HIGH-VOLUME, ZERO-BALANCED HEMOFILTRATION TO REDUCE DELAYED INFLAMMATORY RESPONSE TO CARDIOPULMONARY BYPASS IN CHILDREN

Background: In previous studies, researchers suggested a beneficial ro le of hemofiltration performed during cardiopulmonary bypass in childr en. This study was performed to assess both clinical effects and infla mmatory mediator removal by high-volume, zero-fluid balance ultrafiltr ation during rewarming (Z-BUF). Methods: Twenty children undergoing ca rdiac surgery were assigned randomly to Z-BUF or a control group. Plas ma C3a, interleukin (IL)-1, IL-6, IL-8, IL-10, tumor necrosis factor, myeloperoxidase, and leukocyte count were measured before (T1) and aft er (T2) hemofiltration and 24 h later (T3). The intensive care unit st aff was blinded to the patient's group. Postoperative alveolar-arteria l oxygen gradient, time to extubation, body temperature, and postopera tive blood loss were monitored. Results: Ultrafiltration rate was 4,97 2 (3,183-6,218) mL/m(2) (median [minimum-maximum]) in the Z-BUF group, where significant reductions were observed in postoperative blood los s, time to extubation (10.8 [9-18] vs. 28.2 [15-58] h) and postoperati ve alveolar-arterial oxygen gradient (320 [180-418] vs. 551 [485-611] mmHg at T3). In the Z-BUF group, significant removal of tumor necrosis factor, IL-10, myeloperoxidase, and C3a were observed at T2. Interleu kin 1, IL-6, IL-8, and myeloperoxidase were decreased at T3, suggestin g earlier removal of factor(s) that may trigger their release. Conclus ions: These results suggest that hemofiltration exerts some beneficial clinical effects that are not due to water removal. The role of the e arly removal of factors triggering the inflammatory response, rather t han a direct removal of cytokines, deserves further investigation.