Remifentanil Has Sufficient Hypnotic and Amnesic Effect for Induction of Anesthesia by Itself

摘要

With a small-dose remifentanil, some patients showed no reaction and did not remember it postoperatively. We, therefore, hypothesized that remifentanil may decrease the level of consciousness and/or exhibit amnesic effect when stimulations are avoided. Thirty-patients were divided into two groups: non-stimulation group and stimulation group. Anesthesia was induced with 1 micro-g·kg?1·min?1 of remifentanil using no additional hypnotic agent. In the non-stimulation group, patients were left free from any stimulation except non-invasive blood pressure monitoring. In the stimulation group, patients were asked to follow verbal commands. The level of consciousness was evaluated with electroencephalogram and BIS-value derived from it. In the non-stimulation group, all patients reached the decreased level of consciousness in 5 minutes. In the stimulation group, however, 14 patients were judged to be still conscious. 10 patients could open their mouth at the 5th minute, but 9 of these 10 patients did not remember it postoperatively. In conclusion, remifentanil, with no additional anesthetics, exhibited hypnotic and amnesic effects when stimulations were kept minimal.