Anesthesiology
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Randomized Controlled Trial
Nitrous oxide diffusion and the second gas effect on emergence from anesthesia.
Rapid elimination of nitrous oxide from the lungs at the end of inhalational anesthesia dilutes alveolar oxygen, producing "diffusion hypoxia." A similar dilutional effect on accompanying volatile anesthetic agent has not been evaluated and may impact the speed of emergence. ⋯ Elimination of nitrous oxide at the end of anesthesia produces a clinically significant acceleration in the reduction of concentrations of the accompanying volatile agents, contributing to the speed of emergence observed after inhalational nitrous oxide anesthetic.
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Randomized Controlled Trial
Peristaltic pneumatic compression of the legs reduces fluid demand and improves hemodynamic stability during surgery: a randomized, prospective study.
Perioperative fluid restriction might be beneficial in specific clinical settings. In this prospective, randomized and blinded study, we assessed whether peristaltic pneumatic compression of the legs can support restrictive fluid management strategies by reducing intraoperative fluid demand and improving hemodynamic stability. ⋯ This study demonstrates that peristaltic pneumatic compression of the legs significantly improves hemodynamic stability and reduces fluid demand during minor surgery.
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Randomized Controlled Trial
Bispectral index monitoring, duration of bispectral index below 45, patient risk factors, and intermediate-term mortality after noncardiac surgery in the B-Unaware Trial.
Postoperative mortality has been associated with cumulative anesthetic duration below an arbitrary processed electroencephalographic threshold (bispectral index [BIS] <45). This substudy of the B-Unaware Trial tested whether cumulative duration of BIS values lower than 45, cumulative anesthetic dose, comorbidities, or intraoperative events were independently associated with postoperative mortality. ⋯ This study found no evidence that either cumulative BIS values below a threshold of 40 or 45 or cumulative inhalational anesthetic dose is injurious to patients. These results do not support the hypothesis that limiting depth of anesthesia either by titration to a specific BIS threshold or by limiting end-tidal volatile agent concentrations will decrease postoperative mortality.
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Randomized Controlled Trial
ED(50) and ED(95) of intrathecal bupivacaine in morbidly obese patients undergoing cesarean delivery.
It has been suggested that morbidly obese parturients may require less local anesthetic for spinal anesthesia. The aim of this study was to determine the effective dose (ED(50)/ED(95)) of intrathecal bupivacaine for cesarean delivery in morbidly obese patients. ⋯ Obese and nonobese patients undergoing cesarean delivery do not appear to respond differently to modest doses of intrathecal bupivacaine. This dose-response study suggests that doses of intrathecal bupivacaine less than 10 mg may not adequately ensure successful intraoperative anesthesia. Even when the initial block obtained with a low dose is satisfactory, it will not guarantee adequate anesthesia throughout surgery.