Causes and preventive measures of hemodialysis access obstruction in hemodialysis patients

Patients with uremia undergoing hemodialysis treatment must undergo surgery to establish a hemodialysis pathway. Through the pathway, toxins and excess water produced by human metabolism are removed from the body by a dialysis machine, so that uremic patients will not be life-threatening due to poisoning and systemic edema. Therefore, the hemodialysis pathway is vividly referred to as the lifeline of hemodialysis patients. How to establish and maintain the lifeline of hemodialysis access is a common concern for medical personnel and patients.

Hemodialysis pathways can be blocked by thrombosis at various stages after surgery.

Causes of early thrombosis in the pathway

1. Poor vascular conditions: Patients with chronic renal failure have poor nutritional status, decreased vascular elasticity, calcification, sclerosis, and fibrosis of the blood vessels, with too thin inner diameter to provide high blood flow.

Recommendation: It is very important to evaluate the vascular conditions of patients before surgery. We emphasize that for each patient, preoperative color Doppler ultrasound examination of the blood vessels should be performed by the doctors in the operating group.

2. Patients with chronic renal insufficiency lack awareness of vascular protection, and repeatedly undergo arm vascular puncture, blood sampling, and catheterization for transfusion.

Recommendation: For patients who are expected to undergo hemodialysis treatment, radial artery and cephalic vein catheterization and puncture should be avoided as much as possible.

3. Postoperative vascular torsion and spasm, hematoma compression, or postoperative bandage too tight lead to poor blood flow.

Recommendation: Select hospitals and experienced doctors with unique hemodialysis access to establish hemodialysis access, which can effectively prevent early thrombosis.

Causes of late thrombosis in the pathway

1. Repeated dialysis and repeated puncture of the hemodialysis pathway or improper pressing may cause subcutaneous hematoma at the puncture site, and thrombus may adhere to the tube wall and block blood vessels.

Suggestion: Effective methods for puncture and compression of internal fistula include: Do not use an internal fistula with edema. During puncture of internal fistula, strictly aseptic operation should be performed, and puncture should not be performed near the anastomotic orifice or venous valve, otherwise hematoma may occur and cause internal fistula occlusion. A successful puncture is required, and rope ladder puncture should be adopted. If the puncture fails and swelling occurs, the needle should be immediately pulled out and pressed, fixed with adhesive tape, ice wrapped in ice bags, and then applied with 50% MgSO4 wet and hot after 24 hours. After dialysis, use sterile gauze to compress the venous puncture point instead of the skin puncture point to stop bleeding. The compression intensity should be such that there is no bleeding and vascular tremor can be touched.

2. Low blood pressure and low blood flow. Many patients switch from hypertension to hypotension after long-term hemodialysis, and their blood pressure often drops more after 1 to 2 hours of online hemodialysis, which can induce thrombosis.

Suggestion: For such patients, it is necessary to prepare vasopressor drugs and take appropriate oral vasopressor drugs before boarding, during hemodialysis, or before disembarking, to maintain blood pressure at 17.3-18.7/10.7-12.0kPa.

3. Excessive dehydration causes interstitial water to not be quickly replenished to the blood vessels, resulting in an increase in tangible components in the blood and an increase in blood viscosity.

Suggestion: When patients experience excessive dehydration such as excessive sweating and diarrhea, they should pay attention to supplementing appropriate amounts of water, and if necessary, use low molecular weight heparin to prevent thrombosis.

4. Early use of internal fistula, insufficient venous filling, and insufficient expansion can easily lead to lumen stenosis and thrombosis.

Suggestion: Autologous internal fistula should be established 2 to 6 months in advance, so that the internal fistula can be used after it is fully mature. After fistulation, patients are encouraged to perform functional exercises on the fistulation limbs, such as holding a rubber band and performing compression actions to promote blood flow and prevent thrombosis. Do not apply traditional Chinese medicine on the fistula side, avoid pressing, lifting heavy objects, wearing a watch, measuring blood pressure, blood collection, infusion, etc., and do not use excessive force to prevent internal fistula anastomosis from tearing.

In summary, establishing the concept that hemodialysis access is the "lifeline" of hemodialysis patients, maintaining the normal function of internal fistula, improving long-term patency, and taking preventive measures or treatment for the above reasons can reduce the occurrence of hemodialysis access obstruction in patients with end-stage renal failure to a certain extent.