Inclusion Criteria:  age:18-60 years old American Society of Anesthesiologists (ASA):I-II The spinal orthopedic undergoing elective surgery  Exclusion Criteria:  Severe cardiopulmonary dysfunction Blood coagulation dysfunction Disorders of liver and kidney function Tranexamic acid allergies The history of pulmonary embolism and venous thrombosis of lower limbs Anticoagulant drugs and nonsteroidal anti-inflammatory drugs in 7 days