Almost 1,800 people in Ireland are connected to a machine for 12 hours every week because their kidneys can no longer take care of the body’s needs. It is a daunting prospect for anyone recently diagnosed or living with renal failure but it is necessary – in the absence of a kidney transplant – and life-saving.

Dialysis machines basically perform most, but not all, kidney functions for patients who have permanent or temporary renal failure resulting from disease, birth defect or injury. Kidney dialysis artificially filters and removes waste products and excess water from blood, a process normally performed by healthy kidneys. 

While often referred to as an artificial kidney, renal dialysis is not a cure. In acute renal failure, which is a sudden, severe decrease in the blood-filtering function of the kidneys, dialysis is carried out intensively over a period of days or weeks until the kidneys work normally again. 

Chronic renal failure usually involves progressive kidney dysfunction and may require haemodialysis several times a week for the rest of the individual’s life or until a kidney becomes available for transplant.

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How dialysis works

The main forms of treatment for either of these patient groups are haemodialysis or peritoneal dialysis, depending on each individual case. About 90% of patients undergo traditional haemodialysis, which uses an external machine to clean the blood. 

In haemodialysis, the patient’s blood is pumped through the blood compartment of a dialyser. The dialyser is composed of thousands of tiny synthetic hollow fibres and this fibre wall acts as a semi-permeable membrane. 

Blood flows through the fibres and a special dialysis solution (dialysate) flows around the outside of the fibres (the dialysate compartment). Since the membrane that separates these two compartments is semi-permeable, this allows the passage of certain sized molecules across it, but prevents the passage of other, larger molecules. 

As blood is pushed through the blood compartment in one direction, suction or vacuum pressure pulls the dialysate through the dialysate compartment in a counter current. These opposing pressures work to drain excess fluids out of the bloodstream and into the dialysate, a process called ultrafiltration. 

A second process called diffusion moves waste products in the blood across the membrane into the dialysate compartment, where they are carried out of the body. At the same time, electrolytes and other chemicals in the dialysate solution cross the membrane into the blood compartment. 

In short, the patient’s blood is pumped through an inflow (arterial) blood line to the dialyser where it is filtered and balanced for electrolytes, pH and fluid concentration before being returned to the patient via an outflow (venous) blood line.

An alternative to haemodialysis, peritoneal dialysis uses the patient’s own peritoneal membrane as a blood filter. This membrane is a sac around the abdominal organs and, like the dialysis machine membrane, is semi-permeable. Waste particles can get through it, but the larger blood cells cannot. 

A catheter is surgically inserted into the patient’s abdomen. During treatment, the catheter is used to fill the abdominal cavity with dialysate. Waste products and excess water from the body pass through the natural peritoneal membrane into the dialysate. After a waiting period of four to 24 hours, depending on the treatment method used, this solution is drained out of the abdomen and discarded. 

Unlike haemodialysis, which is usually done three times a week at a supervised clinic, peritoneal dialysis is performed by the patient several times a day in their home or wherever a relatively clean environment can be found. Many patients, when given a choice, feel the newer procedure gives them greater control and independence.

Dialysis in Ireland

Although experiments with dialysis are said to have occurred thousands of years ago, dialysis as we know it has its roots in the 20th century. A resourceful Dutch physician, Dr Willem Kolff (1911-2009), is credited with constructing the first working dialyser in the early 1940s during the Nazi occupation of the Netherlands. Due to the scarcity of available resources, Dr Kolff had to improvise and build the initial machine using sausage casings, orange juice cans, a washing machine, and various other items that were available at the time. His crude artificial kidney has since evolved into modern dialysis machine and preserved countless lives worldwide.

In Ireland, the now state-of-the-art department of nephrology at Beaumont Hospital has its humble origins in ‘Fagin’s den’ on the fourth floor of the Charitable Infirmary, Jervis Street, which was previously the junior doctor’s residence. After the purchase of the country’s first haemodialysis machine (a Kolff twin-coil artificial kidney), dialysis began in Ireland in May 1958.

Since those early days, dialysis and transplant medicine has grown rapidly in Ireland and the renal unit at Beaumont Hospital remains the largest provider of renal replacement therapy in the country, offering a full range of therapies for renal failure including haemodialysis, peritoneal dialysis, plasma exchange therapy and renal transplantation (national centre).

Renal services are currently provided in each of the four HSE areas, where patients are treated under the care of 11 parent renal units and receive their treatment either in these units, or one of eight satellite haemodialysis units, or in their own home. 

In addition, a new renal dialysis unit is under development at Mayo General Hospital having received E1.8 million funding, announced in November this year. This permanent unit will have the capacity to meet the needs of all county Mayo patients currently requiring dialysis and also the expected demand for dialysis in the county over the medium term. The unit will be completed in summer 2013.

According to the Irish Kidney Association, in Ireland there are 1,568 patients receiving haemodialysis, 207 on peritoneal dialysis and 20 on home haemodialysis (31/12/2011 data).

“Analysis of national data indicates there will be an annual national increase in haemodialysis patients of between 20 and 45 per million of the population. Therefore the HSE needs to plan for an annual expansion in dialysis capacity to provide for an additional 85 to170 patients each year,” said a spokesperson for the National Renal Office (NRO).

Home dialysis

The NRO, along with doctors and other health professionals, agrees that the development of home dialysis services in recent years offers a much more convenient and accessible service for appropriate patients. 

In 2009, Beaumont Hospital piloted a home haemodialysis treatment programme in Ireland for a small number of patients with end-stage kidney disease (ESKD). This nurse-supervised programme allows patients who would otherwise have to travel to hospital three times a week for four-hour haemodialysis treatments to treat themselves at home. 

Patients administer the treatment at home six or seven days a week, but for shorter periods. Staff involved in this service train patients to carry out their dialysis at home and patients are followed up in outpatients and home visits. 

Prof Peter Conlon, consultant nephrologist at Beaumont Hospital, developed the home programme on a pilot basis and it is currently being rolled out nationally in conjunction with the NRO, with Beaumont as the lead unit. 

“We offer it to patients that we feel can’t be transplanted generally or are likely to have a long wait for a transplant,” explained Prof Conlon. “They have to be people who are very motivated and have demonstrated that they comply with the whole regime. For some people, it’s difficult for them to get a transplant, so they could be on dialysis for the rest of their life.” 

Home haemodialysis is estimated to cost approximately half that of in-clinic or hospital dialysis, the major outlay being the expense of providing the dialysis machine. Prof Conlon maintained that not only is home dialysis an attractive economic alternative for suitable patients, it is also a more widely preferred option as patients are spared the stress, expense and time spent commuting several times a week and waiting in busy hospitals.

Success rates

How successful dialysis proves to be in the treatment of kidney failure depends on the patient’s age, if he or she has other chronic health conditions, such as heart disease or diabetes, and the underlying causes that led to kidney failure. 

Unfortunately, dialysis can only compensate for the loss of kidney function to a certain extent, and not having kidneys that work properly can place a tremendous strain on the body.

The average life expectancy of a person on dialysis who hasn’t received a kidney transplant is four years. However, many people on dialysis survive for much longer than this (up to 25 years).