T. AKUTSU, H. TAKAGI AND H. TAKANO 
287 
available space, shape, and volume. This pump 
is completely made in one piece vv^ith no connec- 
tions, and actually the inside of the entire tube 
is exactly the same cross-sectional area. If you 
have to design one chamber, it is impossible to 
make that kind of design. 
MiROSLAV Klain, Cleveland Clinic: May I 
ask you what size calf you use for your experi- 
ments? In our experience (and I would like to 
re-emphasize what Dr. Norman said), we use 
calves weighing about 140 pounds. There are 
many more complications with calves this size 
than with calves of about 200 pounds that are 
about 10-12 weeks of age. I think this is very 
important point in order to obtain good results. 
I would like to refer to one question about the 
biolyzed heart. I have used this at the Cleveland 
Clinic and so far have had no thrombolytic com- 
plications with it. The inner surface is some 
specially treated pericardium and the outflow 
and inflow valves are matured valves from an- 
other calf. 
Dr. Akutsu: When I was working at the 
Cleveland Clinic in Dr. Cole's laboratory, we 
tried using calves weighing 120-130 pounds. 
With the first 10 calves, we stopped our pump 
oxygenator suddenly and started the artificial 
heart at full swing from the beginning. Blood 
coming back to the left atrium was not oxygen- 
ated at all, but was just regular venous blood. 
We felt that this problem was a result of work- 
ing with such young calves, and now that we 
are using calves of 160-190 pounds, we don't 
have the problem anymore. 
