PETERS, DONOVAN, KAWAI, KWAN-GETT, ZWAET AND KOLPF 
409 
150 , 
130. 
ELECTROLYTES TH7ICI3H7F8 
Na 
10 J 
6. 
2 . 
60 
BO 
hours 
mEq^ 
Co Mg% 
K mEq^ 
300 
Figure 9. — Plasma electrolytes in a long-surviving calf with an artificial heart. Sodium remains close to control 
values while calcium and potassium tend to decrease in concentration with the initiation of pumping and re- 
main lower than control values. The initial increase in potassium is due to administered potassium which is 
goven routinely postoperatively and with the use of diuretics. 
The blood urea nitrogen for a long-surviving 
calf is shown in Figure 16. 
POSTOPERATIVE CARE PROCEDURE 
After surgery, two people remain with the 
calf at all times to monitor the clinical condi- 
tion of the animal and to see that all of the 
recording and support equipment is operating 
properly. A fluid balance sheet is maintained on 
the animal and intravenous fluids and anal- 
gesics are given as required. Each 12 hours, 10 
million units of Penicillin and 0.5 grams of 
Streptomycin are administered. Diuretics are 
administered as necessary to maintain urine 
output. The animal is allowed to eat and drink 
ad libitum. The animals are maintained on a 
Bird respirator or nasal oxygen to maintain 
an arterial oxygen saturation of at least 90%. 
Blood from donor calves is given as required to 
maintain the hematocrit about 25-35%, All 
urine produced by the animal is saved for analy- 
sis. 
AUTOPSY 
At termination, the animal is given 20,000 
units of heparin to prevent post-mortem clot- 
ting. The animal is suspended in a physiological 
position by bone pins inserted through the ver- 
tebral spines (Figure 17). The brain is removed 
and sectioned. The right and left chest walls are 
removed leaving the sternum intact. If there is 
hydrothorax, a sample is obtained for analysis 
and the volume measured. The exposed lungs 
can now be inspected and inflated by an endo- 
tracheal tube. The lungs are then removed and 
sectioned for macroscopic examination. The 
