Clinical data Among the 49 patients, 28 were male and 21 were female; age ranged from 22 to 77 years old, with a mean of 48.86 years old; among them, 42 cases were radical surgery for Budd-Chiari syndrome (BCS), 1 case was radical surgery for BCS and deep vein thrombus (DVT) removal from the lower extremity; 6 cases were DVT removal from the lower extremity alone. All patients were treated with color multi-color thrombosis before surgery. All patients were diagnosed by color Doppler echocardiography before surgery. The method of autologous blood recovery and transfusion was endotracheal intubation with general anesthesia. At the time of skin incision, 3 mg/kg of heparin was injected into the central vein or the healthy peripheral vein to make it heparinized systemically, after which the bleeding from the surgical field was aspirated by negative pressure at any time and recovered directly into a disposable autologous blood collector (Model 2000 Blood Collector, Xi’an Xijing Medical Supplies Co.) The recovered autologous blood was instantly returned to transfusion in the following two ways: for those who expected huge intraoperative bleeding within a short time (43 cases of BCS radical surgery in this group), a 10-14F vena cava cannula was placed in the lower right atrium through the same chest incision as a donor vessel, and the autologous blood in the disposable autologous blood collector was pressurized by a pressurized pump and filtered by a microembolic filter and then directly returned to the heart through this donor vessel; meanwhile, according to the unit The transfusion rate is controlled according to the bleeding volume, blood pressure and central venous pressure per unit time. For patients whose intraoperative bleeding was not expected to rapidly affect their vital signs (6 patients in this group with DVT extraction of the lower extremities), the above-mentioned autologous blood filtered by the microembolizer was bottled and dripped through the central vein or the unobstructed peripheral vein without a separate donor vessel. After the completion of the main operation, the procedure was completed as usual with the administration of fisetin-neutralized heparin (1-1.5:1 for BCS radical surgery and 0.5:1 for DVT removal from the lower extremity) and tight hemostasis via the vein as appropriate. Results Intraoperative recovery of autologous blood ranged from 1200 to 6000 ml in each patient, with an average of 3990.63 ml, all of which were returned during the operation or within 6 hours after the operation. There were no significant fluctuations in blood pressure, heart rate (rhythm) and other vital signs during and after surgery. No intraoperative blood transfusion was performed in all patients. Except for 3 cases with more postoperative traumatic bleeding and 4 patients with transient hemoglobinuria (relieved in 2-6 h) and early anemia, the hemoglobin and platelets before and after surgery were analyzed by t-test and were not statistically significant (P>0.05). 1 patient with diabetes mellitus and hyperuricemia had postoperative oliguria and azotemia, which were relieved after one week of symptomatic treatment such as diuresis and blood glucose control. The rest of the patients had normal postoperative urine output and no abnormal renal function findings on the third day of rechecking. All patients were discharged from the hospital cured. The follow-up ranged from 3 months to 8 years with good quality of life and no cases of late death. Discussion There is usually more bleeding during radical surgery for venous occlusive disease such as BCS and lower extremity DVT. In order to more adequately drain foreign bodies such as thrombus and tissue fragments distal to the obstruction, ensure surgical outcome, prevent pulmonary infarction, avoid prolonged excessive intraoperative stasis of vital organs, and determine the immediate evacuation effect, we also take controlled bleeding measures intraoperatively. Controlled bleeding often exceeds hundreds or even thousands of milliliters in a very short period of time. If such bleeding is not promptly aspirated and promptly returned, on the one hand, the surgical field will be flooded with blood and the operation cannot continue; on the other hand, massive blood loss will also lead to a sharp drop in blood pressure in a short period of time, which greatly affects surgical safety. The commonly used methods of autologous blood recovery and transfusion play a great role in saving blood and preventing the occurrence of adverse blood transfusion reactions and infectious diseases, but most of them cannot simultaneously take into account the problems of good surgical field exposure, maintaining the integrity of blood components, the timeliness of autologous blood transfusion and economy. Our proposed method of recovery and transfusion of autologous blood after heparinization has the following characteristics and advantages: ① Blood heparinization, the principle is the same as intracardiac direct surgery under extracorporeal circulation: blood does not coagulate after intravenous heparin injection, and negative pressure suction can be performed directly at any time, which is not only easy to perform, but also does not have theoretical and practical safety problems. ②The negative pressure suction is directly connected to the disposable blood retrieval device, so that the bleeding can be recovered quickly without the risk of the surgical field being flooded with blood and blood loss. ③The recovered autologous blood retains almost all the blood components and plasma proteins, and can be directly returned to transfusion after filtration without further in vitro anticoagulation and washing procedures, which can ensure the integrity of blood components and timely return of transfusion to the greatest extent. ④ Disposable blood recyclers are inexpensive and do not require the input of allogeneic blood during and after surgery, which reduces the patient’s financial burden while eliminating the occurrence of infectious diseases. In the author’s opinion, the above four guarantees can significantly broaden the indications for surgery and increase the safety of surgery, which can enable the operator to face a large amount of bleeding during surgery without worrying about the precise operation and improve the surgical results. According to the design concept and our clinical practice, the method of autologous blood recovery and transfusion after heparinization can be applied not only to the above-mentioned intravenous surgical procedures, but also widely used for the prevention of major bleeding and emergency treatment in case of major bleeding in any non-contaminated surgical procedures. In principle, this method of blood recovery and transfusion back is not used in malignant, obviously contaminated or infected surgery, but it is still an effective method to save lives in case of intraoperative fatal hemorrhage and blood source cannot be guaranteed. This method, like extracorporeal circulation, may cause hemolysis and stimulate postoperative systemic inflammatory reactions if the intraoperative blood transfer time is too long and the negative suction pressure is too high and frequent, which may lead to corresponding complications. Therefore, we take measures to reduce and suppress such reactions by routinely applying high-dose peptidase at the beginning of surgery and intraoperatively for patients with heavy preoperative disease, high expected intraoperative bleeding, and long operation time; and avoiding prolonged excessive and frequent negative pressure suction during surgery. This method should be used with caution in patients with preoperative diabetes mellitus and chronic renal insufficiency to avoid aggravating the condition.