The use of aerosolized sympathomimetic broncho-dilators is the preferred treatment of acute bronchospasm. Aerosols of adrenergic agents produce a more rapid onset of action, greater degree of bronchodilation, and reduced side effects when compared with systemic therapy with the same agent. Aerosolized bronchodilators can be administered via metered dose inhaler (MDI) or by hand-held wet nebulizers (HHN). Metered dose inhalers are a convenient and effective method to deliver aerosol medication, but these devices require a significant degree of hand-lung coordination. To obtain the greatest amount of aerosol deposition in the lower respiratory tract, the MDI must be activated during a slow deep inhalation followed by a 10-s end-inspiratory breath hold.
Patients with acute bronchospasm are often too dyspneic to coordinate inspiration with activation of the MDI. However, inhalation of bronchodilator delivered by HHN does not require hand-lung coordination. Although effective, wet nebulizers are much less convenient than MDIs. The average HHN treatment requires 10 to 15 minutes in addition to the time required for preparation of the nebulizer.