Tolazoline in the treatment of congenital diaphragmatic hernias.

SUMMARY Four babies with congenital diaphragmatic hernias each developed a state of transitional circulation. Tolazoline was successfully used to lower the pulmonary vascular resistance and to treat this normally fatal postoperative complication. Some children born with posterolateral (Bochdalek) diaphragmatic hernias, after an initially satisfactory postoperative recovery, develop persistent hypoxia and acidosis and then die. Such deaths, which take place despite apparently effective mechanical ventilation and attempted correction of the acidosis, are thought to be due to severe right-to-left shunting of blood (transitional circulation). It has been shown that it is possible to reverse a transitional circulation by pulmonary vasodilating agents-for example, by tolazoline.1 Four infants, treated for congenital diaphragmatic hernias who developed this complication, survived after the use of tolazoline. Patients and methods The management of an infant who presents within 6 hours of birth with a congenital diaphragmatic hernia at this hospital is standard. Immediate transabdominal repair of the hernia is carried out and an ipsilateral or bilateral chest drain is inserted. Postoperatively infants are paralysed and mechanically ventilated. Direct arterial monitoring both for blood pressure and frequent blood gas analysis is essential, and is preferably carried out preductally via the right radial artery. Acidosis is corrected with 8-4% sodium bicarbonate, but if the baby develops a transitional circulation despite optimum mechanical ventilation and attempted correction of the acidosis, tolazoline is given as a bolus (1-2 mg/kg) over 5 minutes and is generally continued as an intravenous infusion at the same rate per hour. Blood gas analysis is carried out every 15 minutes until the arterial blood gases are stable. When these have been satisfactory for about 12 hours the tolazoline infusion is tailed off and the baby is then weaned on to continuous positive airways pressure (CPAP) and finally extubated. Case 1. A 3-kg boy was born on 22 June 1978 by low forceps delivery at 38 weeks' gestation. He was cyanosed at birth and required endotracheal intubation. A chest x-ray film showed a left diaphragmatic hernia. On admission laparotomy was performed, the left diaphragmatic hernia was repaired, and a left chest drain inserted. Postoperatively the infant required mechanical ventilation and made satisfactory progress for the first 20 hours. He then suddenly became acidotic, hypoxic, and apparently moribund. Attempted correction of the acidosis with sodium bicarbonate produced no improvement; tolazoline was given intravenously as a bolus and continued as an infusion. His condition improved during the next 2 …