SEDATION WITH MIDAZOLAM DURING REGIONAL ANESTHESIA - IS THERE A ROLE FOR FLUMAZENIL

The aim of this study was to reassess the efficacy of flumazenil for r eversal of sedation with midazolam. Twenty-four ASA I or II patients u ndergoing elective surgery under epidural anaesthesia participated. Fo llowing epidural block, midazolam was administered to keep the patient sleepy but still responsive to verbal commands. At the end of surgery the patients were randomly allocated to receive in a double-blind man ner, either flumazenil (0.1 mg . ml(-1)) or placebo. The study drug (m aximum dose: 10 ml) was titrated until the patient became fully awake. Sedation was assessed with the Modified Steward Coma Scale (MSCS), th e Trieger test (TT) and Critical Flicker Frequency (CFF). The assessme nts were done before anaesthesia (baseline), at the end of surgery imm ediately before administration of study drug, and serially afterwards, at 10, 30, 60, 90, 120, 150 and 180 min. Analyses of variance for rep eated measures and pooled t tests were used. The duration of surgery w as (mean +/- SD) 0.72 +/- 0.25 hr. in the flumazenil group and 0.74 +/ - 0.28 hr in the placebo group. The total dose of midazolam was 7.2 +/ - 2.2 mg for the flumazenil group and 8.9 +/- 2.7 mg for the placebo g roup. The volume of study drug administered was 5.5 ml +/- 1.9, equiva lent to 0.55 mg, for the flumazenil group and 6.7 +/- 2.2 ml for the p lacebo group. Critical Flicker Frequency is the only measure which rev ealed a difference (P < 0.005) between the flumazenil and placebo grou ps and this occurred only at the ten-minute assessment. We conclude th at flumazenil is rarely needed when midazolam is titrated to provide l ight sedation during regional anaesthesia. The spontaneous recovery fr om midazolam is fast enough.