This prospective study investigated the impact of mild hypothermia (34–36°C) on coagulation function during thoracic surgeries, comparing standard coagulation tests with thromboelastography (TEG). Sixty-four patients were randomized into two groups:
- Control Group: Passive warming without active temperature regulation.
- Intervention Group: Active warming to maintain normothermia using a forced-air warming system.
Methods
Coagulation assessments included:
- Standard Tests: Prothrombin time (PT), activated partial thromboplastin time (APTT), international normalized ratio (INR), fibrinogen (FBG), and platelet count (PLT).
- TEG Parameters: Measured clotting efficiency (ACT, K time), clot strength (MA), and clot stabilization (α angle). Dual TEGs were performed at 37°C and actual core temperatures in the Control group.
Key Findings
- Core Temperature and Coagulation:
- The Control group showed significantly lower core body temperatures during surgery (36.0°C vs. 36.9°C, p < 0.05).
- TEG at hypothermic core temperatures revealed greater coagulation impairments than tests conducted at 37°C.
- TEG Results:
- Hypothermia prolonged ACT (128.1 vs. 122.2 s) and K time (2.4 vs. 1.9 min), indicating slower clot formation.
- Clot strength (MA) and stabilization (α angle) were significantly reduced at hypothermic temperatures compared to 37°C.
- Postoperative Outcomes:
- Patients in the Control group experienced longer waking times (1.0 vs. 0.7 hours) and more postoperative shivering (6/32 vs. 1/32, p = 0.04).
- Standard Tests:
- PT, APTT, INR, FBG, and PLT showed no significant differences between groups, highlighting the limitations of standard tests in detecting hypothermia-induced coagulopathy.
Implications
The study demonstrates that TEG provides more accurate and temperature-sensitive assessment of coagulation function compared to standard tests. Temperature-adjusted TEG can guide hemostatic interventions, minimizing blood loss and transfusion needs during thoracic surgeries.
