Prophylactic theophylline infusion for prevention of apnea of prematurity.

To assess if there was any advantage in the prophylactic use of theophylline to prevent apnea in preterms, we treated 56 preterms (Group A) < 34 weeks gestation with theophylline infusion and compared these with 25 age and weight matched preterms (Group B) who received no therapy. Aminophylline (25 mg/ml) was infused from admission in all neonates (group A) at rates ranging 0.2 to 0.38 mg/kg/h and blood levels estimated on an Abbots TDX analyser by Fluorescence Polarization Immunoassay, after 5 days infusion. All neonates (Groups A + B) were monitored on a Corometric 505 neonatal monitor. In Group A, 1/48 developed primary apnea while in Group B, 4-21 had primary apnea (p < 0.05). Serum theophylline ranged from 2.3 to 39.5 micrograms/ml with a mean of 12.7 micrograms/ml. The mean serum level of theophylline in 4 cases who exhibited clinical evidences of toxicity was 30.1 micrograms/ml. A statistically significant difference (p < 0.05) was noted in birth weight and serum level inspite of similar infusion rates of theophylline. A linear correlation r = 0.65 was noted between serum level and infusion rate. Multivariate regression analysis, between birth weight and gestational age to serum level, showed a linear correlationship only between birth weight and serum level (r = 0.45).