The Effect of Intravenous Aminophylline on Pulmonary Function in Asthma

A double-blind study of the effect of 0.250 gm aminophylline on pulmonary function was performed on nine patients with asthma. The aspects of pulmonary function studied comprised lung volume and flow rates, arterial blood gas tensions, arterial pH, the ratio of physiologic dead space to tidal volume, the alveolar arterial O₂ gradient and the venous admixture-like effect. All patients had reduced flow rates and increased venous admixture. Seven of nine patients had decreased arterial O₂ tension and saturation. Total lung capacity and forced vital capacity increased slightly after aminophylline administration. There was, however, no statistically significant difference between aminophylline and placebo on flow rates, arterial blood gas tensions, arterial pH or venous admixture. The results suggest that a dose of 0.250 gm aminophylline does not produce maximal bronchodilatation.