Anesthesiology
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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.
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Randomized Controlled Trial Clinical Trial
Upper airway reflexes during a combination of propofol and fentanyl anesthesia.
The effects of intravenous anesthetics on airway protective reflexes have not been fully explored. The purpose of the present study was to characterize respiratory and laryngeal responses to laryngeal irritation during increasing doses of fentanyl under propofol anesthesia. ⋯ Incremental doses of fentanyl depress airway reflex responses in a dose-related manner, except for apnea with laryngospasm.
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Randomized Controlled Trial Clinical Trial
Treatment of incomplete analgesia after placement of an epidural catheter and administration of local anesthetic for women in labor.
Approximately 15% of women still have pain after placement of an epidural catheter and administration of local anesthetic for labor analgesia. Two techniques frequently used to treat this pain were compared: (1) withdrawal of the catheter 1 cm and repeated dosing with additional local anesthetic, and (2) repeated dosing with additional local anesthetic without any catheter manipulation. ⋯ Administration of additional local anesthetic without first withdrawing the epidural catheter will effectively treat most women for whom analgesia is incomplete after the placement of an epidural catheter during labor.