Clonidine premedication decreases propofol consumption during bispectral index (BIS) monitored propofol-ketamine technique for office-based surgery.

Abstract

Propofol-ketamine anesthesia is a room air, spontaneous ventilation (RASV), dissociative intravenous (IV) sedation technique reported to have a near-zero postoperative nausea and vomiting (PONV) rate. Clonidine premedication has been reported to control blood pressure intra- and postoperatively, as well as to reduce the requirements for hypnotic agents. The bispectral index (BIS) monitor is a reproducible, objective, observer independent, quantitative measurement of the hypnotic state. This study was designed to compare the propofol consumption rate during BIS monitored propofol-ketamine anesthesia for office-based, elective female facial rhytidectomy in patients with and without clonidine premedication. Six patients receiving clonidine (200 microg oral premedication administered 30-60 minutes prior to induction of anesthesia were compared with a recent, historical control group of six patients who received no premedication. A BIS of 60-70 was chosen as the standard of comparison for light hypnotic state. A dilute propofol solution was used to gradually titrate anesthesia to a BIS of 60-70 prior to the administration of ketamine. A statistically significant reduction in propofol consumption was observed in the clonidine premedicated female elective rhytidectomy patients compared with those not receiving the clonidine. Other than modestly increased requirements for IV fluids, there were no adverse effects observed with clonidine premedication.