Malignant bone tumors often lead to skeletal complications, known as skeletal related events (SRE). These complications mainly include pathological fractures, severe pain, and spinal cord compression. Typically, SRE reduces overall survival rates and is associated with loss of mobility and social functioning, decreased quality of life, and significantly increased healthcare costs. Surgical resection is an important means of treating malignant bone tumors. The main goal of surgical treatment is to maintain the patient's function and mobility by relieving pain, preventing impending fractures and/or nerve compression, or stabilizing pathological fractures. Surgery for malignant bone tumors often requires extensive exploration, osteotomy, and prosthetic reconstruction. The surgery involves significant trauma and excessive bleeding from the wound. Therefore, there is a significant risk of perioperative blood loss and transfusion during surgery for malignant bone tumors. However, blood transfusion also brings transfusion related risks to patients, increases the incidence of postoperative complications, and increases the healthcare burden on patients and society. Acute normovolemic hemodilution (ANH) may help reduce allogeneic red blood cell transfusion. However, There is a lack of high-quality evidence to support the use of ANH in bone cancer surgery.

Malignant bone tumors often lead to skeletal complications, known as skeletal related events (SRE). These complications mainly include pathological fractures, severe pain, and spinal cord compression. Typically, SRE reduces overall survival rates and is associated with loss of mobility and social functioning, decreased quality of life, and significantly increased healthcare costs. Surgical resection is an important means of treating malignant bone tumors. The main goal of surgical treatment is to maintain the patient's function and mobility by relieving pain, preventing impending fractures and/or nerve compression, or stabilizing pathological fractures. Surgery for bone cancer often requires extensive exploration, osteotomy, and prosthetic reconstruction. The surgery involves significant trauma and excessive bleeding from the wound. Therefore, there is a significant risk of perioperative blood loss and transfusion during surgery for malignant bone tumors. However, blood transfusion also brings transfusion related risks to patients, increases the incidence of postoperative complications, and increases the healthcare burden on patients and society. Therefore, it is particularly important to develop a perioperative blood management (PBM) plan for these patients. Acute normovolemic hemodilution (ANH) may help reduce allogeneic red blood cell transfusion. However, There is a lack of high-quality evidence to support the use of ANH in bone cancer surgery.

Inclusion Criteria:

1. age 18 more than years;
2. undergoing elective bone cancer resection surgery;
3. preoperative hemoglobin ≥12 g/dL;

Exclusion Criteria:

1. using a tourniquet;
2. BMI<18.5 Kg/m^2;
3. international normalized ratio (INR) >1.5 or platelet count <100 × 10^9/L;
4. cardiopulmonary insufficiency;
5. hepatic and renal dysfunction;
6. active infectious disease;
7. allergy to colloid solution;
8. pregnancy;
9. declined participation in the study or declined blood transfusion