Is the Patient State Index Recorded with the Sedline Sedation Monitor Correlated with the Duration of Emergence after Pediatric Surgery: An Exploratory, Single-Center, Blinded, Prospective Cohort Study

Introduction: Following surgery with general anesthesia, some children experience a prolonged emergence. We designed a prospective observational study in children undergoing general anesthesia who were monitored with the SedLine® Sedation Monitoring system (Masimo Corporation, Irvine, CA) to explore the hypothesis that the Patient State Index (PSI) obtained with this monitor could be inversely correlated with the duration of emergence after anesthesia. Materials and Methods: Prospective, observational single center study in a tertiary academic center in the United States. Fifty-six children between the ages of 1 and 12 years scheduled to undergo non-emergent surgery with general inhalational anesthesia were enrolled. Demographic and intraoperative characteristics were recorded. All caregivers were blinded to the PSI. Correlations were derived between PSI, duration of emergence, post-anesthesia care unit Length of Stay (LOS), and hospital LOS. PSI was analyzed in categories of <25, 25-50, and >50 both as absolute time spent in each category, and as the fraction of time compared to the length of the anesthetic. The development of Emergence Delirium (ED) was recorded as a secondary outcome variable. Results: The correlation coefficients between the PSI categories and the outcomes were weak (<0.3). Only two of the correlation coefficients reached statistical significance at p=0.05: fraction and absolute time spent in PSI category >50 and PACU length of stay, indicating that longer periods of PSI >50 during the anesthetic were associated with longer PACU LOS. Three patients (5%) developed ED. Conclusion: PSI measured with the SedLine monitor was not significantly correlated with the duration of emergence. There was a weak positive correlation between intraoperative time spent with PSI readings >50 and PACU LOS. Our sample did not have a high-enough event rate of ED to make statistical inferences about a correlation between PSI, ED and duration of emergence.