Abstract
Transfusion may be performed for a large number of reasons wvhich must be clearly defined because almost all derivatives of blood lack one or more of properties of fresh blood and have, therefore, only a limited therapeutic value. The convenience of blood derivatives must not lead to improper use. War has led to the development of durable blood derivatives suitable for the blood volume restoration essential for the treatment of secondary shock. Stored blood over a certain age must be included in this category.
Experimental evaluation has placed the order of preferment for blood derivatives used for blood volume restoration as citrated plasma, serum, hoemoglobin-Ringer, gum saline, red cells in saline suspension, isotonic saline and glucose. Clinical evaluation of the advantages of plasma over serum and vice versa has not yet been fully decided. Serum preparation, dry or fluid, is technically much easier than plasma. For blood volume restoration in secondary shock there is required an innocuous protein fluid which is retained in the circulation. The amount that needs to be transfused is often incredibly large and must be at least 5o% of the volume lost; the effect requires to be carefully controlled by blood-pressure observations and clinical judgment. Rate also is important. Extensive experience has shown that though citrated plasma is eminently satisfactory it is an advantage to use a proportion of blood when the volume restoration needs to be large.