Background: Comparative studies of albuterol by wet nebulizer or metered dose inhaler have tested fixed doses of medications. We compared the dose-response relationship to albuterol by wet nebulization or metered dose inhaler in acute asthma.
Methods: Randomized, double-blind, placebo-controlled trial. Patients with acute asthma received either albuterol, 0.4 mg, by metered dose inhaler (and holding chamber) or albuterol, 2.5 mg, by wet nebulizer every 30 min until maximal bronchodilation. Forty patients (forced expiratory volume in 1 s [FEV1]: 1.15 +/- 0.43 L; 36 +/- 12 percent predicted) received metered dose inhaler and 40 others (FEV1: 1.08 +/- 0.52 L; 35 +/- 16 percent predicted) received wet nebulization.
Results: Twenty-six patients (65 percent) receiving metered dose inhaler and 30 (75 percent) receiving wet nebulization achieved maximal bronchodilation after two doses. Almost all reached maximal bronchodilation by four doses. The FEV1 improved by 0.72 +/- 0.49 L for metered dose inhaler and 0.68 +/- 0.61 L for wet nebulizer (p = 0.71). A significant linear relationship was seen in both groups (metered dose inhaler r = 0.94; wet nebulizer r = 0.98) between the log dose of albuterol and change in FEV1. About 1/6 the wet nebulizer dose of albuterol was needed to achieve similar response to the metered dose inhaler.
Conclusions: Albuterol by metered dose inhaler provided similar bronchodilation to that achieved by wet nebulization in patients with acute asthma. The cumulative dose-response technique is applicable in the emergency department setting and is helpful in comparing the relative utility of various bronchodilator regimens.