700 ARLIE V. EOCK 



nient. An attempt to restore the fluid loss in all of ' these conditions may 

 be made by giving fluid by one or another of the following methods: by 

 mouth or rectum, permitting absorption from the alimentary tract; by 

 subcutaneous injections, intraperitoneal injections, or intravenous in- 

 fusions. The method adopted will depend upon individual indications. 



In the case of acute hemorrhage, dilution of the blood rapidly occurs 

 by transfer of tissue fluid to the vascular system, and the original volume 

 of the blood plasma is promptly restored, if the hemorrhage is not too 

 great, and if the supply of tissue fluids is normal. The chief danger in 

 acute hemorrhage is due to the rapidity with which blood is lost, rather 

 than the amount of blood released from the circulation. If hemorrhage 

 occurs so suddenly that compensatory mechanisms such as vasoconstriction 

 and tissue fluid dilution cannot maintain the blood pressure at a safe level, 

 transfusion of blood, or intravenous infusion, may be immediately urgent. 

 Complete collapse of patients after hemorrhage is often the result of the 

 concurrent factor of shock, by which the volume of blood tends to be still 

 further diminished. When shock is present the transfusion of blood, or 

 the infusion of a fluid substitute for blood, may be obligatory. A falling 

 blood pressure is a positive indication for such treatment in order to 

 relieve the anoxemia, 1 particularly of the vital centers. A transfusion 

 of blood, or an infusion under such circumstances, by increasing the 

 volume of fluid in the vascular bed, increases the volume output of the 

 heart per systole, and thus tends to restore the arterial pressure to a 

 normal figure. If a state of shock has existed for several hours the 

 transfusion of blood should always be carried out in preference to other 

 intravenous therapy. In cases of hemorrhage, in addition -to transfusion 

 or infusion, an abundant fluid intake by the alimentary tract. should be 

 maintained in order to satisfy completely, not only the blood plasma 

 volume, but the supply of tissue fluid as well. The increased efficiency 

 of the circulation, and the good effect upon the rate of blood regenera- 

 tion as a result of a forced fluid intake in cases of hemorrhage has been 

 recently discussed by Bock and Robertson. 



The question of the use of infusion for the treatment of acute hemor- 

 rhage and shock presents a problem not common to other conditions for 

 which infusions may be indicated, namely, the necessity for an immediate 

 increase in the total mass of circulating blood. Reduction in blood volume 

 below a certain level results in a fall of blood pressure, accompanied by 

 the attendant difficulties which this failure of the circulation imposes upon 

 the organism. In order to restore the efficiency of the circulation, the 

 volume of the blood must be largely restored as rapidly as possible either 

 by transfusion of blood or by the intravenous infusion of a fluid sub- 

 stitute. In addition to the transfusion of blood, which is the most 



*A comprehensive discussion by J. S. Haldane of the cause and effect of anoxemia 

 or oxygen want may be found in the British Med.' Jour., 1919, 2, pp. 65-71. 



