Comparison of salbutamol delivered by nebulizer or metered-dose inhaler with a pear-shaped spacer in acute asthma

Abstract

In severe acute asthma, beta-agonist bronchodilator aerosols are the standard first line of treatment. More controversial are the method of delivery and the dose. The purpose of this study was to compare the efficacy of salbutamol delivered by jet nebulizer with that of salbutamol delivered by metered-dose inhaler (MDI) attached to a pearshaped spacer. Doses were calculated on the basis of the percentage of total dose that reaches the lower airway. Ninety-seven patients, ages 18 to 50 years, with acute bronchial asthma previously treated at a hospital emergency room, were enrolled in this randomized, double-blind, placebo-controlled trial. The MDI-spacer group received salbutamol, delivered via MDI into a spacer device, in four puffs actuated in rapid succession (100 μg per actuation) at 10-minute intervals. The nebulized group was treated with nebulized salbutamol, 1.5 mg, via nebulizer at 15-minute intervals. The final mean dose was 5.61 mg for the MDI-spacer group and 11.8 mg for the nebulized group (2:1 dose ratio). Hospitalization was mandatory if the total treatment time exceeded 6 hours. The spirometric values in both groups improved in a similar manner. There were no differences between groups for any variable at any point studied. The duration of emergency room treatment was 2.17 ± 1.69 hours in the MDI-spacer group and 1.94 ± 1.49 hours in the nebulized group ( P = 0.68). The hospital admission rate was similar in both groups (10.2% and 8.33%, respectively; P = 0.95). There were no differences between groups when patients admitted or discharged were examined separately. Similar patterns were seen in patients with severe airway obstruction (forced expiratory volume in 1 second < 0.9 L). The final mean doses of salbutamol delivered by the nebulizer or the MDI-spacer were equivalent when they were calculated on the basis of the percentage of total dose that reaches the lower airway. Both the MDI-spacer and nebulized regimens provided similar rates of spirometric and clinical improvements. We conclude that there is no demonstrable advantage in a jet nebulizer over an MDI with a spacer for treating acute asthma in the emergency room.