Isovolumische hämofiltration während und nach extrakorporaler zirkulation kann die kardiopulmonale funktion nicht verbessern

Objective: Inflammatory responses and tissue fluid accumulation after cardiopulmonary bypass (CPB) and myocardial ischemia/reperfusion can impair organ function. Hemofiltration (I-IF)(HF) may improve post-pump cardiac and pulmonary function by eliminating inflammatory mediators and fluids. The effect of HF without fluid removal was tested in a standardized model in healthy animals. Methods Twenty-six anesthetized pigs were subjected to crystalloid primed CPB (90 min cardioplegic cardiac arrest, 30 min reperfusion). HF was performed (n=13) during reperfusion and for 30 min post-CPB; filtered volume was replaced by Ringer's lactate. Hemodynamic and pulmonary function as well as the systemic inflammatory response were assessed during 5 h post-CPB. Postmortem myocardial and pulmonary water content was determined by gravimetry, myocardial samples were histologically examined for leukocyte infiltration. 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 34% after hemofiltration. Pulmonary shunt blood flow was not affected, pulmonary compliance was reduced by 10-15%, and pulmonary vascular resistance was doubled in both groups without intergroup differences. Postmortem left lung water content was 10% higher after hemofiltration compared to that of controls. Post-CPB 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: The present data confirm the adverse effects of CPB on cardiac and pulmonary function in a pig model, although organ dysfunction was discrete. Hemofiltration without fluid removal did not appear to affect organ function and could not diminish leukocyte infiltrates in the heart despite a documented reduction in inflammatory cytokines. This is in contrast to results in pediatric cardiac surgery, possibly due to the use of non-colloidal fluids for volume replacement. Thus, reduction of fluid load rather than elimination of inflammatory mediators appears to be the key factor by which hemofiltration can improve recovery following CPB.