Anesthesiology
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Randomized Controlled Trial Clinical Trial
Non-steady state analysis of the pharmacokinetic interaction between propofol and remifentanil.
The pharmacokinetics of both propofol and remifentanil have been described extensively. Although they are commonly administered together for clinical anesthesia, their pharmacokinetic interaction has not been investigated so far. The purpose of the current investigation was to elucidate the nature and extent of pharmacokinetic interactions between propofol and remifentanil. ⋯ Coadministration of propofol decreases the bolus dose of remifentanil needed to achieve a certain plasma-effect compartment concentration but does not alter the respective maintenance infusion rates and recovery times to a clinically significant degree.
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The potential benefit of propofol dose regimens that use physiologic pharmacokinetic modeling to target the brain has been demonstrated in animals, but no data are available on the rate of propofol distribution to the brain in humans. This study measured the brain uptake of propofol in humans and the simultaneous effects on electroencephalography, cerebral blood flow velocity (V(mca)), and cerebral oxygen extraction. ⋯ Description of brain distribution of propofol will allow development of physiologic pharmacokinetic models for propofol and evaluation of dose regimens that target the brain.
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Clinical Trial
Changes of electroencephalographic bicoherence during isoflurane anesthesia combined with epidural anesthesia.
The authors previously reported that, during isoflurane anesthesia, electroencephalographic bicoherence values changed in a fairly restricted region of frequency versus frequency space. The aim of the current study was to clarify the relation between electroencephalographic bicoherence and the isoflurane concentration. ⋯ Changes in the height of two electroencephalographic bicoherence peaks correlated well with isoflurane concentration.
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In a previous study, the authors found that nitrous oxide (N2O) exposure induces c-Fos (an immunohistochemical marker of neuronal activation) in spinal cord gamma-aminobutyric acid-mediated (GABAergic) neurons in Fischer rats. In this study, the authors sought evidence for the involvement of alpha1 adrenoceptors in the antinociceptive effect of N2O and in activation of GABAergic neurons in the spinal cord. ⋯ These findings support the hypothesis that N2O activates GABAergic interneurons through alpha1 adrenoceptors to produce its antinociceptive effect.
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Randomized Controlled Trial Comparative Study Clinical Trial
Randomized controlled trial comparing traditional with two "mobile" epidural techniques: anesthetic and analgesic efficacy.
This follow-up paper to the original COMET study describes in detail the high and low-dose epidural techniques and the subsequent anesthetic characteristics.
The low-dose techniques used infusions of 0.1% bupivacaine with 2 mcg/mL fentanyl, compared with 10mL boluses of 0.25% bupivacaine. Maternal analgesia experience was similar between the groups, all the CSE group experienced better analgesia in the first hour.
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