The main principle is a separation and purification technique that separates small molecules from biological macromolecules by diffusion of small molecules through a semi-permeable membrane into water (or buffer).
Medical dialysis is broadly divided into three main categories: hemodialysis, peritoneal dialysis, and colonic dialysis.
1. Hemodialysis
Hemodialysis is a mature artificial kidney support system. The principle of its treatment is mainly based on the principle of membrane equilibrium, i.e., the exchange of ions and water through the semi-permeable membrane can occur when there is a difference in the ionic concentration and/or pressure of the solution on both sides of the semi-permeable membrane.
In hemodialysis, one side of the semi-permeable membrane is blood and the other side is dialysate. Since there are more uremic toxins in the blood and no toxins in the dialysate, the toxins permeate from the blood side to the dialysate side, thus removing the toxins, and at the same time, by increasing the osmolality of the dialysate or by adopting a negative pressure, the water can be removed from the blood by flowing into the dialysate.
2. Hemodialysis
The principle of peritoneal dialysis is to use the body's own peritoneum as a semi-permeable membrane for dialysis treatment. Peritoneal dialysis is performed by injecting dialysate into the peritoneal cavity, and by means of the difference in solute concentration and osmotic gradient between the plasma in the capillaries on one side of the peritoneum and the dialysate in the peritoneal lumen on the other side, the toxins and accumulated water in the body are cleared through the principle of dispersion and osmosis.
3. Colonic dialysis.
Colon dialysis through the whole colon cleansing, so that the accumulation of toxins in the intestinal wall, intestinal endotoxin and other harmful substances out of the human body, and to establish a clean, effective colon internal environment, more can avoid oral antibiotics caused by the intestinal flora ratio imbalance.
And then make full use of the biological semi-permeable membrane characteristics of the colon mucosa and the natural vast dialysis area, through the colon dialysis method, to actively discharge the body of endotoxin, can achieve the purpose of blood purification, so as to achieve better therapeutic effect, and can be better adjusted to the body's water, electrolyte and acid-base balance.
Expanded information:
The peritoneal membrane in the human abdominal cavity is close to the surface area of the human body. The peritoneum contains a rich supply of blood vessels and blood. Every day, blood circulates constantly through the blood vessels in the peritoneum. When dialysis fluid is injected into the abdominal cavity for peritoneal dialysis, the blood vessels in the peritoneum are exposed to the dialysis fluid.
Excess water and wastes pass through the semipermeable membrane, which has millions of tiny holes, and enter the dialysis solution. After a few hours, the water- and waste-laden dialysis solution is drained out, and new dialysis solution is put in, and the cycle repeats itself, thus cleansing the blood.
Excess water and wastes enter the dialysate through the semipermeable membrane by diffusion and osmosis.
With the peritoneum as the semipermeable membrane, the process by which substances are transferred from the side of high concentration (blood) to the side of low concentration (dialysate) until the concentration of substances on both sides is equal is called diffusion. If blood contains more sodium, potassium, calcium, etc. than fresh dialysate, these tiny substances pass from the blood through the peritoneum into the dialysate by diffusion.
Most of the toxins in the blood, including creatinine and urea nitrogen, enter the dialysate mainly by diffusion. The diffusion stops when the concentration of substances on both sides is equal, which is why the dialysate should be replaced with a new one every 4-6 hours.
The principle of osmosis, for example, is that if you cut a tomato in half and sprinkle it with sugar, water will seep out after a while. Abdominal dialysis is the use of dialysis fluid "sugar water" through the peritoneum to pull out the excess water in the blood, this process is called osmosis. The higher the concentration of glucose in the dialysis solution, the more excess water will seep out of the blood in the same amount of time. The amount of excess water that permeates out of the blood is called the "ultrafiltration volume.
Source; Baidu Encyclopedia - Dialysis
Baidu Encyclopedia - Semipermeable Membrane