Improvement in pulmonary function following antibiotics in infants with cystic fibrosis

Background: Recent studies have shown the presence of lung disease in even asymptomatic infants with cystic fibrosis (CF). While pulmonary function testing (PFT) is often used to follow progression of lung disease and guide treatment in older children with CF, little data is available on change in infant PFTs in young children with CF. Objective: To determine change in infant PFTs before and after antibiotic therapy for pulmonary exacerbation in infants with CF. Methods: Retrospective cohort study of infants with CF who underwent clinically indicated infant PFTs before and after antibiotic therapy for CF pulmonary exacerbation at the University of North Carolina at Chapel Hill. Results: Pre- and post-antibiotics PFT data was available on 11 infants with CF, with a mean age of 102 weeks at time of first PFT. The majority of infants were symptomatic prior to antibiotics, and showed statistically significant improvement in clinical parameters following treatment. Prior to antibiotics, PFTs showed evidence of substantial obstructive disease (mean z-scores for FVC, FEV _0.5, and FEF _25-75 of -1.81, -3.06, and -4.5, respectively) and air-trapping/hyperinflation (mean z-scores for FRCpleth, RV, and RV/TLC of 8.86, 7.1, and 3.31, respectively). Following antibiotics, all of the above parameters showed statistically significant improvement. Discussion: We have shown a statistically significant improvement in infant PFT measures following antibiotic therapy in a cohort of 11 infants with CF, which paralleled improvement in clinical parameters. Though infant PFTs showed improvement, they remained abnormal in the majority of subjects, with persistent airtrapping and hyperinflation after antibiotic therapy. Our findings suggest that infant PFTs are sensitive to acute clinical changes in children with CF, and may be a useful tool in managing infants with CF.