This retrospective study was designed to develop a preoperative nomogram, validated both internally and externally, to supply an individual and precise tool for predicting the probability that patients will require perioperative transfusion therapy.

Perioperative red blood cells (RBCs) transfusion is a necessary guarantee for surgical surgery and one of the indispensable means in modern medical treatment. In recent years, with the continuous improvement of medical standards, various major and complex surgeries have been carried out. The total number of patients receiving surgical treatment increased year by year, and the demand for surgical blood has also increased rapidly. Although unpaid blood donation has been vigorously advocated in recent years, the supply of blood products are still difficult to meet the growing demand for clinical blood. RBCs transfusion is often associated with unavoidable complications such as anaphylaxis and transfusion-related acute lung injury, which may lead to delayed recovery, increased hospital stay and medical costs, and result in serious adverse effects and even death.

Hemorrhage is a common complication of surgery. The effect of blood transfusion treatment and the patient's recovery process will be affected by the amount of blood transfused during the perioperative period. Similarly, blood products that are prepared in advance for surgery often remains unused perioperatively, leading to the waste of valuable blood resources and an increase in hospital expenses. Hemorrhage is one of the leading causes of death in various clinical situations, such as severe trauma, heart surgery, and traffic accidents.Timely and effective high-dose transfusion is directly related to life and death. However, high-dose transfusion may also lead to dilution coagulopathy, increased risk of bleeding, and imbalance in the internal environment.

In brief, there is an urgent requirement for a systematic, evidence-driven tool to comprehensively weigh the risks and benefits of high-dose RBCs transfusion in clinical practice.

Inclusion Criteria:

• Patients undergoing non-cardiac surgery during hospitalization.
• Patients receiving allogeneic RBCs transfusion within 24 hours during and after surgery.

Exclusion Criteria:

• Age under 15 years.
• Patients with incomplete clinical data.

This retrospective study included 【】patients who received RBCs transfusion during non-cardiac surgery at West China Hospital between January 2018 and June 2024.