Management of congenital diaphragmatic hernia by extracorporeal membrane oxygenation (ECMO)

The Story of ECMO

Extracorporeal Circulation in Neonatal Respiratory Failure: A Prospective Randomized Study. By RH Bartlett, DW Roloff, RG Cornell, AF Andrews, PW Dillon, JB Zwischenberger. Pediatrics 1985; 76:479-87. Extracorporeal membrane oxygenation (ECMO) is the use of mechanical devices to replace cardiac and pulmonary function in critical care. In the 1960s, laboratory research showed that extracorporeal circulation could be maintained for days using a membrane oxygenator. In the 1970s, the first clinical trials showed that ECMO could sustain life in severe cardiac and pulmonary failure for days or weeks, leading to organ recovery. From 1980 to 2000, ECMO became standard practice for neonatal and pediatric respiratory and cardiac failure. The critical clinical trial was a prospective randomized trial of ECMO in newborn respiratory failure, published in 1985. This is the classic article reviewed in this publication. This was the first use of a randomized, adaptive design trial to minimize the potential ethical dilemma inherent to clinical trials in which the endpoint is death. Other randomized trials followed, and ECMO is now standard practice for severe respiratory and cardiac failure in all age groups.

Outcome of congenital diaphragmatic hernia

The outcome of congenital diaphragmatic hernia (CDH) differs for different stages of the fetus or infant's life (i.e., antenatal, immediate postnatal, and postoperative). Assessing combined data from nonrandomized studies is technically difficult. Following recognized methods of reviewing such trials, we aimed to review the available literature on the outcome of CDH to provide a guide to clinicians when counselling parents who have a fetus/infant with this condition. Thirty-five studies reporting data for CDH from 1985 to March 1998 were identified using a high sensitive search strategy, hand-searching journals, and reviewing references of relevant studies. These were systematically reviewed. The median overall mortality was 58% (interquartile range (IQR), 43-65%) for babies diagnosed in utero, 48% (IQR, 35-55%) if born alive, and 33% (IQR, 18-54%) postoperatively. Diagnosis before 25 weeks of gestation is not a uniformly bad prognostic indicator (median mortality, 60%). Outcome was worse for those fetuses with other anomalies (median mortality, 93%). The median percentage mortality for all infants born alive and treated in extracorporeal membrane oxygenation (ECMO) centers was 34% (IQR, 26-47%). Median percentage mortality for all ECMO-treated infants was 44% (IQR, 35-50%). Different treatment strategies may have a variable impact on outcome. These figures, together with local data, may help in parental counselling on prognosis for fetuses/infants with CDH.

Improved results in patients who have congenital diaphragmatic hernia using preoperative stabilization, extracorporeal membrane oxygenation, and delayed surgery

Congenital diaphragmatic hernia (CDH) is associated with pulmonary hypoplasia. The pulmonary vascular bed may be extremely reactive to various stimuli, and in the treatment it is important to avoid pulmonary vasospasm. The strategy in our institution since 1990 has involved a prolonged preoperative stabilization with gentle mechanical ventilation. Pressures have been kept as low as possible, and slight hypercarbia has been accepted. Peak inspiratory pressures exceeding 35 cm H2O have been avoided. Extracorporeal membrane oxygenation (ECMO) has been used according to standard inclusion criteria. Nitric oxide and high-frequency oscillation have been added to the therapeutic modalities during the study period. When the patient was considered stabilized, surgical repair was undertaken after a delay of 24 to 96 hours. In patients on ECMO who could not be decannulated, surgical repair was undertaken while on ECMO. From 1990 through 1995, 52 patients were admitted with a diagnosis of CDH. Forty-three of these were risk group patients presenting with respiratory distress within 6 hours after birth. A total of 48 patients survived (survival rate 92%), and 39 of the risk group patients (survival rate 91%). There were only four hospital deaths, all with contraindications to ECMO. It is suggested that the adopted protocol is beneficial in the treatment of CDH and that the fraction of patients who have pulmonary hypoplasia incompatible with life is smaller than previously believed.

Experience with abdominal wall closure for patients with congenital diaphragmatic hernia repaired on ECMO

Congenital diaphragmatic hernia (CDH) and its attendant lack of abdominal domain can create major technical challenges with respect to diaphragmatic and abdominal wall reconstruction, especially in seriously ill infants who require extracorporeal membrane oxygenation (ECMO). The authors reviewed the medical records of all infants with CDH repaired on ECMO at their institution (group 1, 15 patients), and compared them with infants having CDH repair before ECMO (group 2, 20 patients) and with those who had CDH repair but did not require ECMO (group 3, 15 patients). Thirty-seven of 50 patients survived (74%): 10 in group 1, 12 in group 2, and all 15 in group 3. There was a statistically significant difference (P < .001) with respect to the requirement of a polytetrafluoroethylene (PTFE) diaphragmatic patch for patients in group 1 versus those in both groups 2 and 3. There was also a significant difference in the number of patients in whom the abdomen could not be closed (P < .001 for group 1 v groups 2 and 3). Infants who require ECMO before CDH repair are more likely to have large diaphragmatic defects that require prosthetic reconstruction, and abdominal wall closure problems resulting from loss of abdominal domain, which further complicate the management of the physiological derangements from pulmonary hypoplasia and persistent pulmonary hypertension.

Gastroesophageal reflux occurring after repair of congenital diaphragmatic hernia

Over the past 2 decades, 110 patients with congenital diaphragmatic hernia (CDH) were treated in the authors' hospital. Eighty-six survived; of these, 10 patients (11.6%) had gastroesophageal reflux (GER) after repair of CDH. Seven occurred in the past 5 years, during which time advanced intensive care including extracorporeal membrane oxygenation (ECMO) was used. Vomiting started within 4 weeks after repair of CDH in eight cases, and hiatal hernia was demonstrated in six cases. Three patients responded to conservative therapy; the other seven required antireflux surgery. Several factors are believed to be possible causes of the development of GER in CDH cases. Among them, slow pulmonary expansion of the affected side was thought to be the most important. Namely, in a case of CDH associated with severe hypoplastic lung, the esophagus may be deviated to the affected side before the lung is expanded. After expansion, the abdominal esophagus shortens, and GER or a hiatal hernia can occur in severe cases. There were seven such patients in our series of 10. With the increase in the survival rate of CDH cases associated with severe hypoplastic lung, the number of such patients also may increase. Therefore, some additional procedure to prevent the lower esophagus from sliding will be necessary in the repair of diaphragmatic hernia.