Kidney Failure Remedy

DIALYSIS

According to a medical educator the three most important organs in the sustenance of life are, the Brain, the Adrenal cortex and the KIDNEY.

The kidneys are a pair of bean shaped organs located at either sides of the spine. They are the primary excretory organs in the body which are responsible for the removal of wastes and excess water.

Like all the other organs the kidney is susceptible to damages but worst still is that the damage of the kidney is life threatening. It is life threatening because when the kidneys progressively damage to an extent that they can only perform about 5% or less of their original functions; a condition referred to as Chronic Kidney Disease (CKD), toxins accumulates in the body and this leads ultimately to death. A CKD patient’s hope for a longer life expectancy is DIALYSIS or Kidney transplantation.

Dialysis is an artificial process for removing metabolic wastes and excess water from the blood and it is primarily a replacement for a diseased or injured kidney. Dialysis anyways is not a cure for failed kidneys but rather is the use of some specialized procedures to perform the excretory functions of the kidneys. Inasmuch as dialysis alleviates the danger the vitiation of the kidneys may have caused to the excretory system, the endocrine functions of the kidneys still remain deficient. This deficiency of the endocrine functions of the Kidneys is only compensated for by the exogenous administration of the hormones that were naturally synthesized and secreted by the Kidneys; with erythropoietin being the most important.  

Principle of Dialysis

Dialysis works basically on two principles; the diffusion of solutes and ultrafiltration of solvents through a semi permeable membrane. Diffusion is the movement of molecules from areas where they are highly concentrated to areas where they in low concentration. Ultrafiltration is the passage of small molecules through a semi permeable membrane. It is worth noting that in the Kidney, the first stage of urine formation is Glomerular filtration (a.k.a Ultrafiltration), while the other two stages (Tubular reabsorption and Selective reabsorption) are hugely dependent on the principle of diffusion. In dialysis, blood flows through one side of the semi permeable membrane while the dialysate (the dialysis fluid) flows through the other side of the semi permeable membrane. The semi permeable membrane is a thin layered perforated material and its pores are of varied sizes. This perforated membrane permits the passage of solvents (mostly water) and smaller solutes but occludes the passage of larger molecules (e.g. large proteins, formed elements of the blood, etc).

Types of Dialysis

There are two main types of dialysis; Hemodialysis and Peritoneal dialysis and they use different method (though the same principle) in the cleansing and removal of excess water from the blood.

Hemodialysis

Hemodialysis is the type of dialysis that uses a special filtering mechanism to remove the waste of metabolism and excess water from the blood. It does this by circulating blood through a filter outside the body called dialyzer (which contains the semi permeable membrane) via a plastic tube. The dialyzer is a part of the dialysis machine. This treatment often requires a surgical procedure in order to connect an artery and a vein in one limb (this is referred to as arteriovenous fistula or graft depending on the specificity of the procedure) or to tunnel a catheter in the neck. This is important because this type of dialysis must be performed with a fistula, graft or catheter. So in other words this surgical procedure is used to create what is referred to as Access. When a patient is being prepared for the treatment, two needles are placed into the access, these needles are then connected to the tubes that carries blood to the dialyzer. The dialysis machine functions such as to allow only a small amount of blood outside the body per given time and it controls the timing, temperature, pressure and the excretion of wastes and excess water from the blood as it pumps it through the dialysis system. After the blood might have passed through the filter of the dialysis machine it is returned to the body via another plastic tube. Hemodialysis treatments are mostly done in an outpatient dialysis center though it can also be performed at home and on the average it is done two or three times per week and each treatment lasts about two and half hours.

Peritoneal Dialysis

In this type of dialysis a sterile solution containing glucose (referred to as the dialysate) is introduced into the peritoneal cavity and abdominal cavity using a tube. It is the peritoneal membrane here that acts as the semi permeable membrane. The peritoneal membrane is a layer of tissue that contains the blood vessels that lines the peritoneal cavity, abdominal cavity and which supplies the internal abdominal organs. Through the process of diffusion and osmosis (as a result of the difference in the osmolarity of dialysate compared to the body fluid (blood)) waste products are drove from the peritoneal membrane into the dialysate until it nears equilibrium and then the dialysate is drained and replaced by a fresh one. This treatment is done repeatedly about 4-5 times a day. Peritoneal dialysis does not equal the efficiency of hemodialysis but the longer duration of this method of dialysis gives it the same net effect as the hemodialysis. Peritoneal dialysis seems to be more convenient since it does not require a routine appointment with the clinic and it is a procedure the patients are taught to carry out by themselves.

Author:

Orji Emmanuel

Physiologist