[Clinical investigation of flumazenil in reversing the respiratory effects of diazepam].

Eight patients (ASA I-II) scheduled for a minor surgery under lumbar epidural or spinal anesthesia were studied. The patients were sedated with approximately 0.2 mg.kg-1 of bolus injection followed by 0.2 mg.kg-1.min-1 of continuous infusion of diazepam. In order to evaluate the reversing effects of 0.2 mg of flumazenil on the respiratory effects of diazepam, the following parameters were examined at three points, namely 1) control period, 2) during infusion of diazepam, and 3) ten minutes following injection of flumazenil; tidal volume, respiratory frequency, minute volume, inspiratory time/total time of breath (Tl/Tt) and %RC with a respiratory inductive plethysmograph, ventilatory response to carbon dioxide using a modified Read's rebreathing method. We found that with flumazenil, tidal volume and the slope of the ventilatory response curve to carbon dioxide increased and arterial carbon dioxide tension decreased. However, minute volume, respiratory frequency, Tl/Tt and %RC were unchanged with flumazenil. Flumazenil did not change other clinical features and did not produce any abnormal data in laboratory examination. We conclude that flumazenil reverses the respiratory effects of diazepam at least for ten minutes following its injection without producing any complications and side effects.