Lung function in school-aged congenital diaphragmatic hernia patients; a longitudinal evaluation

Children with congenital diaphragmatic hernia (CDH) are at risk for pulmonary morbidity. Data on longitudinal evaluation of lung function in CDH are scarce. We hypothesized that CDH patients would have impaired lung function that worsens over time. We evaluated lung function and its determinants at ages 8 and 12 years.

Dynamic and static lung volumes, and diffusion capacity were measured. Extracorporeal membrane oxygenation (ECMO) treatment, the standardized European neonatal treatment protocol, patch repair, duration of ventilation, type of initial mechanical ventilation, and nitric oxide treatment were entered as covariates in linear mixed models with standard deviation score (SDS) lung function parameters (FEV₁ , FEF _25-75 , and K _CO ) as dependent variables.

Seventy-six children (27 ECMO-treated) born between 1999 and 2009 performed 113 reliable lung function tests. Severity of airflow obstruction deteriorated significantly from age 8 to 12 years: estimated mean difference (95% confidence interval [CI]) SDS FEV₁ was -0.57 (-0.79 to -0.36) and SDS FEF_25-75 was -0.63 (-0.89 to -0.37), both P < .001. Static lung volumes were within normal range and unchanged over time: estimated mean difference (95% CI) SDS TLC -0.27 (-0.58 to 0.04); P = .085. SDS K_CO was below normal at 8 and 12 years and remained stable: -0.06 (-0.22 to 0.35); P = .648. These observations were irrespective of ECMO treatment. FEV₁ and FEF_25-75 were negatively associated with duration of ventilation (P < .001). Baseline data were not related with TLC or K_CO. CONCLUSIONS: CDH patients should be followed into adulthood as they are at risk for worsening airflow obstruction and decreased diffusion capacity at school age, irrespective of ECMO treatment.