Aminophylline therapy for idiopathic apnea in premature infants: effects on lung function.

The effect of aminophylline on lung function was studied in 14 premature infants with apnea (gestational age, 30.2 weeks; birth weight, 1.052 gm). The infants showed compromised pulmonary function with a large difference in alveolar-arterial PO2 gradient (83.9 mm Hg), a low normal lung compliance of 1.1 ml/cm H2O . kg, and a normal inspiratory resistance of 45.3 cm H2O/liter/sec. Aminophylline therapy did not change these functions significantly, but it decreased the incidence of apneic episodes from 29.7 to 4.4 per day. The effectiveness of aminophylline in treating apnea in premature infants must be related to its central stimulating effect and not to an improvement in lung function and oxygenation.