196 



PHYSIOLOGY OF INDUCED HYPOTHERMIA 



0.70 

 0.60- 

 50- 

 0.40- 

 030- 



60 

 501- 



401- 

 30 



to 



301- 

 25 



20- 



35 

 30 



25 

 20 



15 



Osmotic frogllity 

 ' 10 dogs 



Mechonicol frogilify 

 12 dogs 



Criticolfibrinogen index 

 ' l3dogs 



Temperoture 



12 3 4 5 



Time in Hours 

 Fig. 3. — Osmotic fragility, mechanical fragility, critical fibrinogen index. 



at 20° C. it was common to find only 10,000 platelets. These are not destroyed, for 

 they return with rewarming. 



Along wnth drop in the platelet count, the clot retraction is poor. 



There is a marked drop in leukocytes at reduced temperatures. The mean at the 

 reduced level was 3047. They return to normal with rewarming. 



Heparin activity, osmotic and mechanical fragility, and the critical fibrinogen 

 index are not affected by cooling. 



There is a relative increase in the number of lymphocytes with cooling. 



Dr. Dean Warren: We can confirm the constant decrease in white blood counts 

 and platelets, the rise in hemoglobin and hematocrit, and the prolongation of 

 coagulation time. We, too, thought that sequestration was probably the phenomenon 

 responsible for this, but were not able to localize it accurately through our more 

 crude method of splenectomy. 



One factor that we thought might be of importance was that of the delayed 

 adrenocortical response. As has been shown by Ebert, cortisone is somewhat effec- 

 tive in preventing this sequestration phenomenon in other experimental conditions. 

 We gave large doses of cortisone to dogs for 48 hours prior to our experiments, 

 but the fall was similar in all phases of our experiment. Heparin was likewise in- 

 effective in changing this response. 



In addition, we have studied two patients. Although the temperatures were not 



