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Congenital Diaphragmatic Hernia
CHAPTER 90
CONGENITAL DIAPHRAGMATIC HERNIA Shannon N. Acker, MD, Timothy M. Crombleholme, MD
1. What is the most common type of congenital diaphragmatic hernia (CDH)? Congenital abnormalities of the diaphragm include a posterolateral defect (Bochdalek hernia), an anteromedial defect (Morgagni hernia), or the eventration (central weakening) of the diaphragm. The Bochdalek hernia is the most common variant and accounts for approximately 80% of CDH cases. This defect is most common on the left (80%), 20% are right-sided lesions, and <1% are bilateral. 2. How is CDH Diagnosed? CDH is usually diagnosed based on prenatal ultrasound (US) when the stomach is detected in the fetal thorax or at the same cross-sectional level as the heart. US may be obtained as a part of a normal prenatal screening examination or to evaluate a finding of polyhydramnios. Mean age at diagnosis is 24 weeks. Occasionally, the diagnosis of CDH is not made prenatally but may present soon after birth. Neonatal respiratory distress is the most common manifestation of CDH. At birth or shortly thereafter, the infant can develop severe dyspnea, retractions, and cyanosis. On physical examination, breath sounds are diminished on the ipsilateral side. Heart sounds can be heard more easily in the contralateral chest, and the abdomen is scaphoid because of the herniation of abdominal viscera into the chest. 3. How is the diagnosis confirmed? A chest radiograph can be obtained at birth to confirm the diagnosis. The radiograph demonstrates multiple loops of air-filled intestine or stomach in the ipsilateral thorax. If a chest radiograph is obtained before entry of significant amounts of air into the bowel, a confusing pattern of mediastinal shift, cardiac displacement, and opacification of the hemithorax may be observed. Insertion of a nasogastric (NG) tube followed by repeat chest radiograph often demonstrates the tube (i.e., stomach) in the chest and confirms the diagnosis. 4. Are other anomalies associated with CDH? The incidence of associated congenital anomalies among infants with CDH ranges from 10% to 50%. Fewer than 10% of patients with multiple major concurrent anomalies survive. Excluding intestinal malrotation and pulmonary hypoplasia, cardiac anomalies (24%–63%) are the most frequent, followed by skeletal defects (32%), genitourinary (23%), gastrointestinal (17%), central nervous system (14%), and other pulmonary (5%) anomalies. 5. What therapeutic measures should be initiated to stabilize an infant with CDH and respiratory distress at birth? If a prenatal diagnosis of CDH is made, the fetus and mother should be referred to a tertiary care center, preferably with expertise in CDH management. After birth, resuscitation should begin with endotracheal intubation and NG tube insertion. Bag-mask ventilation should be avoided to prevent gastric distention. Arterial and venous access should be obtained via the umbilicus. It is important to maintain temperature, glucose, and volume homeostasis. Goals of mechanical ventilation include maintaining a preductal PO2 >60 mm Hg and PCO2 <60 mm Hg. If conventional ventilator settings fail to achieve these goals, high-frequency oscillatory ventilation can be used to stabilize the infant. 6. When should operative repair occur? The optimal timing of operative repair is still unclear. Previously, infants were taken emergently to the operating room for reduction of the intraabdominal contents and repair of the hernia soon after birth. More recent data suggest that operative repair should be delayed until pulmonary hypertension and the infant’s hemodynamics have stabilized. The length of preoperative stabilization is highly variable, ranging from days to weeks.
