Bispectral index monitoring of sedation during endoscopy

Background: No objective measure of the level of sedation is universally accepted. However, bispectral index monitoring is currently used to objectively measure sedation levels in several clinical settings. This study compares the temporal relationship of bispectral index levels versus the Observer's Assessment of Alertness/Sedation (OAA/S) scale for sedation during endoscopy and proposes a functional bispectral index range for endoscopic procedures. Methods: Fifty consecutive adults undergoing endoscopic retrograde cholangiopancreatography, colonoscopy, or esophagogastroduodenoscopy by a single endoscopist were studied. Intravenous sedation was achieved with diazepam and meperidine. Bispectral index levels (0 to 100) and OAA/S scores (1 to 5) were recorded every 3 minutes by a single trained observer. Results: There were significant temporal correlations between bispectral index levels and OAA/S scores (r = 0.59, p < 0.0001). Bispectral index levels and OAA/S scores corresponded with the need for additional sedation as determined clinically by the endoscopist. An OAA/S score of 3 corresponded to a bispectral index level of 81.49 +/- 9.78. Conclusions: Bispectral index monitoring temporally correlates with the OAA/S scale and therefore provides an objective measure of sedation during endoscopy. This preliminary, observational study suggests that a bispectral index revel near 82 corresponds with sufficient and functional sedation levels for endoscopy.