Renal replacement treatment

The chemist T. Graham was already able to separate urea from urine in 1861 (Jörres 2010). The Dutchman Willem Kolff (1911 - 2009) was the first to develop a dialysis machine suitable for practical use. In 1945, he achieved the first successful dialysis with elimination of approx. 40 g of urea within 6 h in a patient with acute kidney failure by means of the so-called "rotating drum kidney". On her later discharge, the patient showed normal kidney function. In 1947, the Swede Niels Alwall (1904 - 1986) succeeded in developing a dialyzer that not only removed uremic toxins but also provided drainage by controlled ultrafiltration. Such devices were in use in Europe until the 1960s (Hepp 2017).

Intermittent peritoneal dialysis has been used in hospitals since the 1960s and was largely replaced by continuous outpatient peritoneal dialysis at home at the end of the 1970s (Geberth 2011).

In 1960, Frederic Kiil (born in 1921) was the first to develop a dialysis machine that was suitable for the production of larger quantities and thus made dialysis accessible to a larger number of patients.

In 1967, Richard Stewart et al. presented a dialysis machine with capillary membranes, which laid the foundation for the dialyzers still in use today (Hepp 2017).

The first human kidney transplantation was performed by U. Voronoy in 1936 in Kiev. However, it failed because the kidney did not take up its function. In 1954 J. H. Harrison, J. E. Murray and J. P. Merril in Boston performed the first successful kidney transplantation in identical twins (Pfitzmann 2001).

In Germany, the first homologous kidney transplantation was performed in 1963 in Berlin by the urologists W. Brosing and R. Nagel. However, the patient died after 6 days due to a rupture of the transplant. In 1965 the urologist Winfried Vahlensieck (1929 - 2008) in Bonn performed the first successful kidney transplant in Germany (Halling 2015).

The term renal replacement therapy is a generic term for all forms of therapy that exist today for the treatment of terminal kidney failure. They are used:

• to increase renal function (e.g. in intoxications)
• to replace renal function in the event of its limitation or failure due to acute or chronic kidney disease
• for dehydration in cardiac hyperhydration (Herold 2020)

In the case of kidney replacement treatment,:

• Diffusion: Diffusion is the transport of substances from the site of the higher to the site of the lower concentration by a Brownsche-molecular movement (Geberth 2011). In renal replacement therapy, dissolved (low-molecular weight urinary) substances are transferred through a semi-permeable dialysis membrane (Kuhlmann 2015).
• Convection: A filter separates dissolved and undissolved substances from liquids by a hydrostatic pressure gradient. The substances contained in the filtered volume are entrained by the suction of the liquid flow (so-called "solvent drag" [Jacobi 2012]). The transport mechanism of the substances carried along in the filtered volume is called convection (Kuhlmann 2015).
• Ultrafiltration: Ultrafiltration allows the passage or transport of a solution along a semi-permeable membrane due to the hydrostatic pressure difference. With increased pressure on the blood side, for example, the ultrafiltration rate increases (Hörl 2004). The ultrafilter is located at the end of the dialysis circuit and is used to extract plasma water (Kuhlmann 2015).

Currently, approximately 80,000 - 90,000 people in Germany are on dialysis, and the need is increasing worldwide. The reasons for this are multifactorial (e.g. higher life expectancy, age-related reduction in kidney performance, increasing number of hypertensive and diabetic patients, etc.). [Weckmann 2019]). In Europe, the proportion of patients requiring dialysis accounts for 0.1 % (Pfannstiel 2020).

The number of kidney transplants in Germany is between 2,000 and 2,500, and the proportion of living donations rose to 19 % by 2006. The average waiting time for a donor organ is 6 - 7 years (Jocham 2007). There are currently about 11,000 patients on the waiting list for a kidney transplant (Herold 2020).

In dialysis, 3 components are essential:

• the dialyser
• the dialysate circuit
• the extracorporeal circulation

The dialyzer itself consists of a housing that allows blood and dialysate - separated from each other by a membrane - to flow past each other at very high rates (Kasper 2015)

Indication for renal replacement therapy: There are four different clinical pictures which are an indication for renal replacement therapy:

1. acute renal failure (AKI) with:

• life-threatening hyperkalemia (potassium > 6.5 mmol / l) with typical ECG changes
• severe metabolic acidosis with a pH < 7,1
• Occurrence of pulmonary oedema in oliguria/anuria (to control the volume balance)
• manifest uremic syndromes such as neurological deficits, uremic pericarditis etc.
• severe hypo- or hypernatremia
• Hypercalcemia
• Tumor lysis syndrome with hyperuricemia and / or hyperphosphatemia (Kuhlmann 2015)

Note: Dialysis treatment should be given at the latest when the drug treatment is no longer sufficient to control hyperkalemia, excess fluid, acidosis or uremic sequelae. Often the start of dialysis is empirically initiated when urea levels are > 214 mg/dl and clinical signs of recovery of kidney function are missing (Kasper 2015).

