Anesthesiology
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Randomized Controlled Trial Clinical Trial
Intravenous remifentanil: placental transfer, maternal and neonatal effects.
Remifentanil has not been studied in obstetric patients. This study evaluates the placental transfer of remifentanil and the neonatal effects when administered as an intravenous infusion. ⋯ Remifentanil crosses the placenta but appears to be rapidly metabolized, redistributed, or both. Maternal sedation and respiratory changes occur, but without adverse neonatal or maternal effects.
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Randomized Controlled Trial Comparative Study Clinical Trial
A comparison of the posterior versus lateral approaches to the block of the sciatic nerve in the popliteal fossa.
The main disadvantage of the posterior approach to the block of the sciatic nerve in the popliteal fossa (popliteal block [PB]) is the need to place the patient in the prone position. In this study, the authors examined the clinical utility of a recently described lateral approach to PB that is performed with the patient in the supine position, and they compared its ability to provide reliable surgical anesthesia with that of the posterior approach. ⋯ Although blockade using the lateral approach took longer to accomplish, both techniques resulted in clinically acceptable anesthesia in the distribution of the sciatic nerve.
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Randomized Controlled Trial Clinical Trial
Effects of oral clonidine on heart rate changes after neostigmine-atropine administration.
Clonidine reduces heart rate (HR) responses to atropine, whereas neostigmine causes bradycardia. This study was designed to determine whether clonidine premedication would reduce tachycardia after neostigmine-atropine administration. ⋯ Premedication with 5 microg/kg oral clonidine attenuates the initial increases in HR without subsequent decreases in HR.
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This study prospectively evaluated the ability of aspiration to detect intravascular placement of multiple-orifice epidural catheters. ⋯ Under the conditions of this study, which include using multiple-orifice catheters and dilute solutions of local anesthetic and opioid, aspiration and incremental drug injection alone safeguard against the risks of intravenously positioned local anesthetics. These results should not be extrapolated to other clinical settings without further study.
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Volatile general anesthetics depress neuronal activity in the mammalian central nervous system and enhance inhibitory Cl- currents flowing across the gamma-aminobutyric acid A (GABA(A)) receptor-ion channel complex. The extent to which an increase in GABA(A)-mediated synaptic inhibition contributes to the decrease in neuronal firing must be determined, because many further effects of these agents have been reported on the molecular level. ⋯ Together with recent investigations, our results provide evidence that halothane, isoflurane, and enflurane reduced spontaneous action potential firing of neocortical neurons in cultured brain slices mainly by increasing GABA(A)-mediated synaptic inhibition. At concentrations, approximately one half the EC50 for general anesthesia, volatile anesthetics increased overall GABA(A)-mediated synaptic inhibition about twofold, thus decreasing spontaneous action potential firing by half.