Sedation after cardiac bypass surgery: comparison of propofol and midazolam in the presence of a computerized closed loop arterial pressure controller.

Forty patients who had undergone coronary artery graft surgery and who required vasodilator therapy for postoperative hypertension were given infusions of either propofol (2,6,di-isopropylphenol) or midazolam, together with an infusion of morphine for analgesia while ventilation was controlled artificially. Sodium nitroprusside was administered to patients in both groups using a computer-controlled closed loop system. Both agents produced good quality of sedation. Overall times to spontaneous ventilation and tracheal extubation were shorter in the propofol group, but this was not statistically significant. Ease of control of arterial pressure was satisfactory clinically with both agents, although propofol appeared to be associated with a statistically greater incidence of hypotension.