Everything you need to know

How it works!

Hemodialysis functions the same way that your kidneys would by removing toxic waste from the blood as well as excess water from the body. Blood will be filtered from the body into a machine, where all the toxins are removed and then brought back into the body. The machine that filters the blood has two parts to it, one side for the blood the other side for the dialysate. Then there is a thin semi-permeable membrane that separates the two fluids.
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Time Requirements

Most patients require about 9-12 hours a week of dialysis, broken up into 3-4 different trips to the dialysis center. Finding a job that will work around schedules is something that will be difficult for patients. Hemodialysis requires patients to be there for every single appointment, this can add a lot of stress to a patient or a family.


The toxins are removed through a process called diffusion. This means that all the harmful particles will move from an area of higher concentration in the blood to an area of lower concentration in the blood. So in the machine the toxins will pass through the semi-permeable membrane and be filtered out in the dialysate. Dialysate is a fluid that is used on the other side of the membrane to help filter out toxins from the blood. The blood cells will never pass into the dialysate because they are too large to pass through the membrane.

Excess Water

Excess water builds up in the body because they kidneys do not work to filter out the water like they used to. The excess water is also removed in the hemodialysis process through osmosis. The water will move from an area of higher concentration in the blood to lower concentration in the dialysate.

Vascular Access

In order for hemodialysis to work there needs to be vascular access for blood to be removed. The most common way for this to happen is an arteriovenous fistula, this is a permanent access site. It is a site that is surgically made by joining an artery with a vein, which allows for rapid removal and return of the blood. After the site is created it takes about 14 days for it to heal. The patient needs to do exercises to help the access site to mature and for the vessels to grow larger.
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Taking care of your fistula

It is important that each day the patient checks for a thrill, which is a vibrating or buzzing sensation over the fistula. If a thrill is absent it is vital that the patient calls the health care provider or dialysis center immediately. The patient needs to avoid compression of the site, not permitting blood to be drawn, an IV to be inserted, or blood pressure to be taken on the extremity with the dialysis access. It is also important to not wear tight clothing, carry bags or purses on that side, and to not sleep on that side. Each day the site needs to be inspected by the patient and the nurse for redness, swelling, bleeding, drainage, heat, or pain and report them immediately to a health care provider if a symptom is present.

Safety Considerations

Infection is the second leading cause of death in dialysis patients. It is important that dialysis patients keep their fistula clean. Hand hygiene is also an important factor in keeping patients from getting infections. It is recommended that patients get prophylactic antibiotics to prevent the occurrence of infections. Because patients on hemodialysis have weakened immune systems extra precautions should be taken to help keep the patient healthy.

Daily lifestyle changes should also be made when on hemodialysis. Smoking contributes to the progression of kidney failure. The consumption of alcohol should also be limited or prohibited because this can cause complications with dialysis and the body.

During the hemodialysis process the nurse will be assessing vital signs, and the overall condition of the patient. The nurse will also assess the vascular site for the presence of a thrill. The nurse will also be recording weight, they do this so they can keep track of how much water the patient is retaining. During hemodialysis the nurse will also keep watch of the machine to make sure that everything is running correctly. The nurse will also assess lab values before and after treatment.

Safety in the Dialysis Facility | ESRD NCC


Because the kidneys do not work properly diet and fluid restriction is key. Soon after a patient starts hemodialysis they require a few dietary restrictions such as protein, sodium, potassium, phosphorus, and fluid. Proteins that are consumed have to be high quality proteins like eggs, soy, meat, milk, poultry, and fish. This will help prevent poor nutrition. The ideal protein intake is about 1.2 to 1.3 g/kg/day. Sodium is restricted to about 2 to 3 grams per day. Fluids are restricted t an amount that is equal to urine output plus about 500 to 800 mL/day to replace insensible loss like sweating.

If these diet changes are ignored life threatening things can occur like hyperkalemia (elevated potassium), hypertension (high blood pressure), and pulmonary edema.


Since most of the medications are excreted through the kidneys they may need some adjusting from your primary care provider. Many of these medications will be excreted through the dialysis process however some of the medications will need to be adjusted. Many medications also need to be held until the patient goes through hemodialysis. Medications like antihypertensives can cause dangerously low blood pressure if they are given before hemodialysis.

During dialysis an anticoagulant heparin is administered to help keep the blood from clotting. This allows the blood to be thinner and filter through the dialysis machine easier.



Life Threatening Emergencies in the Renal Failure and Dialysis Patient. (n.d.). Retrieved April 2, 2016, from file:///C:/Users/Kayla Merrill/Downloads/hemodialysis emergencies-2011.pdf

Pellico, L. H. (2013). Focus on adult health: Medical-surgical nursing. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins.

Dietary Guidelines for Adults Starting on Hemodialysis. (2015). Retrieved April 02, 2016, from https://www.kidney.org/atoz/content/dietary_hemodialysis

Dietary Guidelines for Adults Starting on Hemodialysis. (2015). Retrieved April 03, 2016, from https://www.kidney.org/atoz/content/dietary_hemodialysis