Of hemodialysis equipment and supplies

What to see

Dialysis machines

 A machine used in dialysis that filters a patient's blood to remove excess water and waste products when the kidneys are damaged,
dysfunctional, or missing. The dialysis machine itself can be thought of as an artificial kidney. Inside, it consists of more plastic tubing that carries the removed blood to the dialyser, a bundle of hollow fibers that forms a semipermeable membrane for filtering out impurities. In the dialyser, blood is diffused with a saline solution called dialysate, and the dialysate is in turn diffused with blood. When the filtration process is complete, the cleansed blood is returned to the patient. Most patients who undergo dialysis because of kidney impairment or failure use a dialysis machine at a dialysis clinic. Also, a machine called a peritoneal dialysis machine can be used chronically at home for dialysis, which eliminates the need for regular hemodialysis clinic treatments. Using this machine during the day and frequently during sleep, the patient can control his/her own dialysis.

 

dialysis catheter

A dialysis catheter is a catheter used for exchanging blood to and from the hemodialysis machine from the patient.
The dialysis catheter contains two lumens:

• Venous
• Arterial

This is a confusing terminology for layperson, because both lumens are in the vein. The arterial lumen (typically red) withdraws blood from the patient and carries it to dialysis machine, while the venous lumen (typically blue) returns blood to the patient (from the dialysis machine). Flow rates of dialysis catheters range between 200 to 500 ml/min.
If a patient requires long-term dialysis therapy, a chronic dialysis catheter will be inserted. Chronic catheters contain a dacron cuff that is tunneled beneath the skin approximately 3–8 cm. The tunnel is thought to add a barrier to infection. The most popular dialysis catheter sold on the market today is the split-tip dialysis catheter. This catheter comprises two free floating tips.

 

  

 

Dialysis fluid filters

 

The quality and purity of the dialysis fluid are of major concern in renal replacement therapies, as large volumes of dialysis fluid come into contact with the patient’s bloodstream during each treatment. This is particularly the case with online haemodiafiltration (HDF), in which large fluid volumes are exchanged. Thus, the use of ultrapure dialysis fluid free from bacterial endotoxins and other microbial contamination is crucial in preventing undesirable acute reactions and influencing long-term patient outcomes. In addition, it has been shown to improve the control of anaemia, making it an important cornerstone of cardioprotective haemodialysis.1 The routine production of ultrapure dialysis fluid and substitution fluid (defined as endotoxins <0.03 IU/mL) relies on the implementation of ultrafilters – such as the DIASAFE®plus filter – within the fluid pathway of the dialysis machine. DIASAFE®plus filters are fitted as standard in the 5008/5008S therapy system and 4008S Next Generation to ensure a high degree of dialysis fluid purity.

 

 

AV Fistula Needle Disposable Arterial Venous Fistula Needle Set
The product is composed of blood collection cannula, clamp, tubing, female luer lock connector. Fixed or rotating wing. ETO sterile. It is intended for use as a blood collection device for blood processing equipment or as a vascular access device for hemodialysis.

   

Bloodline

Bloodline systems with Luer Lock and Spike connector for single-needle, single-needle cross-over and double-needle therapy with Dialog or competitor machines.

Description

In the last years the dialysis therapy has focused more specifically on the clinical situation of patients with chronic renal failure, by promoting techniques and products designed as a global therapeutic system.
Under this perspective, dialysis bloodlines have a key importance both for aspects of biocompatibility and of treatment safety & efficiency.
Today machines can monitor the treatment through biosensors integrated with the single-use device.

 

The usage safety and the efficiency of bloodlines are compulsory to guarantee - together with the other components - the perfect performance of the dialysis treatment according to European standards and to nephrology guidelines.

Additionally, to the standard bloodline systems with Luer Lock, these systems already have a pre-assembled spike and a recirculation system (three-way cock, Discofix C). The system is qualified for the usage of seperate NaCl containers for priming, reinfusion and potential bolus injectionin cominbationwith the dialysis machines mentioned on the lable.

The spike enables the direct connection to the product series Ecoflac plus, NaCl 0,9% and sterile infusion solution.

All the components needed for applying the new Ecoprime system are already included in the pre-connected bloodline system.

