Early warning scores and critical care transfer - patient heterogeneity, low sensitivity, high mortality.

In a diverse hospital population, most triggering patients did not receive critical care and most critical care transfers occurred without triggering. Triggering was an insensitive screening measure for critical illness, followed by poor outcome. Higher scores predicted higher probability of transfer, but not later mortality, suggesting that EWS is being used as a decision aid but is not a true severity of illness score. Other, non-EWS data are needed for earlier detection and for prioritizing access to critical care.