Anesthesiology
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Randomized Controlled Trial Comparative Study Clinical Trial
Prophylactic antiemetic treatment with ondansetron in children undergoing tonsillectomy.
Children undergoing tonsillectomy are at high risk for postoperative vomiting. This study was undertaken to compare ondansetron with metoclopramide and droperidol for the prevention of postoperative vomiting after tonsillectomy. ⋯ The intravenous administration of ondansetron 0.15 mg.kg-1 is highly effective in reducing postoperative emesis in children undergoing tonsillectomy. Metoclopramide and droperidol at the doses tested are ineffective in this population.
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Randomized Controlled Trial Comparative Study Clinical Trial
Diuretic effect of clonidine during isoflurane, nitrous oxide, and oxygen anesthesia.
Because clonidine, a relative selective alpha 2-agonist, inhibits the action of arginine vasopressin (AVP), the authors examined whether clonidine as an oral preanesthetic medication would induce diuresis and also would affect AVP release and its action during general anesthesia. ⋯ Oral preanesthetic medication of clonidine 2.5 or 5 micrograms.kg-1 caused a significant diuretic effect during surgery under general anesthesia, though it did not apparently relate to AVP action. This effect of clonidine could be related to its pharmacological action as an alpha 2-adrenoceptor agonist not necessarily restricted to the kidney. The diuretic effect of clonidine implicates its clinical importance in the management of patients during anesthesia.
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Randomized Controlled Trial Clinical Trial
The interaction of fentanyl on the Cp50 of propofol for loss of consciousness and skin incision.
We have previously demonstrated that the minimum alveolar concentration of isoflurane at 1 atm that is required to prevent movement in 50% of patients or animals exposed to a maximal noxious stimulus is markedly reduced by increasing fentanyl concentrations. Total intravenous anesthesia with propofol is increasing in popularity, yet the propofol concentrations required for total intravenous anesthesia or the interaction between propofol and fentanyl have not yet been defined. ⋯ We defined the propofol concentration required for loss of consciousness and showed that it is reduced by increasing fentanyl concentration and by increasing age. The propofol concentration (alone) adequate for skin incision is high but is markedly reduced by fentanyl. A ceiling effect in the Cp50i for propofol is seen with fentanyl concentrations greater than 3 ng/ml.
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Randomized Controlled Trial Clinical Trial
Repetitive rapid increases in desflurane concentration blunt transient cardiovascular stimulation in humans.
Rapid increases in desflurane concentrations above minimum alveolar concentration (MAC) can cause transient (2-4-min) circulatory changes, possibly from stimulation of rapidly-adapting airway receptors. We hypothesized that the initial increase in concentration would produce greater changes than subsequent increases. ⋯ An initial rapid increase in desflurane to 1.1 MAC produces much more stimulation than do subsequent increases, regardless of the presence of nitrous oxide. The decreased response is consistent with the hypothesis that stimulation of rapidly-adapting airway receptors produce the initial response.
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Comparative Study Clinical Trial Controlled Clinical Trial
High thoracic epidural anesthesia does not alter airway resistance and attenuates the response to an inhalational provocation test in patients with bronchial hyperreactivity.
The functional relevance of an intact pulmonary sympathetic innervation for airway resistance is unknown. We therefore evaluated whether or not pulmonary sympathetic denervation by thoracic epidural anesthesia decreases the threshold of an inhalational provocation with acetylcholine in 20 patients with documented bronchial hyperreactivity scheduled for elective upper abdominal or thoracic surgery. ⋯ We conclude that in patients with bronchial hyperreactivity 1. blockade of pulmonary sympathetic innervation seems to be of no relevance for airway resistance and 2. both epidural and intravenous bupivacaine substantially attenuate the response to an inhalational provocation with acetylcholine.