Diaphragmatic Hernias 

Updated: Oct 22, 2019
Author: Nicola Lewis, MBBS, FRCS, FRCS(Paed Surg); Chief Editor: Eugene S Kim, MD, FACS, FAAP 

Overview

Practice Essentials

In 1679, Riverius recorded the first reported case of a congenital diaphragmatic hernia (CDH); this was after postmortem examination of a 24-year-old man.[1]

The first attempt at surgical repair of a CDH was by Nauman in 1888; the 19-year-old patient presented with acute respiratory distress and an acute abdomen, and a laparotomy was performed. In 1889, O'Dwyer carried out the first repair of CDH in an infant. The first successful repair was in 1905. The patient was aged 9 years, and Heidenhain reduced the hernia and closed the diaphragmatic defect through a midline laparotomy incision. Approximately 20 years later, Hedbolm reported a 58% mortality for patients undergoing surgical intervention for CDH.

In 1940, Ladd and Gross based their diagnosis of CDH on history, physical examination findings, and findings on chest radiography with or without a barium meal.[2]  They advocated early surgical intervention (within the first 48 hours). Gross also described a two-stage closure of the abdominal wall in difficult cases; closure of skin and subcutaneous fascia at the initial surgery and closure of the abdominal wall 5-6 days later. In 1950, Koop and Johnson suggested the transthoracic approach as a means of closing the defect under more direct vision.[3]

As surgical expertise improved, innovative strategies were developed to address large diaphragmatic defects and agenesis of the hemidiaphragm. These techniques included the use of rotational muscle flaps, perirenal fascia, and synthetic patch repairs.

The exponential elucidation of the pathophysiology of CDH was instrumental in improving the survival rate in infants. CDH was no longer considered a primarily surgical disease but, rather, a disease associated with pulmonary hypoplasia, pulmonary hypertension, pulmonary immaturity, and an increased susceptibility of the lungs to ventilation-induced lung injury. This led to a delayed approach to surgical repair and to a gentle but more ingenious respiratory support.

Contemporary management of CDH emphasizes management of pulmonary hypoplasia and persistent pulmonary hypertension. Various gentle alveolar recruitment strategies are employed, and a nonurgent approach is taken to the operative treatment of CDH. Although the suggested window of opportunity for surgery is 24-48 hours after birth, surgical repair can often be safely delayed in stable patients, and the operation can be scheduled on a semielective basis. Urgent surgical repair is almost never necessary and may worsen the pulmonary hypertension.

For patient education resources, see the Digestive Disorders Center, as well as Hiatal Hernia.

Anatomy

The diaphragm is a musculotendinous structure that separates the thoracic cavity from the abdominal cavity. It is composed of a central nonmuscular portion (central tendon) surrounded by a muscular rim in addition to the right and left diaphragmatic crura. The right and left diaphragmatic crura are two muscular bands that originate from vertebral bodies L1-L3 and L1-L2, respectively. These muscular bands insert into the dorsomedial diaphragm.

Most diaphragmatic defects are posterolateral, with 85-90% of these occurring on the left. The label posterolateral may be a misnomer because it is frequently the case that much larger areas of the diaphragm are missing and only a posterior rim of muscle can be found. A hernial sac is present in 10-20% of cases.

The Morgagni defect occurs posterior to the sternum and results from failure of sternal and costal fibers to fuse at the site where the superior epigastric artery crosses the diaphragm. The Morgagni defect is rare and is rarely a cause for surgery in the newborn.

Relevant embryology

The diaphragm is derived from four embryonic structures: the septum transversum, the pleuroperitoneal membranes, mesoderm of the body wall, and esophageal mesenchyme. After the folding of the fetal head at 4-5 weeks' gestation, the septum transversum comes to lie as a semicircular shelf, which separates the heart from the liver. The septum transversum does not completely separate the thoracic cavity from the peritoneal cavity but allows pericardioperitoneal canals to exist on either side of the esophagus.

During the fifth week of gestation, the pleuroperitoneal membranes develop along a line connecting the root of the 12th rib with the tips of the seventh to 12th ribs. The pleuroperitoneal membranes grow ventrally to fuse with the posterior margins of the septum transversum and the dorsal mesentery of the esophagus. Hence, at 6-7 weeks' gestation, the pleuroperitoneal canals are closed; the left closes after the right.

