RESPIRATORY · CONGENITAL
Congenital diaphragmatic hernia
A diaphragmatic defect that leaves the lung small and the pulmonary circulation reactive. The repair waits; the physiology does not.
THE ONE-LINE MODEL
A hole in the diaphragm, but a lung problem
A diaphragmatic defect lets abdominal viscera sit in the chest during the canalicular/alveolar phase of lung growth. The hernia is repairable; the pulmonary hypoplasia and pulmonary hypertension it leaves behind are what make these babies sick and what you manage in the first days.
Pleuroperitoneal canal fails to close
Leaving a posterolateral defect in the diaphragm.
Abdominal viscera herniate into the thorax
Bowel, stomach, spleen, often liver (left); usually liver (right).
The lung cannot grow
Ipsilateral lung is hypoplastic; mediastinal shift compresses the other lung too.
Abnormal pulmonary vasculature
Reduced, muscularised vascular bed -> pulmonary hypertension.
RECOGNISING IT
Before and after birth
Antenatal
- Often found on the ~20 week anomaly scan
- Polyhydramnios
- Absent or intrathoracic stomach bubble
- Mediastinal shift; rarely hydrops
- Allows planned delivery at a centre with surgery and ECMO
At birth
- Scaphoid abdomen (viscera are in the chest)
- Respiratory distress and cyanosis, often immediate
- Bowel sounds in the chest; reduced air entry on the affected side
- Heart sounds displaced away from the side of the hernia
- Left CDH: bowel, stomach, spleen +/- liver. Right CDH: usually liver.
Chest X-ray
The classic film: gas-filled bowel loops in the hemithorax (usually left), mediastinum pushed to the opposite side, a paucity of gas in the abdomen, and the NG tube tip seen curving up into the chest. Confirm the NG tube position - it both decompresses the bowel and helps make the diagnosis.
FIRST-DAY MANAGEMENT
Stabilise the lung and the circulation
A gentle, planned approach
Avoid lung injury; treat PPHN; repair only once stable.
At delivery
- Intubate early. Do not bag-mask - it inflates herniated bowel and worsens lung compression.
- Large NG/OG tube on free drainage to decompress the gut.
- Pre- and post-ductal SpO2 monitoring from the start.
Ventilation
- Gentle, lung-protective ventilation; keep peak pressures low.
- Permissive hypercapnia - accept a higher CO2 to avoid barotrauma.
- HFOV if conventional ventilation needs injurious pressures.
PPHN & surgery
- Treat pulmonary hypertension; iNO if there is adequate LV function.
- Support the circulation (inotropes); ECMO for refractory cases.
- Delay repair until physiologically stable (often >24-48h, once PVR falls).
- Large NG/OG tube on free drainage to decompress the gut; do not bag-mask.
- Minimal handling; pre- and post-ductal SpO2; support gentle ventilation.
- Thermoregulation; prepare for retrieval and surgery.
- Support parents through a high-acuity, often antenatally-diagnosed course.
PROGNOSIS
What predicts outcome
Overall survival is roughly 70-80% in non-syndromic CDH at experienced centres, falling to around 50% when ECMO is needed. Antenatal lung size and liver position are the main predictors.
| Factor | Better | Worse |
|---|---|---|
| Liver position | Abdominal ("liver down") | Herniated into chest ("liver up") |
| Lung-to-head ratio (LHR / o/e LHR) | Higher (e.g. >1.4) | Lower (e.g. <1); liver-up + LHR <0.8 = high mortality |
| Hernia sac | Sac present | No sac |
| Herniated contents | Bowel alone | Stomach / spleen / liver in the chest |
| Associated anomalies | Isolated CDH | Cardiac, chromosomal or syndromic |
CDH in one breath: a posterolateral (Bochdalek), usually left-sided defect, recognised by a scaphoid abdomen and bowel sounds in the chest. Intubate, never bag-mask, pass an NG tube. Ventilate gently with permissive hypercapnia, treat the PPHN, and repair only once the circulation is stable.
Educational summary for clinical teaching. Management of CDH is centre-specific - follow your local and retrieval-service (e.g. NETS) protocols.