Management of Asthma and Chronic Airflow Limitation (Part 3)
Patients were initially evaluated in the hospital emergency room and treated with a single 15-mg dose of nebulized metaproterenol. Thirty minutes later, 44 patients who had not improved sufficiently to be discharged were entered into the study. All patients were then treated with 15 mg of inhaled metaproterenol at hourly intervals for 3 h. Furthermore, patients were randomly assigned to receive either intravenous aminophylline or placebo. The FEV, improved progressively throughout the study to a similar degree in both groups. Aminophylline did not add further benefit, even in the subgroup of patients with severe disease as indicated by an FEVi less than 0.8 L. Moreover, patients treated with aminophylline complained of significantly more adverse effects.
Thus, in life-threatening asthma, repeated relatively large doses of nebulized betas adrenergic aerosols such as metaproterenol or albuterol alone provide optimal bronchodilation. This applies even to the subgroup of patients presenting with more severe disease as reflected by an FEV! less than 35 percent predicted. Additional treatment with intravenous aminophylline adds only increased side effects. Considerably larger than maintenance doses of aerosol bronchodilators (two to six-fold), administered via MDI with valved add-on devices may be just as effective as nebulizers in the majority of patients for “rescue” therapy from the acute severe attack.* High doses of systemic corticosteroids also are indicated in the immediate management of these patients.* Moreover, recent studies also suggest that the addition of an anticholinergic bronchodilator aerosol (ipratropium bromide) may augment the response to and particularly the duration of action of beta2 agents. Aminophylline probably is not required under these circumstances.