Readjustment of hematocrit values after packed red cell transfusion in the neonate.

We studied the effect of packed red cell transfusion on the hematocrit values at 1 and 6 hours after transfusion in neonates. The mean hematocrits measured 1 and 6 hours following a 10 mL/kg transfusion were 40.0 +/- 4.38 and 40.4 +/- 4.40, respectively, in 11 transfusions given over a period of 3 hours. The mean hematocrits at 1 and 6 hours following a 10 mL/kg transfusion were 43.8 +/- 3.9 and 43.4 +/- 4.52, respectively, in 9 transfusions given over a period of 2 hours. The results in the study indicate that there was no significant difference in hematocrit observed between 1 and 6 hours following packed red cell transfusions given over a period of 2 or 3 hours. Therefore it is not necessary to wait for the customary 6 hours to determine the posttransfusion hematocrits, and the use of stored donor blood can be optimized for repeated blood transfusions.