The respiratory effects of reversing midazolam sedation with flumazenil in the presence or absence of narcotics

Abstract

The purpose of this study was to determine the effects of reversal of sedation with flumazenil (F), in the presence or absence of opiates, on arterial oxygen saturation (SaO2) and end-tidal CO2 (ETCO2). Twenty-four patients undergoing surgery and epidural anaesthesia were studied. Twelve patients (Group A) were orally premedicated with diazepam and 0.1 mg.kg-1 morphine i.m. Intraoperative sedation consisted of midazolam 0.1 mg.kg-1 and pethidine 0.7 mg.kg-1 i.v. Twelve patients (Group B) were premedicated with diazepam and sedated intraoperatively with 0.1 mg.kg-1 midazolam. In the recovery room, six patients in each group were randomly allocated to receive 1 mg of flumazenil while the others were allowed to awaken spontaneously (control). Sedation (eyes open vs closed), SaO2, ETCO2, respiratory rate, blood pressure and pulse were non-invasively monitored for 90 min. Administration of flumazenil resulted in a statistically significant increase in the number of patients with eyes open in both groups at 5 min, lasting 15 min in Group A and 30 min in Group B patients. An increase in SaO2 from 15-45 min after injection of flumazenil was observed only in Group B. No significant difference between groups in any other parameter was found. We concluded that reversal of benzodiazepine (BZ) sedation with flumazenil improved SaO2 in patients sedated with only BZ; in the presence of BZ and opiates, flumazenil did not affect respiratory parameters.