Kidney dialysis

Kidney dialysis
Patient receiving hemodialysis
Specialty	nephrology
ICD-9-CM	39.95
MeSH	D006435
[edit on Wikidata]

Kidney dialysis (from

In West European countries, Australia, Canada, the United Kingdom, and the United States, dialysis is paid for by the government for those who are eligible.[3]^[4]

Background

The

The two main types of dialysis,

In peritoneal dialysis, wastes and water are removed from the blood inside the body using the peritoneum as a natural semipermeable membrane. Wastes and excess water move from the blood, across the peritoneal membrane and into a special dialysis solution, called dialysate, in the abdominal cavity.

Types

There are three primary and two secondary types of dialysis:

Hemodialysis

In hemodialysis, the patient's blood is pumped through the blood compartment of a dialyzer, exposing it to a partially permeable membrane. The dialyzer is composed of thousands of tiny hollow synthetic fibers. The fiber wall acts as the semipermeable membrane. Blood flows through the fibers, dialysis solution flows around the outside of the fibers, and water and wastes move between these two solutions.^[9] The cleansed blood is then returned via the circuit back to the body. Ultrafiltration occurs by increasing the hydrostatic pressure across the dialyzer membrane. This usually is done by applying a negative pressure to the dialysate compartment of the dialyzer. This pressure gradient causes water and dissolved solutes to move from blood to dialysate and allows the removal of several litres of excess fluid during a typical 4-hour treatment. In the United States, hemodialysis treatments are typically given in a dialysis center three times per week (due in the United States to

Hemo-dialysis was one of the most common procedures performed in U.S. hospitals in 2011, occurring in 909,000 stays (a rate of 29 stays per 10,000 population).[13]

Peritoneal dialysis

In peritoneal dialysis, a sterile solution containing glucose (called dialysate) is run through a tube into the

This exchange is repeated 4–5 times per day; automatic systems can run more frequent exchange cycles overnight. Peritoneal dialysis is less efficient than hemodialysis, but because it is carried out for a longer period of time the net effect in terms of removal of waste products and of salt and water are similar to hemodialysis. Peritoneal dialysis is carried out at home by the patient, often without help. This frees patients from the routine of having to go to a dialysis clinic on a fixed schedule multiple times per week. Peritoneal dialysis can be performed with little to no specialized equipment (other than bags of fresh dialysate).

Hemofiltration

Hemofiltration is a similar treatment to hemodialysis, but it makes use of a different principle. The blood is pumped through a dialyzer or "hemofilter" as in dialysis, but no dialysate is used. A pressure gradient is applied; as a result, water moves across the very permeable membrane rapidly, "dragging" along with it many dissolved substances, including ones with large molecular weights, which are not cleared as well by hemodialysis. Salts and water lost from the blood during this process are replaced with a "substitution fluid" that is infused into the extracorporeal circuit during the treatment.

Hemodiafiltration

In intestinal dialysis, the diet is supplemented with soluble fibres such as acacia fibre, which is digested by bacteria in the colon. This bacterial growth increases the amount of nitrogen that is eliminated in fecal waste.^[14][15] An alternative approach utilizes the ingestion of 1 to 1.5 liters of non-absorbable solutions of polyethylene glycol or mannitol every fourth hour.^[16]

Indications

The decision to initiate dialysis or hemofiltration in patients with kidney failure depends on several factors. These can be divided into acute or chronic indications.

Depression and kidney failure symptoms can be similar to each other.^{[citation needed]} It is important that there is open communication between a dialysis team and the patient. Open communication will allow giving a better quality of life. Knowing the patients' needs will allow the dialysis team to provide more options like: changes in dialysis type like home dialysis for patients to be able to be more active or changes in eating habits to avoid unnecessary waste products.

Acute indications

Indications for dialysis in a patient with acute kidney injury are summarized with the vowel mnemonic of "AEIOU":^[17]

1. Acidemia from metabolic acidosis in situations in which correction with sodium bicarbonate is impractical or may result in fluid overload.
2. Electrolyte abnormality, such as severe hyperkalemia, especially when combined with AKI.
3. isopropanol, magnesium-containing laxatives and ethylene glycol
   .
4. Overload of fluid not expected to respond to treatment with diuretics
5. Uremia complications, such as pericarditis, encephalopathy, or gastrointestinal bleeding.

Chronic indications

Chronic dialysis may be indicated when a patient has symptomatic kidney failure and low glomerular filtration rate (GFR < 15 mL/min).^[18] Between 1996 and 2008, there was a trend to initiate dialysis at progressively higher estimated GFR, eGFR. A review of the evidence shows no benefit or potential harm with early dialysis initiation, which has been defined by start of dialysis at an estimated GFR of greater than 10 ml/min/1.73². Observational data from large registries of dialysis patients suggests that early start of dialysis may be harmful.^[19] The most recent published guidelines from Canada, for when to initiate dialysis, recommend an intent to defer dialysis until a patient has definite kidney failure symptoms, which may occur at an estimated GFR of 5–9 ml/min/1.73².^[20]

Survival without dialysis

In a review from 2022 survival and quality of life was investigated in patients who had decided against dialysis treatment when reaching end-stage chronic kidney disease. 41 longitudinal studies (cohort studies) with a total of 5.102 patients were evaluated. The mean age of patients per study was 60 – 87 years. The mean estimated glomerular filtration rate (eGFR) at the time of decision per study was 7 – 19 ml/min pro 1,73 m².

