2. DEFINITION
• The migration of abdominal viscera through a defect in
diaphragm in to the chest results in diaphragmatic hernia
• Three types
• 1-Bochdalek –herniation through postero lateral diaphragm
• 2-Morgagni –herniation through substernal foramen
• 3-Herniation through esophageal hiatus
3. EMBRYOLOGY
• Classical theory-four sources
1. Septum transversum forming central tendon
2. Mediastinum and dorsal mesogastrium forming
median portion and crura
3. Pleuroperitoneal membranes forming a small dorsal
portion
4. 4. Thoracic body wall musculature forming major
circumferential muscular part of the diaphragm.
5. • Approximately 1/3rd infants with CDH - stillborn, but
usually result of associated fatal congenital
anomalies.
• When stillborns counted with live births, females
appear to be more commonly afflicted than males.
• Defects more common on left side, with
approximately 80% - left sided and 20% right sided.
6. • Bilateral CDH defects - rare and a high incidence of
associated anomalies.
• Infants with isolated CDH - more likely to be
premature, macrosomic, and male; and about one
third of affected infants may have associated major
defects.
• CDH - thought to represent sporadic developmental
anomaly, although number of familial cases.
7. • Expected recurrence risk in a first-degree relative - estimated
to be 1 in 45, or approximately 2%.
• Structural chromosomal abnormalities - identified in 9% to
34% of CDH infants and include trisomies, deletions, and
translocations.
• Combination of CDH and abnormal karyotype - associated
with a poor outcome.
8. • Cause of CDH - unknown.
• Increasing evidence that CDH may be due to
exposure of genetically predisposed or susceptible
individuals to environmental factors.
• Exposure to pharmacologic agents and
environmental hazards - implicated in its
development.
• Insecticides and drugs - phenmetrazine, thalidomide,
quinine, cadmium, lead, and nitrofen.
9. • Clinical findings of vitamin A deficiency in CDH
infants and effects of vitamin A administration in
nitrofen-induced pulmonary hypoplasia -
strengthened evolving hypothesis that alterations in
retinoid-regulated target genes may be responsible
for CDH development.
10. Associated Anomalies
• Any newborn with a major congenital anomaly, including
infants with CDH, increased incidence of an additional
malformation compared with general population.
• Incidence of associated malformations in infants -10% to 50%.
• Skeletal defects - in as many as 32% of CDH infants and
include limb reduction and costovertebral defects.
• Cardiac anomalies - in 24% of infants.
11. • Cardiac hypoplasia involving left ventricle and often
associated with hypoplasia of aortic arch
frequently described and can be confused with
hypoplastic heart syndromes.
• Clinical significance - limited.
• Most cardiovascular malformations involve cardiac
outflow tract, such as ventricular septal defects,
tetralogy of Fallot, transposition of great vessels,
double outlet right ventricle, and aortic coarctation.
12. • Anatomic anomalies of tracheobronchial tree - in 18% of
patients with CDH and include congenital tracheal stenosis,
tracheal bronchus, and trifurcated trachea.
• Incidence of associated malformations in stillborn infants with
CDH - even higher.
• Neural tube defects and included anencephaly,
myelomeningocele, hydrocephalus, and encephaloceles.
• Even in infants who survive to birth but die shortly thereafter,
neural tube defects - most common malformations.
13. Pathology
• Although cause of CDH uncertain, consequences on
pulmonary development and function well documented.
• During early development of diaphragm, midgut herniated
into yolk sac.
• If closure of pleuroperitoneal canal - not occurred by the time
midgut returns to abdomen during gestational weeks 9 and
10, abdominal viscera herniate through the lumbocostal
trigone into the ipsilateral thoracic cavity.
14. • Resulting abnormal position of bowel prevents
normal counter-clockwise rotation and fixation.
• No hernia sac present, if event occurs before
complete closure of the pleuroperitoneal canal, but
nonmuscularized membrane forms hernia sac in 10%
to 15% of CDH patients.
• In most cases, defect - established by week 12.
• Subsequent postnatal problems relate to effects of
the herniated viscera on the developing heart and
lungs.
15. • The classical left-sided CDH
features a 2.0- to 4.0-cm
posterolateral defect in
diaphragm through which
abdominal viscera have
been translocated into the
hemithorax.
• Herniated contents often
include left lobe of liver,
spleen, and almost the
entire gastrointestinal
tract.
