The Role of Endogenous Heparinization As an Intraoperative Predictive Marker for Postoperative ICU Admission

For each patient, two samples will be collected for ROTEM analysis: one at the beginning of the surgery, during the placement of the arterial line (Start ratio), and another one, at the end, during the completion of the surgical wound closure (Final ratio). The arterial line system will be filled with normal saline (0.9% sodium chloride) without the addition of unfractionated heparin. To avoid sample contamination before sampling, a volume of blood equivalent to 5.5-6 times the dead space (calculated from the catheter tip to the three-way stopcock device) will be aspirated. Blood samples for testing will be stored in specific empty coagulation test tubes (Jiangsu Rongye Technology Co., Ltd, Jiangsu, China) and gently mixed with 3.2%-0.109M sodium citrate, for a total volume of 1.8 ml.