Abstract: Objective    To explore the effect of ulinastatin continuous infusion combined rivaroxaban on coagulation function in patients undergoing major orthopedic surgery. Methods    Forty-five patients undergoing major orthopedic surgery were randomly divided into three groups：ulinastatin continuous infusion (Uc) group, ulinastatin single injection (Us) group and control (C) group. All the patients received patient-controlled intravenous analgesia (PCIA) after the operation and took rivaroxaban orally 12 hours after the operation. Ulinastatin (5000 U/kg) was given intravenously to both group Uc and Us preoperatively, group C given isometric normal saline, group Uc pumped UTI continuous intravenously at the end of surgery(10000 U/kg) to 48 hours through PCIA pump. Hematocrit(HCT), plasma prothrombin time(PT), activated partial thromboplastin time(APTT), thrombin time(TT) , fibrinogen(FIB) were normally tested before surgery(T1), at the end of the surgery(T2), 12 hours(T3), 24 hours(T4), 48 hours(T5) after the surgery. Results     Compared with T1, TT had a downward tendency after the operation in group C and Us (P <0.05), and FIB ,PT ,APTT were significantly increased from 24 hours after the surgery (P <0.05); In group Uc, the changes of TT showed an steady tendency after the operation (P >0.05), PT and APTT became extended 12 hours earlier than group C (P <0.05), there was no substantial difference in the levels of FIB between the three groups in the postoperative period (P >0.05). Conclusion    During the perioperative period, ulinastatin continuous infusion combined rivaroxaban can improve the hypercoagulable state in patients undergoing major orthopedic surgery,and the clinical efficacy is safe.

Key words: Ulinastatin, Rivaroxaban, blood coagulation tests, major orthopedic surgery