Increased hemolysis from saline pre-washing RBCs or centrifugal pumps in neonatal ECMO

Hemolysis is a significant complication of extracorporeal membrane oxygenation (ECMO), with a reported incidence of 12.2%. The aims of this study were (1) to investigate hemolysis caused by saline-washed versus unwashed RBCs, (2) to determine in vitro the effects of saline washing on erythrocyte hemolytic markers and (3) to investigate hemolysis by centrifugal versus roller pumps.

(1) To evaluate the effect of pre-transfusion saline-washing versus non-washing, the peak plasma-free hemoglobin (FHb) and total bilirubin in the first 3 days versus the next 4 days of ECMO were compared (2) Pre- and postsaline-washed RBCs were analyzed for K+ hemoglobin, mean corpuscular volume, FHb and hemolysis at baseline and after 4 h of storage at 4 degrees C. (3) Over 10 000 neonatal ECMO cases were retrospectively reviewed to study the effect of pump type on hemolysis.

(1) The washed blood group had significantly more hemolysis within the first 3 days of ECMO. (2) Immediately after saline washing, the K+ and Hb concentrations were significantly decreased compared with unwashed blood, and these differences were maintained after 4 h. The osmotic fragility of washed RBCs after 4 h of storage at 4 degrees C was significantly higher than at baseline. (3) Hemolysis was reported more often in the centrifugal than in the roller pump group.

(1) Using unwashed RBCs decreased hemolysis within the first 3 days of ECMO. (2) Saline washing, while decreasing the concentration of K+ in the plasma, significantly increases RBC membrane osmotic fragility. (3) Hemolysis is linked to the use of centrifugal pumps.