An assessment of the association of bispectral index with 2 clinical sedation scales for monitoring depth of procedural sedation

Abstract

Objective We conducted a study to assess the correlation of bispectral index (BIS) to 2 clinical sedation scales. Methods This was a prospective, observational study. The BIS number was recorded at baseline and every 30 seconds. One investigator separately monitored the patients for depth of sedation using the Observer's Assessment of Alertness/Sedation and the Continuum of Depth of Sedation scales. Results During the 6-month period, 75 patients were enrolled. The Spearman correlation between the BIS and the Observer's Assessment of Alertness/Sedation was 0.59 (95% confidence interval [CI], 0.44-0.74). The Spearman correlation between the BIS and the Continuum of Depth of Sedation was 0.53 (95% CI, 0.36-0.70). The mean minimum BIS for patients without a complication was 70 (SD, 15.9) compared with 68 (SD, 12.9) for patients with a complication (difference = 2; 95% CI, −7-11). Conclusions Our study demonstrated moderate correlation between BIS and the 2 clinical sedation scales. The correlation is not strong enough to be used reliably in a clinical setting. The mean minimum BIS scores were not significantly different for those with sedation complications vs those without complications.