Asthma: exacerbation: no effect from heliox

Clinical bottom line (level 1a)

  1. Patients attending an emergency setting with acute asthma who receive heliox compared with oxygen or air are not clearly less likely to be admitted to hospital.
  2. Heliox has no effect on peak flow rates.
Rodrigo et al: Cochrane Library 2000; 2 : -
Expires October 2003

The study

Systematic review of all randomised controlled trials of
  • Patients: children or adults with acute asthma seen in an emergency setting
  • Intervention: heliox (helium-oxygen) compared with oxygen or air
  • Outcome:

    Articles found in ?all languages using Cochrane Airways Group Asthma Register (derived from Medline, Emabase, CINAHL, CENTRAL and hand-searching 20 respiratory care journals, - (search terms: ) and searching bibliographies of included studies, known reviews and texts. Primary authors and experts were contacted to identify relevant studies.

    Selection criteria: by 2 independent reviewers
    Appraisal criteria: by 2 independent reviewers using Jadad scale
    Articles excluded if:
    • studies solely involving patients with COPD, or studies combining asthma and COPD patients where results could not be separated
    • patients requiring mechanical ventilation at presentation


    4 studies found involving 288 patients (3 adult, 1 paediatric).
    Studies were not found to be heterogeneous.

    The evidence

    Outcome Time to outcome CER OR
    (95% CI)    		 NN T
    (95% CI)
    admission to hospital hours 8/121
    (6.61%)    		 1.25
    (0.48 to 3.27)     		66
    (NNT = 8 to infinity;
    NNH = 30 to infinity)

    • heliox v. control: PEFR % weighted mean difference: 1.6% (95% CI: -3.4% to 6.6%)

    Comments

    1. Subgroup analysis based on age, methodological quality or dose of helium failed to demonstrate any difference between the two groups.

    Citation

    1. Rodrigo G, Rodrigo C, Pollack C, et al: helium-oxygen mixture for nonintubted acute asthma patients. Cochrane Library 2000; 2 : -
    Search Terms: asthma in Cochrane Library
    Contributor: Chris Ball, October 2001
    Reviewer:

    Clinical Question.
    Patient acute asthma attending emergency department
    Intervention or Exposure heliox
    Comparison oxygen or air
    Outcome pulmonary function, admission to hospital