Objective To investigate the changes of blood coagulation status and the safety of emergency microsurgery in patients with acute trauma to their extremities. Methods Forty seven patients with open injuries to the extremities were divided into 3 groups: in Group Ia (n=20), the patients presented with open injury to a single limb without traumatic shock and chest or head injuries, and they did not undergo microsurgery; while in Group Ib (n=13), an emergency microsurgery was done. In Group Ⅱ , the patients suffered from multiple compound fractures of the extremities with traumatic shock and chest or head injuries. The blood coagulation status of all the patients was evaluated by testing platelet count (PLC), platelet adhesiveness (PadT), serum antithrombin Ⅲ (AT- Ⅲ ), and D-dimer (D-Di) level. Results In Groups Ia and Ib, only PadT was increased and AT- Ⅲ declined preoperatively, then they returned to normal 24h postoperatively. In Group Ⅱ, at different periods after trauma, there was significant evidence of Pg and AT-Ⅲ decline accompanied by high increase of PadT and D-Di level; at 24h postoperatively, the mean values were 49.3% (PadT), 2.7mg/L (D-Di), 1..1g/L (Pg), and 69.1% (AT-Ⅲ), respectively. All these changes got significant difference (P<0.05) when compared with the normal value and those of Groups Ia and Ib, and did not completely return to normal even 72h after operation. Conclusion An emergency microsurgery could be safely performed in patients with ordinary open injuries to their limbs without traumatic shock, however it should be done with caution in cases of severe injuries with traumatic shock, because hypercoagulation status would follow in several hours after injuries. D-Di measurement may be used as a screening test to predict and assess hypercoagulation status more early after trauma. Objective To investigate the changes of blood coagulation status and the safety of emergency microsurgery in patients with acute trauma to their extremities. Methods Forty seven patients with open injuries to the extremities were divided into 3 groups: in Group Ia (n = 20), the patients presented with open injury to a single limb without traumatic shock and chest or head injuries, and they did not undergo microsurgery; while in Group Ib (n = 13), an emergency microsurgery was done. In Group II, the patients suffered from multiple compound fractures of the extremities with traumatic shock and chest or head injuries. The blood coagulation status of all the patients was evaluated by testing platelet count (PLC), platelet adhesiveness (PadT), serum antithrombin III (AT- III), and D- In Groups Ia and Ib, only PadT was increased and AT-III declined preoperatively, then they returned to normal 24h postoperatively. In Group II, at different peri ods after trauma, there was significant evidence of Pg and AT-III decline accompanied by high increase of PadT and D-Di level; at 24h postoperatively, the mean values ​​were 49.3% (PadT), 2.7 mg / L , 1..1g / L (Pg), and 69.1% (AT-III), respectively. All these changes got significant difference (P <0.05) when compared with the normal value of those of Groups Ia and Ib, and did not return completely normal to 72h after operation. Conclusion An emergency microsurgery could be safely performed in patients with ordinary open injuries to their limbs without traumatic shock, however it should be done with caution in cases of severe injuries with traumatic shock, because hypercoagulation status would follow in several hours after injuries. D-Di measurement may be used as a screening test to predict and assess hypercoagulation status more early after trauma.