Objective: Procedural sedation is common in the ED. However, there is no objective physiologic parameter available to monitor a patient's conscious state. The Bispectral Index (BIS) monitor has been validated as an objective measure of depth of anaesthesia. We studied the BIS monitor for this role in procedural sedation.
Methods: A prospective, observational study with convenience sampling of adult patients in ED who underwent procedural sedation. Patients were treated according to standard practice and sedated as determined by the treating physician. Treating physicians were blinded to the BIS value. BIS values were recorded and compared to the Observer's Assessment of Alertness/Sedation Scale (OAAS). Upon recovery, patients were asked about recall of events while they were sedated.
Results: Twelve patients were enrolled and 110 paired readings from 11 patients (7 male) were obtained. It was not possible to obtain readings from one patient. The mean age was 58 years (range 20–94). The Spearman correlation between BIS and OAAS was 0.027 (95% CI −0.582−0.617). For the three patients who received propofol, the correlation was 1.0. There were no episodes of explicit recall of events during the period of sedation.
Conclusions: BIS monitoring is feasible in the ED. Our small study suggests that there is a poor correlation between BIS values and the OAAS scale. Larger studies are required to further explore this relationship. Further developments in brain monitoring technology are also needed before this form of monitoring becomes clinically useful for procedural sedation.