Transfusions of red blood cells (RBCs) are frequently administered for a variety of clinical conditions. The use of an infusion pump has become common practice in nursing. Lack of evidence regarding hemolysis associated with transfusing older RBCs using an infusion pump led one 361-bed acute care suburban medical center to maintain its nursing policy to infuse all blood products by gravity. A combined simulated and clinical study was conducted with 25 units of RBCs. No significant hemolysis was demonstrated as measured by hemolysis index and serum potassium levels. As a result of this study, the nursing policy at the medical center was changed.