Identifying children likely to develop critical illness can be difficult. The assessment tool developed from the advanced paediatric life support guidelines on identifying sick children appears to be sensitive but not specific. If the C&VPEWS was used as a trigger to activate a rapid response team to assess the child, the majority of calls would be unnecessary.

Objective: To determine the use of Paediatric Early Warning Systems (PEWS) and Rapid Response Teams (RRTs) in paediatric units in Great Britain.Design: Cross sectional survey.Setting: All hospitals with inpatient paediatric services in Great Britain.Outcome measures: Proportion of units using a PEWS, origin of PEWS used, criterion included in PEWS, proportion of units with a RRT and membership of RRT.Results: The response rate was 95% (149/157). 85% of units were using a PEWS and 18% had an RRT in place. Tertiary units were more likely than District General Hospital to have implemented a PEWS, 90% versus 83%, and a RRT, 52% versus 10%. A large number of PEWS were in use, the majority of which were unpublished and unvalidated systems.Conclusion: Despite the inconclusive evidence of effectiveness, the use of PEWS has increased since 2005. The implementation has been inconsistent with large variation in the PEWS used, the activation criteria used, availability of an RRT and the membership of the RRT. There must be a coordinated national evaluation of the implementation, impact and effectiveness of a standardised PEWS programme in the various environments where acutely sick children are managed.3 BACKGROUND

The MAC has a low PPV and its full implementation would result in a large number of false positive triggers. Further research is required to determine the relative contribution of the components of this complex intervention (Paediatric Early Warning System, education and MET) on patient outcome.

The NHSIII PEWS has a low PPV and its full implementation would result in a large number of false positive triggers. The issue with PEWS scores or triggers is neither their sensitivity nor children with high scores which require clinical interventions who are not 'false positives'; but their low specificity and low PPV arising from the large number of children with low but raised scores.