R. M. HARDAWAY 
23 
GLASS CLOTTING TIMES -DOGS SILICONE CLOTTING TIMES - DOGS 
in. 
Figure 1. — Glass and silicone clotting times of dog's blood at different pH's. Average values for each pH do not 
represent the average shortest clotting time because some clotting times are going up while others are going 
down. The average lowest clotting time reached at any pH is indicated, as is the minimal silicone clotting 
time at each pH. Note that the average lowest clotting time of heparinized blood is shorter than average 
clotting time for nonheparinized blood at normal pH's. Similar shortening takes place in nonheparinized blood 
but the initial time is so short it has less room to fall. 
the onset of a consumptive coagulapathy and 
micro-infarction of vital organs and death. It 
was also shown that this same phenomena took 
place in open heart surgery. This accounted for 
the poor results in experiments using dogs in 
open heart surgery before clinical use of open 
heart procedures were initiated. It was also 
found that while this same phenomena occurred 
in humans, that the lessened coagulability of 
blood in humans made it less common — occur- 
ring only in the presence of shock. This differ- 
ence between dogs and humans held back open 
heart surgery several years because it was 
thought that humans would react as did the 
dog and die in a short time on the pump. Ac- 
tually, humans exhibit the same phenomena but 
it requires a longer time on the pump, so that 
open heart surgery is feasible. 
The conclusion of the above experiments was 
that the occurrence of DIG required two separ- 
ate initiating factors : ( 1 ) a slow flowing, acid, 
hypercoagulable blood as produced by shock, 
and (2) a thromboplastic agent of some type. 
The first factor without the second would not 
result in DIG. Therefore, hemorrhagic shock 
alone was innocuous and reversible up to the 
point of death. However, many factors could 
contribute a thromboplastic agent into the blood 
stream during shock. A series of investiga- 
tions" was carried out in order to define some 
of these factors. They were found to be: (1) 
bacterial toxins, either indotoxin or endotoxin, 
(2) hemolysis even in minute amounts, (3) tis- 
sue trauma or crushing, and (4) other miscel- 
laneous factors, including cellular debris (am- 
niotic fluid), cancer, and viruses. 
