Abstract: Objective To explore the changes of activated protein C (aPC) level in patients with traumatic liver injury and analyze its correlation with early coagulation dysfunction and prognosis. Methods From March 2016 to July 2019, 80 patients with traumatic liver injury in the Department of Gastrointestinal Hepatobiliary Surgery in our hospital were selected. After admission (at the emergency room), blood samples were collected and tested for aPC, protein C (PC), coagulation factors, tissue plasminogen activator (t-PA) and D-dimer. According to injury severity score (ISS) and base deficit (BD) levels, patients were divided into 4 groups, named minor injury without significant tissue hypoperfusion (ISS < 16, BD < 6) group, minor injury with significant tissue hypoperfusion (ISS < 16, BD > 6) group, severe injury without significant tissue hypoperfusion (ISS > 16, BD < 6) group and severe injury with significant tissue hypoperfusion (ISS > 16, BD > 6) group. We compared the differences in coagulation parameters and aPC levels in each group. The aPC level of patients were divided into quartiles, then patients were divided into 4 groups according to the aPC level: Q1 group (aPC < 2.71), Q2 group (2.71 < aPC < 4.06), Q3 group (4.06 < aPC < 6.09) and Q4 Group (6.09 > aPC). The differences of coagulation parameters and coagulation factor levels in each group were compared. Results Compared with other groups, the PT and APTT levels of patients in the severe injury group with significant tissue hypoperfusion when they arrived in the emergency room were (15.72 ± 0.40) s and (32.95 ± 1.12) s, respectively, which were significantly longer than those in the other groups (P<0.05), the level of aPC was increased (11.26 ± 2.33 ng/mL), and the level of AP was decreased (75.22 ± 3.50 ng/mL) (P<0.05). The PT and APTT times of patients in the Q4 group were the longest (P<0.05), which were (16.43 ± 1.02) and (38.27 ± 5.46)s, respectively. The levels of coagulation factors Va and VIIIa in the Q4 group were significantly lower (P<0.05), respectively (43.20 ± 5.11) and (200.17 ± 32.53)%, tPA and D-dimer levels were significantly increased (P<0.05), respectively (34.26 ± 4.02) and (23.45 ± 5.68) ng/Ml. Then, aPC/PC ratio was significantly related to ventilator-associated pneumonia, multiple organ failure, acute lung injury, and death (P<0.05). Conclusion Patients with traumatic liver injury are more prone to early coagulation dysfunction in the case of insufficient tissue perfusion and severe trauma, and are accompanied by a significant increase in aPC levels. This process may be related to the inhibition of coagulation factors by aPC, and a higher aPC level at admission indicates a worse prognosis after severe trauma.

Key words: Traumatic liver injury, Coagulopathy, Activated protein C