Asthma: severe: the role of iv beta2-agonists is unclear

Clinical bottom line (level 2a-)

  1. Patients with severe asthma who receive iv beta2-agonists compared with control do not clearly have a higher PEFR at 60 minutes, and are not clearly more likely to improve clinically.
Travers et al: Cochrane Library 2001; 2 : -
Expires May 2004

The study

Systematic review of all randomised controlled trials of
  • Patients: severe acute asthma treated in an emergency department (usually pulmonary function tests < 20% predicted and heart rate > 100)
  • Intervention: iv beta2-agonists compared with control: placebo, inhaled beta2-agonists or other standard of care
  • Outcome: pulmonary function

Articles found in all languages using Cochrane Airways Group Register (including Medline, Embase, CINAHL, and CENTRAL and hand-searches of 20 respiratory journals), to 2000 (search terms: detailed in text ) and searching bibliographies of retrieved studies and known reviews. Primary authors and content experts were contacted in addition.

Selection criteria: by 2 independent reviewers
Appraisal criteria: by 2 independent reviewers using Jadad criteria and Cochrane assessment of methodological quality
Articles excluded if: 15 RCTs found involving 584 patients - receiving steroids and inhaled beta2-agonists
Study results were found to be heterogeneous - this was explained in part by the poorer methodology of 8 of the studies identified.

The evidence

Outcome Time to outcome CER OR
(95% CI)		 NNT
(95% CI)
clinical failure 2 hours 20/56
(35.7%)		 1.30
(0.59 to 2.86) 		-16
(NNT = 9 to infinity;
NNH = 4 to infinity)

  • difference in PEFR at 60 minutes: -25 l/min (95% CI: -52 to 2)

Comments

  1. Studies had short follow-up - usually 2-3 hours

Citation

  1. Travers A, Jones AP, Kelly K, et al: intravenous beta2-agonists for acute asthma in the emergency department (Cochrane Review). Cochrane Library 2001; 2 : -
Search Terms: from ACP Journal Club other articles noted
Contributor: Chris Ball, May 2002
Reviewer:

Clinical Question.
Patient severe asthma
Intervention or Exposure iv beta2-agonists
Outcome clinical failure, PEFR