Congenital Diaphragmatic Hernia

Jeff WuPediatric Surgery Clerkship, David Geffen SOM at UCLAMarch 8, 2006

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, oxygenSaturation 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

What is it?1) Failure of diaphragmatic fusion

Foramen of Bochdalek (85-90%)Foramen of Morgagni

What is it?2) Herniation of abdominal contents

into thoracic cavity3) Pulmonary hypoplasia

Incidence~1:2500 live births~1100 cases in the U.S. annually$230M spent on hospitalization

Despite advances in care, survival remains around ~65%

DiagnosisAntenatal:

U/S at ~20 weeks gestation~60% of CDH patients are diagnosed antenatallyProposed prenatal determinants of outcome: polyhydramnios; intrathoracic stomach or liver; abdominal circumference; lung-to-head ratioAlso search for associated malformations

Postnatal:clinical signs of respiratory distressXR: absent diaphragmatic outline, loops of bowel in chest, tip of NG tube in thorax

Initial ManagementGoal: oxygenate, avoid

barotraumaIntubate: conventional mechanical

ventilation+/- SedateNGT for decompression

Pathophysiology1) 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 hypertensioncauses persistent fetal circulation

Medical ManagementGoal: stabilize patient until

definitive surgical repairPulmonary vasodilators: inhaled nitric oxideInotropes, systemic vasoconstrictors: dobutamine, dopamine, epinephrinehigh frequency oscillatory ventilationECMOSurfactantAntenatal steroids?Liquid ventilation?

ECMO

Surgical Management

typically a subcostal incision (thoracotomy rarely considered)

gentle reduction of abdominal visceraidentification and excision of hernia

sac (found in 10%)approximate diaphragmatic tissue with

sutures, Goretex, or muscle flaps

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.

“An ounce of prevention is worth more than a pound of cure.” - Benjamin Franklin

Take home pointsDefect, herniated bowel, and pulmonary hypoplasiaTreat pulmonary hypoplasia/hypertension medically until

stabilizedTiming of surgical therapy based on optimization of

patientPossible new therapies including prevention?

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.