Asthma: acute exacerbations: holding chambers are probably as good as wet nebulisers.

Clinical bottom line (level 1a)

  1. Adults with acute asthma exacerbations who receive beta-agonists by holding chamber compared with wet nebulisation do not clearly have more admissions to hospital, longer stays in the emergency department or more steroids.
  2. Children with acute asthma exacerbations who receive beta-agonists by holding chamber compared with wet nebulisation do not clearly have more admissions to hospital nor use of steroids. They have shorter stays in the emergency department (40 minutes less) and a lower tachycardia.
Cates : The Cochrane Library, Issue 3, 1998. Oxford: Update Software. 1998; 3: -
Expires November 2002

The study

Systematic review of randomised controlled trials of
  • Patients: adults and children (aged >2) presenting to the emergency department with acute asthma exacerbations
  • Intervention: beta-agonists by holding chamber compared with beta-agonists by wet nebuliser
  • Outcome: hospital admission, length of stay, need for steroids


    • Articles found in all using Cochrane Airways Review Group and Cochrane Controlled Clinical Trials Register, ? (search terms: detailed in text ) and bibliographies were also searched, authors and experts contacted for unpublished studies or other relevant articles

    Selection criteria: as above
    Appraisal criteria: two independent blinded reviewer using set criteria (detailed in text)
    Articles excluded if:
    • patients with COPD included and data could not be separated
    • patients already admitted to hospital
    • life-threatening asthma


    twelve studies were included, ivolving 495 patients- six were double-blinded
    There was significant heterogeneity between adults and children so they were analysed separately.

    The evidence

    Outcome Time to outcome CER OR
    (95% CI)    		 NNH
    (95% CI)
    adults: admission to hospital unknown 10/134
    (7.5%)    		 1.12
    (0.45 to 2.76)     		120
    (NNT = 25 to infinity;
    NNH = 9 to infinity)
    adults: use of steroids unknown 8/46
    (17%)    		 0.68
    (0.21 to 2.22)     		-21
    (NNT = 8 to infinity;
    NNH = 7 to infinity)
    adults: tremor unknown 16/108
    (15%)    		 1.42
    (0.67 to 3.01)     		20
    (NNT = 23 to infinity;
    NNH = 5 to infinity)
    children: admission to hospital unknown 7/108
    (6.5%)    		 0.71
    (0.23 to 2.23)     		-56
    (NNT = 20 to infinity;
    NNH = 14 to infinity)
    children: use of steroids unknown 36/81
    (44%)    		 1.43
    (0.76 to 2.71)     		11
    (NNT = 15 to infinity;
    NNH = 4 to infinity)

    • adults:
      • duration in ED (days) (weighted mean difference; 95% CI): 0.020 (-0.403 to 0.443)
      • rise in pulse rate (% baseline) (weighted mean difference; 95% CI): -1.59 (-5.51 to 2.38)
    • children:
      • duration in emergency department (hours) (weighted mean difference; 95% CI): -0.62 (-0.843 to -0.397)
      • rise in pulse rate (% baseline) (weighted mean difference; 95% CI): -10.0 (-14.1 to -5.9)

    Comments

    1. The Cochrane Airways Review Group register of trials has been constructed on computer using Medline and Embase and has been tested against hand-searching to check for the inclusion rate of randomised controlled trials.
    2. The experimental method adopted in many of the studies was to give repeated treatments at short intervals (e.g. one respule via a nebuliser or four actuations of a metered-dose inhaler via a holding chamber every 15 minutes). The number of treatments required was adjusted to the individual patients response, overcoming the uncertainty of dosage delivery from different devices. This method is therefore recommended for practice until further evidence becomes available.
    3. All the studies were small - possible harmful effects may have been missed.
    4. It seems reasonable applying the findings in the community setting.

    Citation

    1. Cates CJ, : Comparison of holding chambers and nebulisers for beta-agonists in acute asthma (Cochrane Review). The Cochrane Library, Issue 3, 1998. Oxford: Update Software. 1998; 3: -
    Search Terms: acute asthma in Cochrane
    Contributor: Chris Ball and Clare Wotton, November 2000
    Reviewer: Santiago Alvarez.

    Clinical Question.
    Patient acute asthma
    Intervention or Exposure beta-agonists by holding chamber
    Comparison by wet nebulisation
    Outcome hospital admission