W. p. GEIS AND M. P. KAYE 
311 
deep hypothermia, showing the changes in heart 
rate and blood pressure with temperature, as 
you cool the animal down in an ordinary bath- 
tub. Of course the expense of this is very little — 
just some ice. You don't have any membrane 
oxygenator or the like, and you use very little 
anesthesic, because once the animal gets cool 
it isn't necessary. With this procedure, we can 
separate the effects of pumping of the artificial 
heart from those of implantation more accu- 
rately than with the other processes. I'm sure 
it's obvious to all of you that if you have hemol- 
yzed blood as a result of cardiopulmonary by- 
pass and any platelets in your system, it's going 
to be difficult to evaluate the materials and 
pumping of the artificial heart. We have cir- 
culatory and respiratory rests for a maximum 
of one hour. We average about 85 minutes with 
the artificial heart in, and then we just put 
the calf back in the bathtub and warm him up. 
Next slide, please. This is a series of records. 
We want to evaluate the hemodynamic effects of 
the artificial heart so that we can then forget 
about our pressure transducers and look at 
other things. We do this first because we know 
that the more pressure transducers we have, 
the more disturbance and variables we will 
have in the system. This is just a typical system 
here where we have right atrial, right ventric- 
ular, pulmonary arterial, left atrial, and left 
ventricular aortic pressures, and you can see 
some of the tracings. This is with a Donovan 
spherical heart. 
Next slide please. This is a typical blood pres- 
sure record for one of our long survivors with 
a total artificial heart. This will give you an 
idea of the parameters we monitor during the 
procedure. 
May I have the slide oflf. Another method that 
we've used is double bypass, introduced by Dr. 
Kwan-Gett. We attach the artificial heart, leav- 
ing the natural heart in; when the artificial 
heart is pumping, we then remove the natural 
heart and sew up the chest. This method, like 
deep hypothermia, produces no hemolysis and 
maintains platelets and coagulation factors. 
We next tried to improve our postoperative 
care procedures, which required extensive 
training of people to work in the Intensive Care 
Unit. We had two people with our calves at all 
times monitoring the animals, watching all the 
equipment, and recording extensive data. 
Now let's quickly go through some of the 
data we got. One of our problems with the arti- 
ficial heart is high central venous pressure. As 
you can see, here's an animal living for a long 
time and the pressure, which should be down 
around zero, is very high. 
Next slide, please. Again we monitor respira- 
tory function all the time. Here's an animal that 
lived for almost 11 days. Blood gas is rather 
normal. He was without any respiratory sup- 
port for a period of one week, and then he re- 
quired nasal oxygen and finally the respirator. 
Next slide please. Here's another thing we 
look at — respiratory function. Dr. Donovan is 
now setting up extensive function tests of the 
lungs. We're measuring diffusion capacities. In 
most of our animals we find a decreasing func- 
tional resistive volume. 
Next slide. Again, more data that we look at : 
blood volume, hematocrit, plasma volume, and 
cell volume. Frequently we have to give blood 
to a calf that has an artificial heart. One thing 
I'll point out is that blood volume in a calf 
with an artificial heart tends to decrease, giv- 
ing us the symptoms of artificial right heart 
failure. 
Next slide. Here's another thing we can moni- 
tor, the electrical atriogram rate. We monitor 
the electrical activity of the natural atria that 
is still there. We actually use this electricity t. 
drive the artificial heart. Last slide. It is im- 
portant to look at the fit of the hearts in the 
animals. We just suspend the animal, remove 
the chest, and take the lungs out, and we can 
then evaluate the hearts and set up new design 
criteria. 
Chairman: Thank you Dr. Peters. I'm sure 
that you'll be available if there are any ques- 
tions. 
