Haemodialysis
What is haemodialysis, and how does it work?
Haemodialysis works in a couple of ways:
· Dialysis – The body’s high waste travels across the dialysis membrane and washed away
· The body’s fluid is also pushed through the dialysis membrane. This removes water, as well as washing more waste along with it
How long will each haemodialysis treatment last and how often? Can I continue to work while on haemodialysis?
Each session lasts 4 to 5 hours. Time is the most important determinant of how effective dialysis is. The patient needs to also consider travel time to and from the dialysis unit. Some of my patients travel 2 hours return. Three sessions a week is standard practice. Therefore haemodialysis is like a part time job.
This has impacts on a person’s life. I have some patients that continue to work. Their employer understands the changes that they are going through. I have other patients who bring their laptop with them and continue to work while hooked up to the machine.
In some circumstances we are able to offer haemodialysis at the patient’s home. This way, they are free during the day. At night they then dialyse themselves. They therefore have to be highly motivated, have good dexterity (to insert the needles themselves) and problem solving skills. The home set up must be suitable and be connected to a clean water supply. They should also have someone else with them at home to call for back up.
In addition, intensive contact with your kidney specialist will be required. This is especially important when starting dialysis to ensure it is running smoothly. As my patients stabilise, I catch up with them every 3 months. In addition, I have a look at my patients’ labs every month in case I need to adjust parathyroid and anaemia medications.
What are the potential side effects of haemodialysis?
As my nurse puts it, dialysis is not a walk in the park.
The most common side effects of dialysis are:
· Low blood pressure – This occurs because of the fluid shifts during dialysis. Fluid is taken off your body, which can cause low blood pressure. Symptoms may include dizziness, yawning, cramps or nausea. It is most common in older patients, those with diabetes, and coronary artery disease. Our nurses can change the dialysis program to change the amount of fluid removed.
· Arrhythmias – The body needs to support itself as well as the dialysis machine. This additional stress can affect the heart. Symptoms may include dizziness, shortness or breath, palpitations or chest pain.
· Cramps, nausea, headache – The removal of toxins and fluid can cause a person to feel unwell. Some patients feel much better after dialysis. However there are many who feel tired after their dialysis sessions until the next day.
In addition, people on dialysis need to monitor other aspects of their health. These include mood, sleep, sexual wellbeing, diet and fluid restrictions, and medications.
What should I eat and drink while on haemodialysis?
Eating large meals during dialysis causes low blood pressure. This is because the blood flow gets redistributed to the gut in order to digest the food. I suggest eating a couple of hours before going to dialysis. A small snack is acceptable whilst on dialysis, including yoghurt, biscuits and cheese.
Fluid intake is tailored to a patient depending on how much they urinate. Those who have only started dialysis may have normal amounts of urine output. These people do not need to regulate their fluid intake as tightly. In those who do not urinate at all I usually suggest around 1-1.2L of fluid maximum a day. This is because each dialysis session (which only occurs 3 days a week) can generally only take off around 3L maximum. This fluid restriction includes all liquids including coffee, tea, and water. Bear in mind that there are hidden sources of fluid eg yoghurts, ice cream and fruit that should also be factored into the equation. Drinking too much fluid can cause buildup increasing heart strain. Symptoms of fluid overload include high blood pressure, shortness of breath, weight gain and fluid in the legs and chest.
Will haemodialysis cure my kidney disease?
Haemodialysis is a type of treatment, however it is not a cure.
Haemodialysis is only around 10% as effective as what a “normal” person’s kidneys can actually perform. Therefore you can think of it as a supportive measure only. In those with acute kidney injury (see previous blog post), there is a hope that haemodialysis will support a patient until their kidneys come back online.
In those with chronic kidney disease (see blog post), haemodialysis may be a medium term solution. In patients considered for transplantation, haemodialysis is used to buy time for them be worked up, listed and transplanted. This usually takes years to occur. For those who are not eligible for transplant, haemodialysis aims to increase lifespan to continue their lives.
What are my options for haemodialysis access, and how will they be placed?
There are three main ways:
· Arteriovenous fistula – An artery and vein are stitched together. By connecting a high pressure artery to a vein, the blood vessel become enlarged, which is then be used for dialysis needle insertion. This usually is done on the arm. This is the preferred access method overall because it carries the least risk of infection. It is also the most durable solution. Months of forward planning is necessary for referral and creation by the vascular surgeon. After creation, at least 6 weeks is required before the fistula is ready to be used. Often, further procedures are required to allow the fistula to be functional.
· Vascular catheter (“vascath”) – A line (around the thickness of a drinking straw) is inserted into the neck. The dialysis machine can then be attached to the line’s ports. This is usually done in emergency situations. A common example is those have unexpected sudden onset kidney failure. The downside of the vascath is infection risk, as there is direct access to the patient’s bloodstream. Many patients also find the line an inconvenience as the overlying protective dressing can be irritating, and the line can get caught on clothing. Showers are also more challenging, as the line site should not get wet.
· Arteriovenous graft – These can be place around one month before dialysis is required. They are not preferred due to increased clotting risk, and last only around 3-5 years. I have also seen some cases where the graft erodes through the skin. This results in immediate need to remove the graft prevent spread of infection.
It is worth knowing about the potential complications of haemodialysis access. These include:
· Narrowing / blockage – In fistulas and grafts, the body’s blood vessels may grow inwards causing narrowing. This may impact on efficiency of dialysis. In the worse case scenario this can clot off completely making dialysis impossible and the fistula painful. At our hospital, regular ultrasound is performed on the vessels to ensure patency. Preemptive action (eg stents) may be performed to prevent occlusion. Vascaths are also subject to being blocked. Clots are attracted inside the vascath much like barnacles on a ship. Sometimes it is possible to flush these out with clot busting medications. From my experience however this is often a temporary measure and the patient will eventually need a new line.
· Steal syndrome – This occurs in fistulas and grafts. Because fistulas are formed at the wrist or elbow, this may divert bloodflow away from the hand. Low circulation into the hand can cause changes to sensation, temperature or weakness. Further procedures may be required to restore blood flow.
· Aneurysm – As a fistula gets needled over the course of years, the wall becomes weak and the vessel can expand. Cosmetically the person may notice the fistula as a bulge. Most of the time this just requires surveillance. If they become too big however they require a procedure in order to prevent rupture.
In summary, haemodialysis is a lifesaving treatment but not a cure. It carries risk, and therefore a frank discussion between a patient and their kidney specialist really needs to occur to weigh up the pros and cons.
Sources:
Levy, Jeremy B., Edwina Anne Brown, Christine M. Daley and Anastasia Lawrence. “Oxford Handbook of Dialysis.” (2001).
