Early warning scores (EWS) identify high-risk hospitalized patients prior to clinical deterioration; however, their ability to identify high-risk pediatric patients in the emergency department (ED) has not been adequately evaluated. We sought to determine the association between modified pediatric EWS (MPEWS) in the ED and inpatient ward-to-pediatric intensive care unit (PICU) transfer within 24 hours of admission.

This is a case–control study of 597 pediatric ED patients admitted to the inpatient ward at Seattle Children’s Hospital between July 1, 2010, and December 31, 2011. Cases were children subsequently transferred to the PICU within 24 hours, whereas controls remained hospitalized on the inpatient ward. The association between MPEWS in the ED and ward-to-PICU transfer was determined by chi-square analysis.

Fifty children experienced ward-to-PICU transfer within 24 hours of admission. The area under the receiver–operator characteristic curve was 0.691. Children with MPEWS > 7 in the ED were more likely to experience ward-to-PICU transfer (odds ratio 8.36, 95% confidence interval 2.98-22.08); however, the sensitivity was only 18.0% with a specificity of 97.4%. Using MPEWS >7 for direct PICU admission would have led to 167 unnecessary PICU admissions and identified only 9 of 50 patients who required PICU care.

Elevated MPEWS in the ED is associated with increased risk of ward-to-PICU transfer within 24 hours of admission; however, an MPEWS threshold of 7 is not sufficient to identify more than a small proportion of ward-admitted children with subsequent clinical deterioration.