Elsevier

Journal of Critical Care

Volume 21, Issue 3, September 2006, Pages 271-278
Journal of Critical Care

Clinical Research—Pediatric
The pediatric early warning system score: A severity of illness score to predict urgent medical need in hospitalized children,☆☆

https://doi.org/10.1016/j.jcrc.2006.06.007Get rights and content

Abstract

Purpose

We developed and performed the initial retrospective validation of a pediatric severity of illness score. The score is to preemptively identify hospitalized children who are likely to require resuscitation to treat cardiopulmonary arrest.

Materials and Methods

The Pediatric Early Warning System (PEWS) score was developed using expert opinion. The score generated contained 20 items, 16 of which were able to be retrospectively abstracted. Validation used a case-control study design in a Canadian university–affiliated pediatric hospital. Eligible patients were younger than 18 years, were admitted to a hospital ward, and had no level-of-care restrictions. Case patients had a code blue called to obtain immediate assistance for treatment of impending or actual cardiopulmonary arrest. Control patients had no code blue event and were not urgently admitted to the intensive care unit within 48 hours of study. A total of 128 controls and 87 cases were compared.

Results

The PEWS score area under the receiver operating characteristic curve was 0.90. The sensitivity was 78% and the specificity was 95% at a score of 5.

Conclusions

Application of the score may have identified more than 3 quarters of code blue calls in our hospital with at least an hour's warning. After further refinement and validation, the PEWS score has great potential to increase the efficiency of care delivery and to improve the outcomes of care provided to hospitalized children.

Introduction

Up to 3% of children admitted to hospital wards require immediate medical assistance for treatment of actual or impending cardiopulmonary arrest [1], [2]. These children have increased morbidity and mortality associated with cardiopulmonary arrest [3], [4]. Currently, this catastrophic clinical deterioration is treated by “code blue” teams called to provide immediate resuscitation.

In adults, preemptive management may prevent cardiopulmonary arrest and improve mortality [5]. The provision of critical care “outreach” services to deliver preemptive care is recommended in Britain [6]. However, the provision of preemptive care relies on the timely identification of patients at risk and referral to the responding medical emergency team. The incomplete identification of patients may have contributed to the negative findings of the MERIT study, a cluster randomized trial of medical emergency teams in 23 Australian hospitals [7].

Two approaches to the timely identification of patients at risk may be used. First is the use of calling criteria, where patients meeting one or more specific “triggering” criteria are referred. Alternatively, “early warning” scores may be used. These severity of illness scores combine clinical parameters into a single score. Patients with scores greater than a threshold are identified and referred.

Early warning scores compliment clinical decision making and can identify trends independent of practitioner experience or clinical workload. Our systematic review found no scores for use in children and found one partially validated adult score [8]. We decided to develop a simple bedside score to preemptively identify children who require resuscitation to treat actual or impending cardiopulmonary arrest (Fig. 1).

Section snippets

Methods

A score to identify children with increasing severity of illness was developed using expert opinion synthesized by a modified Delphi method [9]. The performance of the score was evaluated with a frequency-matched case-control design. Hospitalized children without code blue or urgent intensive care unit (ICU) admission were compared with the sicker children for whom a code blue was called.

Focus groups

Ten nurses (with more than 140 years of combined nursing experience) formed the 2 focus groups (ICU and ward based). The focus groups decided that the PEWS should be able to be scored repeatedly throughout the child's hospital admission. They decided that PEWS score would be calculated by summation of subscores from changing clinical data and more static background factors.

The focus groups generated 47 items (Table 1). After exclusion of 6 staffing-related and 7 dynamic items by the second

Discussion

The PEWS score is the first severity of illness score for children admitted to hospital wards. In the initial evaluation, the PEWS score could differentiate between “well” children requiring routine ward-based care and sicker children who subsequently had an immediate need for medical intervention. At a threshold score of 5, the sensitivity and specificity were 78% and 95%, respectively. The PEWS score identifies patients with at least a 1-hour warning before the code blue event. This should be

Conclusions

A severity of illness score for hospitalized children was developed by using nursing-expert focus groups. The PEWS score can discriminate between children who had a code blue event and those who did not. At a threshold score of 5, the sensitivity and specificity were 78% and 95%, respectively. Prospective evaluation and refinement are required before the score can be used routinely to detect children at risk for this uncommon but highly significant event. Despite these reservations, the PEWS

Acknowledgments

The authors thank the following individuals: BP Kavanagh for review of the manuscript and suggestions about the figures; P Rochon and D Scales for their reviews and thoughtful comments about the manuscript; C Hyslop, K Dryden-Palmer, B Bruinsie, L Mak, R Gateiro, L McCarthy, K LeGrow, J Cvar, L Liske, and E Speed who participated in the focus groups.

Dr Christopher S Parshuram is the corresponding author and acts as guarantor of the manuscript and the underpinning data.

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This work was supported by internal funding from the Department of Critical Care Medicine and the Research Institute at the Hospital for Sick Children, Toronto, Ontario, Canada. The investigators functioned independent of these funding sources, and have no conflict of interest to declare with respect to this publication. Drs C Parshuram and J Hutchison have received peer-reviewed funding from the Heart and Stroke Foundation of Canada to support ongoing research in the prevention and treatment of pediatric cardiopulmonary arrest. This funding was in part related to the work described in the submitted manuscript.

☆☆

H Duncan contributed to the concept, design, interpretation, and manuscript revisions. J Hutchison contributed to the design, interpretation, and manuscript revisions. CS Parshuram contributed to the concept, design, interpretation, and drafting of the manuscript and assisted with its revisions. All authors approved the final submitted manuscript.

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