Speed of recovery and side-effect profile of sevoflurane sedation compared with midazolam

Background: Sedation for surgical procedures performed with regional or local anesthesia has usually been achieved with intravenous medications, whereas the use of volatile anesthetics has been limited. The use of sevoflurane for sedation has been suggested because of its characteristics of nonpungency, rapid induction, and quick elimination. The purpose of this investigation was to assess the quality, recovery, and side effects of sevoflurane sedation compared with midazolam. Methods: One hundred seventy-three patients undergoing surgery with local or regional anesthesia were enrolled in a multicenter, open-label, randomized investigation comparing sedation with sevoflurane versus midazolam. Sedation level was titrated to an Observer's Assessment of Alertness-Sedation score of 3 (responds slowly to voice). Recovery was assessed objectively by Observer'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 converted 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 higher DSST and memory scores during recovery. Seventy-six percent (sevoflurane) compared with 35% (midazolam) returned to baseline DSST at 30 min postoperatively (P < 0.05). More frequent excitement-disinhibition was observed with 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. However, sevoflurane for sedation is complicated by a high incidence of intraoperative excitement.