Effect of bispectral index monitoring on extubation time and analgesic consumption in abdominal surgery: a randomised clinical trial.

PRINCIPLES The aim of this study was to investigate the effect of bispectral index (BIS) monitoring on intra-operative anaesthesia consumption and extubation time. DESIGN Randomised controlled study. METHODS The study included 45 patients undergoing major abdominal surgery under general anaesthesia in a six month period (February - July 2011), aged 18 years or older, and classified as ASA (American Society of Anaesthesiologists) physical status II or III. Patients were randomly assigned to receive BIS-guided anaesthesia or routine anaesthesia care as a non BIS-guided group. At the induction of anaesthesia, and during the operation the following parameters were continuously recorded: BIS level, heart rate (HR), systolic blood pressure (sBP), end-tidal CO2 (etCO2).Operation time and time to extubation were also recorded. On the first post-operative day all patients were visited and interviewed about intra-operative recall. RESULTS BIS levels in the non BIS-guided group were significantly lower from 30 minutes further to the end of the operation, compared to the BIS-guided group (p <0.05). Time to extubation was significantly shorter in the BIS-guided group (17.5 min vs. 75 min, p <0.001). There were no statistically significant differences in the required amounts of anaesthetics. In the post-operative interview, none of the patients reported an episode of intra-operative awareness. CONCLUSION Guiding anaesthesia according to BIS level will result in significantly faster recovery after anaesthesia. The investigation was registered on ClinicalTrials.gov (NCT01470898).