Effect of bispectral index monitoring on desflurane consumption and recovery time in morbidly obese patients undergoing laparoscopic sleeve gastrectomy

BACKGROUND: Morbid obesity magnifies the importance of the fat–blood solubility coefficient of the anesthetic in its relation to emergence and recovery. Using bispectral index (BIS) monitoring for the titration of the administration of inhaled anesthetics such as desflurane may permit a less consumption and more rapid recovery from desflurane anesthesia in morbidly obese patients, which enables earlier maintenance of a patent airway, better protection against aspiration, and better oxygenation. OBJECTIVE: The aim of this study was to investigate the effect of BIS monitoring on postoperative extubation and recovery times, and intraoperative desflurane consumption in morbidly obese patients undergoing laparoscopic sleeve gastrectomy under general anesthesia using desflurane for maintenance. PATIENTS AND METHODS: Forty morbidly obese patients were randomly enrolled in this study and divided into two groups of 20 patients each: Non-BIS group and BIS group. End-tidal desflurane concentration, mean blood pressure, and heart rate were regularly recorded. Recovery times (eye opening to verbal commands, time to extubation, and orientation to time, place, and person) and the time to achieve a modified Aldrete score of ≥ 9 were recorded by blinded study anesthesia nurse. Desflurane consumption was calculated in milliliters through gas usage option of Datex-Ohmeda S/5 anesthesia machine. RESULTS: The mean end-tidal concentrations of desflurane were significantly decreased in the BIS group compared to the non-BIS group (P < 0.05). The mean desflurane consumption and cost were significantly lower in the BIS group (124.8 ± 5.1 ml/patient) compared to the non-BIS group (150.6 ± 6.5 ml/patient) (P < 0.05). Recovery times were significantly shorter in the BIS group versus non-BIS group (P < 0.05). CONCLUSION: The use of BIS monitoring was effective in reducing intraoperative desflurane requirement (cost) and in shortening early recovery times after laparoscopic sleeve gastrectomy in morbidly obese patients without compromising the hemodynamic stability, adequacy of anesthesia, or patient outcome.