Abstract
The aim of this study was to reassess the efficacy of flumazenil for reversal of sedation with midazolam. Twenty-four ASA I or II patients undergoing elective surgery under epidural anaesthesia participated. Following 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 manner, either flumazenil (0.1 mg· ml−1) or placebo. The study drug (maximum dose: 10 ml) was titrated until the patient became fully awake. Sedation was assessed with the Modified Steward Coma Scale (MSCS), the Trieger test (TT) and Critical Flicker Frequency (CFF). The assessments were done before anaesthesia (baseline), at the end of surgery immediately before administration of study drug, and serially afterwards, at 10, 30, 60, 90, 120, 150 and 180 min. Analyses of variance for repeated measures and pooled t tests were used. The duration of surgery was (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 group. The volume of study drug administered was 5.5 ml ± 1.9, equivalent to 0.55 mg, for the flumazenil group and 6.7 ± 2.2 ml for the placebo group. Critical Flicker Frequency is the only measure which revealed a difference (P < 0.005) between the flumazenil and placebo groups and this occurred only at the ten-minute assessment. We conclude that flumazenil is rarely needed when midazolam is titrated to provide light sedation during regional anaesthesia. The spontaneous recovery from midazolam is fast enough.
Résumé
Cette étude vise à réévaluer l’efficacité antagoniste du flumazénil sur la sédation au midazolam. Vingt-quatre patients ASA I et II soumis à une chirurgie élective sous anesthésie épidurale font partie de l’étude. Après le bloc épidural, le midazolam est administré de façon à maintenir le patient assoupi mais toujours apte à répondre à un ordre verbal. A la fin de la chirurgie, les patients sont répartis au hasard pour recevoir à double aveugle soit du flumazénil (0,1 mg · ml−1) soit un placebo. Le produit à l’étude (dose maximale: 10 ml) est titré jusqu’au réveil complet. La sédation est évaluée sur l’échelle modifiée de Steward pour le coma, le test de Trieger et le test de fréquence critique de fusion. Les évaluations sont réalisées avant l’anesthésie (ligne de base), à la fin de la chirurgie immédiatement avant l’administration du produit à l’étude, et séquentiellement par la suite à 10, 30, 60, 90, 120, 150 et 180 min. Des analyses de variance pour mesures répétées et des tests de Student regroupés sont utilisés. La durée de la chirurgie est de (moyenne ± SD) 0,72 h ± 0,25 pour le groupe flumazénil et de 0,74 ± 0,28 h pour le groupe placebo. La dose totale de midazolam est de 7,2 ± 2.2 mg pour le groupe flumazénil et de 8,9 ± 2,7 mg pour le groupe placebo. Le volume administré du produit à l’étude est de 5,5 ± 1,9 ml (équivalence 0,55 mg), pour le groupe flumazénil, et de 6,7 ± 2,2 ml pour le groupe placebo. Le test de fréquence de fusion est la seule mesure qui révèle une différence (P < 0,005) entre les groupes flumazénil et placebo et cette différence n’apparaît qu’à l’étape dix minutes. Nous concluons qu’on a rarement besoin de flumazénil lorsque le midazolam est titré pour produire une sédation légère pendant l’anesthésie régionale, la récupération spontanée après midazolam étant suffisamment rapide.
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Claffey, L., Plourde, G., Morris, J. et al. Sedation with midazolam during regional anaesthesia: is there a role for flumazenil?. Can J Anaesth 41, 1084–1090 (1994). https://doi.org/10.1007/BF03015659
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DOI: https://doi.org/10.1007/BF03015659