Identifying common hemodialysis access complications

Complications related to vascular access sites decrease the efficiency of hemodialysis and can even interrupt it altogether. In this video, from our Dialysis Essentials course, we'll explore some of the common, non-infectious vascular access complications that are associated with hemodialysis, and how to resolve them.

Understanding dialysis doesn't need to be difficult. This course will take you from being a dialysis novice to a dialysis master in no time! In our Dialysis Essentials course, you’ll learn about the different dialysis modalities, the components of a dialysis prescription, the common complications, and how to resolve them. Whether you want to become a dialysis expert, or simply be able to speak confidently to a nephrologist about patient treatment, this course is for you.

Common noninfectious vascular access complications in hemodialysis

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All vascular access types suffer wear and tear from use. Complications related to vascular access sites decrease the efficiency of hemodialysis and can even interrupt it altogether. In this lesson, we'll explore some of the common noninfectious vascular access complications associated with hemodialysis. Let's start with failure of the fistula to mature.

Failure of an arteriovenous fistula to mature

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Fistulas have greater longevity, lower ongoing cost, and reduced risk of mechanical complications compared to grafts. However, fistulas must mature, meaning that the vein must dilate before this type of access can be used. A fistula that has poor flow at the first postoperative visit, usually one to two weeks after creation, needs a careful assessment by imaging to diagnose the problem. Revision of the access site might be required. 

Dialysis access inflow and outflow problems

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Complications can also arise from problems with the blood flowing into the access, the inflow, or with the blood flowing back to the heart, the outflow. Stenosis might become apparent at places where the patient had previous venipunctures. The presence of poor pulse augmentation within the access can indicate an inflow problem.

Signs of outflow stenosis and collateral vein complications

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Outflow problems might be evidenced by extremity edema, indicating central vein obstruction, fistula hyperpulsatility, and lack of fistula collapse when raising the extremity. While on dialysis, abnormalities in direct flow measurements, or inflow-outflow pressures, may signal a problem. If there are multiple collateral branches in a vein draining the fistula, then these branches siphon off the increased venous flow, thereby lessening the fistula pressure that induces maturation. Treatment would be ligation of collateral branches.

Persistent or delayed dialysis access site bleeding

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Patients are sometimes sent to the emergency department from the dialysis center with persistent or delayed access site bleeding. This usually occurs due to the needle punctures during hemodialysis or can result from skin erosion overlying the access. In that case, you need to consider an access infection. If limited to a needle puncture, direct pressure over the site will usually stop the bleeding. If the bleeding cannot be stopped, a suture may be sufficient, but the underlying cause for the prolonged bleeding should be investigated. 

Dialysis access outflow stenosis and recirculation

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Usually, an access has low-resistance venous outflow, but this may be altered by outflow stenosis or obstruction. Elevated outflow venous pressures would predispose to access site bleeding by causing increased back pressure. Outflow stenosis can also lead to recirculation, or cleaning the same blood over and over instead of efficiently cleaning all the blood. This is indicated by the presence of hyperkalemia or poor dialysis adequacy measures. 

Fistulogram imaging and treatment

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A fistulogram is an X-ray procedure to look at the blood flow and check for blood clots or other blockages in the fistula. Contrast dye is used so the blood flow can be seen on X-ray. A fistulogram can be diagnostic and therapeutic, since you can perform angioplasty, stent placement, or thrombectomy during the procedure once the cause for the access dysfunction is diagnosed. Thrombosis of the fistula can occur soon after its construction or as a late complication. Patients should be taught to monitor their fistula daily.

How to diagnose early dialysis access thrombosis

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The diagnosis is made by the loss of a palpable pulse, thrill, bruit, or aspiration of a clot when the site is punctured. Early thrombosis usually occurs from technical factors and almost always requires surgical revision, but can also be caused by inadvertent compression, such as during sleep. For grafts, the entire access should be thoroughly evaluated by imaging.

Causes and treatment of thrombosed fistulas and grafts

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Poor flow, such as caused by stenosis, usually precedes late thrombosis, but hypotension or hypercoagulability may also precipitate thrombosis. It is important to recognize a thrombosed access quickly so the patient can be seen and treated. Treatment for thrombosed fistulas and grafts typically involves either surgical thrombectomy or balloon angioplasty. It should be performed urgently to avoid the need for temporary access with a catheter.

Managing a dialysis access hematoma

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The incidence of hematomas in dialysis patients can be up to 0.2 per patient-year. In a newly mature dialysis access, posterior wall punctures might occur, leading to hematomas. Bleeding will usually stop with pressure, and the extravasated blood will diffuse into local tissue planes. These are usually reabsorbed and can be observed until they have resolved. Some units have instructions for patients to ice the hematoma for 10 minutes every hour while awake until the next session. During the next session, the dialysis technician will have to avoid the hematoma and use other areas along the fistula or graft for needle puncture until the hematoma has resolved.