PLATELET MICROEMBOLI ASSOCIATED WITH MASSIVE BLOOD TRANSFUSION.

In patients undergoing cardiotomy, the heart and lungs are by-passed by draining blood from the superior and inferior vena cava and returning it through a pump into the aorta, usually through a femoral artery. An extracorporeal pump-oxygenator is used for aeration and propulsion. The pump in use in our institution is primed with 2,000 to 3,000 ml. of heparinized blood. This blood, together with the venous return from the vena cava, is delivered into the systemic circulation, duplicating as closely as possible the action of the heart. During operation, blood loss is replaced partially by intravenous infusion but predominantly by addition of blood to the pump oxygenator. The potential for infusion of particulate material with the blood has been examined by several investigators. Refractile colorless material found in many arteries and capillaries has been identified by Lindberg, Lucas, Sheagren and Malm1 as silicone originating from an antifoam compound employed in the oxygenator. Miller, Fonkalsrud, Latta and Maloney2 have identified fat emboli in all patients dying after extracorporeal circulation. We have identified a third type of embolus, which is believed to develop in stored blood and is probably composed principally of leukocytic and platelet material.