Centrifugation vs. Multiple-pass Hemofiltration of the Residual Cardiopulmonary Bypass Volume

Traditional cardiac surgery requires patient connection to the Cardiopulmonary Bypass (CPB) apparatus which takes over the function of the heart and lungs while the surgeon performs the necessary surgery. The residual blood left in the CPB equipment (1.5-2.0 L) is centrifuged and washed leaving only red blood cells (RBCs) suspended in a saline solution. The RBCs are reinfused into the patient as needed by the anesthesiologist. The main problem with this technique is that many of the important components of the blood such as plasma proteins and clotting factors are discarded through cell washing. This study will explore a novel method (multiple-pass hemofiltration) of processing the residual pump blood which will allow the patient to receive their own whole blood with minimum waste of important components. The newer method of processing the residual pump volume has also been termed off-line modified ultrafiltration (off-line MUF) and is similar to the process that the kidneys use to filter the blood. It is hypothesized that multiple-pass hemofiltration of the residual CPB volume will reduce the occurrence of inflammatory responses, preserve plasma proteins, and decrease allogenic blood exposure and improve clinical outcomes as compared to centrifugation.