Aminophylline and its influence on ventilatory endurance in humans.

The purpose of this study was to evaluate whether the previously demonstrated improvement in contractile tension of diaphragmatic muscle with aminophylline results in improved ventilatory endurance. We measured the maximal sustained ventilatory levels during prolonged isocapnic hyperpnea as an index of ventilatory muscle function. This measurement was made in 7 normal subjects and 7 patients with chronic obstructive pulmonary disease during the intravenous administration of saline and aminophylline on 2 separate days. The order of administration of the infusions was randomized. Although both groups showed slightly higher sustained ventilatory levels during aminophylline infusion, the magnitude of change was small and unlikely to have a significant clinical benefit in the setting of respiratory muscle fatigue.