312 THE CIRCULATION OF THE BLOOD 



estimated the total volume of circulating blood by the vital red method 

 and the relative amounts of plasma and corpuscles by measurement of 

 hemoglobin or by means of the hematocrit, and as a result of his inves- 

 tigations has divided the cases of secondary shock into three groups which 

 vary from one another with regard to: (1) The total volume of blood 

 in circulation and (2) the relative amounts of plasma and corpuscles in 

 the blood. The differentiation is not only of great prognostic value, but 

 also invaluable as a guide to the proper plan of treatment. In group 1 are 

 the compensated cases, in which the blood volume is reduced to not more 

 than 80 per cent of the normal, but in which the plasma is relatively 

 greater, being reduced only to 85 or 90 per cent of the normal. In other 

 Yords these cases have reacted like cases of hemorrhage, i. e., there has 

 bv?en a migration of fluid from the tissues into the blood. If kept warm and 

 gi\en fluid per rectum, the patients recover. In the second group, called 

 partially compensated, the blood volume is reduced to 65-75 per cent, with 

 little, if any, evidence of dilution of plasma (i. e., the plasma is also re- 

 duced to 65-75 per cent). Treatment by transfusion either with blood 

 (citrated blood by Bobertson's method, or with gum solutions (vide infra) 

 is necessary and in most cases, if the proper technic is followed in the 

 transfusion, recovery is likely. It is important, however, that the plasma 

 volume be measured a few hours after the transfusion to see whether the 

 desired reaction, namely, a migration of fluid into the plasma, has set in. 

 If not so, a second transfusion is indicated. In favorable cases the plasma 

 volume increases more rapidly than that of total blood, and pari passu the 

 a'rterial blood pressure rises. 



In the third or uncompensated group the blood volume is below 65 per 

 cent and the blood is more concentrated than normal, i. e., there is relatively 

 a greater decrease of plasma. Treatment must be energetic in these cases, 

 but the prognosis is unfavorable because the transfused fluid readily leaves 

 the vessels, causing the lungs and tissues to become edematous. 



With regard to the rationale of the transfusions, it is clear that the 

 added fluid makes good the blood that is lost by stagnation, etc., and so 

 tends to maintain in the circulation a normal pressure for a sufficient 

 time to enable the organism to destroy the toxic bodies. If the shock con- 

 dition has existed for some time, so that the nerve centers are paralyzed, 

 the injections are of no avail. Since many cases of shock in man have 

 also suffered considerably from loss of blood, it is often difficult to decide 

 whether the shock really exists apart from the effects of hemorrhage, the 

 cardinal symptoms of the two conditions being very much alike. The test 

 is afforded by examination of the total blood and plasma volume, and by 

 the reaction to transfusion. After hemorrhage alone there is great migra- 

 tion of plasma into the blood, making this very dilute, and transfusion has 



