194 



PHYSIOLOGY OF INDUCED HYPOTHERMIA 



DISCUSSION 



Dr. C. M. C Olives: We, too, have been interested in the hematologic changes re- 

 sulting from induced hypothermia. Prior to our study, it was our clinical impres- 

 sion that hypothermic dogs seemed to have an increased oozing tendency but that 

 blood shed during surgery into the peritoneal or pleural cavity seemed to clot ade- 

 quately. We undertook to investigate the oozing tendency. Altogether, 62 dogs were 

 cooled to a depth of from 18°-25° C. for from one to four hours, and rewarmed 

 with a Therm-O-Rite machine. For most of the studies arterial blood, obtained 

 from the femoral artery, was used for the determinations. 



Our studies included clotting times in glass (Lee White), bleeding times, clot 

 retraction, hemoglobin estimation, hematocrit estimation, platelet count, pro- 

 thrombin times in plasma (one stage), prothrombin times in serum, mechanical 

 fragility, osmotic fragility, critical fibrinogen index, heparin activity and smears of 

 peripheral blood. Results are summarized in figures 1, 2, 3. 



9 





<o 



C5^ 

 qj 



Q 



50 

 45 

 40 

 35 



35 



IT 30 

 25 



20 



15 



Coogulation 

 Time 

 40 dogs 



Bleeding 

 Time 

 12 dogs 



Hemoglobin 

 8 dogs 



Temperature 



I 2 3 4 5 



Time in Hours 

 Fig. 1. — Coagulation time, bleeding time, hematocrit, hemoglobin. 



