334 
SURGERY AND TRANSPLANTATION 
later, it was further demonstrated/^ and par- 
ticularly by Alican and associates,^°-^2 that 
with exquisite operative technique and meticu- 
lous postoperative management a substantial 
percentage of dogs could be made to survive 
bilateral replantation of the lung performed at 
the same operation. Such success by several 
groups of investigators represented a major 
breakthrough in the development of lung re- 
plantation as a model for the study of numerous 
parameters of lung function. 
In the early months of 1970, we performed 
simultaneous bilateral lung replantation in 26 
dogs. A light anesthesia consisted of intermit- 
tent intravenous doses of thiamylal (Surital) 
sodium, and a respirator delivering a 40-60% 
oxygen-air mixture provided control of respira- 
tion. In each dog, first the right lung was re- 
moved and replaced through a thoracotomy in 
the right fifth intercostal space; then the ani- 
mal was turned to the other side and left lung 
was removed and replaced through a similar 
incision on that side. The excised lung was 
cooled by perfusion through its artery with 
500 cc's of lactated Ringer's solution at 4°C at 
a pressure of 60 centimeters. Ten dogs lived 
more than one month, and seven of these lived 
indefinitely (Figure 11). Most of the remain- 
ing 16 dogs died during the first postoperative 
week, the principal cause of death being severe 
pulmonary edema. Various degrees of pulmo- 
nary edema were also observed in the animals 
that eventually became long-term survivors. As 
a rule, the x-ray films of the chest were re- 
markably clear on the first postoperative day. 
Diffuse edema in both lung fields often de- 
veloped by the third day, but it began to subside 
during the second week and disappeared dur- 
ing the third week of survival (Figure 12). In 
chronic survivors, the lung scans (Figure 13) 
and pulmonary angiograms (Figure 12) were 
normal, where performed. Pulmonary arterial 
pressures were found to be normal in 5 and 
moderately elevated in one of the long-term 
survivors. Blood gas values were also within 
normal limits. 
Most of the research in the lung replantation 
field has been largely with the animal model 
employing the replantation of only one lung. 
Of course, since the animal can readily survive 
on the other lung, the technical imperfections 
and the actual amount of lung function con- 
tributed by the replanted lung have often been 
difl?icult to assess. In marked contrast, the 
functional capacity of the replanted lungs in 
the bilateral replantation model is beyond ques- 
tion. Our experiments with bilateral lung re- 
plantation were performed after the bilateral 
replantation technique had been thoroughly 
standardized in our laboratory. The fact that 
38% of the dogs subjected to a one-stage opera- 
tion of this magnitude lived more than one 
month had an important bearing on the possible 
application of simultaneous bilateral lung re- 
plantation in human patients with severe pul- 
monary emphysema. The success of these ex- 
periments also laid to rest the previous un- 
centainty regarding whether or not the animal 
with simultaneous lung replantation would have 
sufficient respiratory reflex drive to maintain 
adequate respiration. The principal cause of 
early death in our bilateral simultaneous re- 
plantation experiments was pulmonary edema 
which occurred without evidence of thrombosis 
or narrowing at the atrial culf suture lines. The 
course of this edema was followed by means of 
x-ray films of the chest and clinical findings as 
well. The pulmonary edema was generally mani- 
fest on x-ray films after the first postoperative 
day, and its progression was dependent upon 
the degree of activity (and consequent pulmo- 
nary blood flow) of the animal. Dogs which were 
not confined to their cage during the first few 
days sometimes rapidly developed pulmonary 
edenia. For example, three dogs which were 
permitted to walk to the x-ray department dur- 
ing this period succumbed to pulmonary edema 
in a matter of hours after they had struggled 
vigorously against restraint during positioning 
for x-ray films. It appeared that the edema was 
largely due to anoxic and mechanical injury to 
the microvasculature of the graft during the 
operative procedure of replantation. However, 
this injury proved to be potentially reversible. 
The tendency to edema seemed to be intensified 
by any increase in cardiac output in the post- 
operative period. It appeared possible that in- 
terruption of the lymphatic vessels of the lung 
might have played a part in its development, 
since the subsidence and disappearance of the 
