Anesthesiology
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Preconditioning with isoflurane has been shown to confer cardioprotection via activation of mitochondrial adenosine triphosphate-sensitive K+ (mito K(ATP)) channels. However, the relative contribution of mito K(ATP) channel and non-mito K(ATP) channel mechanisms to isoflurane-mediated cardioprotection has not been investigated. ⋯ Mito K(ATP) channel activation is the essential trigger of both preconditioning with isoflurane and combined preconditioning with isoflurane, adenosine, and S-nitroso-N-acetyl-penicillamine. Mito K(ATP) channel activation is also a crucial mediator of cardioprotection afforded by preconditioning with isoflurane. However, enhanced cardioprotection conferred by combined preconditioning is mediated through both mito K(ATP) channel-dependent and -independent mechanisms.
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The authors tested the hypothesis that pretreatment with isoflurane or sevoflurane can protect the heart against neutrophil-induced contractile dysfunction. ⋯ Isoflurane and sevoflurane preconditioned the heart against neutrophil-induced contractile dysfunction. This action was associated with an inhibition to neutrophil adherence and likely involved an increased resistance of the myocardium to oxidant-induced injury; the adenosine triphosphate-sensitive potassium channels played no apparent role.
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Randomized Controlled Trial Clinical Trial
ED50 and ED95 of intrathecal hyperbaric bupivacaine coadministered with opioids for cesarean delivery.
Successful cesarean delivery anesthesia has been reported with use of small doses (5-9 mg) of intrathecal bupivacaine coadministered with opioids. This double-blind, randomized, dose-ranging study determined the ED50 and ED95 of intrathecal bupivacaine (with adjuvant opioids) for cesarean delivery anesthesia. ⋯ The ED95 of intrathecal bupivacaine under the conditions of this study is considerably in excess of the low doses proposed for cesarean delivery in some recent publications. When doses of intrathecal bupivacaine less than the ED95, particularly near the ED50, are used, the doses should be administered as part of a catheter-based technique.
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Comparative Study
Performance evaluation of two published closed-loop control systems using bispectral index monitoring: a simulation study.
Although automated closed-loop control systems may improve quality of care, their safety must be proved under extreme control conditions. This study describes a simulation methodology to test automated controllers and its application in a comparison of two published controllers for Bispectral Index (BIS)-guided propofol administration. ⋯ When simulating closed-loop control of BIS using propofol, the use of a patient-individualized, model-based adaptive closed-loop system with effect site control resulted in better control of BIS compared with a standard proportional integral derivative controller with plasma site control. Even under extreme conditions, the modeled-based controller exhibited no behavioral problems.