  

 Water filters blood

 Water purification system 

Quick Water Guide as a Dialysis Technician: Water Guide Tips for Dialysis Technicians

Patrick Lim

October 10, 2014

Skills

A solute is the solid that is dissolved in a liquid. The solvent is the liquid in which something is dissolved in. Water is the most abundant solvent there is. It will dissolve almost any solid particle to some extent, in varying times. We get most of our water from rain. As rain water passes through the air toward our reservoirs, it picks up impurities like sulfur dioxide and carbon dioxide gases. Since water makes up about 90% of dialysate, its proper treatment used for hemodialysis prevents any complications for the patients. Providing safe water, which is one of the best water guide tips for dialysis technicians to learn, also prevents potential damage to our equipment.

 

Established in 1974, the “safe drinking water act” is rooted on an average daily intake of 2 liters, or approximately 14 liters of water per week. 14 liters of water, along with its associated contaminants, pass through people with healthy kidneys each week. Meanwhile, in the same week, patients undergoing 3-4 hour dialysis treatments are exposed to about 360 liters of water and all the contaminants it could possibly hold. A healthy person can effectively handle some of the contaminants in drinking water. Since healthy kidneys remove most of these contaminants, people with end-stage renal disease do not have that protection. To be safe, water used for dialysis should pass through a water treatment system. This system, comprising a series of devices, takes out specific contaminants.

Water Guide Tips for Dialysis Technicians #1: Know your local water source and the types of contaminants in your water source.

Thoroughly examining the local water source, the water, and its possible contaminants beforehand will help determine the needed pretreatment components. What contaminants will you need to remove from the water? Bear in mind that the recommended standards set by the Association for the Advancement of Medical Instrumentation (AAMI) for water used in Hemodialysis (RD52) are more detailed than drinking water standards. Only limited traces of elements, metals, salts, bacteria and fragments of dead bacteria are allowed, according to the guidelines. Generally, organic/inorganic chemical contaminants and microbial limits are periodically tested, usually once a month. The chart below lists the possible chemical contaminants present in water, their maximum allowable limits, and the symptoms patients may exhibit if contaminant levels are high.

Water Guide Tips for Dialysis Technicians #2: Pretreatment, water purification, and distribution are the three processes that make up the water treatment system for hemodialysis.

Each process of water treatment requires monitors in place to guarantee the safety for dialysis patients exposed to high volumes of water. These monitors provide alarms that alert staff members when contaminants in the water are too high for dialysis use. Periodic monitoring of water quality and temperature is very important if you want to keep your patients free from harm. Sampling of water to be tested are usually prescribed in intervals depending on the facility you work in. For instance, when testing for total chlorine, water samples are collected prior to first patient treatment and then every 4 hours. On the other hand, total water hardness, which could cause scaling of the membranes if too high, is collected at the end of each treatment day. Microbial cultures are tested at least once a month, inorganic chemical contaminants are tested once a year.

Water Guide Tips for Dialysis Technicians #3: Know the typical pretreatment components.

 

Water filter

 

 

 

 

 

 

What is Hemodialysis?

While healthy kidneys have several functions in the body, the most well-known job is to produce urine. When kidney function goes below 10% to 15% kidneys are no longer able to filter the blood and make urine. This causes toxins to build up in the body along with excess fluid. Fortunately, we live in a time when there are treatments and medicines that can replace the functions of the kidneys and keep the body alive. One type of renal replacement therapy — meaning a treatment that replaces kidney function — is hemodialysis. Hemodialysis is a therapy that filters waste, removes extra fluid and balances electrolytes (sodium, potassium, bicarbonate, chloride, calcium, magnesium and phosphate).

How is hemodialysis done?

In hemodialysis, blood is removed from the body and filtered through a man-made membrane called a dialyzer, or artificial kidney, and then the filtered blood is returned to the body. The average person has about 10 to 12 pints of blood; during dialysis only one pint (about two cups) is outside of the body at a time. To perform hemodialysis there needs to be an access created to get the blood from the body to the dialyzer and back to the body. There are three access types for hemodialysis: arteriovenous (AV) fistula, AV graft and central venous catheter. The AV fistula is the vascular access most recommended by the dialysis community; however, you and your doctor will decide which access is best for you.
When a patient goes to hemodialysis, a nurse or technician will check vital signs and get the patient’s weight. The weight gain will tell how much excess fluid the patient has to have removed during the treatment. The patient is then “put on the machine”. Patient with a vascular access (AV fistula or AV graft) will get two needle sticks in their access; one needle takes blood out of the body, the other needle puts it back. Patients with a central venous catheter will have the two tubes from their access connected to the blood tubes that lead to the dialyzer and back to the body. Once the patient is “put on the machine”, the dialysis machine is programmed and then treatment begins.
Blood never actually goes through the dialysis machine. The dialysis machine is like a big computer and a pump. It keeps track of blood flow, blood pressure, how much fluid is removed and other vital information. It mixes the dialysate, or dialysis solution, which is the fluid bath that goes into the dialyzer. This fluid helps pull toxins from the blood, and then the bath goes down the drain. The dialysis machine has a blood pump that keeps the blood flowing by creating a pumping action on the blood tubes that carry the blood from the body to the dialyzer and back to the body. The dialysis machine also has many safety detection features. If you visit a dialysis center, you will likely hear some of the warning sounds made by a dialysis machine.

