Kidney dialysis

Kidney dialysis: kidneys filter the blood, remove the waste material. If kidney failure, waste accumulation in the body, will eventually poison the human body. Kidney dialysis, also known as artificial kidney, it was called hemodialysis (referred to as hemodialysis) or kidney. Hemodialysis English Hemodia1ysis, Hemo refers to the blood, dia1ysis from the Greek, meaning the release of certain substances, the meaning of the English dialysis. It is a kind of blood purification technology. Most of the 500,000 patients who rely on dialysis to survive in the world are hemodialysis. Hemodialysis to reduce the symptoms of patients, prolong survival have a certain significance.
For dialysis in medicine can be divided into two categories: hemodialysis, peritoneal dialysis
Hemodialysis
Hemodialysis (Hemodialysis), referred to as hemodialysis, popular argument also known as artificial kidney, kidney, is a blood purification technology. The use of semipermeable membrane principle, through the proliferation of various harmful and excess of metabolic waste and excessive electrolyte removed from the body, to purify the blood of the purpose, and to absorb the water and electrolyte to correct the purpose of balance.
Peritoneal dialysis
Peritoneal dialysis is the use of peritoneal membrane as a semipermeable membrane, the use of gravity will be prepared by the dialysis fluid prepared by the catheter into the patient's peritoneal cavity, so that the concentration of solute on both sides of the peritoneal concentration gradient, high concentration side of the solute to low concentrations One side of the movement (dispersion); water from the hypotonic side to the hypertonic side of the movement (penetration). Through the peritoneal dialysis fluid constantly replaced in order to achieve the removal of metabolites, toxic substances and correct water, electrolyte balance disorder purposes.
Peritoneal dialysis shortcomings
1. Induction of infection: Because the catheter for peritoneal dialysis is required to be connected to the dialysis bag at the time of fluid exchange, there is a possibility of abdominal infection. Therefore, it is necessary to wash the hands thoroughly when doing any steps related to peritoneal dialysis treatment. For new technologies, the incidence of peritonitis has been significantly reduced.
2. Increased body weight and blood triglycerides: Because dialysis is the use of glucose to remove excess water, it may absorb some of the glucose during dialysis, may increase the weight of patients, blood triglycerides and other lipid , So the need for appropriate exercise and reduce sugar intake.
3. Protein loss too much: in the course of dialysis will lose a little protein and vitamins, so need to add from the food. In addition to maintaining the original normal eating habits, but also intake of some fish, meat, eggs, milk and other high-quality protein, and the best source of vitamins for fruits and vegetables, supply the body needs.
Note / Renal dialysis editor
Instrument: because the kidney dialysis is to rely on the instrument for blood circulation, the patient has a certain risk, so the instrument grade, safety factor is very critical. Some large hospitals are used by foreign imports of carbonic acid machine (such as the Swedish gold plate), and with a full-time maintenance engineers. And some hospitals use acetic acid machine, is out of the models, easily lead to patient headache, hypoxia.
The doctor's request: the doctor must be based on the situation of dialysis patients, the development of individual programs; It is understood that some large hospitals have regular follow-up requirements, according to the patient's situation changes, timely adjustment of the patient's dialysis program.
Requirements for nurses: According to reports, in the United States, kidney nurses must have more than 5 years of surgical clinical experience. Experienced nurses can maintain the fistula of renal dialysis patients, so that it will maintain a "pass" state for a long time.

Consumables: At present, the state provides dialysis with a one-time supplies (such as dialyzers), but because of economic reasons, most hospitals will allow patients to use multiplexed dialyzers, some large hospitals generally do not exceed 6 times, and with There is a high-level reuse machine, this multiplexer can tell the dialyzer whether to achieve reuse indicators.
Dialysis time: to do a dialysis should generally guarantee about four and a half hours, and some hospitals one day for three patients dialysis, for the row of classes, each patient shortened by half an hour, so the patient's toxins There are surviving.