The mesentery of the esophagus condenses to form the left and right crura of the diaphragm, and the mesoderm of the body wall forms the outer rim of diaphragmatic muscle.

The posterolateral diaphragmatic defect is postulated to result from failure of closure of the pleuroperitoneal canals. The canal remains open when the intestines return to the abdomen at 10 weeks' gestation. Some intestine and other viscera enter the thorax and lead to compression of the developing lung at the crucial pseudoglandular stage and shifting of the mediastinum to the contralateral side. This causes compression of the heart and the contralateral lung as well.

In 1984, Iritani proposed a different concept of diaphragmatic development, suggesting that a posthepatic mesenchymal plate develops between the septum transversum and the pericardioperitoneal canals.[4] Lateral growth of this plate leads to closure of the pericardioperitoneal canals, and CDH results from a disturbance in growth of the posthepatic mesenchymal plate.

Pathophysiology

The pathophysiology of CDH involves pulmonary hypoplasia, pulmonary hypertension,[5] pulmonary immaturity, and potential deficiencies in the surfactant and antioxidant enzyme system.

Because of bowel herniation into the chest during crucial stages of lung development, airway divisions are limited to the 12th to 14th generation on the ipsilateral side and to the 16th to 18th generation on the contralateral side. Normal airway development results in 23-35 divisions. Because airspace development follows airway development, alveolarization is similarly reduced.

Development of the pulmonary arterial system parallels development of the bronchial tree, and therefore, fewer arterial branches are observed in CDH. Abnormal medial muscular hypertrophy is observed as far distally as the acinar arterioles, and the pulmonary vessels are more sensitive to stimuli of vasoconstriction.[6]

Pulmonary hypertension resulting from these arterial anomalies leads to right-to-left shunting at atrial and ductal levels. This persistent fetal circulation leads to right-side heart strain or failure and to the vicious circle of progressive hypoxemia, hypercarbia, acidosis, and pulmonary hypertension observed in the neonatal period.

The surfactant system is demonstrably deficient in the lamb model of CDH.[7] Postnatal administration of surfactant in these lambs is associated with dramatic increases in gas exchange, lung compliance, and pulmonary blood flow. However, in human neonates, reports on the status of the surfactant system are inconsistent.[8, 9]

Infants with CDH also have impairment of the pulmonary antioxidant enzyme system and are more susceptible to hyperoxia-induced injury.

In addition, a left ventricular smallness and hypoplasia are observed with CDH. This is believed to arise from decreased in-utero blood flow to the left ventricle, the mechanical compression of the herniated viscus similar to that observed in the lungs, and/or a primary yet unidentified developmental defect that simultaneously causes the diaphragmatic hernia and the lung problems.

Etiology

The initiating factor responsible for the development of CDH is unknown. Wide variations have been noted in the reported prevalence of chromosomal abnormalities (7-31%) in patients with CDH. The prevalence is higher in cases of CDH associated with other defects.[10] Familial occurrence has been noted in fewer than 2% of cases.

The role of drugs and environmental chemicals in the development of CDH is uncertain, but nitrofen, quinine, thalidomide, phenmetrazine, and polybrominated diphenyls have been used to induce CDH in various species. Investigations are exploring the link between CDH and defects in the retinoid signaling pathway in experimental models.

A small (N = 40) study from Japan found maternal dietary intake of vitamin A during pregnancy to be inversely associated with CDH in neonates.[11]

Epidemiology

CDH occurs in approximately 1 per 3000 live births.[10, 12]

The Congenital Diaphragmatic Hernia Study Group recorded a 63% survival rate in 1995-1996 based on data from 62 centers in North America, Europe, and Australia.[13] Survival rates are 60-90% for patients who present within the first few hours of life (see the image below).[14]

Graph illustrating the concept of the hidden morta Graph illustrating the concept of the hidden mortality of congenital diaphragmatic hernia. Image courtesy of Michael Harrison, MD.

Prognosis

Long-term pulmonary disease depends on the degree of pulmonary hypoplasia, barotrauma, and volutrauma sustained in the neonatal period. Bronchopulmonary dysplasia and restrictive and/or obstructive lung disease may be observed.

Failure to thrive is often observed in the presence of optimal feeding regimes.