16. • Stomach - frequently in the chest, some degree of
obstruction at gastroesophageal junction.
• Causes dilation and ectasia of the esophagus.
• Occasionally, kidney may be in the chest tethered by
renal vessels.
• In instances of right-sided defect, large right lobe of
liver can occupy much of the hemi-thorax in addition
to other abdominal viscera.
17. • Hepatic veins may drain ectopically into right atrium,
and fibrous fusion between liver and lung - reported.
• Significantly complicate surgical repair of
diaphragmatic defect.
• Unilateral visceral herniation affects
both ipsilateral and contralateral pulmonary
development, although hypoplasia more severe
on ipsilateral side.
18.
19. . Process of CDH herniation occurs at time of bronchial
subdivision, at this stage that lung development
becomes compromised.
• Although all major bronchial buds present in CDH
lung, number of bronchial branches in affected lung -
greatly reduced.
• Alveolar development - severely affected, and few
normal alveoli exist in the lungs at term.
20. • Pulmonary blood flow - 7% of cardiac output during
normal fetal development, and pulmonary vascular
resistance remains high.
• Fetus preferentially shunts oxygenated blood from
placenta through foramen ovale and ductus arteriosus in
right-to-left direction into systemic circulation.
• At birth, number of hemodynamic changes take place.
• With institution of breathing, pulmonary vascular
resistance falls, as does pulmonary artery pressure
allowing for an increase in pulmonary blood flow
21. • Systemic vascular resistance and left atrial pressure
rise, causing foramen ovale to close.
• Increased arterial oxygen tension induces
spontaneous closure of ductus arteriosus.
• Transition from fetal to an adult-type circulatory
pattern - accomplished.
• Persistent fetal circulation may develop if this
process is interrupted.
22. • After birth and interruption of placental circulatory support,
persistently elevated pulmonary vascular resistance results in
increased pulmonary artery pressures and decreased
pulmonary vascular blood flow.
• Increased vascular resistance results in right-to-left shunting
of blood at either atrial or ductal levels with delivery of
unsaturated blood into systemic circulation.
• As blood flow in shunt increases, oxygen saturation in
systemic circulation falls.
• Mixed venous blood returning to right side of heart becomes
progressively desaturated.
23. • Resulting hypoxia further increases pulmonary
vascular resistance and compromises pulmonary
blood flow while increasing the right-to-left shunt
flow.
• Severe and progressive respiratory failure ensues.
24.
25. DIAGNOSIS
• Diagnosis - often made on a prenatal ultrasound (US)
examination and accurate in 40% to 90% of cases.
• Although considerable variation in detection rates
reported, mean gestational age at discovery is 24
weeks and reported as early as 11 weeks.
• US - routine obstetric care or because of suspicion
concerning presence of polyhydramnios.
26. • Polyhydramnios reported in up to 80% of
pregnancies with associated CDH.
• Mechanism of polyhdramnios - thought to be due to
kinking of gastroesophageal junction by translocation
of the stomach into thorax with resultant foregut
obstruction.
27. A. Ultrasound examination of a 28-week gestation fetus (twin B)
in cross section demonstrating the fetal heart (FH) and stomach
(ST) in the same plane.
B. Ultrasound examination of the same fetus but in a sagittal
plane, demonstrating relationship of the stomach, liver, and
heart
28. • Observing stomach in the fetal thorax at same cross-
sectional level as the heart.
• Additional US findings - absence of stomach in
abdomen and presence of liver or other solid viscera
in thorax.
• Stomach may be small because of interference with
fetal swallowing.
29. • Right side - liver can tamponade hernia site and
obscure diagnosis.
• Diagnosis of CDH may be missed - intermittent
herniation of abdominal viscera into thoracic cavity
has been reported.
30. • Furthermore, when stomach - in normal abdominal
position, herniated small bowel loops not easily
distinguishable from lung parenchyma.
• Misinterpretation can be caused by other diagnoses,
such as esophageal atresia and cystic lung anomalies.
• Functional information concerning fetal breathing can
be obtained by duplex Doppler examination of
amniotic flow at the fetal nares at the time of fetal US.
31. • In addition to diagnosis, prenatal US may also be of
benefit in predicting outcome by using quantitative
techniques to estimate the severity of pulmonary
hypoplasia of the fetal CDH lung.
• 3D estimation of the lung volume, calculation of the
right lung area to thoracic area ratio, and calculation
of the lung to thoracic circumference ratio are three
different measurements that may correlate with
neonatal outcome, but the lung-to-head ratio has been
the most widely used prognostic indicator.