Related information / kidney dialysis editor
Figure: This diagram illustrates the same principle of peritoneal dialysis and renal dialysis. Dialysate into the abdominal cavity, once reached a balanced state, and then be drained out.
Coleman followed John Abel's method, but he used the intestine as a dialysis tube. These dialysis tubes are placed in sterile water, and the waste penetrates into the sterile water through the pores of the casing until the final water and blood contain the same amount of waste. Remove part of the waste of blood flow back to the body.
Later, Coffer's machine was further improved, allowing blood to pass through a large area of ​​multilayer cellophane. Because the plate is too cumbersome, and later replaced by celluloid coil.
The initial artificial kidney dialysis machine only as an emergency measure, in the recovery of renal function before the alternative. But in the early 1960s, smaller artificial kidney dialysis machines allowed patients to dial repeatedly at home.
Transit process
The solute in the blood is cleared by dispersing and convection in two ways. Dispersion is the process by which the solute molecules move through the gradient of the membrane [4,5]. Once the equilibrium is reached, the rate of movement of the solute from the blood to the dialysate is equal to the rate of movement of the dialysate to the blood, and the net movement of the solute on both sides of the membrane is zero. For most solutes, this transport balance does not exist on the one hand because the blood and dialysate flow is too fast, on the other hand because the solute molecules are too large to pass through the dialysis membrane pores. Urea molecular weight 60D, free distribution in the body tissue fluid, can be quickly removed in the dialysis. Therefore, urea is not only a small molecule material transmembrane transport markers, but also dialysis adequacy of the determination of indicators [6-9]. Blood flow is the rate limiting step for urea removal. Macromolecular substance Vitamin B12 molecular weight 1355D, is also a measure of dialysis adequacy of the indicators. Because the molecular weight is too large, not easy through the ordinary dialysis membrane, so the clearance of vitamin B12 and blood flow size of the small, but with the type of dialysis membrane and dialysis time. Convection is based on different transmembrane pressure through the semipermeable membrane of ultrafiltration to remove toxins [4,5]. The semipermeable membrane allows water molecules to pass freely through the membrane pores. Ultrafiltration of water can carry solute into the dialysate, to further enhance the solute removal. Maintenance hemodialysis patients weekly dialysis 3 times, each 3-4 hours, that is, every Monday, three, five or two, four, six dialysis. During dialysis, dietary and metabolic fluids accumulate in the patient, and too much liquid is removed in the next dialysis. Although the patients are drinking water control, but in the dialysis interval, the patient's fluid accumulation often 1-5Kg, which must be dialysis to clear. During the ultrafiltration, the solute of the convective mode is much less dispersed than the dispersion.
There are hundreds of types of dialyzers in today's market, and their properties depend on their solute scavenging ability. Their main part is the dialysis membrane, the type of dialysis membrane, including cellulose film, the group after the replacement of cellulose film, synthetic cellulose film, poly-synthetic film. These films are not only different in composition, but also the area of ​​the film, the thickness and the configuration within the dialyzer are not the same. The most common configuration of the dialyzer is the hollow fiber, the dialysis membrane consists of thousands of hollow fiber, hollow fiber through the dialyzer long axis. The blood flows in the fiber and the dialysate flows in the fiber gap. Another configuration is the plate configuration, and the blood and dialysate flow on both sides of the membrane, respectively. According to the type of membrane can be divided into: conventional dialyzer, cellulose membrane and the group after the replacement of cellulose film composition; efficient dialyzer, by a larger area, urea clearance rate of the membrane composition; high-throughput dialysis (PAN film), polymethylmethacrylate (PMMA) film, which is composed of a polysulfone film, a polypropylene film (PAN) film and a poly (methyl methacrylate) (PMMA) film. The main difference between conventional and high-throughput films is the size of the membrane pores. The high flux membrane has a large pore size and has a greater permeability to macromolecules (some of the molecular solutes and drugs such as vancomycin, with a molecular weight in the range of 1000-5000) and can promote the removal of the liquid. The biocompatibility of these membranes is not the same. Cellulose membrane biocompatibility is poor, can make complement activation and release of cytokines. These cytokines can cause patients with hypotension, fever, platelet activation. The biocompatibility of the modified cellulose film and the unmodified cellulose film is improved, and the biocompatibility of the synthetic film is better. At present, synthetic film becomes the mainstream product of dialyzer. However, due to the higher cost of synthetic film, therefore, it was suggested that the synthetic membrane dialyzer reuse problems. However, the potential benefits and risks of dialyzer reuse do not affect patient morbidity and mortality.
