Dose adjustment (1) Generally the first dose of warfarin 3-5mg, later adjusted according to the laboratory results and the presence of bleeding signs. (2)Inadequate anticoagulation: If the prothrombin time is lower than 1.5 times the normal value or activity > 60%, 1/4-1/8 of the maintenance dose can be added as appropriate; if the prothrombin time is close to normal, find the cause and re-anticoagulate. Wuhan Union Hospital Cardiac Surgery Dong Nianguo (3) anticoagulation overdose: if the prothrombin time is more than 2.5 times normal or activity <25%, the dosage can be reduced by 1/4 a 1/8, such as activity <20%, can be discontinued once, and then adjusted after the next day's laboratory tests, such as misuse (or repeated dosing), no bleeding tendency can be closely observed, there is a bleeding tendency to immediately inject vitamin K1 against, and immediately with the hospital Contact. < p="">(4) Pay attention to the tendency of bleeding: often manifested as epistaxis, gum bleeding, blood in urine, etc., intra-abdominal bleeding manifested as abdominal pain, intracranial bleeding manifested as coma, etc. If there are signs of bleeding, the dosage should be reduced or suspended even if the test is in the appropriate range, and contact the hospital immediately. (5) Pay attention to the presence of thrombosis and embolism: the causes of thrombosis, in addition to insufficient anticoagulation, are also related to the valve material and structure. Thrombosis is manifested as valve acoustic changes, heart failure, etc. When there is cerebrovascular embolism will appear neurological symptoms, such as confusion, hemiplegia, etc.. Limb artery embolism often presents with limb pain. The maintenance dose of anticoagulant is generally around 3mg/day, but due to individual differences, the required dose varies, clinical observation requires a maximum of 12mg/day and a minimum of 0.5mg/day. The management of bleeding complications (1) Minor bleeding: such as gum bleeding, skin bruising, can reduce the dosage of warfarin by 1/4-1/8 according to the laboratory results.(2) Significant bleeding: such as epistaxis, hematuria, can stop the use of warfarin for 1-2 days. (3) Severe bleeding: such as hemoptysis, vomiting blood, intracranial hemorrhage, immediately inject vitamin K1 20mg, observe for 1-2 days after the bleeding stops, and re-anticoagulate. (4) Fresh frozen plasma or coagulation factor concentrates should be used in critical cases to supplement coagulation factors. (5) Do not forget to contact the operating hospital.