[The serum potassium level during and after cardio-pulmonary bypass in children: a comparative study of the effects of the preoperative administration of digitalis and diuretics (author's transl)].

The serum potassium levels were determined in 2 groups. The first group (40 children) was treated preoperatively with digitalis and diuretics. The second group (20 children) received none of these drugs and served as a control group. During the period of bypass, all patients received potassium-chloride, 1 m Eq/per Kg/h, which was infused into the heartlung machine. The serum potassium levels were determined before, during and after extracorporeal circulation. The first group showed a significant decrease in the serum potassium level during and after the bypass. The lower serum potassium levels (less than 4 m Eq/L) had to be corrected by injection of potassium aspartate. In the second group, an increased serum potassium level was observed. It is advisable to reduce the amount of potassium administered by half in patients not pretreated with digitalis and diuretics. In those who have been pretreated with these drugs, hypokalaemia should be avoided by frequent serum potassium estimation and potassium administration if needed.