Carle's obstetric early warning score as a screening tool for critical care admission.

Background objectives: Early warning systems (EWS) involve serial observations (track) with criteria (trigger) to timely identify patients at risk of complications. Carle designed a statistically based clinically modified obstetric early warning score (Carle's OEWS). This study evaluated Carle's OEWS and its individual components for predicting admission to the obstetric critical care unit (OCCU). Maternal near-miss and maternal mortality were the secondary outcomes.

Methods: A prospective observational study was conducted among 1250 pregnant women with a period of gestation ≥28 week admitted in the labour wards of a tertiary centre over 18 months. The physiological parameters of OEWS were recorded and aggregate score was calculated at admission and at regular intervals thereafter, till discharge or OCCU admission.

Results: The area under receiver operating characteristic (ROC) curve of OEWS was 0.975 for predicting OCCU admission, 0.971 for near-miss, and 0.996 for predicting maternal mortality and was significant for all outcomes. All individual parameters, except diastolic blood pressure, had a significant relative risk for predicting OCCU requirement.

Interpretation conclusions: Carle's OEWS is a useful screening tool for predicting obstetric OCCU admission and can be routinely used in labour wards to ensure timely intervention.