Can prehospital Modified Early Warning Score identify non-trauma patients requiring life-saving intervention in the emergency department?

ObjectiveWe aim to investigate whether prehospital Modified Early Warning Score (MEWS) can identify non-trauma patients requiring life-saving intervention (LSI) within 4h of presentation to the ED. MethodsIt was a prospective study of non-trauma ED patients by ambulance who were 16years or older from 1 to 27 November 2013. Prehospital MEWS was calculated according to vital signs measured by the ambulance crew. Data on patients' demographics, triage category, LSI within 4h of ED presentation and 24h mortality were retrieved. LSI was defined as emergency interventions to airway, breathing and circulation, emergency procedures and medications administered. The performance of prehospital MEWS was analysed with sensitivity, specificity, predictive values (PV), likelihood ratios (LR) and the receiver operating characteristic curve. ResultsRecruited during the study period were 1493 patients. The median age was 78years. Of the patients, 49.9% belonged to critical, emergent or urgent triage categories. LSI was required in 321 patients (21.5%). Thirteen died within 24h of ED presentation. The area under the receiver operating characteristic curve of prehospital MEWS relating to LSI was 0.72 (95% confidence interval 0.69 to 0.75). The sensitivity, specificity, positive PV, negative PV, positive LR and negative LR were 0.57, 0.76, 0.40, 0.87, 2.43 and 0.56, respectively, when prehospital MEWS3 was chosen as the cut-off value. ConclusionsPrehospital MEWS is useful in identifying non-trauma patients requiring LSI within 4h of ED presentation. This may in turn enhance the triage accuracy in the ED in addition to clinical assessment.