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Congenital Diaphragmatic Hernia 413 7. What operative approach is used to repair a diaphragmatic defect? There is no single best approach to CDH repair. The operation can be performed from either the abdomen (laparotomy or laparoscopy) or the chest (thoracotomy or thoracoscopy). Thoracoscopic repair may be associated with higher rates of recurrence and unacceptably high levels of acidosis due to CO2 insufflation and is generally reserved for stable infants or older children with delayed diagnosis of CDH. The choice of approach is dependent on the surgeon’s preference. Principles of repair are the same whether approached from the chest or the abdomen—reduce the abdominal contents; assess the amount of diaphragmatic tissue available for repair; and decide whether to repair the defect primarily, using prosthetic tissue, or with the patient’s own tissue. Recent data suggest an abdominal wall muscle flap is safe, even in the setting of extracorporeal membrane oxygenation (ECMO) with an acceptably low rate of recurrence. 8. What factors predict morbidity and mortality in infants with CDH? The degree of pulmonary hypoplasia and severity of pulmonary hypertension are the biggest predictors of morbidity and mortality among infants with CDH. In infants with CDH, the lungs exhibit decreased alveolarization with decreased surface area available for gas exchange as well as immaturity of pulmonary vasculature with hyperplasia of the pulmonary arteries. These histologic changes contribute to elevated pulmonary vascular resistance and pulmonary arterial hypertension. This then leads to right-to-left shunting of deoxygenated blood to the systemic circulation through the patent ductus arteriosus and patent foramen ovale then causing hypoxemia, acidosis, and shock. 9. What strategies can be used to treat pulmonary hypertension among infants with CDH? a. Monitoring: Oximetry or arterial sampling (preductal in the right upper extremity; postductal in the lower extremity) permits early detection of shunting of deoxygenated blood to the systemic circulation. b. Ventilation: Hypercarbia is corrected by mechanical ventilation with adequate sedation. c. Oxygenation: Hypoxemia is corrected by adequate ventilation and high concentrations of inspired oxygen (generally, fraction of inspired oxygen = 100%). d. Resuscitation: Metabolic acidosis is managed by restoring adequate tissue perfusion (intravenous fluids or blood, inotropes, and sodium bicarbonate). e. Rescue: Salvage therapies include administration of pulmonary vasodilators via the ventilatory circuit (nitric oxide) or systemic circulation (Priscoline, prostaglandin E2), high-frequency ventilation, and ECMO. 10. What is the survival rate for patients with CDH? The overall survival rate is 60%–90%. The major determinants of survival are the degree of pulmonary hypoplasia, severity of pulmonary hypertension, and associated major congenital anomalies. Late deaths occur in approximately 10% of children, secondary to persistent pulmonary hypertension. 11. Does in utero intervention have a role in the treatment of patients with CDH? Fetal intervention for CDH is becoming more common. Early trials failed to demonstrate a benefit with in utero repair of the defect. However, current research has focused on the role of tracheal occlusion during the fetal period as a means to promote lung growth. Techniques of in-utero fetoscopic endoluminal tracheal occlusion (FETO) promoting lung growth and development followed by postnatal repair of the diaphragmatic hernia are currently being investigated. Early trials of FETO suggest a potential survival advantage compared to control groups with similar disease severity.
K EY POIN T S: C ON GE N I TA L D I A P H R A G M AT I C H ER N I A 1 . CDH is usually diagnosed in the prenatal period based on routine ultrasonography. 2. Infants with CDH usually develop respiratory distress at birth. 3. CDH should be repaired when the baby is stable from a pulmonary hypertension and hemodynamic standpoint. 4. Morbidity and mortality in CDH are determined by the severity of pulmonary hypertension and degree of pulmonary hypoplasia.
