Skip to main content
  • Poster presentation
  • Open access
  • Published:

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


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.


  1. Konrad D, et al.: Intensive Care Med. 2010, 36: 100-106. 10.1007/s00134-009-1634-x

    Article  PubMed  Google Scholar 

  2. Charlson ME, et al.: J Chronic Dis. 1987, 40: 373-383. 10.1016/0021-9681(87)90171-8

    Article  CAS  PubMed  Google Scholar 

  3. Armitage : Statistical Methods in Medical Research. 4th edition. Oxford: Blackwell; 2002:124-125.

    Book  Google Scholar 

Download references

Author information

Authors and Affiliations


Rights and permissions

This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and permissions

About this article

Cite this article

Raj, A., Zwaal, J. Impact of training in the use of an early warning system on in-hospital cardiac arrests. Crit Care 15 (Suppl 1), P477 (2011).

Download citation

  • Published:

  • DOI: