The cumulative duration of bispectral index less than 40 concurrent with hypotension is associated with 90-day postoperative mortality: A retrospective study

The relationship between intraoperative low bispectral index (BIS) values and poor clinical outcomes has been controversial. Intraoperative hypotension is associated with postoperative complication. The purpose of this study was to investigate the influence of intraoperative low BIS values and hypotension on postoperative mortality in patients undergoing major abdominal surgery.