Anesthesiology
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Randomized Controlled Trial Clinical Trial
Oral transmucosal fentanyl citrate for preanesthetic medication of pediatric day surgery patients with and without droperidol as a prophylactic anti-emetic.
he safety and efficacy of oral transmucosal fentanyl citrate (OTFC) as a preanesthetic medication and the efficacy of droperidol as a prophylactic anti-emetic were evaluated in 100 children aged 2-8 yr undergoing general anesthesia for outpatient surgery. Patients were randomly assigned to one of four groups and managed in a double-blinded manner: 1) placebo lozenge 45 min preoperatively and placebo (normal saline) injected intravenously after induction of anesthesia; 2) placebo lozenge 45 min preoperatively and 50 micrograms/kg droperidol intravenously after induction; 3) 15-20 micrograms/kg OTFC lozenge 45 min preoperatively and placebo intravenously after induction; and 4) 15-20 micrograms/kg OTFC lozenge 45 min preoperatively and droperidol 50 micrograms/kg intravenously after induction. Anesthesia was induced and maintained with halothane and nitrous oxide in oxygen. ⋯ Postoperative nausea and vomiting occurred significantly more frequently after OTFC than after placebo. Prophylactic droperidol did not significantly reduce the incidence of nausea and vomiting. The authors conclude that, in pediatric surgical outpatients, OTFC reliably induces preoperative sedation and facilitates inhalation induction of anesthesia, but it is associated with significant decreases in respiratory rate and SpO2 and a high incidence of postoperative nausea and vomiting that is not significantly reduced by prophylactic droperidol.
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Randomized Controlled Trial Clinical Trial
Accelographic train-of-four at near-threshold currents.
The authors evaluated train-of-four (TOF) fade, as quantified by accelography, in response to neurostimulation at currents ranging from 10 to 60 mA. This was done to determine the range of currents over which measurements of fade remain consistent. In 31 patients (ASA Physical Status 1,2, and 3), anesthesia was induced with fentanyl, midazolam, and thiopental and was maintained with isoflurane and 66% nitrous oxide in oxygen. ⋯ This inconsistency was eliminated by testing at greater than or equal to 10 mA above threshold. TOF ratios obtained at 10 mA above T4 threshold correlated highly with those at 60 mA (Spearman r value = 0.94). The authors conclude that the TOF ratio is consistent over a wide range of stimulating currents and that testing with submaximal currents can be performed reliably at greater than or equal to 10 mA above the T4 threshold.(ABSTRACT TRUNCATED AT 250 WORDS)
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The increased metabolic and respiratory demand during naloxone recovery from opioid-based anesthesia could be related to the return of thermoregulation in hypothermic patients and thus be avoided by preventing intraoperative hypothermia. In this study, we measured O2 uptake (VO2) during naloxone-induced recovery in two groups of patients to determine the effect of intraoperative heat loss on postoperative VO2 changes. In seven patients, intraoperative hypothermia was prevented (normothermic group), whereas hypothermia was allowed to develop in seven other patients (hypothermic group). ⋯ VO2 was integrated throughout the recovery period to calculate recovery energy expenditure. Recovery energy expenditure and intraoperative heat loss were highly correlated (r = 0.88; P less than 0.01). This study demonstrates that the metabolic and respiratory stresses associated with naloxone-induced recovery from opioid-based anesthesia depend on the intraoperative heat loss and can therefore be reduced by preventing intraoperative hypothermia.
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Opioids are known to affect the MAC of inhalational anesthetics. We have determined the interaction between fentanyl and desflurane, following a bolus injection of fentanyl at induction in 134 adult patients. Five groups of patients were studied. ⋯ Recovery was faster in patients who received desflurane than in those who received isoflurane. The authors conclude that the MAC of desflurane is significantly reduced 25 min following a single dose of 3 micrograms/kg of fentanyl and that increasing the fentanyl dose to 6 micrograms/kg produces little further decrease in MAC. Desflurane is also associated with faster recovery from anesthesia than is isoflurane.