How does hemodialysis work?

The dialyzer is the key to hemodialysis. The dialyzer is called the artificial kidney because it filters the blood — a job the kidneys used to do. The dialyzer is a hollow plastic tube about a foot long and three inches in diameter that contains many tiny filters. (Dialyzers are made in different sizes so doctors can prescribe the best one for their patients.) There are two sections in the dialyzer; the section for dialysate and the section for the blood. The two sections are divided by a semipermeable membrane so that they don’t mix together. A semipermeable membrane has microscopic holes that allow only some substances to cross the membrane. Because it is semipermeable, the membrane allows water and waste to pass through, but does not allow blood cells to pass through.
Dialysate, also called dialysis fluid, dialysis solution or bath, is a solution of pure water, electrolytes and salts, such as bicarbonate and sodium. The purpose of dialysate is to pull toxins from the blood into the dialysate. The way this works is through a process called diffusion. In the blood of the hemodialysis patient, there is a high concentration of waste, while the dialysate has a low concentration of waste. Due to the difference in concentration, the waste will move through the semipermeable membrane to create an equal amount on both sides. The dialysis solution is then flushed down the drain along with the waste. The electrolytes in the dialysis solution are also used to balance the electrolytes in the patient’s blood. The extra fluid is removed through a process called filtration. The fluid is pushed off by higher pressure on the blood side than on the dialysate side.

How often is hemodialysis done?

Blood needs to flow through the dialyzer for several hours to adequately clean the blood and rid the body of excess fluid. Traditional, in-center hemodialysis is generally done three times a week for about four hours each session. Your doctor will prescribe how long your treatments will be, usually between 3 to 5 hours, but most common is 4 hours. Talk to your doctor about how long you should be on hemodialysis. Some people feel that dialysis lasts a long time; however, healthy kidneys work 24 hours a day, 7 days a week and dialysis must do the job in only 12 or so hours a week.
Alternative hemodialysis schedules include nocturnal and short daily. Normally, these treatments are performed by people who do home hemodialysis. With nocturnal hemodialysis, the patient has dialysis for about eight hours overnight while sleeping. This is a longer, gentler treatment so patients say they have fewer problems with cramping and the “washed out” feeling reported after traditional hemodialysis. More dialysis centers are beginning to offer in-center nocturnal hemodialysis based on reports of patients feeling better about their quality of life and having good lab results. Short daily hemodialysis is performed five or six times per week for about two to three hours each treatment. Talk to your doctor if you are interested in home hemodialysis or in-center nocturnal dialysis. You may want to ask your social worker if addition treatments, such as the longer nocturnal hemodialysis and short daily hemodialysis will be covered through your insurance.

Advantages and disadvantages of hemodialysis

Hemodialysis is an effective treatment for those with end stage renal disease. However, hemodialysis alone will not provide a complete treatment for those with kidney failure. Diet and fluid restrictions need to be followed, and medicines may need to be taken to replace other functions of the kidneys, such as regulating blood pressure and stimulating production of red blood cells to prevent anemia.
For those who choose in-center hemodialysis, some of the benefits are that they will have their treatments performed in a dialysis center by trained professionals. They can spend their time in dialysis sleeping, reading, writing, watching television, listening to music or doing other quiet activities. There are four days a week when they will not have to go to dialysis. Some of the disadvantages are that they will have to travel to and from hemodialysis three times each week and it takes advanced notice to travel and arrange for dialysis in a visiting dialysis center. The diet restrictions include limiting foods that contain phosphorus,potassium and sodium and drinking a limited amount of fluid. Some people report a “washed out” feeling after hemodialysis and go home to take a nap. Those who perform nocturnal hemodialysis (in center or at home) report that this washed out feeling is not as common. Also, because nocturnal dialysis is performed during nonproductive sleeping hours, many people report they feel that their lives are more “normal” because they don’t have to take time out of their days for dialysis.
People who choose to perform hemodialysis at home say they enjoy the feeling of control they have over their lives. Instead of going to the dialysis center at a certain time, they can choose when to perform hemodialysis around their schedule.
There is another type of dialysis called peritoneal dialysis (PD). PD is done by filling the peritoneum in the abdomen with dialysate and using the peritoneal membrane as a semipermeable membrane. There are diet and fluid restrictions with peritoneal dialysis; however, these are usually not as limited as hemodialysis because this therapy is performed every day. PD treatments are performed at home, and so do not require three visits to a treatment center each week. Peritoneal dialysis also has a nighttime treatment option that makes it easier for patients to work, attend school or travel.
All dialysis treatments have their advantages and disadvantages. Based on your lifestyle and medical needs, you and your doctor can discuss your options and decide which one is right for you.

