Embolic fat as a measure of adequacy of various oxygenators

Previous work has demonstrated that prolonged employment of the filming oxygenator in bypass procedures is associated with considerable deposition of embolic fat within the vascular tree of both humans and experimental animals. Mongrel dogs were subjected to 2 hours of cardiopulmonary bypass in which macrobubble and membrane oxygenators were employed. All other conditions were standardized. All animals were sacrificed shortly after restoration of normal clotting and cardiac function. Brain, lung, liver and kidney specimens were fixed for 24 hours in 10% formalin, after which frozen sections were made and stained with Sudan IV and hematoxylin. Embolic fat was found extensively in brain, liver and kidney tissue in the five animals in which the macrobubble device had been employed. The quantity of fat appeared similar to that previously noted in animals in which the filming device had been used. No fat emboli were noted in tissues obtained from the four animals exposed to the membrane oxygenator. This suggests that the direct contact of blood and gas contributes to the development of embolic fat. Submitted on June 15, 1960