830 GEOKGE E. MINOT AND ARLIE V. BOCK 



IV. Indications for Transfusion 



No detailed account of all of the conditions for which transfusion is 

 indicated will be undertaken here. In a general way they belong to two 

 groups, namely, conditions in which transfusion is an absolute necessity 

 in order to save life and conditions in which the procedure may be desii 

 able either for the comfort of the patient or to shorten convalescence. 



1. Conditions in Which Transfusion is a Necessity. The usus 

 conditions in which transfusion may be obligatory in order to save life 

 are hemorrhage and shock. Since moderate or severe hemorrhage is always 

 accompanied by a state of shock, these two conditions may present the 

 same indications for treatment. They have in common diminished blood 

 volume and low blood pressure, both of which may be corrected, at least in 

 part, by transfusion. In the case of hemorrhage, danger to life lies not so 

 much in the extent of hemorrhage as in sudden loss of blood. The latter 

 may result in a rapid fall of blood pressure to a dangerous level, a state in 

 which the tissues of the body are deprived of oxygen owing to the failure 

 of the circulation. Keith has shown that the blood volume in shock, not 

 complicated by hemorrhage, may be diminished to the same extent as in 

 hemorrhage. In such a. condition the body may not survive for more 

 than a brief period unless energetic measures are taken to increase the 

 volume of the circulating blood, which in turn reacts favorably upon the 

 blood pressure. Fluid substitutes for blood, such as gum-saline, may 

 serve to restore the circulation and may be used instead of blood when 

 the blood loss has not been too great. In shock gum-saline is highly useful 

 if it is used soon after the advent of the condition. However, if such a 

 fluid is not available, normal salt solution may temporarily tide a patient 

 over a brief period of time until transfusion can be carried out. 



The criteria upon which to judge the condition of the patient are blood 

 pressure readings, hemoglobin determinations and pulse rate, as has 

 been discussed by Robertson and Bock. A very low systolic blood pressure, 

 TO mm. of mercury for example, after acute hemorrhage, or in shock, 

 usually means a great diminution in blood volume. Subsequent blood 

 pressure determinations are important to note whether the reaction of 

 the patient is favorable or not. For example, a rising blood pressure is a 

 good prognostic sign. A single hemoglobin estimation, especially if made 

 soon after hemorrhage has occurred, is of little significance. It is im- 

 portant to know whether subsequent hemoglobin readings at hour inter- 

 vals are the same or steadily becoming lower. A flow of fluids from the 

 tissues to the circulation, or internal transfusion, as Gesell has called it, 

 will dilute the hemoglobin, and if this does not fall below 30 per cent, 

 transfusion is not urgent though it may be advised. Cases of hemorrhage 

 and shock in which the hemoglobin remains at a stationary figure for sev- 



