Cochrane review: Holding chambers (spacers) versus nebulisers for beta‐agonist treatment of acute asthma
Authors: CJ Cates , JA Crilly , BH Rowe 
Published: December 2006

Background

In acute asthma inhaled β2‐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. Nebulisers require a power source and need regular maintenance, and are more expensive in the community setting.

Objectives

To assess the effects of holding chambers (spacers) compared to nebulisers for the delivery of ß2‐agonists for acute asthma.

Search strategy

We last searched the Cochrane Airways Group trials register in January 2006 and the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 4, 2005).

Selection criteria

Randomised trials in adults and children (from two years of age) with asthma, where spacer ß2‐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 January 2006 and four new trials have been added. 2066 children and 614 adults are now included in 25 trials from emergency room and community settings. In addition, six trials on in‐patients with acute asthma (213 children and 28 adults) have been reviewed. Method of delivery of ß2‐agonist did not appear to affect hospital admission rates. In adults, the relative risk of admission for spacer versus nebuliser was 0.97 (95% CI 0.63 to 1.49). 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 spacer was used, with a mean difference of ‐0.47 hours (95% CI: ‐0.58 to ‐0.37). 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 spacer in children, mean difference ‐7.6% baseline (95% CI: ‐9.9 to ‐5.3% baseline).

Authors' conclusions

Metered‐dose inhalers with spacer produced outcomes that were at least equivalent to nebuliser delivery. Spacers may have some advantages compared to nebulisers for children with acute asthma.

Plain language summary

Spacers (holding chambers) can be as effective as nebulisers for delivering β2‐agonist drugs to relieve acute asthma.

In acute asthma attacks higher doses of inhaled β2‐agonists (reliever inhalers) are used to overcome the narrowing of the passages in the lungs. The medication can be given by wet nebulisation or from an inhaler with a spacer device (holding chamber). This review now includes in‐patient studies, as well as those in casualty and community setting, comparing these two delivery methods in acute asthma attacks. In adults, no important differences were found between the two methods, whilst in children those randomised to wet nebulisation spent longer in casualty. Metered‐dose inhalers with a spacer can perform at least as well as wet nebulisation in delivering β2‐agonists in acute asthma.