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The importance of urokinase thrombolytic therapy for the maintenance of central venous catheter function

  Hemodialysis therapy is one of the main renal replacement therapies for patients with chronic renal failure. Good vascular access is the basic guarantee for the completion of hemodialysis therapy. An ideal vascular access should be able to provide adequate blood flow for hemodialysis therapy, be able to use for a long time and more frequently, and have fewer complications. The establishment of unblocked and effective vascular access is the key step to maintain the effect of hemodialysis in patients with renal failure, which directly affects the quality of life and survival time of patients.

The importance of urokinase thrombolytic therapy for the maintenance of central venous catheter function

  Why central venous catheter?

  Although the autologous fistula access is the best choice for maintenance hemodialysis in patients with chronic renal failure, the number of patients with poor vascular conditions caused by aging population, diabetic nephropathy, long dialysis time and other factors is increasing. By patient age, hardening of the arteries, vascular lesions, caused by repeated puncture vein stenosis, the patient's own blood vessels, the influence of such factors as more and more patients can't row from internal fistula, or internal fistula embolism can't reuse for many times, greatly affecting the effects of the treatment of patients with hemodialysis, comprehensive analysis of the factors above, long-term indwelling central venous catheter with polyester set has gradually become the important pathways of patients.

  In the process of overseas dialysis patients' treatment, the dialysis patients with tapered catheter account for 14% ~ 17.5% of the total dialysis patients. However, with the increase of patients with long-term hemodialysis catheterization, the incidence rate of complications with poor function of CVC is gradually increasing, and has been paid more and more attention by researchers. The common causes are: thrombosis in the catheter, thrombosis around the catheter, mural thrombosis, fibrin sheath formation, etc. Poor catheter function is one of the important factors affecting the survival rate of dialysis patients, and it is also the main complication of deep venous indwelling catheter. A common complication of central venous intubation is catheter thrombosis, which occurs in up to 25% of cases. In order to avoid long-term use of the catheter, fibrin sheath or thrombosis may occur, resulting in poor blood flow to the catheter, or even blockage of the catheter.

  Catheter dysfunction -- fibrin sheath/thrombosis

  According to foreign guidelines, catheter flow rate is less than 300ml/min, or arterial pressure is less than 250mmHg when blood pump flow rate is less than 300ml/min, or venous pressure is more than 250mmHg, it is considered that catheter function is poor. In view of the fact that the body weight of domestic patients is generally lower than that of foreign patients, the expert group considered that when the catheter blood flow of Chinese adults is less than 200 ml/min, or the blood pump flow is less than 200 ml/min, the arterial pressure is less than 250mmHg, or the venous pressure is more than 250mmHg, it is unable to achieve adequate dialysis, and it was determined that the catheter function is poor. Fibrin sheath and thrombus are one of the main causes of catheter dysfunction. The standard sealing technique and the correct use of sealing heparin concentration and volume according to the catheter volume are also important steps to reduce the catheter dysfunction.

  Thrombolysis: thrombolysis should be performed in urokinase catheter due to the obstruction of catheter flow or difficulty in catheter suction during loading. At least 5000IU/ml of urokinase is recommended. Urokinase thrombolysis was maintained in the catheter for 25 ~ 30min. Alternatively, 0.3ml urokinase solution can be injected every 3 ~ 5min after lOmin is retained. T - PA thrombolysis can also be used, according to the drug or device manufacturer's instructions. Repeated thrombosis and poor flow usually require continuous urokinase infusion. The recommended regimen is to slowly inject urokinase 25,000 ~ 50000IU/48ml normal saline through each dialysis catheter at a flow rate of 2 ~ 4ml/h, with a duration of at least 6h.

  The following procedures are recommended for catheter dysfunction. See the table below.

  Replace the dysfunctional catheter: if multiple thrombolysis is ineffective or the catheter is ectopic, a new catheter can be replaced. (1) replace the catheter through the guide wire. When replacing the catheter, most people think that the tip of the catheter should be about 1 ~ 2cm deep as the original catheter. (2) replace the puncture site and place a new catheter; (3) the balloon destroys the fibrin sheath and replaces the new catheter.

  Functional maintenance of central venous catheters - regular thrombolysis

  Central venous catheter thrombolysis operating current clinical commonly used methods: when the syringe suction catheter unilateral or bilateral, difficulty in pumping blood or cannot extract tube is regarded as intraductal block, to explain to the patient, ask for details of any UK allergies and contraindications, confirmation, agreed to explain and patients before operation, signed informed consent. All routine disinfection for aseptic operation: group A: 200000 U urokinase dissolve in 50 ml saline, each 25 ml put in two micro pump, connecting duct arteriovenous side, adjust the micro pump pumping at the rate of 3 ml/h, 8 h pump, pump after the will of 100000 IU of UK dissolved in 5 ml saline, with 2.5 ml positive pressure seal tube in the arteriovenous catheter, 1 times A day, about 2 ~ 3 times, until the next blood dialysis, the blood flow was observed the situation; Group B: use 20 ml empty catheter for withdrawing needle connection block end, withdrawing to 2.5 ~ 5 ml clip pipe clamp, lumen catheter tube to form a negative pressure cavity, after separation of syringes and catheters, will dilute good 5 ml saline + UK10 IU syringe pipe, open clamp, using negative pressure to make the UK a liquid inlet tube cavity and blocking the embolus to fully mix, keep change after 30 mim 20 ml yo try to smoke suction cavity unobstructed, if still owe unobstructed, can be repeated the operation three times. Thrombolytic therapy was used for both side and unilateral obstruction.

  References on thrombolytic effect of urokinase

  Urokinase is an anti-plasminogen preparation produced by the kidney, which can directly act on plasminogen to convert the activated plasminogen into plasminogen and form a natural thrombolytic drug, which can promote the dissolution of thrombus fibrin and cause thrombosis collapse. The thrombolytic effect of urokinase has not only a strong specificity, but also a small systemic fibrinolytic effect, which greatly reduces the probability of bleeding, and has been widely used in clinical thrombolytic treatment. Studies show that urokinase thrombolysis is a safe and effective method for the treatment of intracatheter thrombosis, and the catheter recanalization rate can reach 80% ~ 90% after urokinase thrombolysis. Intravenous pressure measurement of urokinase intervention patients with regular micro-pump indicated that it could ensure adequate blood flow and dialysis adequacy. However, the measurement value of venous pressure in patients with urokinase pushing method suggests that the cuff patency rate is not good, leading to low hemodialysis flow and the possibility of insufficient dialysis. Micropump urokinase can not only relieve the hypercoagulability of the blood, but also reduce the bleeding probability of the patient, compared with peripheral intravenous infusion, the dose is also within the range of the patient's viscera.

  Relevant research shows that the retention type urokinase thrombolysis method makes the effect of tube recanalization and pumping method, investigate its reason, may be due to the slow pumping of urokinase, urokinase gradually penetrate into the duct wall and catheter around agglutination fibrin, activate fibrinolytic enzyme, promote the dissolution of fibrin sheath, central venous catheter in order to avoid formation of fibrin sheath or thrombosis. The incidence of adverse reactions of micropump urokinase thrombolytic therapy is lower than that of time-reserved urokinase thrombolytic therapy, which further proves the safety and effectiveness of micropump urokinase thrombolytic therapy and is worthy of clinical application. Compared with retained urokinase thrombolytic method, micropump urokinase thrombolytic therapy can significantly reduce the incidence of catheter dysfunction and improve the adequacy of dialysis, which is safe and effective and worthy of clinical application.