Guidelines for blood transfusion have been issued for years. According to these guidelines, red blood cells (RBCs) transfusion should be given when the hemoglobin level is less than 6g/dL or 7g/dL and is unnecessary when the level is more than 10g/dL. However, in all the guidelines, the determination of whether RBCs should be administered when the hemoglobin level is in the range of 6~10g/dL is based on the judgment from anesthesiologists or surgeons. Index of transfusion trigger for patients with hemoglobin level between 6g/dL and 10g/dL is necessary and important in clinical practice.

Based on the aim of blood transfusion that maintain the balance of oxygen supply and oxygen consumption, the investigators hypothesize that index of transfusion trigger for patients with hemoglobin level between 6g/dL and 10g/dL could be calculated by parameters including infusion rate of adrenalin for maintaining normal cardiac output, fraction of inspired oxygen, core temperature, and angina. To verify this hypothesis, the investigators present West China Perioperative Transfusion Score (WCPTS) for the trigger of transfusion according to the patient's history and monitoring parameters, and the investigators design a randomized controlled clinical trial to test this score.

Surgery and trauma are the most common reasons for major blood loss, and blood transfusion provide guarantee for massive hemorrhagic surgery, especially orthopedic, cardiac, liver, and gynecologic procedures. On the other hand, blood transfusion is associated with many risks including hemolytic and nonhemolytic reactions, transfusion related acute lung injury (TRALI), and others. Besides, blood is insufficient worldwide. How to eliminate allogeneic blood transfusion is an important part in clinical practice.

Guidelines for blood transfusion have been issued for years. According to these guidelines, red blood cells (RBCs) transfusion should be given when the hemoglobin level is less than 6g/dL or 7g/dL and is unnecessary when the level is more than 10g/dL. However, in all the guidelines, the determination of whether RBCs should be administered when the hemoglobin level is in the range of 6~10g/dL is based on the judgment from anesthesiologists or surgeons. Index of transfusion trigger for patients with hemoglobin level between 6g/dL and 10g/dL is necessary and important in clinical practice.

Based on the aim of blood transfusion that maintain the balance of oxygen supply and oxygen consumption, the investigators hypothesize that index of transfusion trigger for patients with hemoglobin level between 6g/dL and 10g/dL could be calculated by parameters including infusion rate of adrenalin for maintaining normal cardiac output, fraction of inspired oxygen for maintaining spO2≧95%, core temperature, and angina.

Peri-Operative Transfusion Trigger Score, POTTS The initial score is 6. If a patient's cardiac output is normal without infusion of adrenalin, his spO2 could be maintained more than 95% with FiO2≤35%, his core temperature is less than 38℃, and he has no angina, his score is 6.

If a patient has one or more problems, including his normal cardiac output should be maintained by infusion of adrenalin with its rate ≤0.05μg/kg.min, or his spO2 is maintained more than 95% with 36~50% FiO2, or his core temperature is between 38℃ to 40℃, or chest pain due to exercise,manual labor,or excitement, his score should be added 1 point for each problem.

If a patient has one or more problems, including his normal cardiac output should be maintained by infusion of adrenalin with its rate >0.06μg/kg.min, or his spO2 is maintained more than 95% with >51% FiO2, or his core temperature is >40℃, or sudden onset of chest pain at rest, his score should be added 2 point for each problem.

The initial POTTS score is 6, and the patient's score is calculated by the sum of each item.

Score 6：The transfusion trigger is 6g/dL, and the the patient's Hemoglobin level should be maintained not less than 6g/dL.

Score 7：The transfusion trigger is 7g/dL, and the the patient's Hemoglobin level should be maintained not less than 7g/dL.

Score 8：The transfusion trigger is 8g/dL, and the the patient's Hemoglobin level should be maintained not less than 8g/dL.

Score 9：The transfusion trigger is 9g/dL, and the the patient's Hemoglobin level should be maintained not less than 9g/dL.

Score 10 or >10：The transfusion trigger is 10g/dL, and the the patient's Hemoglobin level should be maintained not less than 10g/dL.

For example, if a patient need ≤0.05μg/kg.min adrenalin to maintain his normal cardiac output (+1), his spO2 could be maintained more than 95% with FiO2≤35%, his core temperature is less than 38℃, and he has sudden onset of chest pain at rest (+2), his POTTS score could be calculated as 6 +1 (≤0.05μg/kg.min adrenalin to maintain his normal cardiac output) +2 (sudden onset of chest pain at rest), and his POTTS score is 9. That means this patient's transfusion trigger is 9g/dL, and his hemoglobin level should be maintained above 9 at this situation.

Inclusion Criteria:

• Height of usual place of residence less than 2,500 metres above sea level
• Perioperative hemoglobin level possibly less than 10g/dL

Exclusion Criteria:

• Emergency operation
• ASA classification V or VI
• Serious blood system diseases
• Dysfunction of hemoglobin
• Hypervolemic hemodilution
• Tumor metastasis
• Psychopathy
• Refuse to sign consent