Subjects and Methods
Candidates for this study were patients between the ages of 18 and 75 years who experienced acute onset of shortness of breath associated with bronchospasm, and had an aerosol bronchodilator treatment ordered by their primary physician as part of their usual medical care. Names of candidates were obtained from the Respiratory Therapy Department where the physician must place orders for aerosol treatment. Patients were not selected on the basis of diagnosis or baseline lung function. Subjects were eligible if they could stand unsupported at the bedside for measurement of height and satisfactorily perform bedside spirometry. All subjects gave informed consent prior to participation in the study.
Sixteen subjects (eight male and eight female) participated in this study. The mean (±SEM) age of the subjects was 45.8 ±4.5 years. One subject with chronic obstructive pulmonary disease (COPD) participated on two occasions one month apart, using MDI-spacer as initial treatment on one emergency department visit, and HHN as initial treatment on the second visit. All subjects demonstrated an obstructive pattern on spirometry (Table 1). Ten subjects had a diagnosis of asthma and four subjects had a diagnosis of COPD as defined by the American Thoracic Society.

Table 1 — Spirometric Data before and after Metaproterenol