The Patient State Index is well balanced for propofol sedation

Background: The SEDLine (TM) monitor derived patient state index (PSI) is used to follow the depth of sedation. The demand for propofol sedation by anesthesiologists or non-anesthesiologists is increasing, and there are only a few studies addressing the relationship between PSI and propofol sedation. We aimed to investigate the ability of PSI index to identify the correct level of sedation of our patients during induction to anesthesia with target-controlled infusions of propofol. Methods: Twenty patients were enrolled in this study. The target effect site concentration of propofol was set at 1.5 mu g/ml followed by increments of 0.5 mu g/ml every five minutes. The PSI values and Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scale were recorded every twenty-five seconds during the infusion of propofol. Patients were considered losing verbal responsiveness at MOAA/S scale <= 2. Also, blood pressure, heart rate, and oxygen saturation were recorded every five minutes. Results: The PSI values corresponding to the sedation of various depths (MOAA/S scales) and alertness with verbal response were significantly different (p <0.001). We observed a good correlation of the PSI values to the decreasing MOAA/S scale (r =0.87667). Conclusions: The PSI index is well correlated with MOAA/S scale and effectively distinguishes the level of sedation during propofol infusion.