• US can be limited by poor acoustic contrast between
fetal lung and herniated viscera, position of the fetus,
and operator experience.
32. • As a result, prenatal MRI - increasing frequency when
obstetric sonography detected complex fetal
anomaly and ideally suited for fetuses with a
diaphragmatic hernia.
33. Chest radiograph of an infant with a right-sided congenital diaphragmatic
hernia demonstrating air-filled loops of intestine in the right hemithorax with
contralateral displacement of the mediastinum. Infant - cannulated for
venoarterial extracorporeal membrane
oxygenation.
34. • After birth, spectrum of respiratory symptoms - determined
by degree of pulmonary hypoplasia and reactive pulmonary
hypertension.
• Most severely affected - respiratory distress at birth.
• Majority demonstrate respiratory symptoms within the first
24 hours of life.
• Classically - scaphoid abdomen and an asymmetric
distended chest.
• Chest may become more distended as swallowed air passes
into stomach and intestines.
• Gastrointestinal distention further compresses pulmonary
parenchyma and affects ventilatory characteristics.
35. • Additional mediastinal compression with impairment
of the contralateral lung.
• Because of the small size of the neonate’s chest,
breath sounds may or may notbe present on the side
of the defect.
• Mediastinal compression with shift into contralateral
thorax may cause deviation of the trachea away from
side of hernia and result in obstruction to venous
return with the hemodynamic consequences of
hypotension and inadequate peripheral perfusion.
36. • Signs of respiratory distress may include cyanosis,
gasping, sternal retractions, and poor respiratory
effort.
• In babies with a left CDH, heart sounds will be heard
best over the rightchest; “dextrocardia” + respiratory
distress = CDH until proven otherwise.
37. • Plain chest radiograph - loops of intestine in the
chest.
• Location of gastric bubble, and its position
confirmed by an orogastric tube.
• Rarely, contrast study of upper gastrointestinal
tract is required.
• Chest radiograph - angulation of mediastinum
and shifting of cardiac silhouette into
contralateral thorax.
38. • Although minimal aeration of ipsilateral parenchyma
may be noted, chest radiographs - unreliable for
estimating degree of pulmonary hypoplasia.
• Once diagnosis confirmed, additional radiographic
and US examinations - to search for associated
anomalies.
• Echocardiography and both renal and cranial US
scans.
39. • Although most CDHs present in first 24 hours of life,
10% to 20% of infants - present later.
• Latter infants - with recurrent mild respiratory
illnesses, chronic pulmonary disease, pneumonia,
effusion, empyema, or gastric volvulus.
• Occasionally, neonatal streptococcal pneumonia may
mask a delayed-onset right CDH.
40. Differential Diagnosis
• Eventration of the diaphragm,
• anterior diaphragmatic hernia of Morgagni,
• congenital esophageal hiatal hernia,
• congenital cystic disease of the lung
• primary agenesis of the lung.
41. Resuscitation
• After birth and confirmation of CDH, all efforts should
be made to stabilize the cardiorespiratory system while
inducing minimal iatrogenic injury from therapeutic
interventions.
• CDH - physiologic emergency and not a surgical
emergency.
• Associated respiratory distress with CDH newborn
results from a combination of two factors:
uncorrectable pulmonary hypoplasia and potentially
reversible pulmonary hypertension.
42. • Clinically, both manifested by increase in pulmonary
vascular resistance and elevated pulmonary artery
pressures, right-to-left shunting at the ductal and
foramen levels, and progressive hypoxemia.
• Because there are no proven therapies to promote
pulmonary growth at this time, therapeutic
interventions - aimed at governing pulmonary
vascular tone.
43. • Resuscitation: endotracheal intubation and
nasogastric tube insertion.
• Ventilation by mask and Ambubag -
contraindicated to avoid distention of the
stomach and intestines that may be in the
thoracic cavity.
• Arterial and venous access - acquired through
umbilicus.
44. • Tracheal occlusion resulted in lung enlargement but
did not reverse pathologic process associated with
pulmonary hypoplasia.
45. • Maintaining proper temperature regulation, glucose
homeostasis, and volume status in neonate in effort to
maintain adequate oxygen delivery.
• Any stressful stimulus can further exacerbate already
elevated pulmonary pressures and lead to increased
shunt flow and further systemic desaturation.
