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  • Poster presentation
  • Open Access

Impact of training in the use of an early warning system on in-hospital cardiac arrests

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  • 1
Critical Care201115 (Suppl 1) :P477

  • Published:


  • Cardiac Arrest
  • Medical Staff
  • Early Warning System
  • Abnormal Physiology
  • Cardiac Arrest Patient


The introduction of an early warning system (EWS) has been associated with a reduction in in-hospital cardiac arrest (CA) [1]. We set out to determine the impact of a programme of training in the use of an EWS on the number and nature of CAs in our hospital.


We conducted a retrospective chart survey of all adult CA patients pre and post implementation of a training programme in the use of the EWS. If a patient develops abnormalities in two or more physiological parameters, the system forces escalation of care through three levels of care, with involvement of junior medical staff at level 1 and senior ICU medical staff at level 3. Abnormal physiology was defined as: SaO2 < 90%, HR <50 or ≥110/minute, systolic blood pressure <90 mmHg, conscious level: only responsive to pain, respiratory rate <10 or ≥25/minute or clinical concern about the patient. Outcome parameters: CA/1,000 bed-days, percentage of CPR attempts deemed inappropriate by two senior intensivists, percentage of patients (in whom CPR attempts were deemed appropriate) with abnormal physiology prior to CA and survival post CA. Charlson's co-morbidity index (CCI) [2] was calculated for both periods. Differences between mean values were tested with Student's t-test and differences between percentages were tested according to the method described by Armitage [3].


After adjusting for age (mean pre: 81.7, post: 81.8 years (P = 0.99)), sex and co-morbidity (CCI pre: 6.4, post: 6.66 (P = 0.79)): CA/1,000 bed-days pre: 0.89, post: 0.76 (P = 0.24); percentage of inappropriate CPR attempts pre: 62.5%, post: 33% (P = 0.11); percentage of cases with abnormal physiology identified prior to arrest pre: 68.8%, post: 75% (P = 0.72); and survival pre: 12.5%, post: 0% (P = 0.20).


Training in EWS was associated with a reduction in the number of CAs and percentage of inappropriate CPR attempts, both of which are in keeping with the literature. However, there was no significant difference in the percentage of cases with abnormal physiology identified prior to CA between both periods and there was no survival benefit after CA. An early warning tool may be unable to prevent CA in a subset of patients with deranged physiology.

Authors’ Affiliations

Kingston Hospital NHS Trust, Kingston upon Thames, UK


  1. Konrad D, et al.: Intensive Care Med. 2010, 36: 100-106. 10.1007/s00134-009-1634-xView ArticlePubMedGoogle Scholar
  2. Charlson ME, et al.: J Chronic Dis. 1987, 40: 373-383. 10.1016/0021-9681(87)90171-8View ArticlePubMedGoogle Scholar
  3. Armitage : Statistical Methods in Medical Research. 4th edition. Oxford: Blackwell; 2002:124-125.View ArticleGoogle Scholar


© Raj and Zwaal 2011

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.