408 
SURGERY AND TRANSPLANTATION 
200, 
0) 
^ 100 
UJ 
m 
ATRIAL ELECTROGRAM 
RATE 
TH 70 
C 12 
12 
36 
60 
84 
HRS. PUMPING 
Figure 8. — Composite of the atrial electrogram in four calves measured from the remnant natural atria attached 
to the artificial heart. This signal can be used to pace the artificial heart. 
Blood Chemistry 
The following blood chemistry determina- 
tions are normally obtained in our long-surviv- 
ing animals. Potassium, sodium, calcium, phos- 
phate, blood sugar, blood urea nitrogen, uric 
acid, cholesterol, total protein, albumin, glob- 
ulin, albumin to globulin ratio, total bilirubin, 
alkaline phosphatase, LDH, SGOT, and free 
plasma hemoglobin. A plot of plasma — Na, Ca 
and K is shovi^n in Figure 9. In addition to the 
blood chemistry measurements, we also periodi- 
cally obtain platelet count, hematocrit and clot- 
ting time. A composite plot of the platelet count 
is shown in Figure 10 and a plot of blood volume 
and hematocrit is shown in Figure 11. In twelve 
of our total heart experiments, studies have 
been made of prothrombin time, partial throm- 
boplastin time, and thromboplastin time. Blood 
clotting factors I, V, and VIII have been deter- 
mined in these twelve experiments as well as 
platelet adhesiveness, platelet survival time, 
fibrin degradation products and clot lysis prod- 
ucts.^'" '^ Other blood chemistries obtained in- 
clude plasma catecholamines and steroids, some 
results of which are shown in Figures 12 and 13. 
Pulmonary 
Blood gases are measured approximately 
every two hours. The determinations are arte- 
rial PO2, oxygen saturation, blood pH and arte- 
rial PCO2. Figure 14 shows arterial PO2 and 
PCO2 for a long survivor. After surgery, ap- 
proximately each 24 hours, determinations are 
made of the respiration rate, tidal volume, 
minute ventilation, oxygen consumption and 
functional residual capacity. The cardiac output 
is estimated using the Fick method. Tidal 
volume, oxygen consumption and functional 
residual capacity are shown in Figure 15 for a 
long-surviving calf 
Renal Function 
In order to determine the condition of the 
kidneys, the following measurements are made: 
serum creatinine, blood urea nitrogen, urine 
creatinine, creatinine clearance, urea clearance 
and urine specific gravity. Microscopic examina- 
tion of the urine is conducted to determine the 
content of red blood cells, white blood cells and 
casts. Urinary potassium is also determined. 
