Heparin bonded circuits have become standard in extracorporeal bypass circuits for open heart surgery. Leukoreduction of allogeneic red blood cells is also considered a standard of care in many countries. Martens and colleagues concluded from this small series of patients that the addition of a leukocyte filter to the heparin bonded circuit is associated with lower coagulation activation, decreased blood loss and reduced transfusion of packed red cells in elective CABG patients. This is a good start but we must be careful not to draw any major conclusion from this study because of its small size and the potential for confounding by all the variables that affect transfusion practice in cardiac surgery.

– R. K. Spence.