A standard dialyzer brochure should contain information on various molecular clearance rates (urea, creatinine, vitamin B12, etc.), and urea clearance has become a common method for comparing the properties of different dialysis membranes. But the clearance rate is affected by a variety of factors such as blood and dialysate flow rates [4,5]. A more standard method is the total transport area coefficient of urea (KoA). Based on the urea clearance data in the dialyzer brochure, the total transport area coefficient of urea can be estimated on the basis of a certain amount of blood flow. The use of this information enables the individualization of dialysis programs.
Although the clearance of small molecules depends on blood flow, the relationship between the two is not strictly linear. Increased blood flow has only a slight up-regulation effect on increasing urea clearance. This is mainly because there is not enough balance between the blood and the dialysis solution, and the thickening of the non-flowing layer on both sides of the dialysis membrane hinders the dispersion of the molecules. Standard blood flow rates for conventional dialysis and high flow dialysis were 200 ml / min and 500 ml / min, respectively. The flow rate of the dialysate is usually 500ml / min, the flow rate of the high flow dialysis dialysate can be increased to 800ml / min, the removal of urea can increase by about 10%
Over the past 10 years, the patient's dialysis dose has been quantified, and some progress has been made in the individualization of dialysis programs. The results of the National Cooperative Dialysis Study (NCDS) in 1981 showed a relationship between patient dialysis and morbidity [7, 8, 25]. This study was divided into four groups according to the difference in mean serum urea concentration (50 mg / dl or 100 mg / dl) and dialysis duration (2.5-3.5 hours or 4.5-5.0 hours). There was no significant difference in mortality at one year of study time, but with high serum urea levels compared with patients with low serum urea levels had a higher rate of trial withdrawal and hospitalization. These data suggest that the use of urea metabolic kinetics and urea as a marker of dialysis adequacy based on the concept of dialysis treatment model, has important clinical significance. It is well known that other uremic toxins are also involved in the overall incidence of uremic patients. But also conducted a number of studies on markers that could represent their in vivo clearance process and attempted to clarify the relationship between these markers and uremic toxin clearance. These markers include creatinine (molecular weight 113D), molecular weight slightly larger than urea, but its distribution is similar, as a marker and no special strengths; vitamin B12, molecular markers of molecular substances, is currently considered with end-stage renal disease patients with multiple uremia Complications are related. As the vitamin B12 molecular weight, ordinary dialysis membrane is not easy to clear, so vitamin B12 and urea compared with a different mode of clearance. The use of vitamin B12 as a representative of dialysis adequacy has not yet established a corresponding theory.
Dialysis patients can occur a lot of complications; the most common complications are hypotension, low blood pressure patients have a variety of clinical symptoms and signs, including nausea, vomiting, dizziness, muscle spasms and headache. The main reason is the excessive removal of water in the blood, more than the body to store water moving speed. If the volume of patients in dialysis depletion, dialysis after the corresponding clinical symptoms, then dry weight is necessary to increase. Another important reason for hypotension is hyperdialine hyperthermia and vasodilatation. The problem can be corrected by lowering the temperature of the dialysate to slightly below body temperature. Acetate as a dialysis solution buffer salt, the acetate has a direct stimulating effect on blood vessels, can cause hypotension. Patient for carbonate dialysis can correct this problem [10,15]. Excessive antihypertensive therapy before dialysis can increase the hypotension, some patients must stop the treatment before dialysis, dialysis followed by medication. Rapid treatment of hypotension includes the patient's supine position, intravenous injection of small doses (100ml) of saline, and reduce the ultrafiltration rate.
