During haemodialysis, the patient’s blood is passed through a filter outside the body and then reintroduced into the body. The filter membrane’s tiny pores filter out waste products and excess water while leaving vital components, such as proteins, in the blood. The process is controlled by a dialysis machine equipped with a blood pump and safety monitoring systems. Drugs can also be administered during the treatment.
For haemodialysis, the preferred procedure is to take blood from a thickened vein which is created by a small operation, where an artery is connected to the vein to allow a higher blood flow, aso called AV-fistula. Alternatively, a catheter can be placed in one of the larger blood vessels.
Haemodialysis treatment can be arranged in several ways. The dialysis treatment can be administered in a specialised clinic or at home. Dialysis in a clinic is usually performed three times a week, and lasts around four hours. Patients travel from home to the clinic, where they are taken care of by specialised doctors and trained personnel throughout the entire treatment. When not at the clinic, patients can lead as normal lives as possible. If the patient’s condition allows, they can perform haemodialysis at home by themselves, and often with the help of a partner. They both learn self-treatment in a training centre. This form of treatment can offer more independence for the patient’s social and professional life.
In attempts to improve dialysis treatment and patient outcomes, haemodiafiltration has emerged as an advanced modality that removes uremic toxins more efficiently than standard dialysis treatment modalities. Unlike low- or high-flux dialysis that removes uremic toxins by diffusion, haemodiafiltration eliminates a broad spectrum of substances predominantly by convection.
Haemodiafiltration has been shown to provide significant clinical benefits for patients in terms of better anemia and phosphate control, reduced inflammation and oxidative stress and increased haemodynamic stability. These clinical benefits collectively contribute to reduced mortality at high convective doses, which has been demonstrated recently by three randomised controlled trials.
An extended clinical experience over the last two decades has established haemodiafiltration as a better alternative to standard dialysis treatment options, and in Europe more patients are treated with this modality than peritoneal dialysis.
Haemofiltration relies exclusively on convection and is thereby more efficient in removing only the larger, but not the smaller, uremic toxins (unlike haemodiafiltration). It is thus used as a renal replacement therapy almost exclusively in the intensive care setting and thus almost always used for acute renal failure.
The peritoneum is a membrane which forms the lining of the abdominal cavity.
It has some similar attributes to the artificial semi-permeable membranes used in haemodialysis.
Its pores allow the passage of certain substances while retaining others: peritoneal dialysis therefore uses this naturally filtering organ.
A cleansing liquid, the dialysis solution, is introduced through a catheter placed in the abdominal wall which ends in the pelvis behind the bladder.
The body’s waste products are brought to the abdominal wall by very thin blood vessels and pass through the pores into the dialysis solution, which also pulls excess water from the body thanks to osmotic processes.
The used dialysis solution is then removed from the body along with the waste products and water, through the catheter.
Just like haemodialysis, peritoneal dialysis can be performed at home (it is often done at night, during sleep) or in a clinic.
Most patients with end-stage renal disease hope to receive a “new” kidney through a transplant. Unfortunately, there are not enough donor organs available. Patients who are medically fit for a transplant are therefore placed on a waiting list. The allocation of donor organs is determined by waiting times as well as the similarity of tissue types between donor and receiver. Higher similarity reduces the risk of early rejection of the transplanted kidney by the patient’s body.
Once implanted in the body and connected to the patient’s blood vessels and bladder, the donor kidney will filter the blood, produce urine, and regulate blood pressure just like healthy kidneys, allowing the patient to live a mostly normal life. However, transplants always carry the risk of rejection by the recipient, who therefore needs to take life-long medication to artificially weaken the body’s defences. This leaves the body more susceptible to some illnesses.
So long as no complications arise, around 50% of transplant recipients can live a normal life for an average of 10 years before the transplanted kidney’s filtering ability diminishes.