The two cases with congengital diaphragmatic hernia, who had corrective surgery within 6 hr of birth, were reported. In both cases, the progressive hypoxia developed after operation in spite of 100% oxygen ventilation by a respirator. This state was induced by right to left shunting through the foramen ovale and the PDA producing a persistent fetal circulation. In the first case, a Swan-Ganz catheter inserted into the pulmonary artery recorded the pressure which was almost equal to the systemic arterial pressure. The pharmacologic treatment using tolazoline, chlorpromazine, and acetylcholine was done during 71 hrs, but their effects remained in minimal and the patient died. In the second case, the catheter was placed at the superior vena cava, because it could not be inserted into the pulmonary artery technically. Tolazoline (2 mg/kg/hr) was injected continuously into the superior vena cava. After 1 hr, the PaO_2 at the descendiag aorta rose from 60 to 224 mmHg with marked improvement in general condition. The drug had been acting effectively until discontinued at 74 hrs. An assisted ventilation was needed during next 56 days for prematurity (birth weight : 1, 350g) and for hypoplasia of the lung of the affected side. Through the experience of the two cases, it was suggested that there are some cases with congenital diaphragmatic hernia, in whom the pharmacologic treatment has a dramatic effect for the progressive hypoxia caused by PFC developing after the operation.
