RESPIRATORY CONDITIONS
Congenital Diaphragmatic Hernia
A practical guide for paediatric registrars · Abdominal viscera in the chest, with lung hypoplasia and pulmonary hypertension
AVOID BAG-MASK
VENTILATION
Diaphragmatic defect
Failure of diaphragm formation lets abdominal viscera herniate into the thorax. The core defect.
Lung hypoplasia
The developing lung is compressed, leaving fewer alveoli and airways (worse on the affected side, but bilateral).
Pulmonary hypertension
Abnormal, muscularised pulmonary vasculature with a reduced cross-sectional area gives high PVR (PPHN).
Right-to-left shunting
High PVR drives a shunt at the duct/foramen ovale, producing severe hypoxaemia.
Mediastinal shift
Herniated viscera shift the mediastinum, compressing the other lung and impairing venous return.
🩺CLINICAL FINDINGS
- Respiratory distress from birth (or antenatally diagnosed)
- Scaphoid (sunken) abdomen - the viscera are in the chest
- Reduced breath sounds on the affected side (usually left); bowel sounds in the chest
- Displaced apex beat / heart sounds (mediastinal shift, usually to the right)
- Cyanosis and hypoxaemia, often labile (associated PPHN)
- Barrel-shaped chest
🔬INVESTIGATIONS
- CXR: gas-filled bowel loops in the hemithorax, mediastinal shift, paucity of abdominal gas, NG tube tip in the chest
- Antenatal ultrasound (often diagnostic); fetal MRI for lung volumes
- Pre/post-ductal SpO₂; echocardiography (PPHN severity, define cardiac anomalies)
- ABG
- Genetics (microarray) given syndromic associations
🚩COMPLICATIONS & RED FLAGS
- Pulmonary hypertension and lung hypoplasia - the main determinants of outcome
- Air leak (avoid high pressures); a contralateral pneumothorax is dangerous
- Associated cardiac and chromosomal anomalies
- Red flag: bag-mask ventilation distends the gut and worsens lung compression - intubate early, do not bag-mask
Add a de-identified CXR here
Classic appearances: gas-filled (sometimes "bubbly") bowel loops in the hemithorax - usually the left - with mediastinal shift to the opposite side, a paucity of gas in the abdomen, and an NG tube curling up into the chest. The differential for bubbly lucencies includes CPAM and loculated air leak.
MANAGEMENT
Protect the lungs, decompress the gut, manage the pulmonary hypertension - and remember repair is not the emergency.
Delivery Room - The Key Don'ts
- If antenatally known, deliver in a tertiary centre with surgical and NICU support
- Intubate promptly; avoid bag-mask ventilation (it inflates the gut and worsens compression)
- Place a large NG / replogle tube on continuous suction to decompress the stomach and gut
- Gentle, lung-protective ventilation - lowest effective pressures, permissive hypercapnia
Stabilise the Physiology
- Target pre-ductal SpO₂ ~85-95% and post-ductal >70% (per CDH-EURO); avoid hyperoxia
- Manage PPHN: optimise oxygenation/ventilation, support systemic BP, iNO/sildenafil for severe disease; HFOV/ECMO in selected cases
- Sedation, minimal handling; vascular access (UVC/UAC) and monitoring
Surgery & Transfer
- Repair is not an emergency - stabilise first, operate once physiologically stable (often days)
- Refer/retrieve early - call NETS for transfer to a surgical centre
- Multidisciplinary care: neonatology, paediatric surgery, cardiology, genetics
Why is bag-mask ventilation contraindicated, and what do you do instead?
Why is surgical repair delayed rather than emergent?
How do lung hypoplasia and pulmonary hypertension each drive outcome?
What pre/post-ductal targets does CDH-EURO suggest, and why permissive hypercapnia?
Take-home message: CDH is a diaphragmatic defect with abdominal viscera in the chest, causing lung hypoplasia and pulmonary hypertension - the two drivers of outcome. Suspect it with a scaphoid abdomen and reduced (usually left) breath sounds. Intubate early and DON'T bag-mask (it distends the gut); decompress with an NG tube on suction, ventilate gently, and manage PPHN. Repair is delayed until the baby is stable - stabilise and refer/retrieve early to a surgical centre.
For educational purposes only. Always align management to current ANZCOR/NRP guidelines and your local SCN/NICU or NETS protocols.