The efficacy of flumazenil versus physostigmine after midazolam-alfentanil anaesthesia in man.

The effects of flumazenil and physostigmine were studied in adult surgical patients recovering from midazolam-alfentanil anaesthesia. Thirty-two patients were anaesthetized with midazolam (0.2 mg kg-1 and 0.36-0.66 mg kg-1 h-1 by infusion) and alfentanil (0.15 mg kg-1 and 0.03-0.15 mg kg-1 h-1 by infusion), vecuronium, 50% nitrous oxide in oxygen, intubated and ventilated. The midazolam and alfentanil infusions were stopped at the end of surgery. Residual neuromuscular blockade and ventilatory depression were antagonized and the patients were extubated. In the recovery room, patients received either flumazenil 1 mg or physostigmine 2 mg i.v. over 10 min in a randomized, double-blind way. Before and up to 2 h after injection, patients were asked to perform two psychomotor tests. The degree of sedation and orientation in time and space were also determined. Seventeen patients received flumazenil and 15 patients received physostigmine. Before injection all patients were heavily sedated. After flumazenil, patients were fully awake within 6-7 min but sedation recurred 10-20 min later. After physostigmine, the degree of sedation did not change. The difference in the degree of sedation was significant until 30 min after injection. The time-course of test scores and orientation were similar to that of sedation. No serious side-effects or haemodynamic changes were observed after flumazenil. After physostigmine, seven patients had an increase in heart rate to 140 beats min-1 and blood pressure decreased in three patients.(ABSTRACT TRUNCATED AT 250 WORDS)