Effect of bispectral index [BIS] monitoring on postoperative recovery and sevoflurane consumption among morbidly obese patients undergoing laparoscopic gastric banding

Early and uneventful postoperative recovery of morbidly obese patients remains a challenge for anesthesiologists. It could be valuable to titrate the administration of inhaled anesthetic, such as sevoflurane, in morbid obese patients, in order to shorten emergence using bispectral index [BIS] monitoring. It would be a great advantage if BIS permitted a more rapid recovery and less consumption in morbidly obese patients with a high cost inhaled agent. The aim of the study is to show whether the titration of sevoflurane based on the BIS monitoring would allow shortening of recovery time in morbidly obese patients and to evaluate whether BIS monitoring would contribute to reduce the amount of sevofLurane administered while providing an adequate anesthesia. Thirty morbidly obese ASA I and II patients undergoing laparoscopic gastric banding [LAGB] procedures were studied. In the first group [15 patients], patients were anesthetized without the use of BIS [non BIS or control group], and sevoflurane being administered according to standard clinical practice [control group]. In the second group [15 patients], sevoflurane was titrated to maintain a BIS value between 40 and 60 during surgery, and then 60-70 during 15 min prior to the end of surgery [BIS group]. Recovery times were recorded. Time to extubation was also noted, as well as the time to achieve a modified Aldrete score of 9 were evaluated subsequently at 10-min intervals until 3 h after surgery by nurses who had no knowledge of the study. Sevoflurane consumption was calculated using the vaporizer weighing method. Awakening and extubation times were significantly shorter in the BIS group [P <0.05]. In the BIS [vs. non BIS] group, there were no significant differences observed in the time to obtain an Aldrete score of 9. The sevoflurane consumption and cost in the BIS group were lower than in the non BIS group [P <0.05]. Bispectral index monitoring during anesthesia for morbidly obese patients provides statistically significant reduction in recovery times. It also has the added advantage in decreasing sevoflurane consumption