Validation of NEWS2 as a triage tool for ambulance transport requests for patients assessed by healthcare professionals.

Abstract

Background: The National Early Warning Score (NEWS2) system, commonly used in hospitals, has shown potential to be an effective prehospital triage tool for ambulance transport requests. This study evaluates the application of NEWS2 for triaging patients in need of transport by ambulance, after assessment by a healthcare professional. The study aims to validate an electronic triage form developed at Oslo Emergency Medical Communication Center (EMCC), focusing on its correlation with patient outcomes and the impact of operator-adjusted emergency codes.

Methods: A retrospective cross-sectional analysis was conducted on 36,865 ambulance transport cases documented at Oslo EMCC from December 2018 to December 2020. Data from the electronic triage form, EMCC's journal records and the Norwegian Cause of Death Registry were linked and analyzed to assess the relationship between NEWS2 scores, emergency codes and patient mortality. Associations between NEWS2 score and mortality at 1, 7 and 30 days were assessed using univariable logistic regression analyses, alongside descriptive sensitivity and specificity analyses. Operator adjustments to system-recommended emergency codes were also evaluated for their influence on outcomes.

Results: Increasing NEWS2 scores were significantly associated with increased mortality at 1, 7 and 30 days, with the strongest association observed for 1-day mortality. In total 40% of cases were upgraded by either the system (17%) or the operator (23%). System-initiated upgrades effectively identified critically ill patients, while operator-initiated adjustments showed minimal impact on mortality.

Conclusions: The findings support the use of NEWS2 as a reliable tool for prehospital triage, aligning with in-hospital findings and supporting consistent patient assessments. While operator discretion plays a role in refining urgency, its impact on mortality was not always significant. The results emphasize the importance of accurate triage to optimize patient outcomes and highlight the need for ongoing evaluation and integration of NEWS2 into EMCC practices. Future research should explore additional outcome measures beyond mortality to assess the broader efficacy of NEWS2 in prehospital settings.

Clinical trial number: Not applicable.