Best Practices in Cold Hemagglutination
During hypothermic cardiopulmonary bypass, when cold blood cardioplegia is utilized, there is a potential risk of red blood cell agglutination. This agglutination is caused by an underlying condition called cold agglutinin disease, which is characterized by the presence of specific antibodies in the serum. These antibodies become active and cause the clumping and breakdown of red blood cells at temperatures below 30ºC. The clumping occurs due to a decrease in negative surface charges, while the extent of complement activation determines the severity of red blood cell breakdown.
Unexpected cold agglutination is thus normally only observed in the cardioplegia administration set when blood is used. There is, however, at least one report of clumping observed in a cardiotomy reservoir at 30ºC. In vitro, agglutination appears reversible on rewarming, but in vivo, it can cause capillary sludging, leading to gangrene and ischemia. In the case of cold blood cardioplegia, sludging might interfere with cardioplegia distribution, resulting in poor myocardial protection and depressed left ventricular function.
For more information on this topic, reference the following studies:
