Effects of dilution, pressure, and apparatus on hemolysis and flow rate in transfusion of packed erythrocytes.

The purpose of this prospective, randomized study was to measure both the independent and interactional effects of dilution, pressure, and apparatus on flow rates and hemolysis during rapid administration of erythrocytes. Administration of undiluted erythrocytes increased the concentration of plasma-free hemoglobin by as much as 270% per unit under certain conditions. Transfusion flow rates for packed red blood cells were found to be determined by dilution, pressure, and apparatus and varied by as much as 450%. No significant correlation was found between flow rate and hemolysis. Regardless of the external bag pressure applied or the transfusion apparatus used, packed erythrocytes should be diluted (with at least 100 ml of normal saline) to decrease hemolysis and increase flow rate.