This study aims to develop an algorithm that can guide targeted bleeding management through thromboelastography (TEG) viscoelastic testing performed on blood samples from patients undergoing open heart surgery. The goal is to develop an algorithm that supports targeted bleeding management based on TEG parameters. The study is prospective, in vitro, and non-invasive. The material will consist of residual blood samples from open heart surgery patients. Analyses will be performed using TEG parameters (R time, K time, MA, LY30). Patients will be randomized using a closed-envelope method and divided into two groups: anesthesiologist standard clinical observation-control (Group K) and anesthesiologist standard clinical observation and TEG analysis (Group T). The sample size is 70 patients per group. From an ethical standpoint, this study uses anonymous data without additional blood collection and ensures patient safety.

Inclusion Criteria:

• Patients who will undergo open heart surgery
• Patients who have given informed consent

Exclusion Criteria:

• Patients undergoing emergency surgery
• Patients with known congenital coagulation disorders
• Patients with a known history of bleeding diathesis
• Patients receiving uninterrupted anticoagulant therapy at an optimal time
• Patients with renal failure under dialysis treatment
• Patients with active malignancy
• Patients who did not provide informed consent