The fundamental conditions of surgical shock

Abstract

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 induced 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, apnœa vera occurs in exactly the same manner as in a normal man after voluntarily forced breathing.

If death from apnœa is prevented by supplying artificial respiration, 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 suggested that the volume of the blood is diminished because of a passage of serum into the tissues. Sherrington and Copeman observed 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 probably 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.