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Aggregate Early Warning Score Results Mixed for High-Risk Pediatric Patients


Dr. Chang

Clinical question: Do rapid response systems (RRS) reduce the rate of critical deterioration (CD) in hospitalized children?

Background: Over the past decade, a majority of pediatric inpatient units and freestanding children’s hospitals have instituted RRSs that utilize medical emergency teams (MET) to rapidly evaluate clinically deteriorating patients. Pediatric RRSs manifest variability between institutions in MET composition and RRS triggers. Prior studies of RRSs in the pediatric population have been mixed, with a lack of robust evidence that RRSs reduce hospital mortality and cardiopulmonary arrest rates. Evaluation of the effect of RRSs in pediatric units and hospitals is complicated by the heterogeneity of pediatric RRS implementation and the overall low rate of in-hospital cardiopulmonary arrest and death. In a 2012 study, the authors defined CD events as those leading to ICU transfer and subsequent mechanical ventilation (noninvasive or invasive) or vasopressor infusion within 12 hours. CD event rates, quantified as an event rate per 1,000 non-ICU patient-days, were found to be associated with a >13-fold increase in risk of in-hospital death and were believed to be a valid proximate outcome for in-hospital mortality.

Study design: Single-center interrupted time series analysis

Setting: 516-bed urban, tertiary care, freestanding children’s hospital.

Synopsis: The RRS at this institution consisted of an aggregate early warning score (EWS), which triggered the response of a MET (within 30 minutes) 24 hours a day, seven days a week. Distinct from the code-blue team, the MET comprised PICU staff, including: (1) a fellow, attending, or nurse practitioner; (2) a nurse; and (3) a respiratory therapist. Researchers compared the 32 months prior to implementation to the 27 months after implementation. An interrupted time series analysis was performed using advanced statistical modeling with adjustments for season, ward, and case-mix index.

Although there were no significant differences in rates of cardiopulmonary arrest or mortality, adjusted analysis revealed a net 62% reduction in CD event rate (IRR=0.38) after initiation of the RRS. Adjusted analysis also found a net 83% reduction in mechanical ventilation events (IRR=0.17) and a net 80% reduction in vasopressor use (IRR=0.20). Of note, these reductions were not significant in the unadjusted analyses. After transfer to the ICU, time elapsed until initiation of either mechanical ventilation or vasopressor use was longer.

Bottom line: With an aggregate EWS identifying high-risk patients requiring rapid evaluation by a MET, a pediatric RRS reduces adjusted rates of CD events but might not yield significant reductions in unadjusted rates of mortality, cardiopulmonary arrest, or CD events.

Citation: Bonafide CP, Localio AR, Roberts KE, Nadkarni VM, Weirich CM, Keren R. Impact of rapid response system imple-mentation on critical deterioration events in children. JAMA Pediatr. 2014;168(1):25-33.

Reviewed by Pediatric Editor Weijen Chang, MD, SFHM, FAAP, associate clinical professor of medicine and pediatrics at the University of California at San Diego School of Medicine, and a hospitalist at both UCSD Medical Center and Rady Children’s Hospital.

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