Blood exchange transfusions in newborns, the effect on serum ionized calcium.

Serum levels of ionized calcium (CaF) were determined in 35 newborn infants subjected to blood exchange transfusion with citrated blood. Eleven of these were supplemented with calcium injections during and after the transfusion. No symptoms or signs accompanied the extremely low calcium levels noted during the exchange transfusion. Intravenous calcium administration often rendered transitory high serum concentrations of ionized calcium. The lowest and highest calcium levels noted during transfusion were 0.28 and 5.16 mmol/l respectively. Calcium levels normalized within 1 day after exchange transfusion without calcium therapy. Repeated exchange transfusions brought about progressively lower calcium values.