Bispectral index for evaluation of recovery after sevoflurane anesthesia

ABSTRACT

Bispectral index [BIS] is a method of monitoring depth of hypnosis during anesthesia. Guided anesthetic administration using BIS target range may be associated with a reduction in volatile anesthetic and faster recovery. We evaluated recovery profile after sevoflurane anesthesia with and without BIS monitoring. 60 ASA I and II patients, aged 20-60 years, were enrolled in this study. Patients were divided randomly into two groups [n= 30]. In group A [GA] concentration of sevoflurane was adjusted according to clinical data. In group B [GB] concentration of sevoflurane was adjusted to keep BIS reading in range of 50 +/- 5. The following emergency times were evaluated spontaneous eye opening, responding to verbal command and orientation time. Also, duration of patients stay in post anesthesia care unit [PACU] was determined and all patients were questioned about recall 24 hours after operation. End tidal sevoflurane concentration was significantly high in GA, during maintenance until stop of inhalational agents, compared to GB. Early recovery times are shorter in GB compared to GA, but not significant. When we compared duration of patients stay in PACU to be eligible for transfer to ward, it was significantly shorter in GB. No patient can recall any events during operation. Compared with standard anesthesia monitoring practice, adjunctive use of BIS monitoring can improve titration of sevoflurane during general anesthesia, leading to improved recovery profile and shorten the duration of stay in PACU. But, consideration of hemodynamic parameters is very important to avoid unaccepted change in HR and MBP, especially in cardiac patients