PUMA - Paediatric early warning system (PEWS): Utilisation and Mortality Avoidance. A prospective, mixed methods, before and after study identifying the evidence base for the core components of an effective PEWS and the development of an implementation package for implementation and use in the UK

UK paediatric mortality is the highest in Europe(4000/yr) (1). There is evidence suggesting that missed deterioration (2,3) and difference in hospital performance contribute (4). Mandatory Child Death Overview Panels review all paediatric deaths in England to identify preventable factors, but recommendations are largely public health focused. The narrative nature of the hospital data collected limits identification of preventable factors. Feedback loops are required to ensure organisational accountability and compliance with initiatives to improve patient safety and reduce harm. Research in adult care identified that acute in-hospital deterioration is often preceded by a period of physiological instability which, when recognised, provides an opportunity for earlier intervention to improve outcome (5,6). The Royal College of Physicians endorsed the implementation of a National Early Warning system(7) to standardise the assessment of acute illness severity, predicting that 6000 lives will be saved annually. A similar intervention may save lives in hospitalised children (8,9,10) but the evidence base for a national Paediatric Early Warning System is uncertain. Definitions 1) A track and trigger tool (11) is derived from physiological, clinical and observational data recorded by staff. This can include data such as respiratory rate, oxygen requirement, peripheral oxygen saturation, effort of breathing, heart rate, systolic/diastolic blood pressure, capillary refill time and a basic neurology assessment. Each component contributes to the calculation of a score which directs staff to undertake certain actions; including, but not limited to, altered frequency of observation, senior nurse or urgent medical review. 2) A Paediatric Early Waring System (PEWS) describes a multi-faceted organisational process imbedded in paediatric wards which may or may not involve a track and trigger score. Track and trigger tools have developed in the UK in an ad hoc way, many based on consensus opinion, with limited evidence base or evaluation of effectiveness (12). There are several reasons for this: a) Evaluation requires significant resource. Currently hospitals use paper based systems to record paediatric physiological signs and clinical assessment, to judge whether a patient is seriously ill or deteriorating. b) There is significant heterogeneity in the track and trigger tools used (12). There is no consensus of the data points which should be collected or the thresholds where clinicians should be concerned. c) Physiological alteration in respiratory and heart rate from birth to adulthood, make it impossible to develop a single standardised score suitable for all sick children. This combination of factors limits the ability to compare the performance of PEW scores. d) Single studies [13,14,15] have been underpowered for the outcomes they studied, for example rates for in-hospital respiratory or cardiac arrest is low (0.19 to 2.45 /1000 admissions) (9). e) Compliance with the monitoring required to calculate track and trigger scores and escalation of concern is varied , which impacts on the ability to demonstrate effectiveness of the intervention. f) This is a complex intervention which involves the use a tool, underpinned by an organisational safety system/culture to identify and respond to patients flagged as at risk of deterioration. That preparedness includes staff training, human resource, senior supervision and effective communication, which impact on patient outcome. There is 85% track and trigger score utilisation in England and Wales [12]. The current ad hoc utilisation of un-validated track and trigger tools and variance in organisational capacity to respond to deterioration represents a serious clinical risk. Research Questions: What is the evidence for the core components of a national paediatric track and trigger tool? What is the evidence that the implementation of paediatric track and trigger tool