[Actigraphic assessment of the effects of hypnotics on the night before surgery in relation with the severity of surgery].

Hypnotics have been used to provide adequate sleep on the night before surgery, but these effects have rarely been investigated. We investigated whether the preoperative hypnotic effects are related with the severity of surgery with quantitative evaluation using actigraph. Sleep time on the night before surgery was evaluated after the administration of brotizolam 0.25 mg in 40 patients awaiting surgery; 20 patients for cardiovascular surgeries (Group I) and 20 patients for general surgeries (Group II). Sleep and awake state were identified by wrist activity measured with a motion-logger actigraph. Sleep time was assessed in total period from 22:00 to 6:00 and its 4 subdivided 2-hour periods (22:00-24:00, 24:00-2:00, 2:00-4:00, 4:00-6:00). The total sleep time in Group II (448 +/- 22 min) was significantly longer than that in Group I (409 +/- 44 min). Group I showed a significant reduction in sleep time in the period of 4:00-6:00 compared with other periods, whereas Group II did not show any difference among 4 periods. Group I showed significant shorter sleep time in the period of 4:00-6:00 compared with Group II. An actigraphic assessment of sleep time has demonstrated the possible influence of the severity of surgery on the sleep time on the night before surgery.