[Experimental studies concerning the hemodynamic and metabolic functions in the canine heart-lung preparation...

In the usual canine heart-lung preparation the coronary blood flow does not remain constant, but increases steadily ; usually, at the moment of the set up of the preparation the coronary blood flow was about 20 ml/min/100 g heart. However, in the course of 2 approximately 3 hours it becomes more than 150 ml/min/100 g heart and the responsiveness of the coronary artery is completely lost under this condition. Concurrently with the increase in the coronary flow, cardiac functions tend to deteriorate. In order to eliminate those experimental disadvantages, we added a donor dog to the heart-lung preparation. It was found that the support by the donor dog resulted in the complete improvement of the above-mentioned deterioration ; the coronary circulation (coronary blood flow and coronary artery and sinus blood oxygen saturation), cardiac function (cardiac output, right atrial pressure, heart rate and others) and cardiac metabolism (myocardial oxygen consumption, mycardial redox potential and others) were kept constant at a favorable state for more than 10 hours.