Dialysis (dialysis): a separation and purification technique that separates small molecules from biological macromolecules through the principle of diffusion of small molecules through a semipermeable membrane into water (or buffer).
Dialysis
A treatment that allows components of body fluids (solutes or water) to pass through a semipermeable membrane and be expelled from the body. It is often used in cases of acute or chronic renal failure, accumulation of drugs or other poisons in the body. Commonly used dialysis methods are hemodialysis and peritoneal dialysis .
Hemodialysis therapy The patient's blood and dialysate are introduced into the dialyzer at the same time (the flow direction of the two is opposite), and the semi-permeable membrane of the dialyzer (artificial kidney) is utilized to remove the excessive toxins and excessive water accumulated in the blood from the body, and the bases are replenished to correct the acidosis, to adjust the electrolyte disorders, and to substitute for the excretory function of the kidney.
Hemodialyzer is commonly known as artificial kidney, there are hollow fiber type, coiled tubing type and plate type 3 kinds. The most commonly used is the hollow fiber type, composed of 1 to 15,000 hollow fibers, the wall of the hollow fiber is the dialysis membrane, with semi-permeable membrane properties. During hemodialysis, the blood flows into each hollow fiber, and the dialysis solution flows outside each hollow fiber. The flow direction of the blood is opposite to the flow direction of the dialysis solution, which removes toxins through the principle of semi-permeable membrane, and removes water through ultrafiltration and osmosis.
The indications for hemodialysis include: ① acute renal failure. ② Acute drug or poison poisoning. Chronic renal failure. ③ Chronic renal failure. ④ Renal failure before renal transplantation or post-transplantation rejection reaction rendering the transplanted kidney non-functional. ⑤ Other diseases (liver failure, schizophrenia, psoriasis, etc.).
Relative contraindications to hemodialysis include: ① extremely critical condition, hypotension, shock. ② serious infection sepsis. ③Severe myocardial insufficiency or coronary heart disease. ③ Severe myocardial insufficiency or coronary heart disease. ④ Within 3 days after major surgery. (5) Those with serious bleeding tendency, cerebral hemorrhage and severe anemia. (6) Those who are uncooperative in mental illness. The patient with malignant tumors.
General patients need hemodialysis 3 times a week, 4-5 hours each time. Dialysis should be started as early as possible to correct irreversible organ damage and metabolic disorders due to excessive accumulation of toxins, and should be started when the creatinine clearance rate decreases to 10-12mL/min. 15-60 years old patients have good and safe results of dialysis, but due to the continuous improvement of dialysis technology and the emergence of new dialysis equipment, patients over 70 years old can also get good results.
In order to ensure the quality of life of dialysis patients and to improve the recovery rate, hemodialysis patients should ensure the daily intake of protein 1.0-1.2 g/kg and 146.3 kJ/kg, and should consume enough water-soluble vitamins and micronutrients to replenish the amount of dialysis loss. The 5-year survival rate of dialysis patients varies from country to country, ranging from 50% to 80%, and the 10-year survival rate of more than 50% has also been reported.
Peritoneal dialysis therapy Peritoneal dialysis utilizes the peritoneum as a semi-permeable membrane and injects peritoneal fluid into the abdominal cavity through a peritoneal tube to remove toxins through the principle of dispersion, to correct the disorders of electrolyte and acid-base balance, and through the principle of osmosis (by adding glucose to the peritoneal fluid to increase the osmolality of the peritoneal fluid) to achieve ultrafiltration of dehydration and to substitute for the excretory function of the kidney.
Peritoneal dialysis has simpler equipment than hemodialysis, can be operated at the bedside, and can avoid sudden changes in fluid balance.
Peritoneal dialysis is divided into continuous ambulatory peritoneal dialysis (CAPD, where the patient can move freely with the equipment), continuous cyclic peritoneal dialysis (CCPD, with the same advantages as CAPD, where the patient relies on the peritoneal wall dialysis machine to perform dialysis at night, and can still work in the daytime), and intermittent peritoneal dialysis (for acute patients). Generally, 4 to 6 PD sessions should be performed per day, with 2,000mL of peritoneal fluid infused into each session. Peritoneal dialysis is not dependent on machines, is easy to operate, and does not require special training of personnel, so it is inexpensive and can be carried out in primary care units. Although the indications of peritoneal dialysis and hemodialysis are the same, they have their own advantages and disadvantages, and cannot replace each other. Therefore, appropriate choices should be made according to the patient's primary etiology, condition, and medical and economic conditions, so as to maximize the benefits for the patient. The following conditions should be given priority to peritoneal dialysis: ① elderly, poor cardiovascular system function. ② the establishment of hemodialysis vascular access difficulties. ③Those with serious bleeding tendency who can not do hemodialysis systemic heparinization. ③ Those who have serious bleeding tendency and can't do hemodialysis with systemic heparinization. ④ Those who have diabetic nephropathy and uremia, adding insulin into the peritoneal cavity can make the blood sugar control better. The following conditions are contraindications to peritoneal dialysis: ① within 3 days after major abdominal surgery. ② Peritoneal adhesions or intestinal obstruction. (iii) Infection of the abdominal wall that cannot be colonized into the peritoneal dialysis tube. ④Abdominal tumors, intestinal fistula, diaphragmatic hernia, and so on.
Aseptic operation is not strict can cause peritonitis, repeated episodes of peritonitis can make the peritoneal wall of the dialysis area is reduced, dialysis efficacy is reduced. In addition, due to the peritoneum on the membrane pore is larger than the aperture on the membrane of the hemodialysis apparatus, so the loss of nutrients from the peritoneal dialysis fluid is more serious than in hemodialysis. Therefore, strict aseptic operation as well as adequate nutrition is the guarantee for the success of peritoneal dialysis. The survival rate of peritoneal dialysis is 90%, 80%, 70%, 65% and 46% in the 1st, 2nd, 3rd, 4th and 5th years respectively, with an annual decrease of about 10%. Survival of 20 years has been reported worldwide.