ViEWS—Towards a national early warning score for detecting adult inpatient deterioration☆

Abstract 

Aim of study

To develop a validated, paper-based, aggregate weighted track and trigger system (AWTTS) that could serve as a template for a national early warning score (EWS) for the detection of patient deterioration.

Materials and methods

Using existing knowledge of the relationship between physiological data and adverse clinical outcomes, a thorough review of the literature surrounding EWS and physiology, and a previous detailed analysis of published EWSs, we developed a new paper-based EWS – VitalPAC™ EWS (ViEWS). We applied ViEWS to a large vital signs database (n=198,755 observation sets) collected from 35,585 consecutive, completed acute medical admissions, and also evaluated the comparative performance of 33 other AWTTSs, for a range of outcomes using the area under the receiver-operating characteristics (AUROC) curve.

Results

The AUROC (95% CI) for ViEWS using in-hospital mortality with 24h of the observation set was 0.888 (0.880–0.895). The AUROCs (95% CI) for the 33 other AWTTSs tested using the same outcome ranged from 0.803 (0.792–0.815) to 0.850 (0.841–0.859). ViEWS performed better than the 33 other AWTTSs for all outcomes tested.

Conclusions

We have developed a simple AWTTS – ViEWS – designed for paper-based application and demonstrated that its performance for predicting mortality (within a range of timescales) is superior to all other published AWTTSs that we tested. We have also developed a tool to provide a relative measure of the number of “triggers” that would be generated at different values of EWS and permits the comparison of the workload generated by different AWTTSs.

Keywords: Monitoring, Outcome, Vital signs, Cardiac arrest, Patient safety, Risk