Clinical Review Extracts from “Clinical Evidence”

Acute asthma

BMJ 2001; 323 doi: (Published 13 October 2001) Cite this as: BMJ 2001;323:841
  1. Mark FitzGerald (, respiratory physician
  1. Centre for Clinical Epidemiology and Evaluation, Vancouver General Hospital, Vancouver, BC, Canada V5Z 1L8



    Spacer devices for delivering inhaled medications from pressurised metered dose inhalers in acute asthma (as good as nebulisers)

    Short courses of oral corticosteroids for acute exacerbations

    Ipratropium bromide added to ß2 agonists for acute exacerbations

    Likely to be beneficial:

    Continuous nebulised delivery of bronchodilators for acute asthma (better than intermittent treatment)

    Oxygen supplementation for acute asthma (no direct randomised evidence available)

    Intravenous magnesium sulphate for people with more severe acute asthma

    Mechanical ventilation for people with near fatal asthma (no direct randomised evidence available)

    Specialist versus generalist care for acute exacerbations

    Asthma education for people with acute asthma

    Unknown effectiveness:

    Intravenous versus nebulised delivery of short acting ß2 agonists for acute asthma


    Definition Asthma is characterised by dyspnoea, cough, chest tightness, wheezing, variable airflow obstruction, and airway hyperresponsiveness. The diurnal variation of peak expiratory flow rate (PEFR) is increased in people with asthma. Chronic asthma is defined as asthma requiring maintenance treat- ment, and will be dealt with in a separate “Extract from Clinical Evidence.1 2 Acute asthma is defined here as an exacerbation of underlying asthma requiring urgent or emergency treatment.

    Incidence/prevalence Reported prevalence of asthma is increasing worldwide. About 10% of people have had an attack of asthma. 3 4

    Aetiology/risk factors Most people with asthma are atopic; exposure to certain stimuli initiates inflammation and structural changes in airways, causing airway hyperresponsiveness and variable airflow obstruction, which in turn cause most asthma symptoms. Stimuli include environmental allergens, occupational sensitising agents, and respiratory viral infections. 5 6

    Prognosis About 10-20% of people presenting to the emergency department with asthma are admitted to hospital. Of these, fewer than 10% receive mechanical ventilation, 7 8 although previous ventilation is associated with a 19-fold increased risk of ventilation for a subsequent episode.9 It is unusual for …

    View Full Text

    Log in

    Log in through your institution


    * For online subscription