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

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.

Anatomy Septum transversum Pleuroperitoneal membranes

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

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)

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

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

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

Case CXR 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

What's next?!

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).

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

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%

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

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

ECMO criteria No strict criteria can accurately predict high mortality

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%)

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)

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

Long-term outcome GERD Neurological outcome

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

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

Surgical Repair

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

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