Anesthesia and analgesia
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Anesthesia and analgesia · Dec 2011
Randomized Controlled Trial Comparative StudyDistal tourniquet or leg position after injection enhances the efficacy of sciatic nerve blockade by the popliteal approach.
In this study, we hypothesized that leg positioning and distal tourniquet application, when compared with neutral positioning of the leg, alters the efficacy of sciatic nerve block performed by the double-stimulation technique. ⋯ Similar beneficial effects might be reached with the application of a distal tourniquet during injection or elevating the patient's leg turned supine immediately after sciatic nerve block with a popliteal approach by a double-injection technique. We suggest that using the leg-up position or application of a distal tourniquet for sciatic nerve block may lead to a more proximal distribution of the local anesthetic and may result in a faster onset of sensory and motor blocks as well as longer duration of blockade.
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Anesthesia and analgesia · Dec 2011
Randomized Controlled Trial Comparative StudyDoes the cerebral state index separate consciousness from unconsciousness?
The Cerebral State Monitor™ (CSM) is an electroencephalogram (EEG)-based monitor that is claimed to measure the depth of hypnosis during general anesthesia. We calculated the prediction probability (P(K)) for its ability to separate consciousness from unconsciousness in surgical patients with different anesthetic regimens. ⋯ The ability of CSM for separation of consciousness and unconsciousness was comparable to other commercially available EEG-based indices.
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Anesthesia and analgesia · Dec 2011
Comparative StudyBupivacaine destabilizes action potential duration in cellular and computational models of long QT syndrome 1.
The effects of the local anesthetic bupivacaine on cardiac action potentials (APs) are mainly attributed to inhibition of cardiac Na(+) channels. The relevance of its ability to also induce high-affinity blockade of human ether-à-gogo-related gene (hERG) channels is unclear. We investigated whether this interaction may functionally become more significant in cellular and computational models of long (L)QT syndromes. ⋯ This study provides evidence that bupivacaine induces inhibition of hERG channels, which is functionally silent under normal conditions but will become more relevant in LQT1-like states in which repolarization relies to a larger degree on hERG channels. Interactions with ion channels other than cardiac Na(+) channels may, therefore, determine the net cardiac effects of bupivacaine when the normal balance of ionic currents is altered.
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Anesthesia and analgesia · Dec 2011
Comparative StudyEnhancing the relative safety of intentional or unintentional intrathecal methylprednisolone administration by removing polyethylene glycol.
Previous studies have shown that intrathecal methylprednisolone is a very effective treatment for postherpetic neuralgia. However, widespread use of intrathecal methylprednisolone is limited by the presence of polyethylene glycol (PEG) as a preservative in the commercial formulation. In this study, we are proposing a method to reduce the concentration of PEG in the methylprednisolone acetate (MPA) suspension by inverting a vial before sterilely aspirating the contents into a syringe for subsequent injection. The purpose of this brief study was to precisely quantify the concentration of PEG in the MPA suspension. ⋯ We believe that by decreasing the PEG concentration using our method, MPA-related complications will potentially be reduced, and this should be considered in patients with postherpetic neuralgia refractory to other treatments who might be candidates for repeated intrathecal injections.
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Anesthesia and analgesia · Dec 2011
Comparative StudyAn uncalibrated pulse contour method to measure cardiac output during aortic counterpulsation.
Less-invasive monitoring systems, such as pulse contour methods, are increasingly being used to estimate cardiac output (CO). However, alterations in the arterial waveform caused by intraaortic balloon pump counterpulsation may affect the ability of pulse contour algorithms to determine CO. We investigated the reliability of an uncalibrated pulse contour method, the MostCare system, in patients with cardiac failure receiving intraaortic balloon pump counterpulsation by comparing its measurements of CO with those determined by an intermittent thermodilution method. ⋯ The MostCare system provided measurements of CO that were comparable to ThD-CO in patients assisted with an intraaortic balloon pump. The reliability of the MostCare system is not significantly affected by changes in arterial waveform morphology caused by inflation and deflation of the intraaortic balloon pump.