Q&A

Heliox of minimal benefit in acute asthma

J Fam Pract. 2003 July;52(7):512-525
By
Kenneth H. Johnson, DO
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  • BACKGROUND: During an asthmatic attack, not all patients respond to treatment with bronchodilators and corticosteroids. Heliox, because of its low density, flows more efficiently through constricted airways with less turbulence and resistance than oxygen or air-oxygen mixtures. Heliox has been studied with mixed results in acute asthma.
  • POPULATION STUDIED: The investigators included studies that enrolled adults and children with acute asthma requiring hospital treatment. They excluded studies of patients with disease but without acute exacerbations, and studies of patients with induced peripheral airway obstruction.
  • STUDY DESIGN AND VALIDITY: This was a meta-analysis of randomized controlled trials found by an extensive search of MEDLINE, EMBASE (the European MEDLINE), and the Cochrane Controlled Trials Registry. They also reviewed the reference lists of included articles, but excluded articles not in English. They identified 8 randomized controlled trials, 2 nonrandomized controlled trials, 4 before-after case series, and a case report. Only 4 randomized controlled trials were included in the meta-analysis.
  • OUTCOMES MEASURED: The primary patient-oriented outcomes were length of hospital stay, and incidence of tracheal intubation and mechanical ventilation.
  • RESULTS: Most studies failed to show any difference between groups after the first hour or so of treatment or any difference in important clinical outcomes. Data were insufficient to determine whether heliox can avert tracheal intubation, change intensive care and hospital admission rates and duration, or affect mortality.
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PRACTICE RECOMMENDATIONS

This meta-analysis showed that heliox, a mixture of helium and oxygen, offers minimal benefit during the first hour of treatment, and this benefit is not sustained. More importantly, it was not demonstrated that there was a difference in important clinical outcomes. Patients on a traditional air-oxygen mixture do just as well in the medium to long term.

Hypoxemic patients are not suitable for heliox therapy. Therefore, heliox should not be used in place of traditional oxygen or oxygen-air mixtures in acute exacerbations of asthma.

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