Consider Reinfusing Autologous Blood Lost During Cardiac Bypass Surgery

Recent evidence suggests stored red blood cells (RBCs) develop biochemical and structural changes that diminish their capacity to deliver oxygen, leading to adverse outcomes and possibly increased mortality. Storing RBCs has also been shown to increase cellular aggregation and reduce deformability in cell membranes, which prevents hemolysis as the cells squeeze through miniscule spaces in the circulatory system under a given level of applied stress.

Since those who undergo cardiac surgery are more likely to receive allogeneic blood transfusions, researchers at Johns Hopkins Hospital set out to investigate the effects of reinfusing autologous blood lost during cardiopulmonary bypass.

In the prospective cohort study published in the June 2014 issue of Anesthesia & Analgesia, 32 patients were divided in 3 groups based on transfusion status:

1. Autologous salvaged RBCs alone
2. Autologous salvaged RBCs plus minimal (<5 units) stored allogeneic RBCs
3. Autologous salvaged RBCs plus moderate (≥ 5 units) stored allogeneic RBCs

Ektacytometry was utilized to measure RBC deformity and aggregation before, during, and 3 days after surgery.

The results of the study indicated that using autologous salvaged RBC transfusion during cardiopulmonary bypass had no effect on cell deformability, as the RBCs remained pliable. The researchers also found that stored allogeneic transfusions with cardiopulmonary bypass resulted in a dose-dependent effect on cell deformability, since deformability impairment lasted up to 3 days in those who received larger amounts of stored allogeneic blood. However, no difference in cellular aggregation was observed among the 3 groups.

The authors concluded the use of autologous salvaged RBCs might benefit some patients, given that stored blood may limit or decrease the delivery of oxygen.