Functional and anatomic esophageal abnormalities are associated with significant gastroesophageal reflux (GER) in 40% of survivors.[6] Prophylactic fundoplication at the time of primary repair for infants requiring a patch repair is advocated by some team as a means of preventing growth disorders or failure to thrive in this subset of patients. Other patients who may go on to require fundoplication include the neurologically impaired and those with chronic lung disease. Most other infants outgrow GER.[15, 16]

The use of extracorporeal membrane oxygenation (ECMO), hyperventilation treatment, and ototoxic medication places this population at a higher risk for sensorineural hearing loss, as well as for neurodevelopmental abnormalities (ie, cognitive and developmental delay, cerebral palsy, seizure disorders, impaired vision).

Altered musculoskeletal development results in thoracic scoliosis, pectus deformities, and a decreased thoracic cavity on the affected side.

In late childhood and adolescence, learning disability, developmental disability, and attention deficit hyperactivity disorder (ADHD) are noted in approximately 50% of patients. In addition to cognitive and attention deficits, behavioral problems are seen. Only a third of these children require placement in a special educational class.[17]

 

Presentation

History and Physical Examination

Antenatal

The diagnosis of congenital diaphragmatic hernia (CDH) is frequently made antenatally prior to 25 weeks' gestation. CDH is usually detected in the antenatal period (46-97%), depending on the use of level II ultrasonography (US) techniques (see Workup).

Postnatal

History and clinical findings vary with the presence of associated anomalies and the degree of pulmonary hypoplasia and visceral herniation. In the infant presenting in the neonatal period without antenatal diagnosis, variable respiratory distress and cyanosis, feeding intolerance, and tachycardia are noted. In the physical examination, the abdomen is scaphoid if significant visceral herniation is present (see the image below). Upon auscultation, breath sounds are diminished, bowel sounds may be heard in the chest, and heart sounds are distant or displaced.

Photograph of a one-day-old infant with congenital Photograph of a one-day-old infant with congenital diaphragmatic hernia. Note the scaphoid abdomen. This occurs if significant visceral herniation into the chest is present.

Late presentation

Patients may present outside of the neonatal period with respiratory symptoms, intestinal obstruction, bowel ischemia, and necrosis following volvulus.

Complications

Associated anomalies are present in 10-50% of patients with CDH; patients with these anomalies have a twofold relative risk of mortality when compared with patients with isolated CDHs.[18] Frequently associated anomalies include cardiac defects, chromosomal anomalies (ie. trisomies 21, 18, and 13), renal anomalies, genital anomalies, and neural tube defects.

 

Workup

Laboratory Studies

Antenatal studies to be considered include the following:

  • Amniocentesis for karyotype analysis should accompany a diagnosis of congenital diaphragmatic hernia (CDH)
  • Maternal serum alpha-fetoprotein may be low in cases of CDH

Postnatal studies to be considered include the following:

The Score for Neonatal Acute Physiology-II (SNAP-II score) has been suggested as a usefull means of assessing the risk of mortality and the need for extracorporeal membrane oxygenation (ECMO) therapy in neonates with CDH.[19] The SNAP-II score is determined on the basis of arterial blood pressure, pH, ratio of arterial oxygen tension (PaO2) to fraction of inspired oxygen (FiO2), body temperature, diuresis, and seizure activity.

Chest Radiography

An early chest radiograph is obtained to confirm the diagnosis of CDH. Findings include loops of bowel in the chest, a mediastinal shift, a paucity of bowel gas in the abdomen, and the presence of the tip of a nasogastric tube in the thoracic stomach (see the image below). Repeated chest radiography may reveal a change in the intrathoracic gas pattern. Right-side lesions are difficult to differentiate from diaphragmatic eventration and lobar consolidation.

Radiograph of an infant with congenital diaphragma Radiograph of an infant with congenital diaphragmatic hernia. Note shift of the mediastinum to the right, air-filled bowel in the left chest, and the position of the orogastric tube.

Ultrasonography and Echocardiography

Level III ultrasonography (US) and echocardiography should accompany a diagnosis of CDH. Antenatal echocardiography may identify cardiac anomalies (more commonly, ventricular hypoplasia, atrial septal defects, and ventricular septal defects).[20]  Decreased left ventricular mass, poor ventricular contractility, pulmonary and tricuspid valve regurgitation, and right-to-left shunting may be seen. Repeated echocardiography is recommended to measure changes in the pulmonary artery pressure, left-to-right shunt, and flow across the ductus arteriosus.

