Background: Benzodiazepines induce sedation and depress high mental functions and respiration. We conducted a prospective, randomized double-blind study on the efficacy of flumazenil in reversing the effects of these functions and the possible relationship between them.
Material/Methods:One hundred and six ASA II-III patients, aged 61±1.6 (SEM) (ranges 20-86) years were sedated intraoperatively with IV midazolam (0.15 mgxkg-1,). All underwent urological and lower abdominal procedures under bupivacaine 0.5% epidural anesthesia. In the recovery room, mental functions, respiratory and cardiovascular indices were assessed before and after the injection of either flumazenil or saline in a randomized, double-blind manner.
Results:All mental functions were restored by 0.3±0.02 mg flumazenil within 5 min of its administration. Flumazenil-treated patients, arousable by skin stimulation only, were fully awake and calm for the 90 min of the study while the controls remained significantly (P<0.01) more sedated for 60 min. Orientation for time and space improved after flumazenil (scale 0-2, from 0.7±0.1 to 1.9±0.1, P<0.001); fine and coarse coordination became 3 times more accurate than in controls. Amnesia at 5 min was reversed in 44% vs. 8% of control patients (P<0.001). Forced vital capacity (FVC) increased after flumazenil (from 2.1±0.2 to 2.8±0.1 L, P<0.02) and correlated (Pearson correlation coefficient, rp= -0.99) significantly (P = 0.0000) with sedation score. Both younger (40±3 years) and elderly (71±1, P<0.01) patients required a similar dose of flumazenil to restore all functions, and were similar throughout study. Heart rate, blood pressure and respiratory rate did not change following flumazenil administration.

Keywords: discoordination, Flumazenil, Midazolam, sedation, Surgery, Vital Capacity