Anesthesiology
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Randomized Controlled Trial Clinical Trial
Interaction between intrathecal neostigmine and epidural clonidine in human volunteers.
alpha 2-Adrenergic agonists are thought to produce analgesia, in part, by activating spinal acetylcholine release. The purpose of the current study was to examine the interaction between intrathecal neostigmine and epidural clonidine for analgesia and side effects in humans. ⋯ These results support enhancement of alpha 2-adrenergic analgesia by intrathecal neostigmine, but do not demonstrate synergy, as observed in animals. Lack of enhancement of side effects suggests this combination may be clinically useful.
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Randomized Controlled Trial Multicenter Study Comparative Study Clinical Trial
Intravenous ondansetron in established postoperative emesis in children. S3A-381 Study Group.
In pediatric postsurgical patients, postoperative vomiting is a common occurrence that can delay recovery and result in unplanned hospital admissions after outpatient surgery. This randomized, double-blind, placebo-controlled, multicenter study evaluated the efficacy and safety of ondansetron in the control of established postoperative emesis in outpatients aged 2-12 yr. ⋯ A single dose of ondansetron (0.1 mg/kg up to 4 mg) is effective and well tolerated in the prevention of further episodes of postoperative emesis in children after outpatient surgery. Administration of ondansetron also may result in a shorter time to discharge.
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Randomized Controlled Trial Clinical Trial
Simulation of an epidural test dose with intravenous isoproterenol in awake and in halothane-anesthetized children.
An epidural test dose containing epinephrine does not reliably produce hemodynamic responses in children under halothane anesthesia. The purpose of this study was to determine hemodynamic responses to intravenous isoproterenol in both awake and halothane-anesthetized children. ⋯ Isoproterenol at a dose of 0.1 microgram/kg is a sensitive indicator for intravascular injection of a test dose in children anesthetized with halothane and nitrous oxide. Isoproterenol at a dose of 0.05 microgram/kg approximates a minimal effective dose in awake children and in infants. After detailed studies on neural toxicity, isoproterenol could be of value as an epidural test agent in children.
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Randomized Controlled Trial Comparative Study Clinical Trial
Isoflurane produces marked and nonlinear decreases in the vasoconstriction and shivering thresholds.
Desflurane decreases the vasoconstriction and shivering thresholds disproportionately at high anesthetic concentrations. This result contrasts with the authors' previous report that isoflurane decreases the vasoconstriction threshold linearly. It is surprising that the basic shape of the concentration-response curve should differ with these two otherwise similar anesthetics. Therefore, the hypothesis that isoflurane produces a nonlinear reduction in the vasoconstriction threshold was tested. Because the effect of isoflurane on shivering remains unknown, the extent to which isoflurane reduces the shivering threshold also was determined. ⋯ The vasoconstriction-to-shivering range remained unchanged by isoflurane administration. In this regard, the effects of isoflurane are similar to those of desflurane, propofol, and alfentanil. The current data differ from the authors' previous report, in that the dose-dependence for vasoconstriction was nonlinear, with isoflurane reducing the threshold disproportionately at higher anesthetic concentrations. Differing dose-dependence in the two studies may result either because the current study's volunteers were not exposed to surgical stimulation and were given less isoflurane, or because of design limitations in the previous protocol.
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Randomized Controlled Trial Clinical Trial
Analgesic efficacy of low-dose ketamine. Somatosensory-evoked responses in relation to subjective pain ratings.
Low-dose ketamine has been shown to exert analgesic effects. Whether ketamine-induced pain relief may be quantitated by somatosensory evoked cerebral potentials has not been established. ⋯ These data indicate that pain relief induced by low-dose ketamine is dose-dependent for the first 30 min after bolus injection. Changes in pain perception may be quantitated by somatosensory-evoked cortical responses. Also, EEG changes are not specific for changes in nociception, but the increase in theta power may reflect the hypnotic effect of low-dose ketamine.