ObjectiveTo investigate the changes of plasma platelet activating factor (PAF) interleukin-8(IL-8) and interferon-γ (IFN-γ) in patients after surgery with extracorporeal circulation (ECC) and their clinical significance. MethodsSeventy-five patients undergoing surgery with ECC in the First College of Clinical Medicine,China Three Gorges University from June 2012 to June 2013 were enrolled in this study. According to the presence of postoperative acute lung injury/acute respiratory distress syndrome (ALI/ARDS) all the 75 patients were divided into 2 groups. In ALI/ARDS group, there were 28 patients including 20 male and 8 female patients with their age of 53.6±8.2 years. In the control group,there were 47 patients without postoperative ALI/ARDS,including 32 male and 15 female patients with their age of 56.9±11.8 years. Dynamic variations of plasma PAF,IL-8 and IFN-γ of these patients were examined with enzyme-linked immunosorbent assay (ELISA) and compared between the 2 groups. ResultsIn ALI/ARDS group,plasma IL-8 and IFN-γ reached peak levels at 48 hours after surgery and gradually decreased after that;plasma PAF reached the peak level at 96 hours after surgery and gradually decreased after that. Postoperative plasma PAF (96 hours after surgery:16 029.5±4 203.7 mU/ml vs. 4 520.1±312.2 mU/ml,P<0.05) IL-8 (48 hours after surgery:48 580.5±8 095.8 pg/ml vs. 5 990.5±1 179.0 pg/ml,P<0.05) and IFN-γ (48 hours after surgery:258.5±76.1 pg/ml vs. 26.1±11.5 pg/ml,P<0.05) of ALI/ARDS group were significantly higher than those of the control group at 48 hours,96 hours and 144 hours after surgery. ConclusionPlasma PAF,IL-8 and IFN-γ change significantly after surgery with ECC,which may play an important role in the pathogenesis of postoperative ALI/ARDS.