Diaphragmatic Hernias Treatment & Management

Updated: Oct 24, 2017
  • Author: Nicola Lewis, MBBS, FRCS, FRCS(Paed Surg); Chief Editor: Eugene S Kim, MD, FACS, FAAP  more...
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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.

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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. [22, 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. [23]

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). [24] 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. [25]

Surfactant rescue or prophylactic therapy is associated with improved oxygenation in some neonates with CDH. [26, 27] 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. [28]

iNO has proven to be a highly selective pulmonary vasodilator and has been used as rescue therapy in infants with persistent pulmonary hypertension of 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. [29]

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.
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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 [30] or fascial flaps [31, 32] 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 [33] 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. [34, 35]

According to a systematic review and meta-analysis by Terui et al, [36]  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. [37]  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. [38] To decrease the hemostatic complications, associated ECMO platelet counts are now maintained above 150,000/μL, and the activated clotting times (ACT) are 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.

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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. [39]

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). [40] (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. [41]

Clinical studies have pointed to an alteration in vitamin A metabolism in fetuses with CDH that is independent of maternal vitamin A levels. [42, 43]  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. [44, 45, 46]

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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; [47] 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.

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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 of the head
  • Developmental evaluation

In the outpatient clinic, chest radiography, pulmonary function tests, nutritional and developmental assessments, and repeated auditory, ophthalmology, and neurology evaluations are performed.

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