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The lung following repair of congenital diaphragmatic hernia
Insights
Congenital diaphragmatic hernia lung development may be affected by pulmonary hypoplasia. Lung function tests show normal airway resistance and ventilation distribution, but reduced pulmonary blood flow on the affected side.
Area of Science:
- Pediatric Pulmonology
- Thoracic Surgery
- Developmental Biology
Background:
- Congenital diaphragmatic hernia (CDH) is associated with pulmonary hypoplasia, impacting lung development.
- Early surgical repair is crucial for managing CDH in infants.
Purpose of the Study:
- To assess the long-term pulmonary development in patients with CDH after early surgical repair.
- To investigate the effects of in-utero pulmonary hypoplasia on lung function in children and adolescents.
Main Methods:
- Pulmonary function tests including total lung capacity, vital capacity, and diffusing capacity.
- Airway resistance and ventilation-distribution assessments using helium-oxygen breathing and xenon 133 radiospirometry.
- Radiographic imaging to correlate with physiological findings.
Main Results:
- Patients exhibited normal total lung capacity and diffusing capacity for carbon monoxide.
- Forced expiratory volume in one second was slightly reduced, but airway resistance and ventilation distribution were normal.
- Reduced pulmonary blood flow to the hernia side was observed in all patients, suggesting persistent vascular abnormalities.
Conclusions:
- Early surgical repair of CDH allows for largely normal lung function regarding airway resistance and ventilation.
- Persistent reduction in pulmonary artery branching on the hernia side impacts pulmonary blood flow distribution.
- CDH survivors may have long-term vascular developmental issues affecting lung perfusion.
Abstract:
To determine the effects of the pulmonary hypoplasia present at birth in infants with congenital diaphragmatic hernia upon subsequent development of the lung, 19 patients who had undergone surgical repair before the age of one year were studied at ages 6 to 18 years. Total lung capacity and vital capacity averaged 99% of predicted value. Diffusing capacity for carbon monoxide was normal. Forced expiratory volume in one second averaged 89% of predicted value and 80% of vital capacity. Total respiratory system conductance and maximum expiratory flow volume curves obtained during air and helium-oxygen breathing were normal. Xenon 133 radiospirometry performed in nine patients revealed equal distribution of lung volumes on the two sides. Ventilation to the hernia side was reduced in only two patients. Blood flow to the hernia side was reduced in all nine patients. Chest radiographs supported the physiologic observations. These findings are consistent with the persistence of a reduction in the number of branches or generations of pulmonary arteries and bronchi on the side of the hernia. Since a substantial part of the vascular resistance resides in peripheral vessels, this developmental abnormality influences the distribution of pulmonary blood flow, although it has little effect on tests reflecting airway resistance or the distribution of ventilation.