• Infants - properly sedated, and any combination of
agents, including midazolam, fentanyl, or morphine, can
be used.
• Muscle paralysis - strongly discouraged because of its
untoward consequences on ventilatory mechanics and
potential morbidity.
46. • Systemic hypotension reversed with intravenous fluid
administration, including crystalloid, blood products,
and colloid.
• Cardiotonic drugs, such as dopamine or dobutamine,
may be required.
• Excessive intravenous hydration - avoided, may lead
to pulmonary edema, loss of compliance, and further
impairment of gas exchange.
47. • Metabolic acid-base disturbances - usually related to
hypoperfusion and should be corrected by fluid
management or bicarbonate administration.
• Metabolic acidosis can be reversed with bicarbonate
administration.
• Severe hypercapnia (PCO2 >70 mmHg) should be
managed by changing ventilator strategy.
• No need for chest tube in absence of active air leak,
pneumothorax, or hemothorax.
48. • Goal of ventilatory support - to maintain minute
ventilation while obtaining a preductal PO2 greater
than 60 mm Hg (SaO2 90% to 100%) with
corresponding PCO2 of less than 60 mm Hg.
• High-frequency techniques using an oscillating
Ventilator - effective in removing carbon dioxide and
temporarily stabilizing an infant in severe respiratory
distress.
49. Pharmacology
• Calcium channel blockers
• Prostacyclin derivatives
• Endothelin receptor antagonists
phosphodiesterase-5 inhibitors such as
sildenafil - under trials.
50. SURGICAL MANAGEMENT
• Timing of surgical repair
• Period of medical stabilization and delayed surgical
repair, to improve overall condition.
• Operative Repair
• Subcostal incision most common approach although
repair can be done through thoracotomy as well.
51. Schematic drawing of an unreduced left
congenital diaphragmatic hernia as seen from
the abdomen.
52. The same hernia but now reduced, demonstrating that
the spleen usually last organ to be reduced from chest
cavity. Sutures have been placed for a primary repair.
55. • Posterior rim of diaphragm must be searched for in
retroperitoneal tissue, because may be rolled up like
a window shade by peritoneum.
• Peritoneum must be opened over this fold and
diaphragmatic tissue mobilized.
• When tissue is adequate, primary repair with
interrupted nonabsorbable suture material.
56. • In some cases, posterior rim of tissue may disappear
along lateral chest wall.
• If enough diaphragmatic tissue anteriorly, can be
sutured directly to body wall with sutures placed
around the ribs.
57. • Drainage of chest cavity on repaired side with a tube
thoracostomy - not indicated except for active
bleeding or uncontrolled air leak due to risk of
barotrauma and pulmonary hypertention imposed by
mechanical ventilation on hypoplastic lung.
58. • Latissimus dorsi muscle flap through a thoracic
approach - best means to prevent further
recurrence.
59. Postoperative Management
• Ventilator support - tailored to keep preductal SaO2
greater than 90% and PCO2 less than 60 mm Hg.
• Echocardiograms - to assess pulmonary
hypertension, shunt flow, and ventricular
performance.
• Weaning from ventilator support - slow and
deliberate as tolerated.
60. EXTRACORPOREAL MEMBRANE
OXYGENATION
• With evolution of delayed surgical repair, ECMO - now
considered part of preoperative stabilization process.
• Successful when used to support an infant with a
reversible process of pulmonary hypertension.
• However, not a treatment for those infants with
irreversible hypoplasia.
• For CDH patients, most common reason for initiation of
ECMO was an Oxygen Index of 40 or greater.
61. • Oxygenation index=MAP x FIO2 x 100/pao2
• Map=mean airway pressure
• Failure to improve in setting of severe pulmonary
hypertension and progressive hypoxemia despite
maximum medical intervention - valid qualifying
criterion for ECMO support.
62. • If infant’s tissue oxygen requirements - not being met
(end-organ failure) despite best conventional care,
ECMO - reasonable consideration.
• Overall survival rates - with ECMO - 34% to 87%
• Dependent on number of variables, including
gestational age and birth weight, respiratory function,
and degree of pulmonary development and associated
pulmonary hypertension.
63. OUTCOME
• Pulmonary issues - most common long-term problems
• Chronic lung disease or bronchopulmonary dysplasia,
• reactive airway disease,
• pulmonary hypertension, and
• pneumonia.
64. • Alveoli in both lung fields may become
emphysematous, as contralateral lung may herniate
across mediastinum.
