Total coronary blood flow measurements and myocardial metabolism during cardiopulmonary bypass in a canine model.

Myocardial respiratory function and total coronary blood flow were evaluated during cardiopulmonary bypass in 18 dogs. The fibrillating heart was found to be associated with an increase in myocardial oxygen utilization and metabolic rate which was compensated for by a corresponding increase in total coronary blood flow. Following anoxic arrest of the heart, there appears to be an initial impairment to oxygen utilization. Oxygen consumption does not return to normal after 15 minutes of restoring coronary blood flow. The stability of the experimental model as outlined in this study is thought to be related to the use of autologous blood in priming the extracorporeal circuit.