Journal of clinical anesthesia
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Randomized Controlled Trial Clinical Trial
Attenuation of the hemodynamic responses to endotracheal intubation with preinduction intravenous labetalol.
Endotracheal intubation following anesthesia induction frequently produces hypertension and tachycardia. This study evaluated the efficacy of preinduction IV labetalol for attenuating the hemodynamic responses to intubation following thiopental and succinylcholine induction of anesthesia. Two hours after diazepam (10 mg by mouth), 60 patients were randomized in a double-blind manner and received IV saline or labetalol at doses of 0.25, 0.5, 0.75, or 1 mg/kg in a parallel design study. ⋯ All doses of labetalol significantly attenuated the rate-pressure product increase immediately postintubation versus placebo. There was a dose-dependent attenuation of the increases in heart rate and the systolic, diastolic, and mean blood pressures versus placebo following intubation. IV labetalol at doses up to 0.75 mg/kg offers an effective pharmacologic means of attenuating preoperative hemodynamic responses to endotracheal intubation.
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Randomized Controlled Trial Comparative Study Clinical Trial
Onset of action between bupivacaine 0.5% and bupivacaine 0.5% plus fentanyl 75 mcg.
This study tested the hypothesis that the addition of fentanyl 75 mcg to bupivacaine 0.5% at the onset of epidural anesthesia for cesarean section reduces the onset time for T4 sensory blockade. The study was conducted in a randomized, double-blind fashion. The same observer performed sensory testing using pain to pinprick. ⋯ For group 1, the mean times for sensory loss at T7, T6, T5, and T4 were 13.1 +/- 3.8 minutes, 15.0 +/- 4.0 minutes, 16.9 +/- 4.3 minutes, and 19.3 +/- 4.9 minutes, respectively; for group 2, the mean times were 8.1 +/- 0.9 minutes, 9.9 +/- 1.1 minutes, 11.3 +/- 1.5 minutes, and 12.7 +/- 2.0 minutes, respectively. Two-factor analysis of variance between groups 1 and 2 showed a significant difference (p less than 0.0001), representing a 35% reduction of mean onset time. The coefficient of variation of the mean onset times for group 1 subjects was 26.6% +/- 1.7% and for group 2 subjects 12.7% +/- 2.2% (p less than 0.001), representing a 50% reduction in between-subject variation.(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Clinical Trial
Effect of labetalol or lidocaine on the hemodynamic response to intubation: a controlled randomized double-blind study.
Labetalol, a combined alpha 1- and nonselective beta-adrenergic blocking drug, was compared to lidocaine or saline to minimize the hypertensive and tachycardic response to intubation in a controlled randomized double-blind study in patients undergoing surgical procedures under general anesthesia. Forty adult patients were divided into four groups of 10 each: placebo (saline), lidocaine 100 mg, labetalol 5 mg, or labetalol 10 mg. The double-blind preparation was administered as an IV bolus just prior to induction and 2 min before the stimulus of laryngoscopy and intubation. ⋯ Labetalol 10 mg prevented a rise in heart rate after intubation compared to patients who received placebo, lidocaine 100 mg, or labetalol 5 mg. The hypertensive response to intubation was similar in all four groups. Labetalol 10 mg IV just prior to induction of anesthesia is a safe and cost-effective means of preventing tachycardia but not hypertension in response to laryngoscopy and intubation.
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Randomized Controlled Trial Comparative Study Clinical Trial
A comparison of vecuronium by continuous infusion with either isoflurane or fentanyl-nitrous oxide anesthesia.
The average infusion rate and efficacy of vecuronium bromide continuous infusions for surgical relaxation in human subjects was evaluated. Nineteen adult patients requiring more than 120 min of neuromuscular blockade for surgery were randomized to receive either fentanyl-nitrous oxide (Group 1) or isoflurane-fentanyl-nitrous oxide (Group 2). Neuromuscular function was monitored using train-of-four evoked electromyography (EMG). ⋯ An infusion of vecuronium at an initial rate of 60.0 micrograms/kg/h was then started and adjusted to maintain the first twitch at 10% of control. The average infusion rate (total infusion dose divided by the duration of the infusion) was 57.2 +/- 14 micrograms/kg/h in Group 1 (n = 10) and 42.4 +/- 12 micrograms/kg/h (n = 9) in Group 2, approximately 25% less (p = 0.02). There was a significant decrease in the infusion rate with time in Group 1 (p = 0.02), but this decrease was not observed in Group 2.
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Randomized Controlled Trial Clinical Trial
A controlled trial of esmolol for the induction of deliberate hypotension.
Twenty-five patients scheduled for lumbar fusion or cerebrovascular surgery were enrolled in an open label treatment controlled study comparing blood pressure and heart rate responses during deliberate hypotension with either esmolol or nitroprusside during steady-state N2O/isoflurane anesthesia. The first 5 patients were empirically assigned to the esmolol group; the remaining 20 patients were randomized to receive either esmolol or nitroprusside. The target of 15% reduction in mean arterial pressure (MAP) from baseline determined during anesthesia was attained with esmolol 195 +/- 10 micrograms/kg/min (mean +/- SEM) for the group (n = 15) or nitroprusside 1.9 +/- 0.3 micrograms/kg/min for the nitroprusside group (n = 10). ⋯ No patient in either group suffered any adverse reaction to hypotension. It is concluded that in moderate doses esmolol is a safe and effective hypotensive agent during isoflurane anesthesia, with no reflex tachycardia and no significant potential for rebound hypertension. A MAP reduction of 30% from preanesthesia baseline was readily obtained with this combination.