Complement activation by different cardiopulmonary bypass priming solutions

Similarities between the known biological activities of complement derived factors and the clinical findings observed in the 'post-pump syndrome' suggest that complement may play a role in the pathogenesis of this syndrome. Mixing of blood with autologous or homologous blood revealed no significant reduction in C3 and C4 concentration, whereas mixing with plasma showed a lower C3 value without differences in C4. Mixing of blood with albumin, Normosol, D5 water and normal saline solution revealed a progressive reduction both in C3 and C4 concentration; mixing with Emagel showed C4 reduction, without reduction in C3 concentration. Our findings suggest that crystalloid solutions used for priming the pump oxygenator circuit are an additional C3 and C4 activating factor. Such activation should be regarded as a 'pre-pump complement activation'.