Congenital Diaphragmatic Hernia

1. Congenital Diaphragmatic Hernia Jeff Wu Pediatric Surgery Clerkship, David Geffen SOM at UCLA March 8, 2006

2. ID/CC: 38 4/7 week gestation newborn male NSVD to 31 y/o mother. PMHx: patient antenatally diagnosed with CDH at 28 weeks. Infant intubated in delivery room Placed on conventional mechanical ventilation PE: Right-deviated trachea; diminished breath sounds on L; abdomen scaphoid pH of 6.74, pCO2 of 111, pO2 of 98, bicarbonate 14.8, oxygen Saturation 82%, and base deficit of -22. High-frequency oscillator: Mean airway pressure of 18, FiO2 100%, Nitric oxide 20 ppm. Amplitude was 38 to 42 and freq 10 Hz. O2 Sat 48%. Head ultrasound was obtained no evidence of intraventricular hemorrhage

3. What is it? • Failure of diaphragmatic fusion Foramen of Bochdalek (85-90%) Foramen of Morgagni

4. What is it? • Herniation of abdominal contents into thoracic cavity • Pulmonary hypoplasia

5. Incidence ~1:2500 live births ~1100 cases in the U.S. annually $230M spent on hospitalization Despite advances in care, survival remains around ~65%

6. Diagnosis Antenatal: U/S at ~20 weeks gestation ~60% of CDH patients are diagnosed antenatally Proposed prenatal determinants of outcome: polyhydramnios; intrathoracic stomach or liver; abdominal circumference; lung-to-head ratio Also search for associated malformations

7. Postnatal: clinical signs of respiratory distress XR: absent diaphragmatic outline, loops of bowel in chest, tip of NG tube in thorax

8. Initial Management Goal: oxygenate, avoid barotrauma Intubate: conventional mechanical ventilation +/- Sedate NGT for decompression

9. Pathophysiology 1) Pulmonary hypoplasia “compression theory”: - modeled in fetal lambs - rationale for early surgery to remove “compressive” bowels from thorax “global embryopathy”: - modeled in newborn rats - rationale for new therapeutic ideas 2) Pulmonary hypertension causes persistent fetal circulation

10. Medical Management Goal: stabilize patient until definitive surgical repair Pulmonary vasodilators: inhaled nitric oxide Inotropes, systemic vasoconstrictors: dobutamine, dopamine, epinephrine high frequency oscillatory ventilation ECMO Surfactant Antenatal steroids? Liquid ventilation?

11. ECMO

12. Surgical Management typically a subcostal incision (thoracotomy rarely considered) gentle reduction of abdominal viscera identification and excision of hernia sac (found in 10%) approximate diaphragmatic tissue with sutures, Goretex, or muscle flaps

13. Developing Therapy • Fetal surgery idea to remove herniated bowels early in development stemmed from “Compression hypothesis”; initial findings demonstrated no survival benefit. • PLUG fetal surgery is an idea which makes use of the observation that laryngeal atresia is associated with enlarged hyperplastic lungs; Plug the Lung Until it Grows • Growth factors injected during embryologic development - Vitamin A important in lung development, maybe can prevent CDH; prenatal treatment of Nitrofen rats with Vit A showed decreased incidence of CDH at term.

14. Take home points Defect, herniated bowel, and pulmonary hypoplasia Treat pulmonary hypoplasia/hypertension medically until stabilized Timing of surgical therapy based on optimization of patient Possible new therapies including prevention? “An ounce of prevention is worth more than a pound of cure.” - Benjamin Franklin

15. References [1] Downard CD, Wilson JM. Current therapy of infants with congenital diaphragmatic hernia. Semin Neonatol. 2003 Jun;8(3):215-21. [2] Smith NP, Jesudason EC, Losty PD. Congenital diaphragmatic hernia. Paediatr Respir Rev. 2002 Dec;3(4):339-48. [3] Jesudason EC. Challenging embryological theories on congenital diaphragmatic hernia: future therapeutic implications for paediatric surgery. Ann R Coll Surg Engl. 2002 Jul;84(4):252-9. [4] O’Neill J, Grosfeld J, Fonkalsrud E. Chap 44. Congenital Diaphragmatic Hernia. Principles of pediatric surgery, 2nd Ed. Mosby 2003.