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Use of heliox for acute asthma in the emergency department

Three Part Question

In [patients with an acute exacerbation of asthma] is [heliox] beneficial in [reducing the severity of the exacerbation]?

Clinical Scenario

A 20 year old male attends the emergency department with a moderate to severe exacerbation of his asthma. HJe does not improve after repeated doses of nebulised salbutamol and atrovent. You have a feeling that heliox might be beneficial in just this sort of situation but wonder whether this is based on evidence or marketing hype.

Search Strategy

Medline 1966-03/04 using the Ovid interface. The Cochrane Library Issue 1, 2004.
[( OR exp asthma OR exp asthma, exercise-induced OR exp bronchial spasm OR broncospasm$.mp OR wheeze$.mp OR exp bronchial hyperreactivity
OR exp respiratory hypersensitivity OR status asthmaticus$.mp OR exp status asthmaticus OR acute asthma$.mp) AND (exp helium OR helium$.mp OR heliox$.mp OR (helium AND oxygen).mp)] LIMIT to human AND English language.
Cochrane: 'heliox'

Search Outcome

Altogether 207 papers were found, of which 6 were considered to be original research of high quality (randomised controlled trials) suitable for inclusion. Secondary citations from these papers were also scanned. These 6 papers have since been subject to meta-analysis by the Cochrane Review group. The Review was first published in 2000 with the most recent substantive amendment made in November 2002.

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Rodrigo G et al,
6 RCTs including 369 patients with acute asthma (5 studies involving adults, 1 study dealing only with children)Meta-analysisSpirometric measurements (PEF L/min, PEF % predicted, FEV1 L, FEV1 % predicted)Use of heliox did not improve pulmonary function compared with standard care (SMD=0.13; 95% CI: -0.09-0.34)Surrogate endpoints


The individual trials examined in the Cochrane review vary widely in the type of patients recruited (age, severity of asthma), delivery of heliox and outcome measures. Outcomes vary between heliox having a beneficial effect and having no effect. There are very few side effects of heliox documented.

Clinical Bottom Line

At the moment the evidence does not support the use of heliox in the emergency department treatment of acute asthma exacerbations.


  1. Rodrigo G, Pollack C, Rodrigo C, et al. Heliox for nonintubated acute asthma patient. The Cochrane Library Issue 1, 2004. Oxford: Update Software.