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JOSEPH C. AUB 



ningham showed that the same effect was obtained as in shock, and that, 

 therefore, the probable explanation for the diminished oxygen content 

 of the venous blood lay purely in the mechanical slowing of the blood 

 flow. While these phenomena are all occurring during the development 

 of shock, and are present to a more or less marked degree before the blood 

 pressure has fallen very low, it is only when the pressure falls below 



Qxyqcn Content of Blood 



in 



Experimental TraumaTic Shock 



Fig. 1. "Normal" means a cat under urethane anesthesia; "Before Shock" means 

 after muscle injury, but before a true shock level of blood pressure has been estab- 

 lished. The oxygen content of the venous blood is markedly reduced. (From Aub 

 and Cunningham.) 



80 mm. Hg that most of the other phenomena accompanying shock are 

 found. Cannon has therefore called 80 mm. the "critical level" of 

 blood pressure in this condition, the probable explanation being that until 

 that level is reached the blood flow and the available oxygen are sufficient 

 to accomplish the normal oxidation required in the tissues. 



Acidosis in Shock 



That there is diminished alkali reserve in the blood in shock con- 

 ditions has been repeatedly shown and confirmed. Crile reported cases 

 which suggested acidosis in shock. Cannon (c) reported the finding 

 of a decreased alkali reserve in shock. He used the method of Van Slyke, 