414 PEDIATRIC SURGERY Bibliography 1. Chiu PP, Sauer C, Mihailovic A, et al. The price of success in the management of congenital diaphragmatic hernia: is improved survival accompanied by an increase in long-term morbidity? J Pediatr Surg. 2006;41(5):888–892. 2. Clugston RD, Greer JJ. Diaphragm development and congenital diaphragmatic hernia. Semin Pediatr Surg. 2007;16(2):94–100. 3. Kinsella JP, Ivy DD. Pulmonary vasodilator therapy in congenital diaphragmatic hernia: acute, late, and chronic pulmonary hypertension. Semin Perinatol. 2005;29(2):123–128. 4. Kitano Y. Prenatal intervention for congenital diaphragmatic hernia. Semin Pediatr Surg. 2007;16(2):101–108. 5. Lally KP, Lally PA, Lasky RE, et al. Defect size determines survival in infants with congenital diaphragmatic hernia. Pediatrics. 2007;120(3):e651–e657. 6. Logan JW, Rice HE. Congenital diaphragmatic hernia: a systematic review and summary of best-evidence practice strategies. J Perinatol. 2007;27(9):535–549. 7. Migliazza L, Bellan C. Retrospective study of 111 cases of congenital diaphragmatic hernia treated with early highfrequency oscillatory ventilation and presurgical stabilization. J Pediatr Surg. 2007;42(9):1526–1532. 8. Rozmiarek AJ, Qureshi FG. Factors influencing survival in newborns with congenital diaphragmatic hernia: the relative role of timing of surgery. J Pediatr Surg. 2004;39(6):821–824. 9. Stolar CJH, Dillon PW. Congenital diaphragmatic hernia and eventration. In: Coran AG, Caldamone A, eds. Pediatric Surgery. 7th ed. Philadelphia, PA: Elsevier, 2012;809–824. 10. Gander JW, Fisher JC, Gross ER, et al. Early recurrence of congenital diaphragmatic hernia is higher after thoracoscopic than open repair: a single institutional study. J Pediatr Surg. 2011;46(7):1303–1308. 11. Barnhart DC, Jacques E, Scaife ER, et al. Split abdominal wall muscle flap repair vs patch repair of large congenital diaphragmatic hernias. J Pediatr Surg. 2012;47(1):81–86. 12. Al-Maary J, Eastwood MP. Fetal tracheal occlusion for severe pulmonary hypoplasia in isolated congenital diaphragmatic hernia: a systematic review and meta-analysis of survival. Ann Surg. 2016;264(6):929–933. 13. Wynn J, Krishnan U, Aspelund G, et al. Outcomes of congenital diaphragmatic hernia in the modern era of management. J Pediatr. 2013;163(1):114–119.
CONGENITAL DIAPHRAGMATIC HERNIA Shannon N. Acker, MD, Timothy M. Crombleholme, MD
1. What is the most common type of congenital diaphragmatic hernia (CDH)? Congenital abnormalities of the diaphragm include a posterolateral defect (Bochdalek hernia), an anteromedial defect (Morgagni hernia), or the eventration (central weakening) of the diaphragm. The Bochdalek hernia is the most common variant and accounts for approximately 80% of CDH cases. This defect is most common on the left (80%), 20% are right-sided lesions, and <1% are bilateral. 2. How is CDH Diagnosed? CDH is usually diagnosed based on prenatal ultrasound (US) when the stomach is detected in the fetal thorax or at the same cross-sectional level as the heart. US may be obtained as a part of a normal prenatal screening examination or to evaluate a finding of polyhydramnios. Mean age at diagnosis is 24 weeks. Occasionally, the diagnosis of CDH is not made prenatally but may present soon after birth. Neonatal respiratory distress is the most common manifestation of CDH. At birth or shortly thereafter, the infant can develop severe dyspnea, retractions, and cyanosis. On physical examination, breath sounds are diminished on the ipsilateral side. Heart sounds can be heard more easily in the contralateral chest, and the abdomen is scaphoid because of the herniation of abdominal viscera into the chest. 3. How is the diagnosis confirmed? A chest radiograph can be obtained at birth to confirm the diagnosis. The radiograph demonstrates multiple loops of air-filled intestine or stomach in the ipsilateral thorax. If a chest radiograph is obtained before entry of significant amounts of air into the bowel, a confusing pattern of mediastinal shift, cardiac displacement, and opacification of the hemithorax may be observed. Insertion of a nasogastric (NG) tube followed by repeat chest radiograph often demonstrates the tube (i.e., stomach) in the chest and confirms the diagnosis. 4. Are other anomalies associated with CDH? The incidence of associated congenital anomalies among infants with CDH ranges from 10% to 50%. Fewer than 10% of patients with multiple major concurrent anomalies survive. Excluding intestinal malrotation and pulmonary hypoplasia, cardiac anomalies (24%–63%) are the most frequent, followed by skeletal defects (32%), genitourinary (23%), gastrointestinal (17%), central nervous system (14%), and other pulmonary (5%) anomalies. 