A practical method for determining the amount of blood passing over during direct transfusion / E. Libman and R. Ottenberg.

  • Libman, Emanuel, 1872-1946.
Date:
1914
Catalogue details

Licence: In copyright

Credit: A practical method for determining the amount of blood passing over during direct transfusion / E. Libman and R. Ottenberg. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    globin, as, on account of tlie ])rocess of blood concentra- tion, the apparent amount calculated from the hemo- globin rise will be slightly larger than the real amount already transfused at any given moment. Our experi- ences, however, in which accurate weighings of donor or patient were used to control the calculation, showed that, while these sources of error may exist, in most cases they are not large enough to affect materially the result of the calculation. We have observations on the hemoglobin rise in ninety-nine transfusions. In thirty-two of these, cal- culations were made on the assumption that it was safe to transfuse one-quarter of the donor's blood volume: and these calculations were used as a guide in the trans- fusion. In the great majority of cases, the hemoglobin was raised to approximate the calculated amount. In only one of these cases in which the calculated amount was not exceeded was there any collapse of the donor. In nine ca.«es the calculated hemoglobin limit was exceeded by loss than 5 per cent., and in two cases it was exceeded by respectively 9 and 10 per cent, without any serious symptoms on the part of donor or patient. It is possible, of course, not merely to calculate the hemoglobin rise to be anticipated from transfusing a given volume of blood, but also to estimate, from an observed hemoglobin rise, the volume of blood wdiich must have been transfuse<l. This is done by simple algebraic calculation, substituting the unknown factor. -V, for the volume of blood transfused, in the preceding formula. Thus, the illiistratiou previously given may be taken. Suppose the donor weighs 190 pounds and has a hemoglobin of 100 per cent. The patient weighs 114 pounds and has a hemoglobin of 30 per cent. The observed rise in hemoglobin is to 50.5 per cent. Then, substituting A' for the unknown amount of blood trans- fu.«ed, we have the equation : (ixao-f- (-VX100) C + A' 50.o Simplifying which, we get: A’ = 2.5 pounds of blood transfused. In order to test the accuracy of the method of calcu- lation, we have by means of this formula calculated back from the observed rise in hemoglobin to the amount of blood transfused in eleven cases in which the amount