Background/purpose: Congenital diaphragmatic hernia (CDH) is initially characterized by severe restrictive lung defect and low lung compliance, but survivors have relatively few abnormalities later in life. We studied the changes in lung growth and function in infants after the repair of CDH.
Methods: Retrospective analysis of pulmonary function tests was performed during the first 24 months of life in 56 infants (33 male and 23 female) after repair of CDH. Lung function (functional residual capacity [FRC], respiratory system compliance [C(rs)] and resistance [R(rs)], and maximum expiratory flow rate at FRC [V'(maxFRC)]) were compared among 4 different ages (0-3, 4-6, 7-12, and 13-24 months).
Results: All indices of lung function (mean +/- SD of z scores) were abnormal during the first 6 months of life but were almost normalized by 24 months (P < .0001): FRC, from -0.84 +/- 0.5 to 3.26 +/- 2.07; C(rs), from -0.87 +/- 0.4 to 1.84 +/- 1.75; R(rs), from 2.85 +/- 2.71 to -0.23 +/- 2.03, and V'(maxFRC), from -1.63 +/- 0.4 to -0.09 +/- 0.94. There was significant correlation (P < .001) between lung function and increase in age, height, and especially weight.
Conclusions: Lung growth and function gradually normalize between 6 and 24 months of life after repair of CDH.