Rationale: Caffeine in the newborn period shortens the duration of assisted ventilation and reduces the incidence of bronchopulmonary dysplasia, but its effects on respiratory function in later childhood are unknown.
Objectives: To determine if children born with birth weight less than 1,251 g who were treated with neonatal caffeine had improved respiratory function at 11 years of age compared with children treated with placebo.
Methods: Children enrolled in the CAP (Caffeine for Apnea of Prematurity) randomized controlled trial and assessed at the Royal Women's Hospital in Melbourne at 11 years of age had expiratory flow rates measured according to the standards of the American Thoracic Society. Values were converted to z-scores predicted for age, height, ethnicity, and sex. Parents completed questionnaires related to their child's respiratory health.
Measurements and main results: A total of 142 children had expiratory flows measured. Expiratory flows were better in the caffeine group, by approximately 0.5 SD for most variables (e.g., FEV1; mean z-score, -1.00 vs. -1.53; mean difference, 0.54; 95% confidence interval, 0.14-0.94; P = 0.008). Fewer children in the caffeine group had values for FVC below the fifth centile (11% vs. 28%; odds ratio, 0.31; 95% confidence interval, 0.12-0.77; P = 0.012). When adjusted for bronchopulmonary dysplasia, the difference in flow rates between groups diminished.
Conclusions: Caffeine treatment in the newborn period improves expiratory flow rates in midchildhood, which seems to be achieved by improving respiratory health in the newborn period. Follow-up lung function testing in adulthood is vital for these individuals. Future placebo-controlled randomized trials of neonatal caffeine are unlikely. Clinical trial registered with www.clinicaltrials.gov (NCT00182312).
Keywords: airway obstruction; bronchopulmonary dysplasia; caffeine; childhood; newborn infant.