Asthma: acute exacerbation: air or oxygen were both effective driving gases for nebulisers.

Clinical bottom line (level 1b-)

  1. There was no clear difference on the effectiveness of salbutamol nebulisers whether oxygen or air was used as the driving gas, in children with acute asthma.
  2. The study was too small to rule out significant harm using air as a driving gas.
Gleeson et al: Archives of Diseases in Childhood 1988; 63: 900-904
Expires November 2002

The study

Unblinded ?concealed randomised cross-over trial with intention-to-treat
Setting: university hospital, UK

26 patients (aged range 2 to 12 years; median 7, 69% male) with 27 episodes of acute asthma with PEFR < 25% or failure to respond to an adequate dose of salbutamol nebuliser

Excluded if
  • <2 years old


    • Control Group: (n = 27, 27 analysed): nebuliser driven by compressed air for 15 minutes
    Experimental Group: (n = 27, 27 analysed): nebuliser driven by 100% oxygen (at 8 l/min) for 15 minutes
    All patients had nebulised salbutamol 0.15 mg/kg to a maximum of 5 mg, iv aminophylline or oral theophylline. Eight had systemic steroids.
    100% followed for 15 minutes

    The evidence

    Outcome Time to outcome CEREERRRR
    (95% CI)    		ARR
    (95% CI)    		NNT
    (95% CI)
    fall in oxygen saturation 2% or more during nebuliser 15 minutes 7
    (25.9%)    		 3
    (11.1%)    		 57%
    (-49% to 88%)    		 14.8%
    (-5.53% to 35.2%)    		 7
    (NNT = 3 to infinity;
    NNH = 18 to infinity)

    Outcome Control Group
    (SD)    		 Experimental Group
    (SD)    		 Mean Difference
    (95% CI)
    change in PEFR (% predicted) 10.1
    (15.8)     		12.0
    (16.4)     		-1.9
    (-11 to 6.9)

    Comments

    1. Patients given oxygen as a driving gas had a transient increase in oxygen saturations (data not given), which declined to previous levels within 5 minutes of stopping the nebuliser. Consequently children with hypoxia need continuous treatment with oxygen.
    2. As nebuliser treatments should be reserved for children with moderate-severe asthma, who are likely to be borderline hypoxic, oxygen should be the gas of standard care.

    Citation

    1. Gleeson JG, Green S, Price JF: air or oxygen as a driving gas for nebulised salbutamol. Archives of Diseases in Childhood 1988; 63: 900-904
    Search Terms: acute asthma in Cochrane
    Contributor: Chris Ball and Clare Wotton, November 2000
    Reviewer: Mona Nabulsi

    Clinical Question.
    Patient children with acute asthma
    Intervention or Exposure air driven nebulised salbutamol
    Comparison oxygen driven nebuliser
    Outcome oxygen saturation and PEFR