ObjectiveTo systematically review the available evidence on paediatric early warning systems (PEWS) for use in acute paediatric healthcare settings for the detection of, and timely response to, clinical deterioration in children.MethodThe electronic databases PubMed, MEDLINE, CINAHL, EMBASE and Cochrane were searched systematically from inception up to August 2016. Eligible studies had to refer to PEWS, inclusive of rapid response systems and teams. Outcomes had to be specific to the identification of and/or response to clinical deterioration in children (including neonates) in paediatric hospital settings (including emergency departments). 2 review authors independently completed the screening and selection process, the quality appraisal of the retrieved evidence and data extraction; with a third reviewer resolving any discrepancies, as required. Results were narratively synthesised.ResultsFrom a total screening of 2742 papers, 90 papers, of varied designs, were identified as eligible for inclusion in the review. Findings revealed that PEWS are extensively used internationally in paediatric inpatient hospital settings. However, robust empirical evidence on which PEWS is most effective was limited. The studies examined did however highlight some evidence of positive directional trends in improving clinical and process-based outcomes for clinically deteriorating children. Favourable outcomes were also identified for enhanced multidisciplinary team work, communication and confidence in recognising, reporting and making decisions about child clinical deterioration.ConclusionsDespite many studies reporting on the complexity and multifaceted nature of PEWS, no evidence was sourced which examined PEWS as a complex healthcare intervention. Future research needs to investigate PEWS as a complex multifaceted sociotechnical system that is embedded in a wider safety culture influenced by many organisational and human factors. PEWS should be embraced as a part of a larger multifaceted safety framework that will develop and grow over time with strong governance and leadership, targeted training, ongoing support and continuous improvement.