In a study involving 18 neonates with CDH, Tanaka et al found the use of M-mode imaging to measure diastolic wall strain to be a useful method for evaluating the diastolic function of CDH patients.[21]

In centers where fetal intervention and postnatal management protocols are determined by antenatal assessment of pulmonary hypoplasia, the lung-to-head ratio (LHR) and the lung-to-thorax transverse ratio (L/T) are calculated.

One definition of the LHR is the area of the contralateral lung (the product of the two longest perpendiculars) divided by the head circumference at the four-chamber view. Standardization of LHR measurements may lead to improved prediction of outcomes in neonates with isolated CDH.[22]  L/T is the ratio of the area of the contralateral lung to the area of the thorax at the four-chamber view on US.[23, 24]

US reveals polyhydramnios, an absent intra-abdominal gastric air bubble, mediastinal shift, and hydrops fetalis. US demonstrates the dynamic nature of the visceral herniation observed with congenital diaphragmatic hernia. The visceral hernia has moved in and out of the chest in several fetuses.

Differential diagnoses on antenatal US are as follows:

 

Treatment

Approach Considerations

No time for repair of congenital diaphragmatic hernia (CDH) is ideal, but the authors suggest that the window of opportunity is 24-48 hours after birth to achieve normal pulmonary arterial pressures and satisfactory oxygenation and ventilation on minimal ventilator settings. The association of CDH with lethal congenital abnormalities is a relative contraindication for repair of the diaphragmatic defect.

Medical Therapy

In contrast to historical management patterns, which focused on the actual repair of the diaphragmatic hernia, contemporary management of CDH emphasizes management of pulmonary hypoplasia and persistent pulmonary hypertension. Various gentle alveolar recruitment strategies are employed, and a nonurgent approach is taken to the operative treatment of CDH.[25, 1]

Immediately after delivery, the infant is intubated (bag-mask ventilation is avoided). A nasogastric tube is passed to decompress the stomach and to avoid visceral distention.

Adequate assessment involves continuous cardiac monitoring, arterial blood gas (ABG) and systemic pressure measurements, urinary catheterization to monitor fluid resuscitation, and both preductal (radial artery) and postductal (umbilical artery) oximetry.

Pressure-limited ventilation should be used, allowing the lowest airway pressures compatible with staying on the steep side of the pressure volume loop and preductal oxygen saturations greater than 90%. Peak inspiratory pressures (PIP) should be less than 30 cm H2O. Hypercarbia is allowed as long as the pH can be buffered.[26]

Alternative means of support (eg, high-frequency oscillatory ventilation [HFOV], extracorporeal membrane oxygenation [ECMO], and inhaled nitric oxide [iNO]) should be considered for patients who fail to stabilize on conventional ventilation.

HFOV is recommended for infants with hypercarbia and hypoxemia resistant to conventional ventilation or requiring high PIP (>30 cm H2O).[27] HFOV uses an oscillating diaphragm to create a sinusoidal column of air within the airways. The diaphragm oscillates at a high frequency and improves gas exchange without increased ventilatory pressures. Increased gas exchange leads to elimination of carbon dioxide, which decreases the stimulus for pulmonary vasoconstriction and decreases pulmonary hypertension. At some institutions, HFOV is chosen as the primary means of ventilation.[28]

Surfactant rescue or prophylactic therapy is associated with improved oxygenation in some neonates with CDH.[29, 30] Surfactant used as rescue therapy is administered within 24 hours of birth in neonates with CDH and a poor prognosis. As prophylactic therapy, surfactant (50-100 mg/kg of Infasurf R) is administered prior to the first breath in neonates with CDH who were given a poor prognosis antenatally.

