A full-term infant born with Apgars of 6, 5, and 5 with severe respiratory distress and a weak cry appears dyspneic and cyanotic.
Physical examination: The baby has a barrel-shaped chest and scaphoid abdomen. Upon auscultation, there are decreased breath sounds, and bowel sounds can be heard in the left chest.
Chest x-ray: Mediastinum is pushed to the right and air-filled loops of bowel are present in the left chest.
Congenital diaphragmatic hernia (CDH) occurs due to in utero herniation of abdominal contents into the thoracic cavity through a defect in the diaphragm, most commonly (80%) via the left pleuroperitoneal canal (foramen of Bochdalek). As a result, the hemithorax is filled with stomach and intestine. The herniated bowel prevents normal lung development on the ipsilateral side. The contralateral lung is also affected, with reduced-size bronchi, less bronchial branching, decreased alveolar surface area, and abnormal pulmonary vasculature characterized by thickening of arteriolar smooth muscle. Less commonly, the defect can be in the anterior diaphragm (Morgani, retrosternal, or parasternal hernia). This occurs more commonly on the right side.
Incidence is 1 in 2500 live births, with 44-66% having other congenital anomalies, including 4-16% with chromosomal anomalies.
In the past decade, medical stabilization of the patient has come to be done prior to surgical repair. Management is directed toward reducing pulmonary hypertension with nitric oxide, moderate alkalosis, and permissive hypercapnia. Patients who are unable to tolerate conventional ventilation are placed on high-frequency oscillatory ventilation. Patients who have failed medical management may be placed on extracorporeal membrane oxygenation (ECMO).
Patients are intubated in the neonatal intensive care unit immediately after birth.
Be careful with positive pressure ventilation so as to not overinflate the healthy lung.
Maintenance is done with volatile agents plus IV narcotics plus muscle relaxant.
Avoid nitrous oxide.
Avoid an increase in pulmonary vascular resistance (PVR) leading to right-to-left shunting, eg, hypoxia, acidosis, hypothermia, and pain.
Mild permissive hypercapnia is usually well tolerated (pCO2 50-60).
Replace significant blood loss.
Postoperatively, these patients continue to require ventilatory support. There may be worsening of pulmonary hypertension and clinical deterioration despite surgical repair. If sudden deterioration of clinical status occurs, consider pneumothorax on the contralateral side.
DOs and DON’Ts
⊗ Do not mask ventilate.
⊗ Do not attempt to manually inflate the contralateral lung; it is at risk for pneumothorax.
⊗ Do not use nitrous oxide.
✓ Do use pressure-limited ventilation to maintain preductal oxygen saturation at greater than 85-90%; tolerate mild hypercapnia.
Surgical repair is via a subcostal transabdominal incision on the affected side. The bowel is reduced from the chest, and the diaphragmatic defect is ...