The Fundamental Conditions of Surgical Shock. 141 



It seems that the anemic condition always observed in the skin 

 in shock is also found in the organs generally. Further experi- 

 ments are being performed to ascertain the location of the blood. 



89 (499) 



The fundamental conditions of surgical shock. 



By YANDELL HENDERSON. 



[From the Physiological Laboratory of the Yale Medical School.] 

 Death in shock may be either from failure of respiration, or 

 from failure of the circulation. In Crile's experiments, and in my 

 own, the former mode of death was much more common than the 

 latter. As I have recently shown, deaths of this type occur also 

 in human beings after intense pain. The excessive breathing in- 

 duced by pain diminishes the carbon dioxide content of the blood 

 and tissues. This acapnia is the cause of the depression of all 

 functions so characteristic of shock. Finally, apnoea vera occurs 

 in exactly the same manner as in a normal man after voluntarily 

 forced breathing. 



If death from apncea is prevented by supplying artificial res- 

 piration, as in the majority of Crile's experiments, or by continual 

 afferent irritation, as in my own, the circulation fails. Crile 

 proved that this is not heart failure. Seelig and Lyon have proved 

 that it is not vaso-motor failure, but that on the contrary the 

 peripheral arteries are in intense constriction. Malcolm has sug- 

 gested that the volume of the blood is diminished because of a 

 passage of serum into the tissues. Sherrington and Copeman ob- 

 served a considerable increase in the specific gravity of the blood 

 even before arterial pressure had fallen to a low level. The balance 

 between the water content of the blood and of the tissues is prob- 

 ably in part dependent upon their relative carbon dioxide contents. 

 Acapnia may alter the tonus of the veins, or the relative osmotic 

 pressure of the blood and the tissue fluids, or the imbibition tension 

 of the colloids of blood and tissues. Thus acapnia diminishes the 

 volume of the blood. 



I find that acapnia induced by excessive artificial respiration, 

 or by excessive natural breathing during stimulation of afferent 

 nerves (i. e., trauma), involves a lowered venous pressure and 



