CONGENITAL DIAPHRAGMATIC HERNIA Dr Osama Bawazir

1. CONGENITAL DIAPHRAGMATIC HERNIA Dr Osama Bawazir Assistant Professor , Consultant Pediatric surgeon FRCSI, FRCS(Ed), FRCS (glas), FRCSC, FAAP,FACS.

2. CDH-Epidemiology • 1 in2000- 4000 births • 95.8% posterolateral defects (Bochdalek) • 84.4% left side • 13.2% right side • 2.4% bilateral • Morgagni and pars sternalis hernias rare • 1/3 will have associated anomalies.

3. Anatomy Septum transversum Pleuroperitoneal membranes

4. Pathophysiology • Combination of events… • Physical compression • Pulmonary hypoplasia bilaterally (ipsilateral>contralateral) • Smaller bronchi • Less branching • Decreased alveolar SA • Pulmonary hypertension • Lack of pulmonary arterioles • Increased thickness of muscle • Abnormally high vascular reactivity of vessels • Right to left shunt

5. Diagnosis • Prenatally • U/S – can diagnose 50%, 50% “normal”, • as early as 15 weeks • Polyhydramnios • Absent or intrathoracic stomach bubble • Mediastinal or cardiac shift away from hernia • Assess other organs • Amniocentesis for chromosomes, alpha fetoprotein (18 weeks)

6. Diagnosis • Postnatal • RD in the first 24hours. scaphoid abdomen (majority) • After 24h with vomiting, cough, cyanosis, gastric outlet obstruction, herniation of liver, spleen, bowel.

7. Prognostic Indicators • *Herniated organs (liver) • *Lung to head ratio (LHR) • <0.6 poor, 0.6-1.35 61% survive, >1.35 100% survive • Associated anomalies • Birth weight and Apgar score ( the CDH study group) • Measurement of L/T ratio • L/T normal ~ 0.52, severe < 0.26

8. Importance of Prenatal Dx • Check for associated anomalies • Plan for delivery at tertiary perinatal centre +/- ECMO • Options for parents • Prenatal therapies, termination, treatment after delivery

9. Case • Male, 36 week GA, 30 yr. old G1P0 • SVD • Apgars 31,75,910, ETT in DR • BW – 2,700 g • Normal pregnancy • U/S – 28 week  CDH • Amnio – Normal, 46XY • On exam • Scaphoid abdomen • Bowel sounds over left chest CXR

10. What's next?!

11. Management • SVD • Initial resuscitation • Supplemental O2 • No bag & mask • ETT with mechanical ventilation • Ventilation strategies* • Watch for pneumothorax (usually contralateral) • NG tube • Fluid status • Inotropic support • Delayed surgery ( until patient is stable).

12. CMV • Require high setting, high FiO2 • High OI=30 (OI= MAP×FiO2×100/PaO2) • Paralysis • Amp and gent • NG tube • Inotropic support

13. Ventilation Strategies • Prevent conditions that raise pulmonary vascular resistance (hypoxemia, acidosis, hypotension and hypercarbia)  hyperventlation to control hypoxemia Aim: pH > 7.45, PCO2 < 35 , PaO2 > 60  barotrauma. Wung et al. showed that some of the mortality in CDH infants was,infact,due to ventilator-induced lung injury • Gentle ventilation with permissive hyper-capnea • Low PIP, pressure-limited ventilation, minimal set RR, minimal sedation and tolerance of high PCO2 > 50  survival>90%

14. Ventilation Strategies • HFOV • Good in animal models • little benefit • Nitric oxide • Selective pulmonary vasodilator • Result in Pt with CDH have been discouraging • Surfactant • ECMO

15. Preoperative management • If alternative ventilator strategies fail-consider Extracorporeal Membrane Oxygenation (ECMO) • Failure: • PaO2<40mmHg in 100% FiO2 • Pulmonary HTN persists • Decide failure early

16. ECMO criteria No strict criteria can accurately predict high mortality

17. ECMO in CDH • 1st ECMO for CDH by german et al.in 1977 • Treat infant post CDH repair • Now ECMO is strategy of pre-op stabilization.(only 5% post repair in 2001) • ECMO provides effective short-term support • The overall survival reported to ELSO is 52% only.(?? 64% in90 &52% in 01) • Survival was similar in 2 studies (one use ECMO in 50% and the other 1%)

18. Mode of ECMO in CDH • Traditionally VA ( hemodynamically unstable) • VV is an acceptable initial mode for CDH . • No difference between R & L side CDH in regard to failure of VV and need to conversion to VA (Dimmitt et al) {??R CDH low venous drainage  VA} • Infants with CDH tend to had smaller veins (frenkner et al)

19. CDH surgery on ECMO • Risk of bleeding (early report significant hemorrhagic complications  low survival ) • Close coagulation monitoring bleeding can be avoided. • Aminocaproic acid { 5% re-exploration for bleeding Vs 26% , circuit change (downard et al)} • CDH study group data • 54% repaired on ECMO 30% following ECMO • Survival was 49% in infant repair on ECMO Vs 83% after ECMO

20. Long-term outcome • GERD • Neurological outcome

21. Pt put on ECMO • Start wean of ECMO in 10 days • Had surgical repair then in 24 hr had de-cannulation

22. Surgical Repair • First repair in 1940 (Ladd & Gross) • 1970’s – Early intervention • Emergent surgery to alleviate the compression of the “good” lung • Current practice allows a period of stabilization prior to repair • CDH is a physiologic emergency, not a surgical emergency • Pulmonary hypertension is the primary determinant of mortality

23. Surgical Repair

24. New Advances • In utero • Surgical repair - >70% mortality • Tracheal ligation • 27-28 weeks GA • Causes distention and secondary hyperplasia • Good results in 40% of patients • Ventilation strategies

25. Thank You