Determination of red cell volume in infants needing blood transfusion

The total circulating red cell volume (RCV) is a better guide to the oxygen -carrying capacity of the blood in the whole circulation than is the haemog lobin concentration (Hb) or haematocrit in a blood sample. Pre- and post-tr ansfusion RCV (and blood volume (BV)) may be determined by flow cytometry b y exploiting antigen differences between transfused donor red cells and the recipient's red cells. This paper describes the use of red cell antigen di fferences of Duffy, Kidd, MN and RhD between donor and recipient. In 20 infants, transfused on 21 occasions, pretransfusion RCV ranged from 1 2 to 39 mL kg(-1) body weight. Only at one transfusion could no usable dono r-recipient antigen differences be exploited. Measurement of RCV, used routinely, may determine the transfusion requireme nts of sick infants more accurately, with the aim of normalizing RCV and BV - securing euvolaemia - at the end of the transfusion. This may allow a co mplete correction of the RCV deficiency at the first occasion of transfusio n. This approach may reduce donor exposures and also optimize oxygen transp ort and organ perfusion of the infant undergoing intensive management, perh aps leading ultimately to improved survival rates and fewer long-term compl ications of neonatal intensive care.