Temperature Effect on Coagulation Function in Mild Hypothermic Patients Undergoing Thoracic Surgeries: Thromboelastography (TEG) versus Standard Tests

Abstract Purpose Our previous research has revealed that mild hypothermia leads to excessive bleeding in thoracic surgeries, while the underlying mechanism stayed unrevealed by the standard coagulation tests. The research question in this study was: “How does mild hypothermia impair the hemostatic function in patients receiving thoracic surgeries?”. The purpose was to detect the disturbed coagulation processes by comparing the TEG parameters in patients receiving active vs. passive warming during thoracic surgeries. Methods Standard coagulation tests and thromboelastography (TEG) were adopted to compare the hemostatic functions in patients receiving active vs. passive warming during thoracic surgeries. Furthermore, blood samples from passive warming group were retested for TEG at actual core body temperatures. Results Sixty-four eligible patients were included in this study. TEG revealed that mild hypothermia significantly disturbed coagulation by decreasing MA (59.4 ± 4.5mm vs. 64.2 ± 5.7mm, p = 0.04) and α angle (70.4 ± 5.2° vs. 74.9 ± 4.4°, p = 0.05), and prolonging ACT(122.2 ± 19.3s vs. 117.3 ± 15.2s, p = 0.01) and K time(1.9 ± 1.0s vs. 1.3 ± 0.4min, p = 0.02). TEGs conducted under core body temperatures revealed more impaired coagulation than those incubated at 37℃. Furthermore, postoperative shivering and waking time were significantly increased in mild hypothermic patients. Conclusion Mild hypothermia significantly impaired coagulation function in patients receiving thoracic surgeries, which could be detected by TEGs other than the standard coagulation tests. Temperature-adjusted TEGs may provide a preferable method of hemostatic monitoring and transfusion guidance in thoracic surgeries, which warrants further clinical investigations.