Prophylactic surfactant therapy and natural surfactants are thought to be more efficacious. No definitive evidence of a surfactant deficiency in human neonates has been identified, and surfactant as rescue therapy has not been shown to improve outcome.[31]

iNO has proven to be a highly selective pulmonary vasodilator and has been used as rescue therapy in infants with persistent pulmonary hypertension of the newborn (PPHN). iNO produces pulmonary vasodilatation, decreases the ventilation-perfusion mismatch, and reverses the ductal shunting observed in PPHN. Limited success has been gained in the use of iNO in patients with CDH, but the efficacy of iNO improves after surfactant therapy.[32]

The selection criteria for ECMO eligibility in CDH are the standard criteria used for other neonates with respiratory failure, as follows:

  • pH less than 7.15
  • Oxygenation index greater than 40
  • Failure to respond to maximal medical treatment

ECMO should be reserved for patients who fail to respond to the alternative therapies if the extent of pulmonary hypoplasia is not considered to be lethal and when acute deterioration occurs in the postoperative period. ECMO in these cases provides respiratory support without additional barotrauma or oxygen toxicity. It allows time for the transition from fetal circulation, as well as the maturation of the pulmonary parenchyma (see the image below).

Newborn baby with congenital diaphragmatic hernia Newborn baby with congenital diaphragmatic hernia on venoarterial extracorporeal membrane oxygenation (ECMO). Note the arterial and venous cannulas connected to the bedside cardiovascular bypass machine.

Surgical Therapy

Although the suggested window of opportunity for surgery is 24-48 hours after birth, surgical repair can often be safely delayed in stable patients, and the operation can be scheduled on a semielective basis. Urgent surgical repair is almost never necessary and may worsen the pulmonary hypertension.

Preparation for surgery

The priorities in preoperative care are to provide appropriate ventilatory management of the newborn and to determine whether the patient has any other associated congenital anomalies, particularly cardiac abnormalities. Echocardiography should always be performed prior to surgical repair.

Operative details

A subcostal incision is made. The abdominal viscera are examined, and the hernia is reduced by gentle traction. A hernia sac is sought and excised if found.

After careful dissection of the posterior leaf of the diaphragm, primary repair can be accomplished in a single layer with nonabsorbable sutures. If the diaphragmatic defect is large enough to preclude primary closure, a prosthetic patch, or rotational muscle flaps[33] or fascial flaps[34, 35] can be used. If the patient is stable, the malrotation is corrected and Ladd bands are lysed.

Open transthoracic repair of a left-side and right-side diaphragmatic hernia has been reported. However, this approach is not commonly used.

Thoracoscopic or laparoscopic repair was established earlier on for late presenters and neonates requiring minimal ventilator support. Thoracoscopic repair is now being performed on neonates on HFOV[36] and iNO. Exclusion criteria are not clearly defined; however, intrathoracic liver or stomach, inability to tolerate a period of manual ventilation, and large or anterolateral defects have been cited as reasons for initial open repair or conversion to open repair.

Thoracoscopic repair yields improved visibility, reduced need for postoperative opioids, and decreased duration of ventilation (possibly related to the patient group selected). In studies by Gander et al and Okazaki et al, the recurrence rate was as high as 23% among infants undergoing thoracoscopic repair in the newborn period.[37, 38]

According to a systematic review and meta-analysis by Terui et al,[39]  although endoscopic surgery for CDH appears to be associated with a relatively low mortality, it also appears to be associated with a higher recurrence rate. The evidence was not conclusive, but the authors suggested that endoscopic surgery should not be performed routinely in neonates with CDH but should be limited to selected cases. 

A single-center study by Tyson et al found thoracoscopic CDH repair to be as safe as open repair, with comparable outcomes.[40]  In this study, there were no hernia recurrences after thoracoscopic repair at a median follow-up of 27 months.

If abdominal closure may interfere with chest wall or diaphragmatic compliance or lead to abdominal compartment syndrome, then a temporary silo with delayed primary closure of the fascia or skin can be safely accomplished.

The use of chest tubes is controversial, as is the use of suction. The authors prefer to use a chest tube but limit suction to 5 cm H2O. Most authors in North America suggest avoiding the use of suction to minimize mediastinal shift.

The patient with a right-side defect and an intrathoracic liver presents unique problems to the surgeon. The neonatal liver is extremely friable, and kinking of the hepatic veins and the inferior vena cava can accompany the return of the liver to the abdomen. Careful manipulation of the liver into the abdomen must be accompanied by hemodynamic monitoring. Occasionally, a two-cavity (right chest and abdomen) approach may be necessary to reduce the viscera.

Another well-described technique is to repair the diaphragmatic hernia via thoracotomy. Such an approach typically allows reduction of the liver and viscera back into the abdomen with excellent exposure of the diaphragm.

