Objective: Bispectral index (BIS) is a processed electroencephalogram that is extensively used to monitor intraoperative anesthetic depth. There have been studies on the effects of BIS monitoring during cardiac surgery on operative and postoperative results. However, these studies have reported different results. This study evaluated the effects of BIS monitoring on opioid use and postoperative recovery in patients undergoing on-pump coronary artery bypass surgery.

Methods: A total of 114 patients who underwent elective on-pump coronary bypass graft surgery were ultimately included in the study and were prospectively randomized into BIS (-) and BIS (+) groups (51 and 63 patients respectively). In BIS (-) group, fentanyl doses were given according to clinical parameters such as hemodynamic changes and follow up pupils. In BIS (+) group, fentanyl doses were adjusted to keep BIS levels between 40 and 50.

Results: There were no differences between the two groups with respect to age, sex, body mass index, smoking history and severity of comorbidities. Intraoperative fentanyl use was significantly lower in BIS (+) group; 2676±527.4 and 1632.5±325.5 in BIS (-) and BIS (+) groups respectively (p<0.001). The durations of postoperative intubation (10.5±2.7 vs. 8.05±2.9 h; p<0.001), intensive care unit (ICU) (2.8±0.9 vs. 2.4±0.7 days; p=0.02) and hospital (5.6±3.7 vs. 4.3±1.7 days; p=0.03) stays were also significantly shorter in BIS (+) group.

Conclusion: BIS monitoring during on-pump coronary bypass surgery decreases the need for opioid use during surgery. It is also associated with decreased time to extubation and shorter durations of ICU and hospital stays.