Speed of recovery and side-effect profile of sevoflurane sedation comparedwith midazolam

Background: Sedation for surgical procedures performed with regional or loc al anesthesia has usually been achieved with intravenous medications, where as the use of volatile anesthetics has been limited. The use of sevoflurane for sedation has been suggested because of its characteristics of nonpunge ncy, rapid induction, and quick elimination. The purpose of this investigat ion was to assess the quality, recovery, and side effects of sevoflurane se dation compared with midazolam. Methods: One hundred seventy-three patients undergoing surgery with local o r regional anesthesia were enrolled in a multicenter, open-label, randomize d investigation comparing sedation with sevoflurane versus midazolam. Sedat ion level was titrated to an Observer's Assessment of Alertness-Sedation sc ore of 3 (responds slowly to voice). Recovery was assessed objectively by O bserver's Assessment of Alertness-Sedation, Digit Symbol Substitution Test (DSST), and memory scores, and subjectively by visual analog scales. Results: Significantly more patients in the sevoflurane group had to be con verted to general anesthesia because of excessive movement (18 sevoflurane and 2 midazolam; P = 0.043). Of remaining patients, 141 were assessable for efficacy and recovery data (93 sevoflurane and 48 midazolam). Sevoflurane and midazolam produced dose-related sedation. Sevoflurane patients had high er DSST and memory scores during recovery. Seventy-six percent (sevoflurane ) compared with 35% (midazolam) returned to baseline DSST at 30 min postope ratively (P < 0.05). More frequent excitement-disinhibition was observed wi th sevoflurane (15 [16%] vs. midazolam; P = 0.008). Conclusions: Sevoflurane for sedation produces faster recovery of cognitive function as measured by DSST and memory scores compared with midazolam. Ho wever, sevoflurane for sedation is complicated by a high incidence of intra operative excitement.