What Is Renal Dialysis?

Artificial kidney is a device that replaces kidney function. It is mainly used to treat renal failure and uremia. It draws blood out of the body using dialysis, filtration, adsorption, membrane separation and other principles to eliminate excess nitrogenous compounds, metabolism products or excess drugs in the body, adjust the electrolyte balance, and then lead the purified blood back into the body. There is also blood purification using human biofilms (such as the peritoneum).
Artificial kidney

Chinese name: Artificial kidney
Category: Device to replace kidney function

Use: Treatment of renal failure and uremia
Purpose: Blood purification

Brief introduction of artificial kidney

The most important device used in the artificial kidney treatment method is the "artificial kidney", which simulates the function of the human kidney.

Artificial kidney is a kind of artificial organ which is widely used in clinic and has obvious curative effect. In terms of the treatment effect of chronic uremia with advanced chronic nephritis, its five-year survival rate reaches 70% to 80%, and about half of the patients can partially recover the labor force. Due to the above-mentioned achievements, the therapeutic scope of artificial kidneys has gradually expanded and entered the field of treatment of immune diseases, which has received attention from various quarters, and has become one of the most active fields in artificial organ research.

How does artificial kidney work?

The artificial kidney currently in clinical use is a dialysis treatment device. Dialysis therapy includes hemodialysis, hemofiltration, hemoperfusion, and peritoneal dialysis. It is a technology that uses hemodialysis machine, hemofiltration machine, hemoperfusion device and peritoneal dialysis tube to treat patients.

Hemodialysis is commonly known as "artificial kidney", a treatment method in which blood and dialysate are placed on both sides of a synthetic semi-permeable membrane, using different concentrations and osmotic pressure to diffuse and infiltrate each other. Hemodialysis can remove excess water and metabolic waste from the patient's body, and absorb the electrolytes and bases that the body lacks from the dialysate to achieve the purpose of correcting the water-electrolyte and acid-base balance.

Artificial kidney artificial kidney basic technology

After long-term research and clinical application, the techniques of artificial kidney mainly include hemodialysis, hemofiltration, hemoperfusion and peritoneal dialysis.

Hemodialysis: the oldest and most widely used method. There are two main ways to complete the artificial kidney replacement function: to remove metabolites through the diffusion effect of the semi-permeable membrane; to remove water from the blood using ultrafiltration pressure and osmotic pressure. Because this method is safe and easy to use, it can be applied to most patients with renal failure.
hemofiltration: a dialysis method developed on the basis of hemodialysis. The basic principle is: by increasing the blood pressure in the dialyzer, the water, small molecular substances and some molecular substances in the plasma are excluded, and then the replacement fluid is input. Because this method is closer to kidney function, dialysis is better than hemodialysis alone.
Plasma exchange, immunoadsorption, hemoperfusion:
Plasma exchange: the human blood is taken out of the body, the plasma is separated, and the blood cells are mixed with the corresponding replacement solution and returned to the body.
Immunoadsorption: A technology developed by plasma exchange that removes pathogenic substances in the blood circulation through the principle of adsorption, thereby achieving therapeutic goals. The process is to pass the plasma through an adsorption column containing a ligand to adsorb the pathogenic substances.
Hemoperfusion: Similar to immunoadsorption, the toxicants, drugs and their metabolites are adsorbed by the adsorbent in the adsorption tank to achieve the therapeutic purpose.

Peritoneal dialysis: use the peritoneum as a semi-permeable membrane, by injecting dialysate into the abdominal cavity, by means of the difference in solute concentration and osmotic pressure in the capillary plasma on both sides of the peritoneum and the dialysate in the peritoneal cavity, and cleared by diffusion and osmosis The body's metabolic waste and excessive moisture. With the continuous improvement of peritoneal dialysis technology, more and more patients with chronic renal failure are now treated with peritoneal dialysis.

Artificial kidney structure commonly used in artificial kidney

Artificial kidney (hemodialysis system) is mainly composed of four parts: hemodialysis machine, dialyzer, dialysate, and water treatment device.

Hemodialysis machine: The main functions of a hemodialysis machine are maintaining extracorporeal circulation, ultrafiltration dehydration, preparing dialysate and supplying it to a dialyzer, and physiological monitoring.

Dialyzer: Material exchange is performed through the dialyzer membrane. Metabolites in the blood enter the dialysate through the dialyzer membrane through the principles of diffusion and convection, and the substances needed by the body enter the blood through the dialyzer membrane.

Dialysate: Correct electrolyte and acid-base balance disorders of dialysis patients, and wash away metabolites filtered from the blood.

Water treatment device (continuous hemodialysis system generally does not have a water treatment device): prepare high-purity water to supply hemodialysis machine to prepare dialysate.

Artificial kidney disease

Artificial kidney is an effective method for treating acute and chronic renal failure and certain acute drugs and poisoning. Its indications are as follows:
(1) Acute renal failure: no urine or oliguria for more than 2 days (48h), accompanied by hypertension, water poisoning, pulmonary edema, or cerebral edema; hyperkalemia; metabolic acidosis, Correction is invalid.

(2) Chronic renal failure with the following conditions: Heart failure or uremic pericarditis; Uncontrollable hyperphosphatemia, clinical and X-ray examinations reveal soft tissue calcification; Severe electrolyte disorders or Metabolic acidosis; marked retention of water and sodium; severe symptoms of uremia.
(3) Acute drug or poisoning: Toxins can be precipitated through the dialysis membrane, and the dose of the poisons is not large and the rate of action of the poisons is not too fast. Dialysis should be performed within 8 to 16 hours after taking the poison. Emergency dialysis: After treatment with conventional methods, the condition is still worse, such as coma, dull or disappeared reflexes, apnea, refractory hypotension, etc .; The poison that has been known to enter the body or the blood poisoning concentration has been measured to death Dose; The organs that normally excrete poisons have significantly reduced function due to the primary disease or have been damaged by the poisons; Combined with lung or other infections.
(4) Others: First aid for refractory congestive heart failure and acute pulmonary edema; Hepatobiliary diseases such as liver failure, liver cirrhosis refractory ascites, and complete obstructive jaundice; water and electrolyte disorders For example, dilute hyponatremia and hyperkalemia due to various reasons; Schizophrenia; Psoriasis.

At present, the concept and goal of blood purification treatment have changed from maintaining the patient's life to improving the patient's quality of life and promoting its return to society. To achieve this goal, further maturation of blood purification technology is required. The hemodialysis membrane, which plays a central role, has made great progress so far, but the replacement of renal function is still incomplete and non-physiological. This also requires researchers to continue to work on developing new membrane materials and modifying existing membrane materials to further provide more complete renal replacement therapy and improve the long-term prognosis of patients with renal failure.

Artificial kidney extended reading

1. Left force. Current Situation and Prospects of Hemodialysis at Home and Abroad, Progress in Blood Purification Management, 2013, 13 (8): 8-9

2. Zheng Li, Xu Hui. Research progress of blood purification dialysis membrane, International Journal of Urology, 2013, 33 (2): 270-274

3 Li Li, Wang Xiaoyun. Recent Development of Blood Purification Dialysis Membrane, China Blood Purification, 2007, 6 (11): 610-613

4. Dong Xinggang, Chen Jianghua, He Qiang. 10-year review and prospect of biological artificial renal tubules, International Journal of Transplantation and Blood Purification, 2008, 6 (2): 24-25

5. Wei Yong, Liming Hui, Zhang Yan. Overview of Ultrafiltration Design and Ultrafiltration Performance of Modern Hemodialysis Machines, Medical Equipment, 2004, 25 (2): 39-40