Dialysis
What is Dialysis?
Dialysis is the major treatment for kidney failure. It is the medical word for filtering waste products and removing fluid from the body that kidneys are no longer able to remove.
- Haemo dialysis: (Figure 3)
- Peritoneal dialysis: (Figure 4)
Haemo Dialysis:
Haemodialysis is the process of removing waste product and excess fluid from the blood. This is done by circulating blood through a filter, called a dialyzer, or artificial kidney. The dialyzer is used with a dialysis machine. There are different types and brands of dialysis machines, but they all work to produce the same results. Ideally a patient with chronic kidney failure should have hemodialysis three times a week each session lasting from three and half to four hours. Frequent dialysis as mentioned above keep the patient more stable, fit and free from untoward complications like fluid overload, lack of general wellbeing etc. He or she can also take a diet with minimal restrictions.
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What is Peritoneal Dialysis (PD)?
In essence peritoneal dialysis involves the transport of solutes and water across a "membrane" that separates two fluid containing compartments.
These two compartments are:
a. The blood in the peritoneal capillaries which in renal failure contains an excess of urea, creatinine, potassium, and so forth.
(b) The dialysis solution in the peritoneal cavity, which contains sodium, chloride and lactate and is rendered hyperosmolar by the inclusion of a high concentration, of glucose. The peritoneal membrane that acts as a "dialyzer" is actually a heteroporous, heterogeneous, semi permeable membrane with a relatively complex anatomy and physiology. Peritoneal dialysis is divided into CAPD (Continuous Ambulatory Peritoneal Dialysis) and APD (Automated Peritoneal Dialysis). CAPD has to be done daily (3-4 cycles a day at eight hourly interval) either by patient himself or any family member or helpers who can be trained to do such dialysis. This can also be done by a machine (Cyclar) where the peritoneal dialysis catheters are connected to the machine for continuous dialysis overnight and disconnected in the morning
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Why do kidney failure patients need to have Dialysis?
They need to have dialysis because the kidneys are not working well. The kidneys, when they are healthy, filter out waste products and fluids from the body to keep a balance of chemicals and fluids steady. The dialysis machine acts in place of kidneys to:
- Remove waste products
- Remove excess fluid
- Help with the chemical balance in your body
- Help control blood pressure
What Dialysis machine cannot do?
The human kidney also produces hormones needed for producing red blood cells (Erythropoietin) and vitamin D, without which our body cannot absorb calcium from foods, which causes weakness of bones.
Other hormones, regulated by the kidneys are rennin angiotensin for control of blood pressure and salt (electrolyte) balance in the body. In kidney failure patients all the above mentioned hormones need supplementation in the food or drug schedule to maintain satisfactory health.