Original ArticleA single-centre cohort study of National Early Warning Score (NEWS) and near patient testing in acute medical admissions☆
Introduction
Predicting clinical outcomes in acutely unwell patients can be challenging. Early warning scores (EWS) are often used to identify patients who may benefit from an escalation of care. In the United Kingdom, the National Early Warning Score (NEWS) is becoming universal [1], [2]. NEWS weighs various physiological measurements by severity (Table 1) and the results are combined to give a composite score, which reflects how unwell the patient is [3]. EWS, like NEWS, have the potential to improve risk assessment in acutely unwell patients. NEWS is associated with admission to a critical care unit (level two or three care) and death in studies of patients with cancer, sepsis and medical diagnoses [4], [5], [6], [7], [8]. However, there is wider scope for using EWS as tools for prognostication in acutely unwell patients.
Near patient testing on admission to hospital, for example arterial or venous blood gas sampling, is increasingly common and some blood gas variables are associated with clinical outcome [9]. In the literature there are established correlations between poor prognosis and elevations in serum lactate or acid base derangement in critically ill patients, as well as raised serum glucose following myocardial infarction. [10], [11], [12], [13], [14]. The combination of EWS with near patient testing offers the exciting prospect of improving risk stratification in acute medical patients. Limited evidence suggests that the addition of serum lactate to EWS improved association with clinical outcome, compared to EWS alone [15]. However, it is unknown whether lactate or other blood gas variables could improve the utility of NEWS, in predicting clinical outcome [15].
We aim to determine whether combinations of NEWS and three blood gas variables (lactate, glucose and base-excess) on admission to hospital are associated with mortality or critical care unit (level two or three care) escalation within the first 48 h of hospital admission. We hypothesise that NEWS combined with any of the blood gas variables is more strongly associated with outcome compared to NEWS alone.
Section snippets
Study design
This was a planned secondary analysis of a prospective observational cohort study of undifferentiated adult medical ward patients. We have previously described the study design and data collection in detail [4]. Patients were identified for inclusion from the acute medical take list. We included all new unplanned medical admissions to the acute admissions unit at a large teaching hospital, during a 20-day period between 25th March and 13th April 2013. Patients that were not admitted via the
Results
Data from 453 patients were available. Cases with missing predictors were excluded from the analysis, as well as eight patients with an ambiguous record of the primary outcome, leaving 322 cases in the primary analysis and 310 cases in the secondary analysis (Fig. 1). Demographic data for the cases without blood gas data are provided in supplemental table 1. Of the cases included in the primary analysis, 33 (10.2%) blood gas samples were arterial, 285 (88.5%) were venous and 4 (1.2%) were not
Discussion
Our principal finding is that composite variables combining NEWS with either lactate or base excess were associated with death or critical care unit escalation within 48 h of hospital admission. However, NEWS alone was more strongly associated with this outcome. We did not identify associations between any combination of NEWS and blood gas variables with hospital length of stay. This supports our other published work, which suggests that NEWS is a poor predictor of hospital length of stay [4],
Conclusion
The combination of admission NEWS and either lactate or base excess is associated with death or critical care unit escalation within 48 h of hospital admission. But, NEWS alone was more strongly associated with this outcome measure. This research represents the first study to examine the relationship between combinations of NEWS and near patient testing, and clinical outcomes in medical ward patients. Our results sit in contrast with previous work in this field and, as such, should be
Conflict of interest statement
There are no conflicts of interest.
Acknowledgements
TA is a Medical Research Council and British Journal of Anaesthesia Clinical Research Training Fellow at the time of publication, but not while this research was carried out.
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Pre-hospital National Early Warning Score (NEWS) is associated with in-hospital mortality and critical care unit admission: A cohort study
2018, Annals of Medicine and SurgeryCitation Excerpt :This was a planned secondary analysis of data from an observational cohort study of adult patients admitted to a single hospital with acute medical presentations [4,11]. The methods and results of the main study have been published previously [4,11]. All new adult medical admissions to the Acute Assessment Unit (AAU) at the Royal London Hospital between 25th March and 13th April 2013 that were brought to hospital by ambulance were included in this analysis.
The surgical safety checklist and patient outcomes after surgery: a prospective observational cohort study, systematic review and meta-analysis
2018, British Journal of AnaesthesiaCitation Excerpt :Our results are therefore more widely generalizable and indicate a need for research and quality improvement to ensure safe and effective patient care in low- and middle-income countries. Examples may include rapid response systems and early warning scores.31–33 The largest study to evaluate the surgical safety checklist to date was a cohort study of an implementation project performed in acute care hospitals in Canada.34
Prognostic value of early warning scores in the emergency department (ED) and acute medical unit (AMU): A narrative review
2017, European Journal of Internal MedicineCitation Excerpt :The NEWS outperforms the REMS with an AUROC of 0.696 in these patients in one study [19]. The NEWS was also used in the general ED population and deemed to be a fair predictor of the composite outcome in the general ED population (AUROC 0.74–0.79) [34,35,40]. Adding the lactate to the NEWS further improved the composite outcome to an AUROC of 0.84 [40].
A modified Elixhauser score for predicting in-hospital mortality in internal medicine admissions
2017, European Journal of Internal MedicineCitation Excerpt :In 2008 a model was developed which included sex, age, admission type, a laboratory-based acute physiology score and a comorbidity score based on administrative data to predict IHM and 30-day mortality evaluating > 250.000 patients [26]. Recently in Europe two scores have been evaluated, the National Early Warning Score (NEWS) [27] and the PROFUND index [28], both based on clinical data, on the other hand, data regarding a score summarizing patients' clinical condition and IHM are scarce. Prediction of the risk of IHM represents a key factor in the management of elderly hospitalized patients, however mortality in older adults results from a combination of biological, functional, nutritional, psychological and environmental factors, not easily collected during admission.
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Original Article