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Abstract

Introduction: While critically ill patients may be admitted to the pediatric intensive care unit (ICU) at any time, staffing and other factors may vary by day of the week or time of day. The purpose of this study was to evaluate whether off-hours admissions (nights and weekends) were independently associated with increased mortality in a large database sample of pediatric ICUs. Methods: A retrospective cohort study of admissions of children <18 years of age to pediatric ICUs was performed using the Virtual PICU Systems (VPS,LLC) database. Off-hours was defined as nighttime (7:00pm-06:59am) and weekend (Saturday or Sunday any time). Regression analysis was performed using a mixed-effects multivariate model with clustering at the hospital level, using Pediatric Index of Mortality 2 to adjust for severity of illness. The primary outcome was death in the pediatric ICU. Results: Data from 246,184 admissions to 100 pediatric ICUs from January 1st, 2009 to September 29th, 2012 were included in the analysis. Patients admitted during off-hours were more likely to be unscheduled admissions, had a higher predicted risk of mortality, and had a higher unadjusted ICU mortality (off-hours 2.8% mortality vs. weekdays 2.2%, p<0.001). Multivariate regression revealed that, after adjusting for severity of illness and other significant factors, off-hours admission was associated with reduced odds of mortality (OR 0.91, 95%CI 0.85-0.97, p=0.004), as was nighttime admission (OR 0.87, 95%CI 0.82-0.93, p<0.0001), while weekend admission had no association with mortality (OR 1.0, 95%CI 0.93-1.07, p=0.9). Peak mortality was observed during the morning hours from 06:00-10:59am, and post-hoc multivariate analysis revealed that admission during this period was independently associated with death (OR 1.22, 95%CI 1.10-1.33, p<0.0001). Conclusions: Off-hours admission does not independently increase odds of death in a large sample of pediatric ICUs. Admission during the morning period from 06:00-10:59am, which often includes morning rounds, is associated with increased risk of death in our cohort and may warrant further investigation in the pediatric ICU population.