Two previous studies comparing nebulizer and MDI-spacer methods in acute exacerbations of COPD were also unable to demonstrate a difference in efficacy but did not employ a crossover design. Jasper et al compared delivery of metaproterenol by nebulizer (15 mg) and MDI-spacer (two puffs; 1.3 mg) in a mixed population of patients with asthma and COPD who were hospitalized for airflow obstruction. Treatment (either nebulizer or MDI-spacer) was randomized, but neither the patients nor investigators were blinded. Spirograms were read by a blinded observer. The InspirEase spacer was used in this study. The two treatments were associated with equivalent improvement in spirometric data initially and at discharge. Although the treated populations included a substantial number of asthmatic subjects, covariant analysis showed that this had no significant effect on the conclusions. other
Turner et al studied patients with asthma and COPD treated in the emergency room. These investigators analyzed their data for patients with COPD separately. Using a double-blind protocol, patients were randomized to receive either MDI-spacer (placebo) and nebulizer (15 mg of metaproterenol); or MDI-spacer (three puffs; 1.95 mg of metaproterenol) and nebulizer (placebo). Three treatments spaced at 30-minute intervals were administered without a crossover limb. Equivalent improvements in the FEVj, FVC, and Borg scores were found 30 minutes after the first and third treatments. Our protocol used a less intense regimen of treatment that is more typical of standard inpatient intervals for treatment. The results of the current study are consistent with the previous two studies. On the other hand, as mentioned previously, Moss and co-workers found an advantage for the nebulizer in the setting of an acute exacerbation.
Because the improvement in expiratory flow rates after bronchodilation in patients with COPD is often small, other considerations, such as improvement in dyspnea, are important. Many patients with COPD seem to develop an emotional attachment to the nebulizer. Because this treatment is associated with hospitalization, patients may assume it to be more powerful. Our study’s design sought to eliminate this factor by including MDI-spacer and nebulizer administration in each treatment block. We found equivalent improvements in dyspnea after active medication delivery from both systems; however, because we did not compare bronchodilator therapy with placebo, we cannot prove that the entire improvement in dyspnea was not due to a placebo effect (ie, bronchodilator medication did not improve dyspnea). Turner and coworkers also found equivalent improvements in the Borg score after nebulizer and MDI-spacer administration of metaproterenol in the emergency room. The Borg scores in their study were higher and the improvements greater, probably due to the fact that their study was performed in the setting of the emergency room.