Objective To observe the effect of CO2 artificial pneumothorax on perioperative coagulationfibrinolysis in patients undergoing thoracoscopic esophagectomy.Methods A total of 80 patients with thoraciclaparoscopic combined esophageal resection in our hospital from November 2017 to June 2018 were randomly divided into CO2 artificial pneumothorax group (P group) and nonCO2 artificial pneumothorax group (N group)

40 cases in each group.The patient′s tissue plasminogen activator(t-PA)，plasminogen activator inhibitor(PAI1)，thromboelastogram(TEG)，Polymer (D-D) and blood gas analysis were measured at 5 time points included before anesthesia(T1)，artificial pneumothorax 60 minutes or single lung ventilation 60 minutes(T2)，artificial pneumothorax stop 30 minutes or double lung ventilation 30 minutes(T3)，postoperative first day(T4) and postoperative third day(T5).Results Compared with the N group，the pH value of the P group was significantly decreased at T2(P<0.05)，the PaCO2 was significantly increased (P<0.05)，and the R and K values of the TEG were significantly prolonged (P<0.05)

the angle and MA decreased significantly (P<0.05)，t-PA increased significantly(P<0.05).After 30 minutesof artificial pneumothorax，the pH value，PaCO2 and t-PA gradually recovered to the preoperative level(P>0.05).On the first day after operation，the R value，K value，α angle and MA value of TEG were restored to the preoperative level(P>0.05).The postoperative D-D was significantly increased in both groups(P<0.05)，but there was no statistically significant difference between two groups(P>0.05).Conclusion Respiratory acidosis caused by the establishment of CO2 pneumoperitoneum can significantly reduce the coagulation function of patients during the operation

enhance the fibrinolysis function

and return to the preoperative level on the first day after the operation.