Short communicationCREWS: Improving specificity whilst maintaining sensitivity of the National Early Warning Score in patients with chronic hypoxaemia☆
Introduction
The National Early Warning Score (NEWS),1 an adaptation of the VitalPAC Early Warning Score (ViEWS),2 is being introduced in hospitals across the UK following a recommendation by the Royal College of Physicians.1 NEWS includes three respiratory parameters: respiratory rate, use of supplementary oxygen, and oxygen saturations. Points for oxygen saturations begin to be allocated when levels fall below 96%. Patients with respiratory conditions associated with chronic hypoxaemia such as chronic obstructive pulmonary disease (COPD) often have oxygen saturations below the “normal” range of 94–98%, even when their condition is stable.3 This could lead to persistently high NEWS, resulting in poor specificity of NEWS in this population. Persistent triggers could lead to unnecessary reviews and alarm fatigue,4 where important triggers are not acted on because of the frequency of clinically insignificant triggers – the “crying wolf” phenomenon. Modification of NEWS for patients with chronic respiratory conditions has been suggested as a possible solution,1, 5, 6 though adoption of a standardised evidence-based approach has not occurred to date.
The aim of the present study was to investigate whether patients with respiratory conditions associated with chronic hypoxaemia have persistently high NEWS even during stability, and to design a simple variant of NEWS to improve specificity whilst maintaining sensitivity for such patients; a Chronic Respiratory Early Warning Score (CREWS).
Section snippets
Methods
Data was collected between August and October 2012 on respiratory wards at Ysbyty Gwynedd and Wrexham Maelor Hospital; two NHS District General Hospitals in North Wales, UK. Both wards care for a mixture of respiratory and general medical patients. Data was collected prospectively from patients’ hospital notes, prescription and observations charts using standardised proformas. For patients re-admitted during the study period, only data from the first admission was included. The components of
Results
Two hundred and seventeen admissions were reviewed. Forty-seven patients (22%) were re-admitted to hospital within 30 days of discharge, with twenty-one patients (10%) re-admitted to the same ward within the data collection period; for these patients, only the first admission during the study period was included. Of the 196 included admissions, 98 (50%) were male; 91 (46%) had COPD; and mean age was 70 years (range 19–102, interquartile range 63–82). Ninety-eight patients (50%) had an arterial
Discussion
The present study shows that patients with CH, defined as those with target oxygen saturations of 88–92%, have persistently high NEWS during stability/at discharge. NEWS is based on an early warning score system designed to maximise both sensitivity (the ability to detect patients at risk of dying) and specificity (the minimisation of false alarms) for unselected patients admitted to Medical Admissions Units.1, 2 However, NEWS clearly lacks specificity for CH patients, who make up a significant
Conclusion
CREWS is a simple variant of NEWS for patients with chronic hypoxaemia that could reduce unnecessary triggers and alarm fatigue, whilst still identifying the sickest patients.
Conflict of interest statement
C. Subbe is principal investigator for a study by Philips Healthcare exploring bedside monitoring. The other authors have no relevant conflicts of interest. No external funding was received for this study.
Acknowledgements
We thank Dr. Rhys Jones and Dr. Amanda Skingle for their help with data collection.
References (12)
- et al.
ViEWS—towards a national early warning score for detecting adult inpatient deterioration
Resuscitation
(2010) - et al.
Hospital-wide physiological surveillance – a new approach to the early identification and management of the sick patient
Resuscitation
(2006) National Early Warning Score (NEWS): standardising the assessment of acute-illness severity in the NHS
(2012)- et al.
BTS guideline for emergency oxygen use in adult patients
Thorax
(2008) Monitor alarm fatigue: an integrative review
Biomed Instrum Technol
(2012)- et al.
S29 The Proposed National Early Warning System (NEWS) Could Be Hazardous For Patients Who Are at Risk of Hypercapnic Respiratory Failure
Thorax
(2012)
Cited by (0)
- ☆
A Spanish translated version of the abstract of this article appears as Appendix in the final online version at http://dx.doi.org/10.1016/j.resuscitation.2013.08.277.