Bispectral index monitoring of midazolam and propofol sedation during endoscopic retrograde cholangiopancreatography: A randomized clinical trial (the EndoBIS study)

Introduction: Bispectral index (BIS) monitoring provides a non-invasive measure of the level of sedation. The purpose of this randomized, single-blind clinical trial was to evaluate whether BIS monitoring of sedation would lead to improved oxygenation and a reduced rate of cardiopulmonary complications during endoscopy. Patients and methods: Patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) under procedural sedation with a combination of low dose midazolam and propofol were randomly assigned to either standard monitoring of sedation only (BIS-blinded arm) or an open arm in which additional BIS monitoring was available (BIS-open arm). In the BIS-open arm, propofol administration was to be withheld if BIS values were <55.The primary study end point was the mean oxygen saturation per patient. Secondary end points were the rates of cardiopulmonary complications, propofol dose, quality of sedation (patient cooperation as rated by the endoscopist and patient satisfaction), and recovery. Results: A total of 144 patients were enrolled and included in the intention-to-treat analysis. Mean oxygen saturation per patient was 97.7% in the BIS-open arm and 97.6% in the BIS-blinded arm (P=0.71). Total rates of cardiopulmonary complications, single numbers of hypoxemic, bradycardic, and hypotensive events, mean propofol doses, and quality of sedation also showed no statistically significant differences between the groups. However, BIS monitoring did result in faster recovery of patients as reflected by shorter times to eye opening (P=0.001), first verbal response (P=0.02), and leaving the procedure room (P<0.001). Conclusions: The use of additional BIS monitoring did not lead to improved oxygenation or a reduced rate of cardiopulmonary complications. Recovery times after the procedure were shorter than with standard monitoring alone, but the clinical benefit for daily practice may be limited.