Abstract
The author made experimental studies on dogs concerning the circulatory influence of hypotension of 80mm.Hg induced by repeated massive hemorrhages and transfusion by means of blood reservoir technique, and simultaneously he observed the influence of administration of norepinephrine, hydrocortisone and chlorpromazine.
1) Repeated massive hemorrhages and intermittent severe hypotension cause a grudual exhaustion of compensatory mechanism of the circulatory system. The process is clearly illustrated by fluctuations of the blood loss curve, which can be divided into three stages, i. e., bleeding stage, balanced stage and stage of back flow as is exactly the case of non-repetitive hemorrhage. The circulatory influence of massive hemorrhages persists for fairly long time regardless of restitution of normal blood volume by transfusion.
2) There is individual difference in the time of shift of the stages, and it is not always proportional to the time of repetition of hemorrhage.
3) Repeated massive hemorrhages and transfusions cause such a great influence upon the circulation that they shorten the course of exhaustion
4) In the course of breakdown, norepinephrine, hydrocortisone and chlorpromazine show prolonging effects on the process, while ACTH is ineffective.
