Rapid Response SystemsExploring the performance of the National Early Warning Score (NEWS) in a European emergency department☆
Introduction
The triage of patients at the time of presentation to emergency departments (EDs) is crucial to the provision of safe patient care. Accurately triaging patients is difficult, requires experience and may be subject to inter-observer variability1, 2, 3. Several triage systems have been developed for use in the ED, including the Emergency Severity Index (ESI) and the Manchester Triage Scale (MTS)4, 5, 6. These systems provide a method of categorizing all incoming ED patients by level of acuity ranging from life threatening to non-urgent and dictate how quickly patient should be seen.
However, while virtually all EDs employ triage systems to determine treatment priority, the evidence suggests that less attention is paid to the longitudinal monitoring of patients once they are in the department.7 There are no widely used scores specifically designed to detect deteriorating patients or to predict the chance of early intensive care unit (ICU) admission or death in ED patients. Further, small, single-site studies have demonstrated that longitudinal measurement of routine hemodynamic parameters in EDs is poor.7 These factors suggest that deteriorating patients may be at risk of going undetected during their ED stay and are therefore vulnerable to develop serious adverse events,8, 9 such as unexpected cardiac arrest and unnecessary ICU admission, with a higher consumption of resources through longer lengths of hospital stay (LoS).
First introduced in 1997, early warning scores (EWS) were developed in response to concerns about the failure to detect deteriorating physiological parameters in ward patients.10 They are based on patient's vital signs and linked to ‘triggers’, which mandate the escalation of monitoring or call for assistance. However, while EWS are now widely used internationally, there are many different EWS scoring systems, with many being adapted for use in individual hospital.11 The National Early Warning Score (NEWS), developed in conjunction with the Royal College of Physicians of London, has been more rigorously tested and performs better than any of the 33 published systems commonly in use.12 It has a good ability to discriminate ward patients at risk of cardiac arrest, death or unexpected intensive care unit (ICU) admission and it is currently being promoted as a standardized system across the UK.
The utility of NEWS has not yet been studied in an ED. The aim of this study was to explore the performance of NEWS with regard to predicting adverse outcomes, such as ICU admission and death, in adult patients as well as the ability of NEWS to predict the need for hospital admission in an ED population. The study also aimed to assess the feasibility of the use of NEWS as a structural monitoring tool in a Dutch ED.
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Design and setting
A prospective, observational feasibility study was performed at the ED of the VU Medical Center (VUmc), an academic urban tertiary care centre in Amsterdam, with approximately 31000 ED visits per year. The ED of the VUmc uses the Emergency Severity Index (ESI) for triage.5
Study population
Eligible patients were those of 18 years and older presenting to the ED of the VUmc during the 6 week study period (7th January till 15th February 2013, between 1200 and 2000 h) with an ESI of 2 and 3 not triaged to the
Patient population
A total of 300 patients were assessed for eligibility. Complete data was able to be collected for 274 patients at moment of entry to the ED (Table 3). For 247 of these 274 patients, the NEWS was calculated an hour later (Table 4). Only 133 of the 247 patients could be followed up to calculate the NEWS at discharge from the ED (admitted to the ward or discharged home). It was not possible to collect data for all patients at all-time points due to organizational reasons. The demographic
Discussion
To the best of our knowledge this is the first prospective study performed in an emergency department to evaluate the performance of the NEWS, a standardized score. We found that the NEWS was significantly correlated with patient outcomes, including 30 day mortality, hospital admission, and length of stay at all-time points. ICU admission was significantly correlated with NEWS at T0 and T1.
Several studies have been performed to investigate the value of early warning scores in identifying
Conclusion
The NEWS measured at different time points was a good predictor of patient outcomes. The NEWS can be of additional value in the ED, although not specifically as a triage system, but as a means to longitudinally monitor patients throughout their stay in the ED and in the hospital. Through its use, clinical staff has a better indication whether a patient is more at risk. Hereby making it possible to timely intervene and stabilize a patient before further deterioration occurs. Moreover, it may
Conflict of interest statement
No conflicts of interest.
Acknowledgement
The authors are grateful for the invaluable help of Dr. Peter van de Ven, Department of Epidemiology and Biostatistics, VU Medical Centre, in reviewing our manuscript.
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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.2015.02.011.