Relationship of illness severity and length of stay to functional outcomes in the pediatric intensive care unit: a multi-institutional study

Abstract

Objective: The purpose of this study was to establish relationships between illness severity, length of stay, and functional outcomes in the pediatric intensive care unit (PICU) by using multi-institutional data. We hypothesized that a positive relationship exists between functional outcome scores, severity of illness, and length of stay.

Design: The study used a prospective multicentered inception cohort design.

Setting: The study was conducted in 16 PICUs across the United States that were member institutions of the Pediatric Critical Care Study Group of the Society of Critical Care Medicine.

Patients: In total, 11,106 patients were assessed, representing all admissions to these intensive care units for 12 consecutive months.

Measurements: Functional outcomes were measured by the Pediatric Overall Performance Category (POPC) and Pediatric Cerebral Performance Category (PCPC) scales. Both scales were assessed at baseline and discharge from the PICU. Delta scores were formed by subtracting baseline scores from discharge scores. Other measurements included admission Pediatric Risk of Mortality scores, age, operative status, length of stay in the PICU, and diagnoses. Interrater reliability was assessed by using a set of ten standardized cases on two occasions 6 months apart.

Main results: Baseline, discharge, and delta POPC and PCPC outcome scores were associated with length of stay in the PICU and with predicted risk of mortality (p < .01). Incorporation of baseline functional status in multivariate length of stay analyses improved measured fit. Mild baseline cerebral deficits in children were associated with 18% longer PICU stays after controlling for other patient and institutional characteristics. Moderate and severe baseline deficits for both the POPC and PCPC score predict increased length of stay of between 30% and 40%. On the standardized cases, interrater consensus was achieved on 82% of scores with agreement to within one neighboring class for 99.7% of scores.

Conclusions: These data establish current relationships for the POPC and PCPC outcome scales based on multi-institutional data. The reported relationships can be used as reference values for evaluating clinical programs or for clinical outcomes research.