MIDAZOLAM PROPOFOL BUT NOT PROPOFOL ALONE REVERSIBLY DEPRESS THE SWALLOWING REFLEX

General anaesthetics depress swallowing and this is a reason to delay oral intake after general anaesthesia. The swallowing reflex was studi ed 2 h after general anaesthesia for patients undergoing colonoscopy. Forty-one patients were anaesthetized with midazolam 75 mu g.kg(-1) fo llowed by a continuous infusion of propofol and 39 patients with propo fol 1.5 mg.kg(-1) bolus followed by an infusion. Swallowing reflex was measured by electromyography 2 h after induction of anaesthesia, befo re and 5 min after the administration of flumazenil (0.2 mg) or placeb o. Two h after anaesthesia, the stare of consciousness was almost norm al in all patients and did not change after flumazenil. At two hours, the latency times for the swallowing reflex in patients treated with p ropofol alone were of 1.4 +/- 0.4 s and were significantly shorter (P < O.05) than the value of 1.9 +/- 0.8 s observed in patients who recei ved midazolam with propofol. In the latter group the latency time of t he swallowing reflex was significantly reduced following the administr ation of flumazenil bur not placebo. In patients who received propofol without midazolam, the administration of flumazenil or placebo was no t associated, with significant changes in the latency times. There wer e also no significant differences in the latency times in the subgroup that received midazolam followed by flumazenil and the propofol alone groups that did or did not receive flumazenil. These results suggest that midazolam still exerts a depressive effect on the swallowing refl ex 2 h after its administration despite the recovery of normal conscio usness.