The Impact of Bispectral Index on Isoflurane Consumption and Recovery Profile in Patients Undergoing Upper Abdominal Surgery

Abstract
Background: Isoflurane requires careful administration and monitoring. Its excessive usage in patients may cause significant morbidity because of hypotension, tachycardia and delay in recovery. The Bispectral index (BIS) monitoring may be useful for titration of volatile anesthetic agents more precisely than what is possible by usual clinical parameters.
Aim: Our aim is to evaluate the effect of BIS monitoring on isoflurane consumption and recovery profile with monitor-ing of heamodynamic changes in adult patients undergoing upper abdominal surgery.
Patients and Methods: This study was carried out on 90 patients, 18-60 years, ASA I-II, scheduled for upper abdominal surgery under general anesthesia. Patients were randomized into two equal groups (45 patients in each group): Group I: SP group: Patients in the SP group had continuous assessment by standard clinical practice. Group II: BIS group: Patients in the BIS group had continuous assessment of BIS monitoring. The following parameters were compared between the two groups: Intraoperative hemodynamics, intraoperative isoflurane consumption, the time taken to extubate the patients, recovery duration using modified aldrete score.
Results: There was statistically significant decrease in isoflurane consumption in BIS group as compared to SP group, while there was significant negative correlation between BIS and both time to extubate the patients and recovery time in BIS group. the heamodynamic changes showed insignificant difference between both groups.
Conclusions: The use of BIS index, in adult patients undergoing upper abdominal surgery under general anaesthesia, significantly decreases isoflurane consumption and improves recovery profile.