Background: In acute asthma inhaled beta-2-agonists are often administered to relieve bronchospasm by wet nebulisation, but some have argued that metered-dose inhalers with a holding chamber (spacer) can be equally effective. In the community setting nebulisers are more expensive, require a power source and need regular maintenance.
Objectives: To assess the effects of holding chambers compared to nebulisers for the delivery of beta-2-agonists for acute asthma.
Search strategy: We last searched the Cochrane Airways Group trials register in November 2002 and the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 3, 2002).
Selection criteria: Randomised trials in adults and children (from two years of age) with asthma, where holding chamber beta-2-agonist delivery was compared with wet nebulisation.
Data collection and analysis: Two reviewers independently applied study inclusion criteria (one reviewer for the first version of the review), extracted the data and assessed trial quality. Missing data were obtained from the authors or estimated. Results are reported with 95% confidence intervals (CI).
Main results: This review has been updated in 2003 and has now analysed 1076 children and 444 adults included in 22 trials from emergency room and community settings. In addition, five trials on in-patients with acute asthma (184 children and 28 adults) have been added to the review. Method of delivery of beta-2-agonist did not appear to affect hospital admission rates. In adults, the relative risk of admission for holding chamber versus nebuliser was 0.88 (95% CI 0.56 to 1.38). The relative risk for children was 0.65 (95% CI 0.4 to 1.06). In children, length of stay in the emergency department was significantly shorter when the holding chamber was used, with a weighted mean difference of -0.47 hours, (95% CI -0.58 to -0.37 hours). Length of stay in the emergency department for adults was similar for the two delivery methods. Peak flow and forced expiratory volume were also similar for the two delivery methods. Pulse rate was lower for holding chamber in children, weighted mean difference -7.6% baseline (95% CI -9.9 to -5.3% baseline).
Reviewer's conclusions: Metered-dose inhalers with holding chamber produced outcomes that were at least equivalent to nebuliser delivery. Holding chambers may have some advantages compared to nebulisers for children with acute asthma.