Renal Dialysis is the medical process carried out to remove excess water and waste from the blood stream. This process is mainly carried out on patients suffering from renal failure, a condition that leads to loss of kidney function, resulting in the blood stream not being purified.
Renal Dialysis can also be used for disturbances in the kidney function, which may be caused by any injury or external damage, and chronic kidney diseases.
There are five different types of renal dialysis, of which 3 are primary and 2 are secondary processes.
The primary processes include:
1. Hemodialysis: This type of dialysis involves the removal of water and wastes from the blood by the process of circulating it through a filter outside the body. This filter is called a dialyzer and contains a semi-permeable membrane. Blood and dialysate, the fluid used for the process, flow in opposite directions of the membrane, while diffusion properties ensure that maximum concentration of urea and other wastes are removed from the blood. This dialysis procedure is the most effective amongst all renal dialysis processes.
2. Peritoneal Dialysis: Waste and excess water are filtered from the blood stream inside the body using a peritoneal membrane, also called the peritoneum. The water and waste move through this semi permeable membrane to the dialysate which is then removed from the body. Peritoneal dialysis can be easily carried out at home.
3. Hemofiltration: Like the hemodialysis process, this dialysis procedure too involves the pumping of blood through the dialyzer. The difference between the two procedures is that that hemofiltration does not require any dialysate during the process. Pressure is used to enhance the flow of water across the semi-permeable membrane, with the dissolvable impurities moving along with the water.
The secondary processes carried out in cases of renal failure are:
1. Hemodiafiltraton: This procedure combines the principles of hemodialysis and hemofiltration, ensuring an efficient process.
2. Intestinal Dialysis: The process of intestinal dialysis involves the intake of high quantities of soluble fibres or non-absorbable solutions at regular intervals. This promotes bacterial growth along the colon, which in turn leads to an increase in the amount of nitrogen to be eliminated in fecal waste. This procedure is also used for patients suffering from renal calculi (kidney stones).
There are 3 types of renal dialysis machines:
1. Coil Dialyzer: This dialyzer comprises long membrane tubes placed between support screens and wound around a plastic core.
2. Parallel Plate Dialyzer: Membrane sheets are mounted on plastic support screens in this dialyzer. The arrangement is then stacked in multiple layers, resulting in parallel channels for flow of blood and dialysate.
3. Hollow Fiber Dialyzer: Several fibres make up this dialyzer with polyurethane used at the ends to provide support. This machine ensures low resistance to the flow of fluids and provides high efficiency.