Clinical paperAn eight year audit before and after the introduction of modified early warning score (MEWS) charts, of patients admitted to a tertiary referral intensive care unit after CPR☆
Introduction
Failure to identify acute physiological deteriorations in acutely ill patients and act upon them can result in increased severity of illness; worsening morbidity and mortality particularly when cardio-respiratory arrest occurs.[1], [2], [3], [4], [5] During the 1990s, audit in the UK noted increased mortality rates in ward-based intensive care admissions compared to those from operating theatres and Accident and Emergency Units.6 Authors raised concerns about standards of practice in relation to detection of clinical deterioration and consequently developed the principle of “early recognition” via Early Warning Scores (EWS) to trigger skilled, experienced senior help for at-risk patients.7
Review of EWS in 2000 noted that regular use of such charts ensured earlier and more appropriate intensive care referrals and EWS evolved into MEWS (Modified Early Warning Score) with further potential for identifying at-risk patients.8 MEWS recognises that patients’ conditions frequently deteriorate over several hours and by regularly monitoring the basic clinical indicators of oxygen delivery (respiratory rate, heart rate, blood pressure, oxygen saturation) and tissue perfusion (capillary refill time, conscious level, oxygen saturation, urine output) ward-staff can gauge relative stability, triggering assistance when necessary (Fig. 1, Fig. 2). Increased MEWS scores have been associated with increased mortality and NCEPOD (National Confidential Enquiry into Patient Outcome and Death) has referred to this association when stating the need for early recognition of critically ill patients.[9], [10], [11]
In the UK these issues precipitated guidance from the Audit Commission and Department of Health with the latter using the publication Comprehensive Critical Care to recommended their use in May 2000.[12], [13] Additionally the facilitators of early recognition of at-risk patients were recommended as being the Critical Care Outreach Service or CCOS.[7], [14], [15], [16] Where cardiac arrests occurred outcomes were deemed dependent on effective cardiopulmonary resuscitation (CPR) and appropriate critical care interventions, consequently Comprehensive Critical Care stated that CCOS effectiveness would be gauged by measures related to intensive care outcome; they included severity of illness on admission to intensive care, mortality (intensive care and in-hospital) and re-admission rates.[13], [17] Other markers were the number of cardiac arrest calls in the hospital and the proportion of patients admitted to intensive care having undergone CPR.[12], [13] To measure such outcomes, data collection would also be necessary.[12], [13], [16]
The Freeman Hospital (FH) accordingly established a CCOS in 2001 consisting of six week-day sessions for consultant intensivists, supported by two senior intensive care nurses (1.5 whole time equivalents or WTEs). Initially the service directly supported a geographically separate high dependency unit (HDU) and the hospital's surgical wards. From August 2003 (when a new intensive care unit opened) the service expanded to cover other ward areas and with 6.5 WTEs in 2005 became 24/7, an important development in that survival rates from in-hospital cardiac arrests are known to be lower during nights and weekends.18 The profile of the CCOS increased and in addition to clinical support to wards, education was provided with respect to early recognition of at-risk patients and the use of MEWS charts (Fig. 1, Fig. 2).19 At the same time service reconfiguration within the Newcastle upon Tyne Hospitals resulted in all acute medical admissions being referred to another hospital (the Royal Victoria Infirmary or RVI) where MEWS-charts had a similar developmental background. Additionally the Trust's Resuscitation Committee introduced “Do Not Attempt CPR” (DNACPR) forms in 2005 with the aim of reducing the incidence of futile CPR.
Further developments included the introduction of a locally installed intensive care database in 2001 designed to capture intensive care outcome measures, e.g. mortality rates and severity of illness on admission as judged by their APACHE (Acute Physiology and Chronic Health Evaluation) II score. This was replaced in 2006 by the Intensive Care National Audit and Research Council Case Mix Programme (ICNARC-CMP) which in addition to APACHE II had its own severity of illness scoring system shown to be a greater predictor of hospital mortality.20 A series of local changes therefore occurred as a consequence of national trends in critical care services; they culminated in the introduction of MEWS charts, a 24/7 CCOS and re-location of acute medical admissions.
Section snippets
Methods
Best practice dictates that data collection and audit have a key role in monitoring the impact of such changes. We therefore performed a retrospective analysis of prospectively collected data in two four-year periods; 2002–05 and 2006–09. The second period being the four years, following the introduction of MEWS charts, 24/7 CCOS and re-location of acute medical admissions.
The primary aims were to assess whether (in the 2006–09 period) there had been a reduction in the proportion of cardiac
Results
Total adult admissions to FH (2002–05 vs. 2006–09) numbered 213 117 and 235 516 respectively. The overall annual admission rate increased by 10.5% with the proportion of emergency admissions reducing from 31% (n = 66 305) to 28% (n = 66 457; p < 0.001) (Table 1). The second audit period was associated with a significant reduction in the proportion of cardiac arrest calls to adult care areas, relative to both total admissions and emergency admissions (767 vs. 584; p < 0.0001). Hospital deaths reduced from
Discussion
After approximately 10-years the overall effectiveness of critical care outreach and equivalents remains uncertain. Evidence from Australia has linked the introduction of Medical Emergency Teams (METs) with reductions in cardiac arrest and mortality rates and work in the UK has suggested a reduction in intensive care re-admission rates.[21], [22] In the UK a randomised study on a single hospital site demonstrated significant reductions in hospital mortality when patients were cared for on wards
Conflict of interest statement
No conflict of interest declared.
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A Spanish translated version of the abstract of this article appears as Appendix in the online version at doi:10.1016/j.resuscitation.2010.09.480.