Effect of cardiopulmonary bypass and hemofiltration on plasma cytokines and protein leakage in pigs

Background: The hypothesis that an inflammatory process during and after ca rdiopulmonary bypass (CPB) impairs hemodynamics and causes increased capill ary protein leakage and that this is possibly ameliorated by hemofiltration (HF) was tested. Method: 26 anesthetized pigs were subjected to 120 min CP B (90 min cardioplegia followed by 30 min reperfusion, combined with conven tional and modified HF in 13 animals). Hemodynamics, leukocytes, cytokines (IL-1ra, IL-8, IL-10, TNF-alpha), LNPI, plasma protein, and the half-life o f i.v. injected Evans Blue (t/2) were assessed before and after CPB. Result s: CPB was followed by depression of left ventricular function and activati on of inflammatory mediators. Although a slight elimination of some inflamm atory mediators occurred, HF did neither improve cardiac function nor reduc e the inflammatory process. Plasma protein was lost during CPB and hemofilt ration by protein trapping to the surfaces of the CPB system, by filtration across the hemofilter, and by increased microvascular filtration (solvent drag). The latter was probably due to an increased filtration pressure in c onsequence of the reduction of plasma colloid osmotic pressure by the cryst alloid primed CPB. t/2 did not indicate an increased microvascular protein leakage after CPB. Conclusion: Hemofiltration is ineffective in improving c ardiac function or reducing the inflammatory response of CPB in the pig mod el.