Clinical application of the National Early Warning Score 2 in prehospital emergency care: a study of evaluating risk with an objective scoring of severity.

Abstract

Objective: The National Early Warning Score 2 (NEWS2) is a tool used internationally to detect risk of clinical deterioration and promote rapid intervention. Although it has been extensively validated in hospital settings, few prospective studies have sought evidence of the score's ability to identify patients at high risk during prehospital emergency care. This study aimed to assess the ability of the NEWS2 to predict high risk for poor outcomes in out-of-hospital emergencies.

Methods: Prospective cohort study of patients evaluated by emergency medical technicians before arrival for treatment at a tertiary care hospital. NEWS2 findings for all eligible patients were recorded and then analyzed according to patient survival or not.

Results: We included 1307 patients (mean age 64.5 years); 51% were males, 1268 were survivors, and 39 were nonsurvivors). The median (interquartile range) NEWS2 score for survivors (3 [1-6]) was significantly lower than the median for nonsurvivors (14 [11-17]) (P .001). The areas under the receiver operating characteristic curves (AUCs) demonstrated that the NEWS2 was a significant predictor of poor outcomes such as all-cause mortality (AUC, 0.95; 95% CI, 0.93-0.98), admission to the intensive care unit (AUC, 0.93; 95% CI, 0.91-0.94), and later in-hospital mortality (AUC, 0.83; 95% CI, 0.80-0.87). Multivariate logistic regression analysis identified significant associations between the NEWS2 assessment and mortality (adjusted odds ratio, 1.599; 95% CI, 1.447-1.766; P .001). A NEWS2 score greater than 4 reliably identified patients at high risk for both early death (P .001) and later in-hospital death (P .001).

Conclusions: The NEWS2 is useful for evaluating patients in prehospital emergency care, enabling responders to quickly recognize serious clinical scenarios and identify patients at high risk for early in-hospital mortality.