Research

Characteristics and outcome for admissions to adult, general critical care units with acute severe asthma: a secondary analysis of the ICNARC Case Mix Programme Database

Dheeraj Gupta¹, Brian Keogh², Kian Fan Chung³, Jon G Ayres^4,9, David A Harrison⁵ , Caroline Goldfrad⁶, Anthony R Brady⁷ and Kathy Rowan⁸

¹Visiting Fellow, Department of Respiratory Medicine, Birmingham Heartlands Solihull NHS Trust, Birmingham, UK

²Consultant in Anaesthesia and Intensive Care, Department of Anaesthesia, Royal Brompton Hospital, London, UK

³Professor of Respiratory Medicine, National Heart and Lung Institute, Imperial College, London, UK

⁴Professor of Respiratory Medicine, Department of Respiratory Medicine, Birmingham Heartlands Solihull NHS Trust, Birmingham, UK

⁵Statistician, Intensive Care National Audit and Research Centre, Tavistock House, Tavistock Square, London, UK

⁶Statistician/Data Manager, Intensive Care National Audit and Research Centre, Tavistock House, Tavistock Square, London, UK

⁷Senior Statistician, Intensive Care National Audit and Research Centre, Tavistock House, Tavistock Square, London, UK

⁸Director, Intensive Care National Audit and Research Centre, Tavistock House, Tavistock Square, London, UK

⁹Current address: Professor of Environmental and Occupational Medicine, and Head of Department, Liberty Safe Work Research Centre, Aberdeen, UK

author email corresponding author email

Critical Care 2004, 8:R112-R121doi:10.1186/cc2835

Published:	3 March 2004

Abstract

Introduction

This report describes the case mix, outcome and activity (duration of intensive care unit [ICU] and hospital stay, inter-hospital transfer, and readmissions to the ICU) for admissions to ICUs for acute severe asthma, and investigates the effect of case mix factors on outcome.

Methods

We conducted a secondary analysis of data from a high-quality clinical database (the Intensive Care National Audit and Research Centre [ICNARC] Case Mix Programme Database) of 129,647 admissions to 128 adult, general critical care units across England, Wales and Northern Ireland over the period 1995–2001.

Results

Asthma accounted for 2152 (1.7%) admissions, and in 57% mechanical ventilation was employed during the first 24 hours in the ICU. A total of 147 (7.1%) patients died in intensive care and 199 (9.8%) died before discharge from hospital. The mean age was 43.6 years, and the ratio of women to men was 2:1. Median length of stay was 1.5 days in the ICU and 8 days in hospital. Older age, female sex, having received cardiopulmonary resuscitation (CPR) within 24 hours before admission, having suffered a neurological insult during the first 24 hours in the ICU, higher heart rate, and hypercapnia were associated with greater risk for in-hospital death after adjusting for Acute Physiology and Chronic Health Evaluation II score. CPR before admission, neurological insult, hypoxaemia and hypercapnia were associated with receipt of mechanical ventilation after adjusting for Acute Physiology and Chronic Health Evaluation II score.

Conclusion

ICU admission for asthma is relatively uncommon but remains associated with appreciable in-hospital mortality. The greatest determinant of poor hospital survival in asthma patients was receipt of CPR within 24 hours before admission to ICU. Clinical management of these patients should be directed at preventing cardiac arrest before admission.