Renal Replacement Therapies (RRTs)

Renal Replacement Therapies (RRTs)

RRTs are treatments for people whose kidneys have failed almost totally to work as a cleaning organ in the body. Their aim is to replace what native kidneys do normally, so toxins and extra body water can be excreted from body. RRTs include two main groups: Dialysis and kidney transplantation.

What is dialysis?
Dialysis is a way of replacing kidney function by using a filter membrane ( either native or artificial) to clean blood and filter out toxins, wastes, and extra body water that produced by normal metabolism. It is important to know that it does not treat the kidneys, which means, it will not improve the original kidney function.

Who needs dialysis? Is dialysis absolutely necessary? When to start? Do I need dialysis life-long once started?

In general, people who have severe chronic kidney disease (stage 5) with either glomerular filtration rate (GFR) below 10 ml/min or symptoms of uraemia will need to be started on dialysis. However, it also subjects to other factors, such as people’s wishes and preference, functional capacity, and other medical conditions that may subject dialysis to cause more harm.

Dialysis is necessary to prolong life when kidney function fails completely. People who have end stage kidney failure will only have few weeks to months to live if dialysis is not started promptly. People started on dialysis in average will have 5 or more years to live depending on other medical conditions. People on dialysis die later mostly not due to dialysis itself, but due to heart attack, stroke, and infections. These are mainly caused by their underlying health problems such as diabetes and high blood pressure. Again, dialysis is life-saving.

The decisions on the timing of starting dialysis are normally made by kidney physicians in conjunctions with patient’s understanding and agreement. It is important to understand the concept of dialysis and start the process of preparing for dialysis way before the time comes. The entire process of preparation for dialysis may take up to few months. This process include patient education, medical and psychological assessment, choosing type of dialysis, and dialysis access formation. Although dialysis can be started urgently without this process via a neck line, but the fact is that people who had planned dialysis do better and have less complications compared to those who started urgently.

Once dialysis is started, almost all will need it life-long. It has a huge impact on people’s daily activity, family, occupation, finance, and mental health. People will need lots of support from family, social services, and health professionals. Kidney department in Hospital can provide most of supports for difference aspects.

There are other indications for start on dialysis such as severe acute kidney injury, poisoning, or some haematological malignancies and conditions. In most of these cases, dialysis is temporary until the kidney function returns.

How to do dialysis? Are there different types of dialysis?
There are two main type of dialysis: Haemodialysis and Peritoneal dialysis.

Haemodialysis (HD) uses an artificial membrane filter to clean blood. It needs blood to be transported out of body into the filter for cleaning before returning to the body. It needs a large blood vessel access such as an arteriovenous fistula (AVF) or a large venous catheter to transport large volume of blood per minute for cleaning. Once started, most of people will need 3 sessions per week, 4-5 hours per session. This can be done in a hospital or in-centre setting, or sometimes people can be trained to do it themselves at home or community houses with machine provided.

Peritoneal dialysis (PD) uses people’s own peritoneal membrane overlying the abdominal organs as the filter. It is an effective natural filter to excrete toxins and extra water in the body. People who chose PD needs to have a tube to be inserted into their abdominal cavity. Clean dialysis fluid (normally with glucose in it) is infused into the cavity and stays in for 3-4 hours allowing toxins and extra water to be exchanged. The resultant fluid in the cavity (dirty fluids) is then drained out before another clean bag is infused in. In general, people need to do 4 exchanges a day. In between exchanges, PD patients are able to carry on with their normal activities. Instead of being attached or hooked to a machine for hours 3 times a week like in haemodialysis, PD provides more freedom and all can be done in the community with minimal hospital contact.

The choice of dialysis modality is dependent on individual circumstances and largely people’s choice to suit their life style. There are limited data suggesting which one is better or worse, and they can be inter-changed when situation changes.


What are the side effects of dialysis?
Although dialysis is an artificial way of mimicking what normally good kidneys will do, it does not replace all functions of kidneys. Hormones such as vitamin D and erythropoietin that are processed or secreted by kidneys are not produced by dialysis. People need medications to replace these hormones while they are on dialysis.

Dialysis itself may also create side effects or complications. These include bleeding due to clotting disturbance, low blood pressure, stress to heart causing irregular heartbeats, stroke, infections, cramps, nerve damage, immune system suppression, skin changes and calcium deposition, etc. Most of complications only develop after years of dialysis.