294 
SURGERY AND TRANSPLANTATION 
DISCUSSION 
Chairman Michael P. Kaye: Thank you 
very much Dr. Donawick. The paper is open for 
discussion. May I ask that discussants identify 
themselves by name and home city. 
Stan Allen, Salt Lake City: What dose of 
heparin do you use for your calves just before 
they go on extracorporeal circulation ? 
Dr. Donawick : We haven't done extracorpo- 
real circulation procedures in a number of 
years, but we used 3-5 milligrams per kilogram 
when we did. At that time we had a problem 
with platelet aggregations on the oxygenators, 
and we attempted to remedy it by using in- 
creased doses of heparin. I don't know whether 
or not that is the current thinking, and would 
refer questions on heparin use and dosage to 
Dr. Ross. 
C. Grant La Farge, Children's Hospital 
Medical Center, Boston, Mass. : I have a com- 
ment for those of you who are still using the 
barbiturates, notably sodium thiopental or pen- 
tobarbital. We've done studies with about 500 
calves, and our routine regimen is to begin 
anesthesia with sodium thiopental and maintain 
it with halothane. 
Karl T. Weber, Birmingham : I'd like first to 
laud Dr. Donawick for having the courage to 
begin studying these physiological questions 
some years ago. When we first began our work 
2V2 years ago, we were in constant consultation 
with him. We have now used some 200 calves, 
and I'd like to comment on our experiences with 
anesthesia. With the use of intravenous ketam- 
ine in doses of 2 milligrams per kilogram for 
both the induction and maintenance of anes- 
thesia, we've been able to have the animals 
standing v^^ithin 30 minutes after open thoraco- 
tomy with a great deal of instrumentation in 
the heart. We've also been able to discard the 
volatile anesthetics and their attendant equip- 
ment, and have eliminated the need for an anes- 
thetist. 
I'd also like to echo Dr. LaFarge's comments 
about the lethality of the barbiturate anesthet- 
ics and their marked suppression of post-opera- 
tive recovery in calves. 
Gerald Moss, Rensselaer Polytechnic Insti- 
tute and Albany Medical College: We've used 
about 400 calves in the last 13 years, and I'd 
like to make a few comments on our experi- 
ences. The veterinarians and the veterans of 
bovine surgery have a barbiturate cocktail 
which seems to work, although it may be that 
the other anesthetics are better. In this com- 
mercially available mixture, the barbiturate is 
combined with magnesium sulfate and chloral- 
hydrate, and the necessary amount of barbitur- 
ate is thereby reduced. 
I'd also like to mention the Jersey cow, which 
is about the smallest of the dairy breeds and has 
a newborn calf that weighs 25-40 pounds. An 
animal this size is comparable to the dogs you 
have used, and is sometimes more convenient to 
work with than a larger animal, and fresh blood 
is readily available at blood banks. The male 
calves of a dairy breed are cheaper than dogs in 
our area because they ire not used for breeding 
and don't give much meat. 
We too have found that the heparin require- 
ments have gone up. We empirically use about 
quadruple the amount on a weight basis that 
we'd use for humans or dogs. We work with 
day-old or month-old animals, and we have 
noted that the younger the animal, the greater 
our problem with lung changes. We have found 
the lung lesion to be related to brain oxygena- 
tion. We can induce this lung lesion, which looks 
just like hyaline membrane disease, in 15 min- 
utes with cerebral hypoxemia. Although it 
would appear that high inspiratory pressure 
might very well be a way of avoiding this le- 
sion, the mechanism seems to be centrally neu- 
rogenic. And we do get hemorrhage and atelec- 
tasis, as well as edema and hyaline membranes 
within 15-20 minutes in the newborn with cere- 
bral hypoxemia. 
