Abstract
The effect of fresh autologous blood transfusion on platelet count and blood requirement in the early postoperative period is examined in a control group and in patients receiving early and late autologous replacement. Withdrawal of blood in the autologous groups appeared to enhance platelet numbers as the autologous groups had higher mean platelet counts than the control group immediately after bypass, in spite of having lower mean haematocrit. After bypass all groups showed a progressive rise in platelet count with time. A substantial part of the rise was explained by haemoconcentration resulting from fluid shifts but there was also an increase in the total circulating platelet numbers. There was no difference in postoperative blood loss between the three groups. Autologous blood replacement hastens the postoperative rise in platelet count but does not alter the postoperative blood loss.