Patients on hemodialysis are often surprised to learn that the complex dialysis machine next to them on the dialysis floor isn’t the device that’s cleaning their blood of excess wastes and fluid. Instead, a filter, called a dialyzer that is about a foot long, encased in plastic and inserted into a holder on the front or side of the dialysis machine, is actually doing the work of cleaning the blood. The dialysis machine supports the work of the dialyzer with pumps, heaters, safety monitors and alarms.
Dialyzer reuse has been practiced in the United States since the early 1960s. Patients who choose to reuse their dialyzers are given an individual dialyzer that they will continue to use for the number of times specified by their doctor or until it is no longer efficient. Patients do not “share” dialyzers; each patient has his or her own.
A dialyzer is often referred to as an “artificial kidney.” Its function is to remove the excess wastes and fluid from the blood, when the patient’s kidneys can no longer perform that task.
Dialyzers are made of a thin, fibrous material. The fibers form a semipermeable membrane, which allows smaller particles and liquids to pass through. The dialyzer is encased in a sealed plastic cylinder about a foot long and approximately two to three inches in diameter with openings at the top and bottom. During treatment dialysate (dialysis solution) and your blood flow through the dialyzer (but they never touch). Fresh dialysate from the machine enters your dialyzer through one opening and blood enters through the other. Wastes are filtered out of your blood into the dialysate. Dialysate containing waste products leaves the dialyzer and is washed down the drain, while the cleaned blood goes back into your body.
There are different sizes of dialyzers. These sizes are related to the blood volume that will go through them, which depends on the patient's size and weight. Your kidney doctor will prescribe the right-sized dialyzer for you.
Dialyzers can remain functional after more than one use, which is why many facilities reuse them. Dialyzers are reused for a certain number of times or until it no longer works efficiently, whichever comes first. Each doctor sets his or her own policy for the maximum number of reuses. Some dialysis facilities do not reuse dialyzers, and patients at those facilities are given new dialyzers for each hemodialysis session.
Patients are given the choice of whether or not to reuse their dialyzers. Facilities that reuse must follow strict guidelines to ensure the reused dialyzers are labeled with the patient’s name, cleaned properly, sterilized and working so the patient can have an optimal dialysis treatment.
Patients only reuse their own dialyzer, meaning that no other patient has or will ever use it. Dialyzers are never shared between patients. After your dialysis session is complete, a facility member (either your renal nurse or a patient care technician) will take you off the dialysis machine and seal your dialyzer, which is labeled with your name, in a plastic bag. The dialyzer is then sent to a reuse technician who will follow strict procedures to make sure your dialyzer is clean, sterile and in good working condition before you use it again.
The reuse technician will first do a visual inspection of the dialyzer for blood or fiber clots. The technician will also note the number of times the dialyzer has been used. If the dialyzer is due to be replaced, the technician will replace it with a new one in the size prescribed by the physician. If the dialyzer can be reused, the technician will place it into the reuse machine to start the cleaning process.
The reuse machine cleans the dialyzer using water treated with reverse osmosis. This water is highly purified and cleans the dialyzer without leaving traces of particles and chemicals. After cleaning, the machine performs a pressure test and blood volume test. The pressure test checks for any holes in the dialyzer. The blood volume test ensures that the dialyzer’s capacity is above 80% of the dialyzer’s stated size. If there are any holes in the dialyzer, or if the blood volume is less than 80% of the dialyzer’s size, it is replaced with a new one. If any problems are detected during the reuse test, the reuse machine indicators let the reuse technician know, and the dialyzer is disposed of in the proper manner.
After the reuse machine has cleaned and tested the dialyzer, it will then be filled with disinfectant and stored for at least 11 hours. Just before the patient’s next dialysis treatment, the dialyzer is rinsed with saline solution until all disinfectant is removed. A test is performed to make sure no disinfectant is left in the dialyzer. Once it is tested, the dialyzer is ready to use for the dialysis treatment.
Various studies have examined the issue of reuse. These studies have found that the mortality rate between patients who reuse dialyzers and patients who do not was the same.
Dialysis facilities that reuse dialyzers must follow strict guidelines set forth by the Association for the Advancement of Medical Instrumentation (AAMI). The AAMI guidelines make provisions for patient safety, among them:
Different factors can affect your Kt/V and URR (urea reduction ratio), standard measures of how effective your dialysis treatments are. Although reuse may affect Kt/V and URR levels, following the correct standards of reuse for monitoring fiber volumes and testing the reuse dialyzers makes this a rare issue. If you are on reuse and are concerned about your Kt/V or URR levels, talk to your renal nurse and your kidney doctor.
Reuse can be helpful to the patient and to the planet.
Patient advantages of reuse Since each dialyzer is inspected by a reuse technician, the technician can note any blood clots in the dialyzer and alert a renal nurse. Blood clots could mean you are not getting enough heparin, which is a medicine given before and throughout hemodialysis. Heparin thins the blood to allow it to pass easily through the dialyzer and prevent it from clotting, which would reduce the dialyzer’s ability to remove wastes and fluid. Blood clots in the dialyzer may make your dialysis session less effective and can lower your Kt/V.
Environmental advantages of reuse Dialyzer reuse helps to reduce negative environmental consequences in several ways. On average, it only takes 9.6 reuse dialyzers to treat one patient for one year, versus an average of 153 single-use dialyzers. The reuse of all dialyzers in a single year would eliminate the production of up to 46 million dialyzers and reduce the amount of medical waste ending up in landfills by more than 62 million pounds.
Dialyzer reuse also reduces the amount of harmful toxins created by waste processing. In order to be properly disposed of, dialyzers first have to go through a decontamination process requiring they either be incinerated or microwaved before being sent to landfills. When dialyzers are incinerated, the process produces emissions and ash that have negative health effects on the surrounding communities. While the microwave process does not produce harmful toxins, it does nothing to reduce the amount of medical waste that ends up in landfills.
By choosing dialyzer reuse, you can dramatically reduce the negative impact on the environment. Dialyzer reuse reduces your carbon footprint, helps relieve America of its dependence on crude oil, sends less non-biodegradable waste to landfills and ultimately benefits the dialysis patient by keeping costs lower without compromising clinical outcomes.
If proper procedures are followed for inspecting, cleaning and disinfecting your dialyzer, you should have no problems. If the reuse procedure is not followed properly you may have problems with your Kt/V levels or a physical reaction. However, these problems are rare, and because you are being closely monitored during treatment, if these issues arise, they can be resolved quickly.
Patients are always given the option of using single-use dialyzers for their treatment sessions. If you feel more comfortable using your dialyzer only once, your dialysis facility will be able to accommodate you.
Hepatitis B will prevent you from reusing your dialyzer. Patients diagnosed with this condition will be given single-use dialyzers. There may be other situations when a doctor may prescribe a single-use dialyzer. Whether you should use single-use or a reuse dialyzer is a decision made by your kidney doctor and you.
If your facility is a single-use facility, it may not have the means to accommodate reuse. You will need to be referred to a different dialysis facility if you wish to reuse.
Many patients ask to see their dialyzer before treatment. By looking at your dialyzer, you can verify several important things:
Patients should also monitor their reactions during dialysis. Any discomfort you may feel should be discussed with your patient care technician and your dialysis nurse.
You should also be aware of your Kt/V and URR levels. If they fall below an acceptable range, this may mean your dialysis sessions are not as effective at removing the toxins from your blood. Although it’s rare, an inefficient dialyzer may be the problem. However, there are other reasons that should be looked into as well. Discuss your levels with the health care team at your dialysis facility and your kidney doctor to find a solution to achieving more effective treatments.
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