Anesthesiology
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Remote preconditioning is known to be cardioprotective, but the exact mechanism has not been fully elucidated. The objective of the current study was to investigate the role of kappa-opioid receptors in cardioprotection by remote preconditioning and reveal possible underlying mechanisms. ⋯ Activation of cardiac kappa-opioid receptors is involved in the cardioprotection induced by remote preconditioning, and the mitochondrial permeability transition pore may participate in the postreceptor pathway.
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The concept of the axillary "sheath" has been a central tenet of brachial plexus regional anesthesia for many years. Recent investigations have cast doubt on its nature and existence. This study further examines the issue. ⋯ The sciatic nerve is not surrounded or enveloped by a "sheath"--it lies in the tissue plane between rigid anatomical structures. Similarly, the brachial plexus lies in the tissue plane between the rigid anatomy of the chest wall, scapula, humerus, and pectoral fascia. This finding is inconsistent with the concept of the axillary sheath.
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In contrast to hypnosis, there is no surrogate parameter for analgesia in anesthetized patients. Opioids are titrated to suppress blood pressure response to noxious stimulation. The authors evaluated a novel model predictive controller for closed-loop administration of alfentanil using mean arterial blood pressure and predicted plasma alfentanil concentration (Cp Alf) as input parameters. ⋯ The authors' controller has a similar set-point precision as previous hypnotic controllers and provides adequate alfentanil dosing during surgery. It may help to standardize opioid dosing in research and may be a further step toward a multiple input-multiple output controller.