284 
SURGERY AND TRANSPLANTATION 
Figure 9. — Postoperative sheep whose neck is fixed between two metal bars and body is being supported with wide 
canvas bands. The bands are hooked to several springs which are attached to a sturdy frame. 
table, but were used only to help the calf stand 
when it was not strong enough to do so alone. 
Presently the calf's movement is controlled by 
using only a simple stanchion. The left side of the 
cage has a wall defect through which all tubings 
and wires connecting the calf to the machine 
are led so that the calf can stand up or lie 
down without causing kinking or twisting of 
the wires and tubings. After the calf has re- 
covered well enough to stand, pressure trans- 
ducers are fixed to a specially designed harness 
at the level of the implanted artificial heart so 
that the calf can stand or lie down without in- 
terfering with the pressure recordings. 
ANESTHESIA 
For implantation of total artificial hearts in a 
large experimental animal, the authors selected 
first calves which weighed around 50 to 60 kg. 
As Larson et al.^ ^ suggested, anesthesia was 
induced with ether and maintained with Flu- 
othane. McCrady et al.^ induced anesthesia 
with a mixture of nitrous oxide and Fluothane 
and maintained it with the same gases. In each 
of these reports, the depressive action of barbi- 
turates was stressed. However, Joel and 
Sautter* used pentobarbital sodium in 15 calves 
with success, but the calves' chests were not 
opened and the surgical procedure was not ex- 
tensive. 
In our experiments, when ether was used in a 
calf weighing more than 60 kg, anesthesia deep 
enough for intubation took 15 to 20 minutes to 
achieve. With 7 to 8 mg/kg body weight of 
Nembutal, intubation was possible without dif- 
ficulty and no laryngeal reflex was noted. Flu- 
othane is an important early cause of difficulty 