The median survival per study was:

• all 41 studies: 1 – 41 months
• studies from continental Europe (11 studies, 1.021 patients): 6 – 37 months
• studies from Asia (7 studies, 1.147 patients): 7 – 41 months
• age 70–79 years (9 studies, 607 patients): 7 – 41 months
• age 80+ (25 studies, 3.186 patients): 1 – 37 months

The longest survival times per study from the three studies with the highest median were 82, 79, and 75 months.

During the observation periods of 8 to 24 months mental well-being improved, and physical well-being and quality of life were largely stable until the late phase of the illness.

The authors of the review reached the following conclusion: “Our findings challenge the common misconception that the only alternative to dialysis for many patients with advanced CKD is no care or death.”^[21][22]

In a review from 2021 25 studies were analyzed that had compared survival times and quality of life between patients with and without dialysis. Survival was generally longer with dialysis, but from the age of 80 and in elderly patients with comorbidities this effect became uncertain. Concerning quality of life there was a trend that patients without dialysis had an advantage.^[23]

Dialyzable substances

Characteristics

Dialyzable substances—substances removable with dialysis—have these properties:

1. Low molecular mass
2. High water solubility
3. Low protein binding capacity
4. Prolonged elimination (long half-life)
5. Small volume of distribution

Substances

• Ethylene glycol
• Procainamide
• Methanol
• Isopropyl alcohol
• Barbiturates
• Lithium
• Bromide
• Sotalol
• Chloral hydrate
• Ethanol
• Acetone
• Atenolol
• Theophylline
• Salicylates
• Baclofen

Missing dialysis

Given dialysis patients have little or no capacity to filtrate solutes and regulate their fluid volume due to kidney dysfunction,^[24] missing dialysis is potentially lethal. These patients can be hyperkalaemic leading to cardiac dysrhythmias and potential cardiac arrest,^[25] as well as fluid in the alveoli of their lungs which can impair breathing.^[26]

Some medications can be used in the short term to decrease serum potassium and stabilise the cardiac muscle so as to facilitate stabilisation of acute patients in the setting of missed dialysis. Salbutamol and Insulin can decrease serum potassium by up to 1.0mmol/L each by shifting potassium from the extracellular space into the intracellular spaces within skeletal muscle cells, and calcium gluconate is used to stabilise the myocardium in hyperkalaemic patients, in an attempt to reduce the likelihood of lethal arrhythmias arising from a high serum potassium.^[27]

Given that dialysis patients have little to no kidney function,

Pediatric dialysis

Over the past 20 years, children have benefited from major improvements in both technology and clinical management of dialysis.

In children, hemodialysis must be individualized and viewed as an "integrated therapy" that considers their long-term exposure to chronic renal failure treatment. Dialysis is seen only as a temporary measure for children compared with renal transplantation because this enables the best chance of rehabilitation in terms of educational and psychosocial functioning. Long-term chronic dialysis, however, the highest standards should be applied to these children to preserve their future "cardiovascular life"—which might include more dialysis time and on-line hemodiafiltration online hdf with synthetic high flux membranes with the surface area of 0.2 m² to 0.8 m² and blood tubing lines with the low volume yet large blood pump segment of 6.4/8.0 mm, if we are able to improve on the rather restricted concept of small-solute urea dialysis clearance.^[32]

Dialysis in different countries

In the United Kingdom

The

A UK study found that receiving dialysis at home is less costly than receiving dialysis in hospital.[35]^[36] However, many people in the UK prefer to receive dialysis in hospital for various reasons such as providing regular social contact. Encouraging people to have dialysis at home could lead to savings for the NHS, as well as reducing the impact of dialysis on people's social and professional lives.^[35][37]

In the United States

Since 1972, insurance companies in the United States have covered the cost of dialysis and transplants for all citizens.^[38] By 2014, more than 460,000 Americans were undergoing treatment, the costs of which amount to six percent of the entire Medicare budget. Kidney disease is the ninth leading cause of death, and the U.S. has one of the highest mortality rates for dialysis care in the industrialized world. The rate of patients getting kidney transplants has been lower than expected. These outcomes have been blamed on a new for-profit dialysis industry responding to government payment policies.^[39][40][41] A 1999 study concluded that "patients treated in for-profit dialysis facilities have higher mortality rates and are less likely to be placed on the waiting list for a renal transplant than are patients who are treated in not-for-profit facilities", possibly because transplantation removes a constant stream of revenue from the facility.^[42] The insurance industry has complained about kickbacks and problematic relationships between charities and providers.^[43]

In China

The Government of China provides the funding for dialysis treatment. There is a challenge to reach everyone who needs dialysis treatment because of the unequal distribution of health care resources and dialysis centers.^[44] There are 395,121 individuals who receive hemodialysis or peritoneal dialysis in China per year. The percentage of the Chinese population with Chronic Kidney Disease is 10.8%.^[45] The Chinese Government is trying to increase the amount of peritoneal dialysis taking place to meet the needs of the nation's individuals with Chronic Kidney Disease.^[46]

In Australia

Dialysis is provided without cost to all patients through Medicare, with 75% of all dialysis being administered as haemodialysis to patients three times per week in a dialysis facility.^[47] The Northern Territory has the highest incidence rate per population of haemodialysis,^[48] with Indigenous Australians having higher rates of Chronic Kidney Disease and lower rates of functional kidney transplants than the broader population.^[49] The remote Central Australian town of Alice Springs, despite having a population of approximately 25000, has the largest dialysis unit in the Southern Hemisphere.^[50] Many people must move to Alice Springs from remote Indigenous communities to access health services such as haemodialysis, which results in housing shortages, overcrowding, and poor living conditions.^[51]

History

In 1913,

• colloid chemistry
• Dialysis tubing
• List of US dialysis providers
• Vitamin and mineral management for dialysis
• Nephrology
• Hepatorenal syndrome

References