Asthma- acute exacerbation: Ipratropium improves peak flow and reduces hospital admissions

Clinical bottom line (level 1a)

  1. Patients attending emergency departments with acute asthma exacerbations who receive ipratropium and beta-agonists compared with beta-agonists alone are less likely to be admitted to hospital (NNT = 19 at 60 minutes) .
  2. Patients who receive ipratropium and beta-agonists have a greater improvement in FEV 1 (on average 100 ml) and PEFR (on average 32 l/min) than patients given placebo and beta-agonists.
Stoodley et al: Annals of Emergency Medicine 1999; 34: 8-18
Expires November 2002

The study

Systematic review of all randomised placebo-controlled trials of
  • Patients: presenting to hospital emergency departments with acute asthma exacerbations
  • Intervention: ipratropium bromide (500 micrograms) and beta-agonists by metered-dose inhaler or wet nebulizer compared with placebo and beta-agonists
  • Outcome: change in peak expiratory flow rates (PEFR) or forced expiratory volumes (FEV 1 ) after 1 hour, hospitalisation


    • Articles found in English, French or Italian using Medline, Embase, CINAHL, Biological Abstracts, the Cochrane database, Current Contents, 1966 to 1997 (search terms: detailed in text ) and contacting pharmaceutical companies to identify unpublished studies.

    Selection criteria: see above
    Appraisal criteria: by 2 independent reviewers using a validated scoring system. Authors were contacted if necessary.
    Articles excluded if:
    • aged < 18
    • COPD exacerbation
    • insufficient data provided


    10 double-blind randomised controlled studies found involving 1377 patients. Most patients received steroids and were followed for 30 to 90 minutes.
    Studies were found to be heterogeneous - this was due to one study. Heterogeneity was resolved once data was re analysed without this study.

    The evidence

    Outcome Time to outcome CER RR
    (95% CI)    		 NNT
    (95% CI)
    hospitalisation 60 minutes -/532
    (20%)    		 0.73
    (0.53 to 0.99)     		19
    (11 to 500)

    • ipratropium v. placebo: weighted mean improvement
      • FEV1: 100 ml (95% CI: 50 to 149)
      • PEFR: 32 l/min (95% CI: 16 to 47)

    Comments

    1. The yardstick of success of emergency care is avoidance of hospital admissions and artificial respiration, rather then spirometric improvement, and this aspect requires further validation.
    2. The admission rate for control patients was not given - assumed to be 20%.
    3. No severe adverse effects were noted in patients using ipratropium.

    Citation

    1. Stoodley RG, Aaron SD, Dales RE: The role of ipratropium bromide in the emergency management of acute asthma exacerbation: a metaanalysis of randomized clinical trials. Annals of Emergency Medicine 1999; 34: 8-18
    Contributor: Chris Ball and Musab Hayatli, October 1999
    Reviewer: Chris van Weel

    Clinical Question.
    Patient
    Intervention or Exposure
    Outcome