How Does a Dialysis Machine Work?

By Joe S., DaVita Bio-medical Technician

Dialysis patients are all too familiar with the routine of their treatments:  Go to the clinic, get weighed, have their temperature and blood pressure taken, get stuck with needles (unless the patient has a catheter access), have tubes connected from their access to the dialyzer and then sit in the chair until it is time to go home. While waiting, have you ever wondered how a dialysis machine works?

As “the machine man,” I would like to take this opportunity to explain how your dialysis machine works by answering some of the most frequently asked questions.

What does my dialysis machine do?

The dialysis machine mixes and monitors the dialysate. Dialysate is the fluid that helps remove the unwanted waste products from your blood. It also helps get your electrolytes and minerals to their proper levels in your body. The machine also monitors the flow of your blood while it is outside of your body. You may hear an alarm go off from time to time. This is how the machine lets us know that something needs to be checked.

What are those plastic jugs sitting in front of my machine? 

The plastic jugs hold the liquids used to mix the dialysate. The machine mixes the dialysate, which is made up of an acidified solution, bicarbonate and purified water. The acidified solution contains electrolytes and minerals. You may hear it referred to as “acid.” The other solution is bicarbonate or bicarb, which is like baking soda. Both are mixed inside the machine with purified water. While you are dialyzing, dialysate and your blood flow through the dialyzer (but they never touch). Fresh dialysate from the machine enters your dialyzer throughout your treatment. Impurities are filtered out of your blood into the dialysate. Dialysate containing unwanted waste products and excess electrolytes leave the dialyzer and are washed down the drain.

How does my blood get in and out of my body? 

Blood tubing carries your blood from your access to the dialyzer. The blood tubing is threaded through the blood pump. You’ll see the blood pump turning in a circular motion. The pumping action of the blood pump pushes your blood through the dialyzer and back into your body.

What’s in the syringe that’s attached to my machine?

Blood tends to clot when it moves through the blood tubing. To prevent this the nurse will give you a drug called “heparin.” Your doctor orders the amount of heparin you get at each treatment. That amount of heparin is drawn up into a syringe then placed on the machine into the “heparin pump.” The heparin pump is programmed to release the right amount of heparin into your blood tubing during your treatment. The heparin prevents your blood from clotting.

How does the machine keep me safe?  

One problem that may occur during dialysis is that air gets into the blood tubing. To prevent this from happening, blood tubings have two air traps built into them. One trap is before the dialyzer and the other is after it. These traps catch any air that may get into the system. If air does get past these traps an internal machine air sensor shuts down the blood pump and an alarm will sound. All blood flow is stopped until the air is removed.

Why are there so many alarms? 

The machine continuously monitors the pressures created by your blood inside the blood tubing and dialyzer. It also monitors the blood flow, temperature and proper mixture of the dialysate. If any of these go out of range, the machine lets us know by sounding an alarm, blinking lights and shutting down blood or dialysate flow. It also lets us know if your blood pressure is too low or high. Oh yes, it also alarms when it’s time to go home.

Want to know more?

I realize that this may not answer all of your questions. That’s why I invite you to ask the bio-medical technician (machine person) at your dialysis center any questions you have. Your bio-medical technician will be happy to share any information with you. The more you know, the more comfortable you will be with your treatments.

Hemodialysis

Hemodialysis                                

(Intermittent Hemodialysis)

In hemodialysis, a patient’s blood is pumped into a dialyzer containing 2 fluid compartments configured as bundles of hollow fiber capillary tubes or as parallel, sandwiched sheets of semipermeable membranes. In either configuration, blood in the first compartment is pumped along one side of a semipermeable membrane while a crystalloid solution (dialysate) is pumped along the other side, in a separate compartment, in the opposite direction. Concentration gradients of solute between blood and dialysate lead to desired changes in the patient’s serum solutes, such as a reduction in urea nitrogen and creatinine; an increase in HCO ₃ ; and equilibration of Na, Cl, K, and Mg. The dialysate compartment is under negative pressure relative to the blood compartment and has a higher osmolality to prevent filtration of dialysate into the bloodstream and to remove the excess fluid from the patient. The dialyzed blood is then returned to the patient.