Surgical repair while the patient is on ECMO was initially associated with increases in mortality, surgical site hemorrhage, and intracranial hemorrhage.[41] To decrease the hemostatic complications, the associated ECMO platelet count is now maintained above 150,000/μL, and the activated clotting time (ACT) is decreased to 160-180 seconds.

Use of aminocaproic acid in the perioperative period decreases the fibrinolysis associated with use of the ECMO circuit and leads to decreased hemorrhagic complications. Intraoperative and postoperative blood loss is decreased with the following:

  • Use of electrocautery for skin incision
  • No dissection of the posterior leaf if primary repair is unlikely
  • Use of prosthetic patch repair
  • Limited blunt and sharp dissection
  • Judicious use of electrocautery
  • Application of topical thrombin to the suture line

Repairing the diaphragmatic hernia after decannulation from ECMO avoids the hemostatic complications associated with ECMO. This leads to recurrent pulmonary hypertension in some patients. The authors prefer repair on ECMO when the patient is ready for decannulation. Therefore, the patient tolerates decannulation if bleeding occurs.

Experimental Fetal Surgery

Experimental fetal surgery has been expanding rapidly. The fetus with CDH that is most likely to benefit from in-utero intervention has lethal pulmonary hypoplasia and no coexisting other lethal congenital anomalies. To date, no antenatal parameter has been able to reliably predict the occurrence of lethal pulmonary hypoplasia. Hence, selection criteria for in-utero intervention remain controversial.[42]

Current trends in fetal surgery for severe CDH focus on manipulation of lung growth by temporary occlusion of the fetal trachea using minimal access surgery (see the image below).[43] (See Fetal Surgery for Congenital Diaphragmatic Hernia.)

Diagram illustrating the sheep model of PLUG, the Diagram illustrating the sheep model of PLUG, the trachea used for the fetal management of congenital diaphragmatic hernia. Image courtesy of Michael Harrison, MD.

The immature lung in fetuses with CDH should benefit from antenatally administered corticosteroids. In the fetal lamb model, corticosteroid administration at 24 and 48 hours prior to delivery was associated with significant increases in lung compliance. Clinical trials using late antenatal steroids have failed to demonstrate improved survival, length of stay, and duration of ventilation.[44]

Clinical studies have pointed to an alteration in vitamin A metabolism in fetuses with CDH that is independent of maternal vitamin A levels.[45, 46]  In addition, experimental work has evaluated at the positive impact of antenatal vitamin A on lung development in animal models of CDH. In the nitrofen rat model, a decrease in the incidence of diaphragmatic hernias and pulmonary hypoplasia has been noted. In the lamb model, improvement in ventilation and a decrease in ventilation-induced lung injury has been observed.[47, 48, 49]

Complications

Complications observed in the early postoperative period include recurrent pulmonary hypertension and deterioration in respiratory mechanics and gaseous exchange. Less commonly observed complications include recurrence of the CDH, which is more common with patch repair[50] ; leakage of peritoneal fluid and blood into the thorax; and development of an ipsilateral hydrothorax. Small-bowel obstruction may occur secondary to adhesions or volvulus.

Long-Term Monitoring

Continued care is provided for survivors of CDH by a multidisciplinary team consisting of a social worker, a nutritionist, a physiotherapist, a pediatrician/neonatologist, a neurologist, and a pediatric surgeon.

The following screening tests could be performed before discharge:

  • Chest radiography
  • ABG evaluation
  • Brainstem auditory evoked potentials
  • Computed tomography (CT) or ultrasonography (US) of the head
  • Developmental evaluation

In the outpatient clinic, chest radiography, pulmonary function tests, and nutritional and developmental assessments are performed, as well as repeated auditory, ophthalmologic, and neurologic evaluations.

 

Guidelines

Canadian CDH Collaborative Guidelines for Congenital Diaphragmatic Hernia

In 2018, the Canadian Congenital Diaphragmatic Hernia Collaborative issued guidelines for diagnosis and management of congenital diaphragmatic hernia (CDH).[51]

Recommendations for antenatal diagnosis included the following:

  • Ultrasonographic measurement of observed-to-expected (O/E) lung-head ratio (LHR) should be done between 22 and 32 weeks of gestational age to predict the severity of pulmonary hypoplasia in isolated CDH.
  • In left-side CDH, an O/E LHR < 25% predicts poor outcome. In right-side CDH, an O/E LHR < 45% may predict poor outcome. 
  • Fetal magnetic resonance imaging (MRI) should be used (where available) for the assessment of lung volume and liver herniation in moderate and severe CDH.

