CONGENITAL DIAPHRAGMATIC-HERNIA - A TALE OF 2 CITIES - THE BOSTON EXPERIENCE

Infants with congenital diaphragmatic hernia (CDH) show a wide range o f anatomic and physiological abnormalities, making it difficult to com pare the efficacy of management protocols between institutions. The pu rpose of this study was twofold: (1) to analyze the results of treatme nt of CDH in a large tertiary care pediatric center using conventional mechanical ventilation (CMV) with extracorporeal membrane oxygenation (ECMO) as rescue therapy, and (2) to compare these results with those of a parallel study by a similar large urban center that used high-fr equency oscillating ventilation (HFOV) as rescue therapy without ECMO. All patients who had CDH diagnosed within the first 12 hours of life and were referred for treatment before repair (between 1981 and 1994) were included in the analysis (n = 196). CMV was used initially in all patients, with conversion to ECMO for refractory hypoxemia or hyperca pnea. Between 1981 and 1984, ECMO was not available. Between 1984 and 1987, ECMO was offered postoperatively. Between 1987 and 1991, ECMO wa s offered preoperatively. In all three groups, aggressive hyperventila tion and alkalosis was the norm, Since 1991, permissive hypercapnia ha s been used, HFOV was used in three patients as stand-alone therapy wi th one survivor. Twenty patients died without repair: Ten had other le thal anomalies, eight died before ECMO could be instituted, and two di ed of ECMO-related complications. Overall, 104 patients (53%) survived and 92 (47%) died. Ninety-eight patients (50%) received ECMO, and 43 (44%) survived. Survivors had significantly higher 1- and 5-minute Apg ar scores and higher postductal PO(2)s than did nonsurvivors. Associat ed anomalies were present in 39%, who had a significantly lower surviv al than those with isolated CDH. Antenatal diagnosis and side of the d efect had no impact on outcome. Survival was not improved with the ins titution of ECMO or delayed repair but rose significantly to 69% (84% with isolated CDH, P = .007) with the introduction of permissive hyper capnea. Autopsy results from nonsurvivors showed other lethal anomalie s and significant barotrauma as the primary causes of death. Compariso ns between the Boston and Toronto series showed similar patient demogr aphics and no significant differences in survival in any time period. The two series differed in the number of associated anomalies, their i mpact on survival, and in the prognosis of right-sided CDH. From the i ndividual and combined analyses the authors concluded: (1) CMV with EC MO as rescue produced an overall survival in CDH patients equivalent t o CMV with HFOV in a parallel series, (2) neither HFOV nor ECMO has si gnificantly improved outcome in CDH patients, (3) institution of permi ssive hypercapnia has resulted in a significant increase in survival, and (4) the leading causes of death in CDH patients appear to be assoc iated anomalies and pulmonary hypoplasia, which are currently untreata ble. Barotrauma, which may contribute in up to 25% of deaths in CDH pa tients is avoidable. Copyright (C) 1997 by W.B. Saunders Company.