5. What therapeutic measures should be initiated to stabilize an infant with CDH and respiratory distress at birth? If a prenatal diagnosis of CDH is made, the fetus and mother should be referred to a tertiary care center, preferably with expertise in CDH management. After birth, resuscitation should begin with endotracheal intubation and NG tube insertion. Bag-mask ventilation should be avoided to prevent gastric distention. Arterial and venous access should be obtained via the umbilicus. It is important to maintain temperature, glucose, and volume homeostasis. Goals of mechanical ventilation include maintaining a preductal PO2 >60 mm Hg and PCO2 <60 mm Hg. If conventional ventilator settings fail to achieve these goals, high-frequency oscillatory ventilation can be used to stabilize the infant. 6. When should operative repair occur? The optimal timing of operative repair is still unclear. Previously, infants were taken emergently to the operating room for reduction of the intraabdominal contents and repair of the hernia soon after birth. More recent data suggest that operative repair should be delayed until pulmonary hypertension and the infant’s hemodynamics have stabilized. The length of preoperative stabilization is highly variable, ranging from days to weeks.
412
Congenital Diaphragmatic Hernia 413 7. What operative approach is used to repair a diaphragmatic defect? There is no single best approach to CDH repair. The operation can be performed from either the abdomen (laparotomy or laparoscopy) or the chest (thoracotomy or thoracoscopy). Thoracoscopic repair may be associated with higher rates of recurrence and unacceptably high levels of acidosis due to CO2 insufflation and is generally reserved for stable infants or older children with delayed diagnosis of CDH. The choice of approach is dependent on the surgeon’s preference. Principles of repair are the same whether approached from the chest or the abdomen—reduce the abdominal contents; assess the amount of diaphragmatic tissue available for repair; and decide whether to repair the defect primarily, using prosthetic tissue, or with the patient’s own tissue. Recent data suggest an abdominal wall muscle flap is safe, even in the setting of extracorporeal membrane oxygenation (ECMO) with an acceptably low rate of recurrence. 8. What factors predict morbidity and mortality in infants with CDH? The degree of pulmonary hypoplasia and severity of pulmonary hypertension are the biggest predictors of morbidity and mortality among infants with CDH. In infants with CDH, the lungs exhibit decreased alveolarization with decreased surface area available for gas exchange as well as immaturity of pulmonary vasculature with hyperplasia of the pulmonary arteries. These histologic changes contribute to elevated pulmonary vascular resistance and pulmonary arterial hypertension. This then leads to right-to-left shunting of deoxygenated blood to the systemic circulation through the patent ductus arteriosus and patent foramen ovale then causing hypoxemia, acidosis, and shock. 9. What strategies can be used to treat pulmonary hypertension among infants with CDH? a. Monitoring: Oximetry or arterial sampling (preductal in the right upper extremity; postductal in the lower extremity) permits early detection of shunting of deoxygenated blood to the systemic circulation. b. Ventilation: Hypercarbia is corrected by mechanical ventilation with adequate sedation. c. Oxygenation: Hypoxemia is corrected by adequate ventilation and high concentrations of inspired oxygen (generally, fraction of inspired oxygen = 100%). d. Resuscitation: Metabolic acidosis is managed by restoring adequate tissue perfusion (intravenous fluids or blood, inotropes, and sodium bicarbonate). e. Rescue: Salvage therapies include administration of pulmonary vasodilators via the ventilatory circuit (nitric oxide) or systemic circulation (Priscoline, prostaglandin E2), high-frequency ventilation, and ECMO. 10. What is the survival rate for patients with CDH? The overall survival rate is 60%–90%. The major determinants of survival are the degree of pulmonary hypoplasia, severity of pulmonary hypertension, and associated major congenital anomalies. Late deaths occur in approximately 10% of children, secondary to persistent pulmonary hypertension. 11. Does in utero intervention have a role in the treatment of patients with CDH? Fetal intervention for CDH is becoming more common. Early trials failed to demonstrate a benefit with in utero repair of the defect. However, current research has focused on the role of tracheal occlusion during the fetal period as a means to promote lung growth. Techniques of in-utero fetoscopic endoluminal tracheal occlusion (FETO) promoting lung growth and development followed by postnatal repair of the diaphragmatic hernia are currently being investigated. Early trials of FETO suggest a potential survival advantage compared to control groups with similar disease severity.