Recommendations for ventilation included the following:

  • Newborns with CDH and immediate respiratory distress should be preferentially intubated at birth. Bag-valve-mask ventilation should be avoided.
  • Sedation should be provided to all mechanically ventilated newborns with CDH. Deep sedation and neuromuscular blockade should be provided selectively to those with greater ventilation or oxygen requirements. 
  • A T-piece should be used with the ventilator to avoid a peak inspiratory pressure (PIP) higher than 25 cm H 2O.
  • An arterial carbon dioxide tension (PaCO 2) between 45 and 60 mm Hg and a pH between 7.25 and 7.40 should be targeted in all newborns with CDH.
  • Supplemental oxygen should be titrated to achieve a preductal saturation of at least 85% but no greater than 95%.
  • Gentle intermittent mandatory ventilation (IMV) should be the initial ventilation mode for newborns with CDH who require respiratory support. High-frequency oscillatory ventilation (HFOV) or high-frequency jet ventilation (HFJV) should be used when the PIP required to control hypercapnia using IMV exceeds 25 cm H 2O.

Recommendations for hemodynamic support included the following:

  • Treatment of poor perfusion (capillary refill >3 s, lactate >3 mmol/L, urine output < 1 mL/kg/hr) and blood pressure below norms for age should include (1) judicious administration of crystalloid, generally not exceeding 20 mL/kg; (2) inotropic agents such as dopamine or epinephrine; and (3) hydrocortisone.
  • If poor perfusion continues, assessment of cardiac function (via echocardiography or central venous saturation) should be performed.

Recommendations for echocardiography included the following:

  • Two standardized echocardiograms, one within 48 hours of birth and one at 2-3 weeks of life, are needed to assess pulmonary vascular resistance, as well as left ventricular (LV) and right ventricular (RV) function. Additional studies may be conducted as clinically indicated.

Recommendations for management of pulmonary hypertension included the following:

  • Inhaled nitric oxide (iNO) is indicated for confirmed suprasystemic pulmonary arterial hypertension without LV dysfunction, provided that lung recruitment is adequate. In the absence of clinical or echocardiographic response, iNO should be stopped.
  • Sildenafil should be considered in patients with refractory pulmonary hypertension (ie, hypertension unresponsive to iNO) or as an adjunct in weaning iNO.
  • Milrinone should be used to treat cardiac dysfunction, particularly if it is associated with pulmonary hypertension.
  • Prostaglandin E1 can be used to maintain ductus arteriosus patency and reduce RV afterload in patients with pulmonary hypertension with RV failure or in the presence of a closing ductus. 

Recommendations for extracorporeal life support included the following:

  • The possibility of extracorporeal life support should be discussed during antenatal counselling for CDH, and the discussion should disclose that available evidence does not suggest a survival benefit to its use. 

Recommendations for surgery included the following:

  • The following physiologic criteria should be met before surgery: (1) urine output >1 mL/kg/hr, (2) fraction of inspired oxygen (FiO 2) < 0.5, (3) preductal oxygen saturation between 85% and 95%, (4) normal mean arterial pressure for gestational age, (5) lactate < 3 mmol/L, and (6) estimated pulmonary artery pressures less than systemic pressure.
  • Failure to meet these criteria within 2 weeks should prompt consideration of either attempted repair or a palliative approach. 
  • For diaphragmatic defects that are not amenable to primary repair, oversized tension-free polytetrafluoroethylene/GORE-TEX patches should be used. 
  • A minimally invasive surgical approach or technique should not be used in the repair of neonatal CDH, because of the high rates of recurrence. 
  • In patients on extracorporeal life support, surgery should be avoided until after decannulation. If the patient cannot be weaned off extracorporeal life support, consideration should be given to either surgery or palliation, as appropriate. 

Recommendations for long-term follow-up included the following:

  • Standardized multidisciplinary follow-up is recommended for children with CDH to provide surveillance and screening, optimal and timely diagnosis, and clinical care adjusted to the level of risk.
  • It is recommended to identify the subset of CDH survivors at high risk for long-term morbidity as comprising those infants and children who require extracorporeal life support, who have been repaired with a patch, or who required respiratory support at 30 days of life.