F. T. GALYSH AND R. F. WALLIN 
1041 
PO2 mmHgtSE. 
60 
20 
80 
40 
i 
i 
ART VEN 
PCO2 mmHg±S.E 
40 
30 
20 
10 
0 
ART VEN 
pH±S.E. 
□ DISC 
m BUBBLE 
7.4 
7.3H 
7.2 
7.1 
70 
1 
1 
ART VEN 
Figure 7. — Comparison of mean blood gas and pH values 
achieved in perfusion v/ith disc (n = 10) and bubble 
(n = 18) oxygenators. 
Figure 8. — Inability to effectively defoam calf blood in 
bubble oxygenator. Note that the undefoamed blood 
front (white line) had advanced over a considerable 
portion of the defoaming sponges. 
pH values observed in perfusions with disc and 
bubble oxygenators. These are composite means 
of all values in all animals taken at 5, 15, 30, 60 
and 90 minutes of total cardiopulmonary by- 
pass. Both types of oxygenators were quite 
efficient in transferring oxygen and carbon 
dioxide. The apparent lower pH reflecting rela- 
tive metabolic acidosis in animals perfused with 
the disc oxygenator is probably related to the 
greater body mass (weight) of animals in this 
group. 
Foaming of calf blood in the extracorporeal 
circuit has been a continuous, troublesome prob- 
lem with both disc and bubble oxygenators. We 
have not encountered serious foaming with the 
blood of other species. An adult sized upflow 
Sarns bubble trap proved to be only partially 
effective in removing micro-bubbles from the 
circuit. Other investigators^*' have recognized 
this problem and combated it by increasing ini- 
tial heparin dosages to 5 mg/kg and adding An- 
tif oam A or 95 % ethyl alcohol directly into the 
oxygenator. Choosing not to increase heparin 
dosage and not to use Antifoam A which may 
embolize systemically, we used ethyl alcohol as a 
defoaming agent with only modest effectiveness. 
However, the use of Pluronic F 68,^ a nonionic 
detergent has all but eliminated the problems of 
foaming (Figures 8 and 9). If foaming is a 
problem as bypass is initiated, from 2 to 3 
grams as a 10% solution in water are added to 
'^Wyandotte Chemicals Corp., Wyandotte, Mich. 48192 
the oxygenator. Pluronic F 68 is well tolerated 
at this dose level. We have administered as 
much as 500 mg/kg intravenously to dogs with 
no evidence of hemodynamic changes or other 
signs of toxicity. 
CARDIAC DIMENSIONS 
In the interest of selection of an appropriate 
animal model for evaluation of the Anstadt- 
Skinner paraventricular cup (direct mechanical 
assist device) and as an aid in designing cups 
for the selected species, we estimated the di- 
FiGURE 9.— Effect of pluronic F68 on defoaming of calf 
blood in a bubble oxygenator. Note that the unde- 
foamed blood front has receded to a point very close 
to the venous oxygenating column spill-over point onto 
the defoaming sponges. 
