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 haemoglobin concentration (Hb) or haematocrit in a blood sample. Pre- and post-transfusion RCV (and blood volume (BV)) may be determined by flow cytometry by exploiting antigen differences between transfused donor red cells and the recipient's red cells. This paper describes the use of red cell antigen differences of Duffy, Kidd, MN and RhD between donor and recipient. In 20 infants, transfused on 21 occasions, pretransfusion RCV ranged from 12 to 39 mL kg(-1) body weight. Only at one transfusion could no usable donor-recipient antigen differences be exploited. Measurement of RCV, used routinely, may determine the transfusion requirements 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 complete correction of the RCV deficiency at the first occasion of transfusion. This approach may reduce donor exposures and also optimize oxygen transport and organ perfusion of the infant undergoing intensive management, perhaps leading ultimately to improved survival rates and fewer long-term complications of neonatal intensive care.