K EY POIN T S: C ON GE N I TA L D I A P H R A G M AT I C H ER N I A 1 . CDH is usually diagnosed in the prenatal period based on routine ultrasonography. 2. Infants with CDH usually develop respiratory distress at birth. 3. CDH should be repaired when the baby is stable from a pulmonary hypertension and hemodynamic standpoint. 4. Morbidity and mortality in CDH are determined by the severity of pulmonary hypertension and degree of pulmonary hypoplasia.
414 PEDIATRIC SURGERY Bibliography 1. Chiu PP, Sauer C, Mihailovic A, et al. The price of success in the management of congenital diaphragmatic hernia: is improved survival accompanied by an increase in long-term morbidity? J Pediatr Surg. 2006;41(5):888–892. 2. Clugston RD, Greer JJ. Diaphragm development and congenital diaphragmatic hernia. Semin Pediatr Surg. 2007;16(2):94–100. 3. Kinsella JP, Ivy DD. Pulmonary vasodilator therapy in congenital diaphragmatic hernia: acute, late, and chronic pulmonary hypertension. Semin Perinatol. 2005;29(2):123–128. 4. Kitano Y. Prenatal intervention for congenital diaphragmatic hernia. Semin Pediatr Surg. 2007;16(2):101–108. 5. Lally KP, Lally PA, Lasky RE, et al. Defect size determines survival in infants with congenital diaphragmatic hernia. Pediatrics. 2007;120(3):e651–e657. 6. Logan JW, Rice HE. Congenital diaphragmatic hernia: a systematic review and summary of best-evidence practice strategies. J Perinatol. 2007;27(9):535–549. 7. Migliazza L, Bellan C. Retrospective study of 111 cases of congenital diaphragmatic hernia treated with early highfrequency oscillatory ventilation and presurgical stabilization. J Pediatr Surg. 2007;42(9):1526–1532. 8. Rozmiarek AJ, Qureshi FG. Factors influencing survival in newborns with congenital diaphragmatic hernia: the relative role of timing of surgery. J Pediatr Surg. 2004;39(6):821–824. 9. Stolar CJH, Dillon PW. Congenital diaphragmatic hernia and eventration. In: Coran AG, Caldamone A, eds. Pediatric Surgery. 7th ed. Philadelphia, PA: Elsevier, 2012;809–824. 10. Gander JW, Fisher JC, Gross ER, et al. Early recurrence of congenital diaphragmatic hernia is higher after thoracoscopic than open repair: a single institutional study. J Pediatr Surg. 2011;46(7):1303–1308. 11. Barnhart DC, Jacques E, Scaife ER, et al. Split abdominal wall muscle flap repair vs patch repair of large congenital diaphragmatic hernias. J Pediatr Surg. 2012;47(1):81–86. 12. Al-Maary J, Eastwood MP. Fetal tracheal occlusion for severe pulmonary hypoplasia in isolated congenital diaphragmatic hernia: a systematic review and meta-analysis of survival. Ann Surg. 2016;264(6):929–933. 13. Wynn J, Krishnan U, Aspelund G, et al. Outcomes of congenital diaphragmatic hernia in the modern era of management. J Pediatr. 2013;163(1):114–119.