Your guide to the world for dialysis

11-12-2012

Haemodialysis

Haemodialysis is a treatment method during which excess water and waste substances, which come mostly from the metabolism process, are removed from the patient’s blood. Dialyses are required by people suffering from renal failure – a disease of an organ that is a specific filtration system in human body.

 

Haemodialysis, just as peritoneal dialysis, has been performed since mid 1940s. In 1960, it became a standard therapy used all over the world. Dialysis treatments replace the renal function without treating the kidneys. A sick organ must be dialysed during a patient’s whole life, unless it is replaced during transplantation. The treatment system uses an artificial kidney, known as a dialyser, built as a filter comprised of thousands of very thin tubes which permit the flow of the patient’s blood through the tubules. Around the tubes there is a dialysis fluid (specially selected in terms of chemical composition) absorbing waste substances, which are then removed from the body together with the fluid. Excess water is removed using increased pressure inside the tubes during ultrafiltration.

 

Haemodialysis can be performed and the patient’s blood can reach the dialyser only if appropriate access to the patient’s blood vessels has been provided. Such a passageway to the patient’s blood is usually created via a small surgery on their arm or leg. Vascular access must be prepared well in advance, usually several months before dialysis. There are three methods of creating vascular access in a patient:

 

  1. Arteriovenous fistula – access is provided via surgically created connection between an aorta and a vein. It is usually created on the forearm of the non-dominant arm, very rarely on the arm. Haemodialysis in this case involves inserting two needles into the vessels of the arteriovenous fistula: one to draw blood to the dialyser and one to return it (purified) to the circulation system.

 

Advantages of such a connection:

 

  • it works for a longer period,
  • lower risk of infections,
  • excellent blood flow,
  • lower probability of blocking;

 

Disadvantages:

 

  • longer maturation time after the surgery,
  • connection through insertion of two needles;

 

  1. Arteriovenous graft – used when blood vessels cannot be used to make a fistula; a section of a synthetic vessel (whose length may vary) is implanted between the artery and the vein. This vessel (graft) is a soft, flexible tube into which dialysis needles are inserted. A graft causes more complications, such as narrowing, clotting or an infection and it is used only if vessels cannot be connected naturally.

 

Advantages of such a connection:

 

  • it works longer than a catheter,
  • excellent blood flow,

 

Disadvantages:

 

  • longer maturation time,
  • connection to the dialyser through insertion of needles,
  • higher risk of infections;

 

  1. Venous catheter – it is inserted in patients who cannot have a fistula or a graft for whatever reason. A catheter – a flexible tube with two lumens – is usually implanted in the area of the chest. One tip of the catheter is located in a large vein, sometimes near the heart, while the other tip is outside the patient’s body.

 

Advantages of such a connection:

 

  • usable immediately,
  • dialysis does not require inserting needles;

 

Disadvantages:

 

  • higher risk of infection,
  • can be blocked,
  • caution required during showering and general hygiene activities;

 

Each haemodialysis treatment takes no more than 4 hours and it is provided 3 times a week. The time devoted to dialysing depends on the patient’s body weight, a good and large-flow fistula, the patient’s renal function, the quantity of fluids accumulated since the last treatment, the quantity of toxins in the body and the type of the dialyser used.

 

The complications that can appear as a result of haemodialyses include: anaemia, cramps, dryness, itching skin and loss of boy weight. Long-term complications may encompass depression, weakened sexual functions, improper bone regeneration and the related pain. It is very important to maintain proper hygiene and test the arteriovenous fistula. A patient can obtain the essential information on the latter at dialysis facilities – from the physicians and nurses who work there.

 

Renal failure is not a condition that can be cured – unfortunately, it is a fatal disease. Dialyses let the patients lead fairly normal lives.

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