2 muscle spasm
Dialysis in the muscle spasm may also be related to the movement of the liquid. Excessive ultrafiltration in dialysis can lead to muscle tissue perfusion and then cause muscle spasms. Attempts to be treated include reduction of ultrafiltration, intravenous hypertonic saline or glucose for improved circulation [37,38]. Long-term prophylactic treatment was treated with quinidine 260 mg 2 hours prior to dialysis. Spasmodic exercise and stretching of the limbs are also helpful in improving symptoms.
High sensitivity reaction
It is reported that the high sensitivity of the dialysis membrane, especially for the first time, is directly related to the dialysis membrane itself or to the ethylene oxide used for dialyzer disinfection [40,41]. The most common dialysis membrane that causes high sensitivity reactions is a non-radical replacement cellulosic membrane (biocompatible), or when high flow polypropylene film is used in combination with an angiotensin converting enzyme inhibitor. The occurrence of the latter high sensitivity reaction and angiotensin converting enzyme inhibitors inhibit bradykinin metabolism.
Dialysis imbalance syndrome is a clinical syndrome recognized by the initial phase of dialysis more than 30 years ago. Its etiology and brain edema. Recently started by dialysis patients, because of its high plasma urea levels, and thus have a higher risk. The rapid clearance of extracellular urea reduces the osmotic pressure of the plasma, which in turn leads to free water entering the brain tissue. A decrease in intracellular pH during chronic renal failure is considered to be the result of increased intracellular organic acid production. Increased intracellular organic acid production caused by increased osmotic pressure, which led to the transfer of water from the cell into the cell, and ultimately cause brain edema. Clinical symptoms occur during dialysis or after dialysis, including effects on central nervous system (CNS), such as headache, nausea, hallucinations, and some patients with convulsions and coma. The purpose of treatment is to prevent the occurrence and development of dialysis imbalance, including early dialysis in new patients with short-term, low blood flow rate of progressive dialysis. For symptomatic patients can also be directly intravenous injection of high salt or mannitol.
Dialysis-related long-term complications include thrombosis, vascular access infections, aluminum poisoning and amyloidosis.
Symptoms / Renal Dialysis Editors
① arrhythmia: often caused by hypokalemia, hypokalemia mostly repeated use of low potassium or potassium-free dialysis solution. Hemolysis can produce hyperkalemia and thus induce arrhythmia, but very rare. Before the use of digitalis drugs in patients with dialysis due to decreased serum potassium concentration and changes in pH, can occur digitalis poisoning induced arrhythmia.
Prevention and control measures are: diet control potassium foods to prevent hyperkalemia, strict restrictions on the use of dialysis patients digitalis drugs, and the use of potassium> 3.0mmol / L dialysate. Arrhythmia can be used when the anti-arrhythmic drugs, but need to adjust the dose according to drug metabolism.
② pericardial tamponade: hemodialysis and after a short period of time occurred in the pericardial tamponade mostly bleeding, often in the original uremic pericarditis based on the application of heparin caused by pericardial hemorrhage.
Clinical manifestations: ① progressive decline in blood pressure, with signs of shock; jugular vein engorgement, liver, Qi pulse, central venous pressure; ③ heart sector expansion, heart sounds distant; ④ B supercardioplegia large volume of fluid and so on.
Treatment measures: dialysis should be immediately stop dialysis, to protamine and heparin, and close observation of changes in condition. Severe signs of congestion may be pericardial puncture drainage or direct surgical drainage drainage. Preventive measures are mainly suspected to have uremia pericarditis patients, especially in the heart before the smell and pericardial friction in patients with low molecular weight heparin or no heparin dialysis.
Hemodialysis topic / kidney dialysis editor
Kidney dialysis
Kidney dialysis
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