Bispectral Index Monitoring: Ability to Detect Deep Sedation during Endoscopy

Abstract

Background: Clinical practice guidelines recommend monitoring the depth of anesthesia during endoscopic examination of the gastrointestinal tract using sedation scales, despite their subjective nature, while the use of the bispectral index, an objective measure, during sedation, remains controversial. The main objective of this study was to assess the ability of bispectral index monitoring to characterize the depth of anesthesia during endoscopy. Methods: We conducted a cross-sectional study to assess the performance of the bispectral index using data from a multicentre clinical trial with 180 patients undergoing scheduled colonoscopies. Sedation was monitored using the bispectral index and Ramsay Sedation Scale. Data on sedation were recorded at five-time points (t1 to t5) during the colonoscopy. Results: Bispectral values were significantly associated with Ramsay scores (rho, -0.73; p < 0.0001). In regression analysis, each unit increase in bispectral value was associated with a reduction in the risk of a high Ramsay score (> 3) at all points (OR 0.922; 95% CI: 0.865–0.979; p < 0.0001 at t1). Receiver operating characteristic curve analysis found areas under the curve of 0.8272 for a bispectral index cut-off for deep sedation of 69.76 (sensitivity, 95.35%; negative predictive value, 97.53%) when reaching the colic flexure (t2) and 0.8399 for a cut-off of 69.29 (sensitivity, 96.15%; negative predictive value, 98.81%) at the end of the colonoscopy (t5). Conclusion: Bispectral index monitoring enables objective real-time reliable assessment of sedation. It enables easy continuous monitoring with a very good performance for detecting deep sedation and correlates with a clinical scale routinely used in endoscopic procedures.