Abstract 1109

With the trend to earlier discharge of premature neonates, a significant number of infants are now sent home receiving theophylline for residual immaturity of the central respiratory drive.

While some physicians empirically discontinue theophylline at 48 weeks' corrected gestation, historically at our institution, these infants have returned for repeat sleep studies when methylxanthines are discontinued. Unfortunately, follow-up studies are time consuming, expensive and disruptive to families. In an effort to select which infants require follow-up study, we retrospectively examined the charts of a cohort of premature infants < 2000 g discharged home receiving theophylline. We speculated that respiratory and CNS injury would be important factors in increasing the risk of apnea, and hypothesized that doxapram use; the duration of ventilation, CPAP or supplemental oxygen; and the presence of intraventricular hemorrhage or periventricular leukomalacia would predict at which corrected gestational age (CGA) an infant could have his/her Theophylline discontinued without a follow-up study. During a one-year period, 27 premature infants [birth weight 1279±456 g (mean±SD), GA 29±3 wk, CGA at discharge 36±4 wk] underwent one or more repeat sleep studies after discharge home. An infant was considered to have failed the apnea study if we detected any apnea >10 seconds' duration associated with >10% desaturation and/or >10% change in heart rate. As expected, the percentage of infants passing their sleep study was positively correlated with increasing CGA (23% by 42 wk, 54% by 44 wk, 69% by 46 wk, 88% by 48 wk); however, three infants (11%) did not pass until 52 weeks. There was considerable variability in duration of ventilation (9±17 days), time the infant received CPAP (20±27 days) and the number of days of oxygen supplementation (37±54 days). However, as expected, each distribution was skewed by infants <1000 g. A total of 13 infants (48%) received doxapram to treat their immature central respiratory drive. Only 4 infants had intraventricular hemorrhage (1 grade III and 3 grade II) and a total of 3 had mild periventricular leukomalacia. Using multivariate analysis, we attempted to determine whether these variables could predict the corrected gestational age at which an infant passed the follow-up study. No statistically significant relationships could be detected or inferred. Within the limits of this retrospective study, we conclude that the doxapram use, ventilator, CPAP or oxygen duration and the presence of intraventricular hemorrhage or periventricular leukomalacia do not predict which neonates do not need repeat sleep studies after the discontinuation of theophylline. However, physicians should be cautious of empiric discontinuation of theophylline at 48 weeks' CGA because a significant number of our patients have respiratory instability up to 52 weeks' CGA.