The Effect of Total Body Perfusion on Digitalis Tolerance

¹ Departments of Pediatrics and Surgery, University of Oklahoma Medical Center and Children's Memorial Hospital

1. The effect of total body perfusion on digitalis tolerance was studied clinically in 84 infants and children undergoing open heart surgery and experimentally in eight mongrel dogs subjected to total body perfusion.

2. The clinical studies consisted of comparison of immediate postperfusion electrocardiograms to preperfusion electrocardiograms. There was no statistically significant difference between the incidence of postperfusion electrocardiographic arrhythmias in patients who had been digitalized prior to perfusion and in patients who had not received digitalis. Additionally there was no correlation between the incidence of postperfusion arrhythmias and the degree of the preperfusion electrocardiographic evidence of digitalis effect.

3. Studies of the effect of perfusion on digitalis tolerance in the dog were performed both for digitalis administered prior to perfusion ("tissue fixed") and for digitalis administered following perfusion. Perfusion was associated with no significant change in sensitivity to "tissue fixed" digitalis; however, all of the animals tested showed a decreased tolerance to digitalis administered one hour folloeing perfusion. Decreased tolerance to digitalis persisted at four hours in 80 per cent of animals and at seven hours in 40 per cent of animals.

4. The application of this information to the administration of digitalis to patients undergoing open heart surgery is discussed.