EFFECT OF THEOPHYLLINE ON LUNG-FUNCTION TESTS, SLEEP QUALITY, AND NIGHTTIME SAO2 IN CHILDREN WITH CYSTIC-FIBROSIS

The effect of theophylline (T) was studied in 12 children with cystic fibrosis (CF) (seven males and five females) aged 7 to 17 yr (mean, 11.8 +/- 2.8). T or placebo (P) was taken for 10 days in a double-blind, crossover controlled trial. During Nights 9 and 10 of each study period, the subjects slept in a sleep laboratory, where complete polysomnographs were recorded. Patients were subdivided according to T blood levels above or below 10-mu-g/ml: live children had a mean serum T of 11.7 +/- 1.6-mu-g/ml (Group 1), and seven patients had serum T levels of 6.7 +/- 1.5-mu-g/ml (Group 2). There was no difference in pulmonary function between the two periods, but Group 2 had significantly better baseline lung function (p < 0.01). During sleep while on T, Group 1 had a higher mean Sa(O2) (93.1 +/- 0.3% T versus 90.7 +/- 0.3% P; p < 0.0001), less time with a decrease greater than 5% in Sa(O2) from baseline (43.7 +/- 7.9 min T versus 85.8 +/- 7.9 min P; p < 0.01), and a lower heart rate (HR), (77.9 +/- 5.1 bpm T versus 86.1 +/- 4.2 bpm P; p < 0.01). Group 2 did not show differences in these parameters. T significantly disrupted sleep as measured by sleep efficiency and total wake time independently of serum level (p < 0.01). There was no significant effect of T on the incidence of apnea, hypopnea, or body movements during sleep. We conclude that T treatment in children with moderate to severe CF appears to have a protective effect on arterial oxygen desaturation during sleep, but wakefulness increases and sleep efficiency decreases.