 

The patient is usually systemically anticoagulated during hemodialysis to prevent blood from clotting in the dialysis machine. However, hemodialysis treatment may also be done with regional anticoagulation of the dialysis circuit (using heparin or trisodium citrate) or with saline flush, in which 50 to 100 mL of saline every 15 to 30 min clears the dialysis circuit of any blood clots.

The immediate objectives of hemodialysis are to correct electrolyte and fluid imbalances and remove toxins. Longer term objectives in patients with renal failure are to

• Optimize the patient’s functional status, comfort, and BP
• Prevent complications of uremia
• Prolong survival

The optimal “dose” of hemodialysis is uncertain, but most patients do well with 3 to 5 h of hemodialysis 3 times/wk. One way to assess the adequacy of each session is by measuring BUN before and after each session. A ≥ 65% decrease of BUN from predialysis level ([predialysis BUN − postdialysis BUN]/predialysis BUN × 100% is ≥ 65%) indicates an adequate session. Specialists may use other, more calculation-intensive formulas, such as KT/V ≥ 1.2 (where K is the urea clearance of the dialyzer in mL/min, T is dialysis time in minutes, and V is volume of distribution of urea [which is about equal to total body water] in mL). Hemodialysis dose can be increased by increasing time on dialysis, blood flow, membrane surface area, and membrane porosity. Nightly hemodialysis sessions (6 to 8 h, 5 to 6 days/wk) and short (1.5 to 2.5 h) daily sessions, when available, are used selectively for patients who have any of the following:

Clinical Calculator: Urea Reduction Percentage in Hemodialysis (PRU)            

    

Clinical Calculator: Volume of Distribution of Urea            

Clinical Calculator: Kt/V Dialysis Dose Formulae MultiCalc            

• Excessive fluid gain between dialysis sessions
• Frequent hypotension during dialysis
• Poorly controlled BP  

Hyperphosphatemia that is otherwise difficult to control

These daily sessions are most economically feasible if patients can do hemodialysis at home.

 

Vascular access                        

Hemodialysis is usually done through a surgically created arteriovenous fistula. However, dialysis can be done through a central vein catheter 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 wk 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 (50% functional at 1 yr) and may be useful for patients in whom creation of an arteriovenous fistula is impossible.

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 3 to 6 mo to mature and become usable, so in patients with chronic kidney disease, the fistula is best created at least 6 mo 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.

Vascular access complications

Complications such as infection, stenosis, thrombosis (often in a stenotic passage), and pseudoaneurysm or aneurysm, 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.

The fistula may be monitored for signs of impending failure by serial Doppler dilution blood flow measurements, thermal or urea dilution techniques, or by measurement of the static venous chamber pressures. One of these tests is usually recommended at least monthly. Treatment of stenosis, thrombosis, pseudoaneurysm, or aneurysm may involve angioplasty, stenting, or surgery.

Dialysis complications

Complications are listed in Complications of Renal Replacement Therapy.

Hypotension is most common and 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).

Many patients also have restless leg syndrome, cramps, pruritus, nausea and vomiting, headache, and chest and back pain. In most cases, these complications occur for unknown reasons, but some may be part of a first-use syndrome (when the patient’s blood is exposed to cuprophane or cellulose membranes in the dialyzer) or dialysis dysequilibrium syndrome, a syndrome thought to be caused by too rapid removal of urea and other osmolytes from the serum, causing osmotic movement of fluid into the brain. More severe cases of dialysis dysequilibrium manifest as disorientation, restlessness, blurred vision, confusion, seizures, and even death.

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 ß ₂ -microglobulin (the protein causing the amyloidosis) is removed more effectively with these dialyzers.

 

 Prognosis                          

Overall adjusted annual mortality in hemodialysis-dependent patients tends to be about 20%. The 5-yr 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. Blacks have usually had a higher survival rate in all age groups. Nonhemodialysis contributors to mortality include comorbidities (eg, hyperparathyroidism, diabetes, undernutrition, other chronic disorders), older age, and late referral for dialysis.

Last full review/revision July 2014 by James I. McMillan, MD