Utility of a Single Early Warning Score in Patients with Sepsis in The
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Downloaded from http://emj.bmj.com/ on August 23, 2017 - Published by group.bmj.com EMJ Online First, published on March 9, 2013 as 10.1136/emermed-2012-202186 Original article Utility of a single early warning score in patients with sepsis in the emergency department Alasdair R Corfield,1 Fiona Lees,2 Ian Zealley,3 Gordon Houston,4 Sarah Dickie,5 Kirsty Ward,2 Crawford McGuffie,5 on behalf of the Scottish Trauma Audit Group Sepsis Steering Group ▸ Additional material is ABSTRACT physiological parameters, a composite score can be published online only. To view Background An important element in improving the assigned to a patient, allowing early identification please visit the journal online fi (http://dx.doi.org/10.1136/ care of patients with sepsis is early identi cation and of patients who are at risk of critical illness. EWS emermed-2012-202186). early intervention. Early warning score (EWS) systems were initially established to assist in the manage- allow earlier identification of physiological deterioration. ment of patients in the general ward setting.13 14 1Emergency Department, Royal Alexandra Hospital, Paisley, UK A standardised national EWS (NEWS) has been proposed More recently there has been interest in the use of 2Information Services Division, for use across the National Health Service in the UK. EWS in the emergency department (ED) with National Services Scotland, Aim To determine whether a single NEWS on reports from single centres,15 16 although their use Glasgow, Scotland, UK emergency department (ED) arrival is a predictor of in the ED remains controversial.17 The use of a 3Radiology Department, Ninewells Hospital, Dundee, outcome, either in-hospital death within 30 days or standard single national EWS (NEWS) across the Scotland, UK intensive care unit (ICU) admission within 2 days, in National Health Service (NHS) in the UK has been 4Anaesthetic Department, patients with sepsis. recommended to improve patient care.18 Crosshouse Hospital, Methods Data were collected over a 3-month period In this study, we aimed to evaluate an EWS in a Kilmarnock, Scotland, UK as part of a national audit in 20 EDs in Scotland. All national cohort of patients with sepsis presenting to 5Emergency Department, Crosshouse Hospital, adult patients who were admitted for at least 2 days or EDs, to determine whether a single EWS in the ED Kilmarnock, Scotland, UK who died within 2 days were screened for sepsis criteria. was a useful predictor of outcome, either death or Patients with systemic inflammatory response syndrome intensive care unit (ICU) admission. Correspondence to fi criteria were included. An EWS was calculated based on Dr Alasdair R Cor eld, initial physiological observations made in the ED using Emergency Department, METHODOLOGY Royal Alexandra Hospital, the NEWS. Paisley PA2 9PN, UK; Results Complete data were available for 2003 Study population a.corfi[email protected] patients. Each rise in NEWS category was associated Data were collected over a 3-month period with an increased risk of mortality when compared to between March and May 2009 as part of the Received 28 November 2012 the lowest category (5–6: OR 1.95, 95% CI 1.21 to Scottish Trauma Audit Group (STAG) Sepsis Audit. Revised 7 February 2013 Twenty of the 25 mainland district general and Accepted 12 February 2013 3.14), (7–8: OR 2.26, 95% CI 1.42 to 3.61), (9–20: OR 5.64, 95% CI 3.70 to 8.60). This was also the case for teaching hospital EDs in Scotland participated in the combined outcome (ICU and/or mortality). the audit (Appendix 1). Conclusions An increased NEWS on arrival at ED is Adult patients (>16 years) attending as an emer- fi associated with higher odds of adverse outcome among gency were identi ed prospectively from ED or patients with sepsis. The use of NEWS could facilitate admission unit records. Hospital information patient pathways to ensure triage to a high acuity area systems were then interrogated to ascertain of the ED and senior clinician involvement at an early whether the patient had an inpatient stay of at least fi stage. 2 days. Patients who died within the rst 2 days, and who therefore may have been omitted from data collection, were identified retrospectively using General Register Office Scotland records. INTRODUCTION Patients who had an obviously non-infective cause Sepsis is defined as a systemic inflammatory for attendance such as acute cardiac ischaemia, response syndrome, provoked by an infection.12 trauma or stroke were excluded. This process iden- Sepsis continues to be a major cause of morbidity tified 27 046 patients who required case note and mortality in developed and developing coun- review in order to determine the presence of tries,34and is a significant burden on healthcare ‘sepsis’ criteria. systems in these countries.5 An important element The Surviving Sepsis Campaign Guidelines6 in improving the care of patients with