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Congenital diaphragmatic hernia (CDH)
In congenital diaphragmatic hernia the real problem is not the hole in the diaphragm but hypoplastic lungs with pulmonary hypertension — so the infant is stabilised first with gentle ventilation and repaired later, and the operation is not an emergency.
Why it matters in the exam
Exam questions turn on three decision points: the delivery room (immediate intubation, no bag-mask ventilation, a gastric tube to decompress the stomach), ventilation ("gentle" ventilation with permissive hypercapnia and a preductal saturation target) and the timing of surgery (only after physiological stabilisation, sometimes on ECMO). Another recurring question is prenatal assessment — the lung-to-head ratio expressed as observed/expected (o/e LHR) and liver position in the chest are the key predictors of mortality.
The common type is the posterolateral Bochdalek hernia, mostly on the left (about 85%). The Morgagni hernia is anterior, retrosternal, usually on the right, tends to be found later and incidentally, and is repaired through an abdominal or laparoscopic approach. A newborn with CDH has a scaphoid abdomen, heart sounds displaced to the right and reduced breath sounds on the left; the X-ray shows bowel loops in the chest and the tip of the gastric tube above the diaphragm.
Fetal endoluminal tracheal balloon occlusion (FETO) was tested in the TOTAL trials: in severe left CDH (o/e LHR below 25%) the balloon was placed at 27–29 weeks and improved survival, while in moderate CDH (o/e LHR between 25% and 34%) it was placed at 30–32 weeks with no significant survival benefit and more preterm births. After repair, watch for recurrence (more common with a patch), reflux, chylothorax and poor growth.
Key points
- The problem is pulmonary hypoplasia and pulmonary hypertension.
- Immediate intubation and a gastric tube, no mask ventilation.
- Gentle ventilation with permissive hypercapnia and preductal saturation 80–95%.
- Surgery only after stabilisation; ECMO when ventilation fails.
- o/e LHR and liver position predict outcome; FETO for severe left CDH.
Summary table
| Stage | What is done | Target or number | Trap |
|---|---|---|---|
| Prenatal | Ultrasound and MRI, fetal echo, karyotype | o/e LHR and liver position predict survival | Not every CDH qualifies for FETO |
| Delivery room | Immediate intubation, gastric tube, venous access | No bag-mask ventilation | Bagging inflates the stomach and compresses the lung further |
| Ventilation | Gentle ventilation, permissive hypercapnia | Preductal saturation 80–95%, PaCO2 between 50 and 70 mmHg, PIP up to 25 cmH2O | Do not aim for a normal PaO2 |
| Pulmonary hypertension | Echo, inhaled NO, support of ventricular function | Maintain systemic blood pressure | Inhaled NO does not improve survival in all patients |
| Surgery | Abdominal or thoracic repair, with a patch for a large defect | Only after stabilisation | Emergency surgery on day one is wrong |
Free exam questions
אישה בהריון בשבוע 23 פונה לייעוץ לאחר אבחנה של בקע סרעפתי CDH – בעובר. מה מהבאים נכון לגבי הטיפול האפשרי לעובר? (the question as examined, in Hebrew)
- א. תיקון הסרעפת בניתוח תוך-רחמי הוכח כטיפול היעיל ביותר
- ב. החדרת בלון לטרכיאה של העובר יעילה רק במקרים של CDH ימני
- ג. 34 החדרת בלון לטרכיאה של העובר דורשת את הוצאתו עד שבוע
- ד. בשלב זה כבר אין מקום לביצוע התערבות תוך רחמית
איזה מהמשפטים הבאים מסביר את תיאוריית הפגיעה הכפולה במנגנון יל"ד ריאתי הקשור ל- CDH ) two hit hypothesis ?( (the question as examined, in Hebrew)
- א. ב- CDH , בזמן התפתחות העובר, ישנה פגיעה בהתפתחות רקמת הריאות וגם בהתפתחות אספקת הדם הריאתית
- ב. ב- CDH ישנה פגיעה בהתפתחות הריאות בשלב מוקדם וגם בהתפתחות הסרעפת בשלב מאוחר יותר
- ג. ב- CDH ישנה פגיעה בשניים מתוך חמשת שלבי ההתפתחות הריאתית ) embryonic pseudoglandular, canalicular, saccular, alveolar
- ד. ב- CDH ישנה פגיעה ריאתית בשלב העוברי וגם לאחר הלידה
In the full version for subscribers
- A simple algorithm
- Memory aid
- Exam traps
- 5 review cards
- Enough for IMLE
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Sources
- CDH EURO Consortium: Standardized Postnatal Management of Infants with Congenital Diaphragmatic Hernia — 2015 update, 2016 — Delivery room, ventilation and surgical timing
- TOTAL trial: Fetoscopic endoluminal tracheal occlusion for severe and moderate left CDH (two randomized trials), 2021 — Gestational timing and outcomes
- Holcomb and Ashcraft's Pediatric Surgery, 7th edition (2019) — Congenital Diaphragmatic Hernia and Eventration
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.