Hemodialysis

In-center hemodialysis is the most common type of hemodialysis in the United States. Most treatments are done 3 times a week for 3 to 5 hours per session. The main advantage of in-center hemodialysis is that the dialysis staff fully controls the dialysis treatment. The dialysis technician cannulates the fistula, decides how much fluid to remove, and does the entire dialysis treatment under the supervision of the dialysis nurse and the nephrologist.

In-center nocturnal hemodialysis is done 3 times a week for 6 to 8 hours per session. This modality is most suitable for patients who have high fluid gains, low blood pressure, or difficult-to-control phosphorus. It is also attractive for those who work during the day but who do not want to do home dialysis.

Home hemodialysis is as viable as in-center hemodialysis. Patients treated with home hemodialysis have longer survival and better control of hypertension, phosphorus and fluid levels, and better quality of life than with in-center hemodialysis. Home hemodialysis is most commonly done 5 to 7 days a week for about 2 hours per session. However, home hemodialysis can also be done on a 3-times-per-week daytime schedule or on a nocturnal schedule. Most home hemodialysis programs require a care partner capable of helping in case help is needed. As with peritoneal dialysis, home hemodialysis requires more patient involvement than in-center hemodialysis.

• Surgically created arteriovenous fistula (preferred)

• Central vein catheter

Hemodialysis is usually done through a surgically created arteriovenous fistula.

Surgically created arteriovenous fistulas are better than central venous catheters because they are more durable and less likely to become infected. But they are also prone to complications (thrombosis, infection, aneurysm, or pseudoaneurysm). A newly created fistula may take 2 to 3 months to mature and become usable. However, additional time may be needed for fistula revision, so in patients with chronic kidney disease, the fistula is best created at least 6 months before the anticipated need for dialysis. The surgical procedure anastomoses the radial, brachial, or femoral artery to an adjacent vein in an end-of-the-vein to the side-of-the-artery fashion. When the adjacent vein is not suitable for access creation, a piece of prosthetic graft is used. For patients who have poor veins, an autogenous saphenous vein graft is also an option.

A central vein catheter can be used for dialysis if an arteriovenous fistula has not yet been created or is not ready for use or if creation of an arteriovenous fistula is impossible. The primary disadvantages of central vein catheters are a relatively narrow caliber that does not allow for blood flow high enough to achieve optimal clearance and a high risk of catheter-site infection and thrombosis. Central venous catheterization for hemodialysis is best done by using the right internal jugular vein. Most internal jugular vein catheters remain useful for 2 to 6 weeks if strict aseptic skin care is practiced and if the catheter is used only for hemodialysis. Catheters with a subcutaneous tunnel and fabric cuff have a longer life span (29 to 91% functional at 1 year) and may be useful for patients in whom creation of an arteriovenous fistula is impossible.

Complications of vascular access include

• Infection

• Stenosis

• Thrombosis (often in a stenotic passage)

• Aneurysm or pseudoaneurysm

These complications significantly limit the quality of hemodialysis that can be delivered, increase long-term morbidity and mortality, and are common enough that patients and practitioners should be vigilant for suggestive changes. These changes include pain, edema, erythema, breaks in the skin overlying the access, absence of bruit and pulse in the access, hematoma around the access, and prolonged bleeding from the dialysis cannula puncture site. Infection is treated with antibiotics, surgery, or both.

Complications are listed in table Complications of Renal Replacement Therapy.

The most common complication of dialysis is

• Hypotension

Hypotension has multiple causes, including too-rapid water removal, osmotic fluid shifts across cell membranes, acetate in the dialysate, heat-related vasodilation, allergic reactions, sepsis, and underlying conditions (eg, autonomic neuropathy, cardiomyopathy with poor ejection fraction, myocardial ischemia, arrhythmias).

Other frequent complications include

• Restless legs syndrome

• Cramps

• Pruritus

• Nausea and vomiting

• Headache

• Chest and back pain

Dialysis-related amyloidosis affects patients who have been on hemodialysis for years and manifests as carpal tunnel syndrome, bone cysts, arthritis, and cervical spondyloarthropathy. Dialysis-related amyloidosis is believed to be less common with the high-flux dialyzers in wide use today because beta-2 microglobulin (the protein causing the amyloidosis) is removed more effectively with these dialyzers.

Overall adjusted annual mortality in hemodialysis-dependent patients is about 16%. The 5-year survival rate is lower for patients with diabetes than for patients with glomerulonephritis. Death is generally mostly attributable to cardiovascular disease, followed by infection and withdrawal from hemodialysis. Nonhemodialysis contributors to mortality include comorbidities (eg, hyperparathyroidism, diabetes, undernutrition, other chronic disorders), older age, and late referral for dialysis.