sepsis is defined sepsis as ‘infection, documented or sus- early identification and early intervention, which pected’ and the presence of some of a number of has been shown to improve outcomes.67 general variables indicating physiological derange- Physiological deterioration often precedes clinical ment. Patients were included in the audit if they deterioration as patients develop critical illness.89 had: (a) a suspicion or confirmation of infection Recognition of this led to the development of within 2 days of attendance; and (b) two or more fi To cite: Cor eld AR, Lees F, the concept of the patient at risk and medical of the following physiological derangements: tem- Zealley I, et al. Emerg Med J 10–12 Published Online First: emergency teams. Early warning score (EWS) perature >38.3°C or <36°C; heart rate >90 bpm; [please include Day Month systems were then further developed to allow respiratory rate >20/min; white cell count of Year] doi:10.1136/emermed- earlier identification of physiological deterioration. >12 000/μl or <4000/μl or >10% immature 2012-202186 By assigning numerical values to various forms; acutely altered mental status; systolic blood CorCopyrightfield AR, et al. Emerg Article Med Jauthor2013;0:1– (or6. doi:10.1136/emermed-2012-202186 their employer) 2013. Produced by BMJ Publishing Group Ltd under licence. 1 Downloaded from http://emj.bmj.com/ on August 23, 2017 - Published by group.bmj.com Original article Of the 5285 patients identified, complete data were collected for 3890 (74%). Age, gender, length of stay, critical care attend- ance and outcome were recorded for all patients who met the sepsis criteria (N=5285). For each of these variables, the sample population (N=3890) was representative.19 For the purposes of this analysis, only patients who presented with or developed signs of sepsis prior to leaving the ED were included (N=2489). In this sample of 2489 patients, patients were excluded if they did not have a full set of observations made as part of their first set of observations. This resulted in a final sample size of 2003 patients (figure 1) Definition of NEWS The NEWS contains six physiological parameters (table 1), each of which is assigned a value of between 0 and 3 along with an additional parameter for supplemental oxygen, which scores 0 or 2. The score for each of the seven parameters is summed to calculate the NEWS which may range between 0 and 20; the higher the score, the greater the deviation from normality. The NEWS is based on previous similar scoring systems.11 12 15 Observations taken on attendance were used to calculate the NEWS. For some analyses patients were divided into four cat- egories based on their total score: 0–4, 5–6, 7–8, 9–20. This analysis grouping was based on the distribution of NEWS scores to give four approximately equal sized groups for comparison. In order to assess the effect of age on all endpoints an age adjusted NEWS was also calculated (+0 points for <50 years, +2 points for 50–70 years, +3 points for >70 years).20 The NEWS uses an AVPU (alert, voice, pain, unresponsive) score to define the patient’s level of consciousness. Where an AVPU score was unavailable, the Glasgow Coma Score (GCS) Figure 1 Patient study inclusion pathway. ED, emergency was considered to be an acceptable alternative (GCS 15=A, department. GCS <15=V,P,U). pressure <90 mm Hg; and blood glucose >7.7 mmol/l (in the Endpoints absence of diabetes). Primary endpoints were ICU admission within 2 days of attend- ance and 30-day mortality (in hospital). A combined endpoint of ICU admission and/or mortality was also assessed. Data collection A total of 5285 patients fulfilled the entry criteria. Data were Statistical analysis collected retrospectively by local audit coordinators at each hos- All analyses were carried out using SPSS V.17.0 for MS pital on a variety of demographic, physiological, process and Windows. outcome variables using a standardised proforma. Where avail- Differences between medians were tested using the Mann– able, patient observations taken on attendance were recorded. Whitney U test. ORs for each endpoint were estimated using All patients were followed to discharge or death. The difficulties logistic regression, with NEWS group as the independent vari- encountered in obtaining and extracting data from case notes able and age as a continuous covariate. Receiver operating were such that a pragmatic decision was taken to stop data col- characteristic (ROC) curves plotting sensitivity (true positives) lection in July 2010. against 1-specificity (false positives) were used to measure the Table 1 National early warning score NHS early warning score 32 1 0 1 2 3 Respiration rate ≤89–11 12–20 21–24 ≥25 Oxygen saturations ≤91 92–93 94–95 ≥96 Supplemental oxygen Yes No Temperature ≤35° 35.1–36° 36.1–38° 38.1–39° ≥39.1° Systolic blood pressure ≤90 91–100 101–110 111–219 ≥220 Pulse ≤40 41–50 51–90 91–110 111–130 ≥131 Conscious level A V,P,U A, alert; NHS, National Health Service; V,P,U, voice, pain, unresponsive.