Timely recognition of deterioration of hospitalised children is important to improve mortality. We developed a modified Paediatric Early Warning Score (PEWS) and studied the effects by performing three different cohort studies using different end points. Taking unplanned Paediatric Intensive Care Unit admission as end point and only using data until 2 h prior to end point, we found a sensitivity of 0.67 and specificity of 0.88 to timely recognise patients. This proves that earlier identification is possible without a loss of sensitivity compared to other PEWS systems. When determining the corresponding clinical condition in patients with an elevated PEWS dichotomously as 'sick' or 'well', this resulted in a total of 27 % false-positive scores. This can cause motivational problems for caregivers to use the system but is a consequence of PEWS design to minimise false-negative rates because of high mortality associated with paediatric resuscitation. Using the need for emergency medical interventions as end point, sensitivity of PEWS is high and it seems, therefore, that it is also fit to alert health-care professionals that urgent interventions may be needed.
Conclusion: These data show the effectiveness of a modified PEWS in identifying critically ill patients in an early phase making early interventions possible and hopefully reduce mortality.