Dialysis- Modalities

What are the Modalities for Dialysis?

Once the kidney fails, there are three options.  None of these options are a cure but a form of treatment. The three types of treatment will be discussed below.  Peritoneal dialysis (PD), hemodialysis (HD), and palliative care.

Peritoneal Dialysis (PD)

This is a type of dialysis which the patient’s peritoneum is used as the dialysis membrane.  The peritoneum is an anatomical structure which covers the abdominal organs.  This natural organ filters the toxins and excretes waste from the body.  The peritoneum has two layers which together forms a “pocket” called peritoneal cavity. Fluid is instilled into the peritoneal cavity using   peritoneal catheter (Peritoneal catheter is implanted by the surgeon into the abdominal wall.).  The dialysis fluid is instilled into the cavity by either gravity (CAPD) or a machine called cycler (CCPD).  The fluid is left in for several hours, during that time, waste materials and excess fluids pass through the membrane and are then drained from the cavity via the peritoneal catheter.  No needles are involved for this type of dialysis.  It is done primarily during the night when you are sleeping.  Once medical advantage is that is preserves your veins and arteries for future use.  Patient of this type of modality have better blood chemistries, flexible schedules, independence, and above all are able to travel to anywhere in the world.  It is also the self-esteem due to empowerment of the patient.  More liberal diet compared to other methods, better “feel-good feelings” compared to hemodialysis and research has shown that patient of this modality has better transplant outcome compared to hemodialysis.  The downside of this modality is that it requires home supplies and storage space, risk for infection, and requires dialyzing daily.

Hemodialysis

Is a medical treatment in which an artificial filter outside the body is used to clean the blood.  An access is needed to remove blood from the body to the machine which is attached to an artificial filter.  Two needles are need for hemodialysis. One is to remove the blood through the access to the machine for filtering.  Another needle is needed to return the filter blood back to the body.  The blood is pumped passed a semipermeable artificial dialysis membrane called a dialyzer.  Poisons and toxins removed through this method are diffused into a liquid called dialysate.  The dialysate are then discarded along with the toxin; the purified blood is then return to the body.  Because the patient’s blood is outside the body, for this process, the dialysis machine has a warmer to keep the blood at body temperature.  Once the blood is outside the body in the tubing system, there is a tendency to form clots which can be fatal.  A blood thinner called heparin is given to prevent the clotting in the plastic tubing.  Hemodialysis can be done in three ways:

  1. In-Center hemodialysis
  2. Home hemodialysis
  3. Nocturnal dialysis

In-center hemodialysis is usually done at a dialysis facility usually three to four times per week.  These sessions last three to four hours and are done during the day.  Nurses and technicians are involved in setting up and operating the dialysis machine.  The main advantage of in-center hemodialysis are patients are able to meet nurses three times per week and emergencies are addressed immediately, social support from in-center, and patients are not directly involved in their care.  The disadvantage of in-center hemodialysis are the treatment schedules are strict, lack of independence,  are at high risk for nosocomial infection due to exposures to other patients, difficult traveling.  Overall, hemodialysis as a modality has several disadvantages.

Nocturnal hemodialysis is done at night in-center, sessions usually last six to eight hours during the night.  Nurses and technicians operate the dialysis machine.  The advantages and disadvantages for this modality are the same as in-center.

Home hemodialysis is done about five to six times per week.  Sessions are 2.5-3hrs during the day; a partner is required for this modality.  The partner could be a spouse, a family member, a caregiver, or a paid hemodialysis technicians or a nurse.  Training usually takes about one month for this method.  The advantages of home hemodialysis include independence and convenience of dialyzing at home. It has a relatively flexible schedule compared to in-center hemodialysis.  Traveling is relatively possible compared to in-center hemodialysis.  The disadvantages for this modality are: treatments are done during the day, frequent needle sticks, and the need for having a partner.

The main disadvantage for hemodialysis is a permanent access such as a fistula or graft is required.  There are greater risk for clots and infections.  It can also cause steal syndrome.  The fistula can decrease the amount of blood flow to the hand, making it painful, cold, and pale.  It is called steal syndrome because the fistula steals blood from the distal part of the hand.  Doctors refer to this as ischemia.  Fistula and grafts remains permanent in the body and are difficult to remove.  Frequent clotting can lead to exhaustion of vascular access for future use.

Palliative care

Also known as conservative treatment is a type of treatment to keep patient comfortable.  The treatment may be either hemodialysis or peritoneal dialysis and is given as necessary.  This type of treatment is mainly a part of end of life therapy.