taken up by the patient, the vaporizer dial setting required to maintain a constant Etsevo is lower than when 100% oxygen is used. With higher fresh gas flows (LFA), this effect of nitrous oxide becomes insignificant, presumably because the proportion of excess gas leaving the pop-off valve relative to the amount taken up by the patient increases. However, other unexplored factors affecting gas kinetics in a circle system may contribute to our observations.
-
Randomized Controlled Trial Clinical Trial
P6 acupoint injections are as effective as droperidol in controlling early postoperative nausea and vomiting in children.
P6 acupuncture in adults is reported to be an effective preventive treatment for postoperative nausea and vomiting (PONV). It is not clear, however, whether this technique is effective as a preventive treatment for PONV in children. ⋯ In children, P6 acupoint injections are as effective as droperidol in controlling early postoperative nausea and vomiting.
-
Randomized Controlled Trial Clinical Trial
A neuroanatomical construct for the amnesic effects of propofol.
This study was designed to identify neuroanatomical locations of propofol's effects on episodic memory by producing minimal and maximal memory impairment during conscious sedation. Drug-related changes in regional cerebral blood flow (rCBF) were located in comparison with rCBF increases during a simple word memory task. ⋯ As amnesia becomes maximal, rCBF reductions induced by propofol occur in brain regions identified with working memory processes. In contrast, medial temporal lobe structures were resistant to the global CBF decrease associated with propofol sedation. The authors postulate that the episodic memory effect of propofol is produced by interference with distributed cortical processes necessary for normal memory function rather than specific effects on medial temporal lobe structures.
-
Randomized Controlled Trial Clinical Trial
Pharmacokinetics of tranexamic acid during cardiopulmonary bypass.
Tranexamic acid (TA) reduces blood loss and blood transfusion during heart surgery with cardiopulmonary bypass (CPB). TA dosing has been empiric because only limited pharmacokinetic studies have been reported, and CPB effects have not been characterized. We hypothesized that many of the published TA dosing techniques would prove, with pharmacokinetic modeling and simulation, to yield unstable TA concentrations. ⋯ Tranexamic acid pharmacokinetics are influenced by CPB. Our TA pharmacokinetic model does not provide support for the wide range of TA dosing techniques that have been reported. Variation in TA efficacy from study to study and confusion about the optimal duration of TA treatment may be the result of dosing techniques that do not maintain stable, therapeutic TA concentrations.