Hyperaldosteronism after heart surgery in children. Part I: Treatment with aldosterone antagonists.

The course of postoperative hyperaldosteronism and its effect on fluid and electrolyte metabolism were studied in children undergoing open and closed heart surgery. Serum sodium was transiently depressed and red cell sodium concentration remained unchanged. Serum and red cell potassium concentrations were low. Hematocrit did not change significantly during the postoperative period ruling out overhydration. Therefore, the electrolyte changes are interpreted to indicate body potassium loss. That hyperaldosteronism caused potassium loss is suggested by an inverse relationship between plasma aldosterone and red cell potassium concentration. No significant differences were observed between patients undergoing open and those undergoing closed heart surgery. An additional, alternately selected group of patients undergoing open heart surgery was treated with aldosterone antagonists beginning 48 hours before surgery. Treatment did not change the course or extent of hyperaldosteronism. Specifically, potassium loss was not diminished and there was no difference in urine volume postoperatively. We conclude that aldosterone antagonists in the dosage used had no effect on the course of postoperative hyperaldosteronism.