Inhaled atropine sulfate in acute asthma.

We administered inhaled atropine sulfate to acute asthmatics already receiving therapeutic doses of adrenergic agonists, theophylline, and corticosteroids. Following atropine, hyperinflation diminished whereas vital capacity and expiratory flow rates breathing air and helium-oxygen increased (p less than 0.025 - p less than 0.005). Initial density dependence correlated inversely with changes in density dependence after atropine (r = -0.69, p less than 0.001). We conclude that: (1) inhaled atropine sulfate was effective therapy for acutely ill asthmatics already being treated with multiple antiasthmatic agents; (2) atropine caused large and peripheral airways bronchodilatation, and (3) the predominant site of bronchodilatation after atropine was related to the site of flow limitation before atropine.