Adrenocortical functions were studied in 15 infants under 1 year of age, operated on under hypothermia for congenital cardiac diseases consisting mainly of ventricular septal defect. Adrenocortical functions were examined pre- and postoperatively, by eosinophil cell count in the peripheral blood and determination of urinary output of 17-OHCS and 17-KS. Thorn's test was also done before operation. As controls, the same examinations were performed in general surgical cases of infants, on cases of open heart surgery in young children operated on under hypothermia and in general surgical cases of adults.
Insufficiency of the adrenocortical function was found preoperatively in children and adults with acquired or congenital heart diseases of long duration, while in infants a latent hypofunctional state was observed only in cyanotic or very severe cases. The other cases, in general, had well maintained adreno-cortical function as was revealed in large urinary 17-OHCS output.
Infants with congenital heart diseases seemed to have adrenocortical functions enough to tolerate open heart operation under hypothermia. Even in such cases, however, hormonal balances were liable to be disturbed as indicated by retarded recovery with conspicuous fluctuations of the eosinophil count and of excretion of 17-OHCS and 17-KS.