CONGENITAL DIAPHRAGMATIC HERNIA

Dr Osama BawazirAssistant Professor , Consultant Pediatric surgeon

FRCSI, FRCS(Ed), FRCS (glas), FRCSC,FAAP,FACS.

CDH-EpidemiologyCDH-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.

AnatomyAnatomy

Septum transversum

Pleuroperitoneal membranesPleuroperitoneal membranes

PathophysiologyPathophysiology• 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

DiagnosisDiagnosis

• 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)

DiagnosisDiagnosis

• Postnatal– RD in the first

24hours. scaphoid abdomen (majority)

– After 24h with vomiting, cough, cyanosis, gastric outlet obstruction, herniation of liver, spleen, bowel.

Prognostic IndicatorsPrognostic 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 DxImportance 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 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

• What's next?!

ManagementManagement• 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– 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 managementPreoperative management

• If alternative ventilator strategies fail-consider Extracorporeal Membrane Oxygenation (ECMO)

• Failure:– PaO2<40mmHg in 100% FiO2– Pulmonary HTN persists– Decide failure early

ECMO criteriaECMO criteria

No strict criteria can accurately predict high mortality

ECMO in CDHECMO 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 CDHMode 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 ECMOCDH 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 outcomeLong-term outcome

• GERD

• Neurological outcome

Pt put on ECMOStart wean of ECMO in 10 daysHad surgical repair then in 24 hr had de-cannulation

Surgical RepairSurgical 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 RepairSurgical Repair

New AdvancesNew 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

Thank You