A comparison of the hemodynamic effects of labetalol and sodium nitroprusside in patients undergoing carotid endarterectomy.

The hemodynamic effects of labetalol and sodium nitroprusside were compared in 19 subjects who became hypertensive at the conclusion of elective carotid endarterectomy. Following randomization and standard anesthetic protocol, treatment was administered when blood pressure exceeded 160 mmHg systolic or 90 mmHg diastolic at the conclusion of surgery. Group 1 subjects (n = 9) received 0.25 mg/kg labetalol in divided doses, followed by repeat doses of 0.50 mg/kg until blood pressure was less than 160/90 mmHg or until they had received 300 mg total dose. Group 2 subjects (n = 10) were started on a nitroprusside infusion at 0.5 micrograms/kg/min, titrated to achieve blood pressure less than 160/90 mmHg, or up to a rate of 6.0 micrograms/kg/min. Data were collected at 15-minute intervals for 12 hours. Analysis with repeated measures analysis of covariance (p less than 0.05) found no significant differences between groups in any measured parameter. A significant time effect was found for both groups. The results suggest that labetalol is an effective alternative to nitroprusside for the management of postoperative hypertension in this patient population. For the majority of such patients, labetalol may be the drug of choice for postendarterectomy hemodynamic control.