FCPS TOACS Mock Test · Congenital Diaphragmatic Hernia

❓ Q1. Describe the findings on this chest X-ray. What is the most likely diagnosis?

✅ Model Answer:
• X-ray findings: Gas-filled loops of bowel (stomach and small intestine) visible in the left hemithorax. Mediastinum shifted to the right. Scaphoid abdomen (lack of abdominal gas).
• Diagnosis: Left-sided congenital diaphragmatic hernia (CDH) – most commonly Bochdalek hernia (posterolateral defect).
• Differential: CCAM, eventration of diaphragm, pneumatocele.

❓ Q2. What are the key prenatal predictors of poor outcome in CDH, and what fetal interventions can improve survival?

✅ Model Answer:
• O/E LHR (observed/expected lung-to-head ratio) <25% → severe pulmonary hypoplasia.
• Liver herniation into chest → worse prognosis.
• Polyhydramnios → risk of preterm delivery.
• Fetal intervention: FETO (fetoscopic tracheal occlusion) – balloon placed at 27-29 wk, removed at 34 wk.
• TOTAL trial: FETO improved survival in severe CDH from 15% to 40% (but increased PPROM & preterm birth).

❓ Q3. Describe your immediate delivery room management for this infant.

✅ Model Answer:
1. Immediate intubation (ETT) – avoid bag-mask ventilation (distends stomach/bowel, worsens respiratory compromise).
2. Place orogastric tube (large bore, continuous suction) – decompress stomach.
3. Start gentle ventilation – PIP <25 cmH₂O, PEEP 3-5, rate 40-60, permissive hypercapnia (PaCO₂ 45-65).
4. Secure IV access, check glucose, calcium – may need inotropic support.
5. Early echocardiogram – assess PPHN, RV function, exclude structural cardiac anomalies (20% CDH have CHD).
6. Transfer to tertiary NICU (ECMO capable).

❓ Q4. What is your ventilation strategy in the first 48 hours to avoid lung injury?

✅ Model Answer:
• 'Gentle ventilation' protocol: low peak inspiratory pressure (PIP <25), low rate, avoid volutrauma.
• Permissive hypercapnia (accept PaCO₂ up to 60-65 mmHg) with pH >7.20.
• Avoid hyperoxia – target SpO₂ 85-95% (pre-ductal).
• High-frequency oscillatory ventilation (HFOV) if PIP >25 required or persistent hypoxemia.
• Inhaled nitric oxide (iNO) for PPHN (though CDH may be less responsive).
• ECMO reserved for OI >40 or failure to maintain pH/PaO₂.

❓ Q5. When do you perform surgical repair and what are the options?

✅ Model Answer:
• Delay repair until after stabilization (usually 48h – 7 days) – once PPHN resolved, FiO₂ <0.5, minimal inotropes.
• Open repair (subcostal laparotomy) – primary closure if defect small; Gore-Tex patch for large defects.
• Minimally invasive (thoracoscopy/laparoscopy) – only for stable infants, not routine.
• If on ECMO, repair can be performed on ECMO or after decannulation depending on centre protocol.
• Post-operative complications: PPHN recurrence, chylothorax, recurrence (~10%).

❓ Q6. What long-term complications and follow-up are required for CDH survivors?

✅ Model Answer:
• GERD (gastroesophageal reflux) >50% – may require fundoplication.
• Chronic lung disease – BPD, reactive airways, exercise intolerance.
• Pulmonary hypertension – monitor with echocardiogram, sildenafil if needed.
• Neurodevelopmental impairment – especially if ECMO used (hearing loss, CP, cognitive delay).
• Musculoskeletal – scoliosis, pectus excavatum.
• Follow-up: multidisciplinary clinic (respiratory, gastroenterology, developmental paediatrics, audiology).

⚕️ FCPS MCPS MD Paediatrics TOACS · Mock Test