Anesthesiology
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Randomized Controlled Trial Clinical Trial
Desflurane slightly increases the sweating threshold but produces marked, nonlinear decreases in the vasoconstriction and shivering thresholds.
Shivering is rare during general anesthesia. This observation suggests that anesthetics profoundly impair shivering. However, the effects of surgical doses of volatile anesthetics on control of shivering have yet to be evaluated. Furthermore, the effects of desflurane on sweating and thermoregulatory vasoconstriction remain unknown. Accordingly, the authors determined the concentration-dependent effects of desflurane on sweating, vasoconstriction, and shivering. ⋯ The observed linear increase in the sweating threshold was similar in pattern and magnitude to that produced by most general anesthetics. The approximately 3 degrees C reduction in the vasoconstriction threshold by 0.8 MAC desflurane was similar to that observed previously during isoflurane and propofol anesthesia. However, the threshold was reduced less than expected at 0.5 MAC, suggesting that the dose-response relationship for vasoconstriction is nonlinear. Shivering was induced without difficulty in this study although the response is rare in surgical patients. It is likely that shivering during general anesthesia is rare because thermoregulatory vasoconstriction usually prevents body temperature from decreasing the required additional 1-1.5 degrees C.
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Randomized Controlled Trial Clinical Trial
Effects of storage time on quantitative and qualitative platelet function after transfusion.
Platelet transfusions are being used increasingly in patients with thrombocytopenia to improve hemostatic function before surgery and invasive procedures. However, there are limited data on the immediate quantitative and qualitative platelet response after transfusion. Some authors have suggested that transfused platelets require time in vivo to regain maximal function, which is dependent on the duration of platelet storage. Therefore, the timing of surgery and invasive procedures with optimal platelet function may not be occurring. ⋯ In patients with chemotherapy-induced thrombocytopenia, platelet transfusion causes an immediate increase in number and function, which is independent of storage time. This quantitative and qualitative increase persists unchanged for 2 h after transfusion, suggesting that there is no acute "warm-up-time" necessary for transfused platelets to regain maximal function. Fresh platelets demonstrate increased aggregation and dense granule release compared to 4-day stored platelets and may impart improved hemostatic function in vivo.