Zero-balanced hemofiltration during and after cardiopulmonary bypass in pigs results in a reduction of plasma cytokine levels with no associated effects on cardiorespiratory function

Background: Investigation of the effects of hemofiltration on cardiorespiratory function, inflammatory responses and tissue fluid accumulation after cardiopulmonary bypass (CPB) in a randomized animal study. Methods: 26 pigs were subjected to crystalloid primed CPB (90min cardioplegic cardiac arrest, 30min reperfusion). Hemofiltration was performed (n=13) during reperfusion and for 30min postCPB; filtered volume was replaced by equal volumes of ringer's lactate. PostCPB observation period was 5h. Results: Following CPB, heart rate was increased, aortic pressure, cardiac output, and dP/dtmax were reduced in both groups. Alveolar-arterial oxygen difference was not affected in control animals, but was transiently increased by 50% after hemofiltration. Pulmonary shunt blood flow was not affected, pulmonary compliance was reduced by 10%-15%, pulmonary vascular resistance was doubled in both groups without intergroup differences. Post mortem left lung water content was 10% higher after hemofiltration compared to controls. PostCPB elevation of plasma levels of TNF-α and IL-10 could be prevented by hemofiltration while myocardial leukocyte infiltration was not different between the two groups. Conclusions: In an adult porcine model of CPB, hemofiltration with replacement of the hemofiltrate with equal volumes of Ringer's lactate results in a reduction in TNF and IL-10 plasma levels with no associated effects on heart leukocyte infiltration or immediate post CPB cardiorespiratory function.