LEUKOCYTE DEPLETION RESULTS IN IMPROVED LUNG-FUNCTION AND REDUCED INFLAMMATORY RESPONSE AFTER CARDIAC-SURGERY

Leukocyte depletion during cardiopulmonary bypass has been demonstrate d in animal experiments to improve pulmonary function, Conflicting res ults have been reported, however, with clinical depletion by arterial line filter of leukocytes at the beginning of cardiopulmonary bypass. In this study, we examined whether leukocyte depletion from the residu al heart-lung machine blood at the end of cardiopulmonary bypass would improve lung function and reduce the postoperative inflammatory respo nse. Thirty patients undergoing elective heart operations were randoml y allocated to a leukocyte-depletion group or a control group. In the leukocyte-depletion group (n = 20), all residual blood (1.2 to 2.1 L) was filtered by leukocyte-removal filters and reinfused after cardiopu lmonary bypass, whereas in the control group an identical amount of re sidual blood after cardiopulmonary bypass was reinfused without filtra tion (n = 10). Leukocyte depletion removed more than 97% of leukocytes from the retransfused blood (p < 0.01) and significantly reduced circ ulating leukocytes (p < 0.05) and granulocytes (p < 0.05) compared wit h the control group. Levels of the inflammatory mediator thromboxane B -2 determined at the end of operation (p < 0.05) were significantly lo wer in the depletion group than in the control group, whereas no stati stical differences in interleukin-6 levels were found between the two groups. After operation, pulmonary gas exchange function (arterial oxy gen tension at a fraction of inspired oxygen of 0.4) was significantly higher in the leukocyte-depletion group 1 hour after arrival to the i ntensive care unit (p < 0.05) and after extubation (p < 0.05). There w ere no statistical differences between the two groups with respect to postoperative circulating platelet levels and blood loss, and no infec tions were observed during the whole period of hospitalization. These results suggest that leukocyte depletion of the residual heart-lung ma chine blood improves postoperative lung gas exchange function and is s afe for patients who are expected to have a severe inflammatory respon se after heart operations.