Elsevier

Resuscitation

Volume 84, Issue 4, April 2013, Pages 465-470
Resuscitation

Clinical paper
The ability of the National Early Warning Score (NEWS) to discriminate patients at risk of early cardiac arrest, unanticipated intensive care unit admission, and death

https://doi.org/10.1016/j.resuscitation.2012.12.016Get rights and content

Abstract

Introduction

Early warning scores (EWS) are recommended as part of the early recognition and response to patient deterioration. The Royal College of Physicians recommends the use of a National Early Warning Score (NEWS) for the routine clinical assessment of all adult patients.

Methods

We tested the ability of NEWS to discriminate patients at risk of cardiac arrest, unanticipated intensive care unit (ICU) admission or death within 24 h of a NEWS value and compared its performance to that of 33 other EWSs currently in use, using the area under the receiver-operating characteristic (AUROC) curve and a large vital signs database (n = 198,755 observation sets) collected from 35,585 consecutive, completed acute medical admissions.

Results

The AUROCs (95% CI) for NEWS for cardiac arrest, unanticipated ICU admission, death, and any of the outcomes, all within 24 h, were 0.722 (0.685–0.759), 0.857 (0.847–0.868), 0.894 (0.887–0.902), and 0.873 (0.866–0.879), respectively. Similarly, the ranges of AUROCs (95% CI) for the other 33 EWSs were 0.611 (0.568–0.654) to 0.710 (0.675–0.745) (cardiac arrest); 0.570 (0.553–0.568) to 0.827 (0.814–0.840) (unanticipated ICU admission); 0.813 (0.802–0.824) to 0.858 (0.849–0.867) (death); and 0.736 (0.727–0.745) to 0.834 (0.826–0.842) (any outcome).

Conclusions

NEWS has a greater ability to discriminate patients at risk of the combined outcome of cardiac arrest, unanticipated ICU admission or death within 24 h of a NEWS value than 33 other EWSs.

Introduction

The use of early warning scoring systems, also known as physiological, aggregate weighted track and trigger systems,1 has been recommended in a range of UK reports regarding the early recognition and response to patient deterioration.1, 2, 3, 4, 5, 6, 7, 8 These systems allocate points in a weighted manner, based on the derangement of patients’ vital signs variables (e.g., pulse rate, breathing rate, blood pressure) from arbitrarily agreed ‘normal’ ranges. The sum of the allocated points – the early warning score (EWS) – is used to direct care, e.g. to increase vital signs monitoring, involve more experienced staff or call a rapid response team (e.g. outreach or medical emergency team). A range of EWS is in use in hospitals in the UK, with a significant degree of variation in the measured physiological variables, the weightings assigned, and the thresholds for triggering specific responses.9, 10

In 2007, the report of the Acute Medicine Task Force of the Royal College of Physicians, London (RCPL) recommended that “…physiological assessment of all patients should be standardised across the NHS with the recording of a minimum clinical data set result (sic) in an NHS early warning (NEW) score…”.7 In 2010, we developed a novel early warning scoring system – ViEWS (VitalPAC Early Warning Score11) – which performed better than 33 other published systems when used to discriminate survival from non-survival at 24 h post observation. ViEWS was developed using an iterative, pragmatic, ‘trial and error’ approach, with the cut-offs for its scoring bands being deliberately adjusted to maximising its ability to predict in-hospital death within 24 h of a vital signs dataset.11 No attempt was made to modify ViEWS with respect to maximise its ability to discriminate any other outcome.

Members of the RCPL National Early Warning Score Design and Implementation Group (NEWSDIG) made minor adjustments to ViEWS, based on clinical opinion, to develop the National Early Warning Score (NEWS) (Table 1).12 (One of our group – GBS – was a member of NEWSDIG). As part of the development of NEWS, our group undertook an evaluation of NEWS versus other existing EWS systems for the RCPL. This article shows the application of NEWS to the same large vital signs database used in the ViEWS publication,11 but now also applied to additional clinical outcomes, i.e., cardiac arrest and unanticipated intensive care unit (ICU) admission.

Section snippets

Method

Local research ethics committee approval was obtained for this study from the Isle of Wight, Portsmouth and South East Hampshire Research Ethics Committee (study ref. 08/02/1394). The study considered only pseudoanonymised data.

Results

198,755 vital signs datasets (94,376 from males) were obtained from 35,585 patient episodes. The mean (median) ages of the patients were 67.7 (72.6) yrs (male 65.9 (69.7); female 69.4 (75.5)). The number of observation sets followed by death within 24 h was 1999 (1%), irrespective of any of the other three outcomes. When we applied the precedence rules as described in the methods, of the 198,755 observation sets, 199 were followed by cardiac arrest, 1161 by unanticipated ICU admission, 1789 by

Discussion

The measurement of vital signs and the use of EWS systems are essential components of the ‘Chain of Prevention’, a paradigm for structuring the early recognition and response to patient deterioration.20 However, despite the clear advantages of standardisation (e.g., standardised training, reduced confusion and misunderstanding during use, and transferability across organisations), there has been a lack of consistency in the choice of EWS used in the NHS.9, 10 Failure to adopt a common EWS has

Conclusions

We have demonstrated that the National Early Warning Score (NEWS), recently developed by a multiprofessional team at the Royal College of Physicians of London and proposed for use in all NHS hospitals, is able to discriminate patients at risk of the combined outcome of cardiac arrest, unanticipated ICU admission or death within 24 h of a NEWS value better than 33 other EWSs. NEWS also performed better than the other 33 systems for the individual outcomes of unanticipated ICU admission or death,

Conflict of interests statement

VitalPAC is a collaborative development of The Learning Clinic Ltd (TLC) and Portsmouth Hospitals NHS Trust (PHT). PHT has a royalty agreement with TLC to pay for the use of PHT intellectual property within the VitalPAC product. Professor Prytherch and Drs Schmidt, Featherstone and Meredith are employed by PHT. Professor Smith was an employee of PHT until 31/03/2011. Dr. Schmidt, and the wives of Professors Smith and Prytherch are shareholders in TLC. Professors Smith and Prytherch, and Dr.

Funding

None.

Acknowledgements

The authors would like to acknowledge the co-operation of the nursing and medical staff in the study hospital.

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    A Spanish translated version of the abstract of this article appears as Appendix in the final online version at http://dx.doi.org/10.1016/j.resuscitation.2012.12.016.

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