2. terminal chronic kidney disease in:

• uremic symptoms such as uremic gastroenteritis with nausea and vomiting, disturbed day and night rhythm, pruritus, uremic encephalopathy, uremic pericarditis etc.
• Hyperhydration with fluid lung / oedema
• refractory hypertension
• renal acidosis (pH < 7.2 and base excess < - 10 mmol / l)
• Reduction of the glomerular filtration rate (at a GFR < 7 ml / min / 173m2 KOF even in the absence of uremic symptoms; in the case of additional diabetes mellitus or malnutrition already earlier)
• Hyperkalemia (with a serum potassium of > 6.5 mmol / l there is an emergency indication)
• renal anaemia (despite adequate substitution of erythropoietin and iron, Hb is < 8.5 g / dl)(Herold 2020)

Note: In case of chronic kidney disease, it is recommended to determine the optimal start individually for each patient, arbitrary creatinine or urea levels are missing. However, previous studies have shown that starting dialysis before the onset of pronounced uraemia symptoms is associated with an increase in life expectancy (Kasper 2015).

3. cardiac-related hyperhydration:

In the cardio-renal syndrome, after fluid withdrawal by dialysis, there is a recompensation of the heart failure and thus a better kidney blood flow with improved kidney performance and decreasing retention values. As a result, the indication for dialysis is given early, possibly already at a GFR of e.g. 20 ml / min (Kuhlmann 2015).

4. intoxications:

Intoxications with dialysable or ultrafilterable toxic substances may require renal replacement therapy for extracorporeal toxin elimination. These substances include various alcohols, barbiturates, bromides, carbamazepine, caffeine, lithium, methotrexate, salicylates, theophylline, valproic acid, etc. (Kuhlmann 2015 / Herold 2020)

The goals of kidney replacement therapy are:

• Elimination of urinary substances (such as urea, creatinine, uremic toxins)
• Elimination of water
• Elimination of toxic substances
• Correction of the electrolyte or acid-base balance
• Avoidance of complications of chronic kidney disease (Herold 2020)

Method of kidney replacement treatment:

There are different methods available for renal replacement therapy:

1. hemodialysis (HD)

2. hemofiltration (HF) in the form of

- continuous arteriovenous hemofiltration (CAVH)

- continuous venous hemofiltration (CVVH)

3. hemodiafiltration (HDF is a combination of hemodialysis and hemofiltration)

4. peritoneal dialysis (PD) in the form of

- machine-supported processes such as:

- automated PD (APD)

- continuous cyclic PD (CCPD)

- nocturnal intermittent PD (NIPD)

- non-machine supported PD such as:

- continuous outpatient PD (CAPD)

5. substained low efficiency dialysis e.g. Genius dialysis (SLED)

6. continuous veno-venous hemofiltration (CVVHD)

7. kidney transplantation (see "Surgical therapy") (Herold 2020 / Kuhlmann 2015)

1. haemodialysis (HD)

With up to 80 % - 85 %, HD is the most frequently used procedure in Germany. The aim of haemodialysis is, on the one hand, the removal of urinary substances (Jörres 2010) and, on the other hand, the restoration of the intra- and extracellular fluid balance as found in normal kidney function (Herold 2020).

Carrying out HD: HD is performed via a dialysis access such as:

- AV catheter for temporary access (e.g. the large-lumen, non-tunnelled Shaldon catheter in the right jugular vein, subclavian vein or femoral vein)

- AV fistula or AV vascular interponate in the case of permanent dialysis access (e.g. the cimino- Brescia shunt located between the radial artery and a forearm vein)

heparinized blood is passed through the dialyzer on one side of the membrane at a flow rate of approximately 300 - 500 ml / min, while on the other side of the membrane the dialysate is passed in the opposite direction at 500 - 800 ml / min (Kasper 2015). The principle of HD is based on diffusion (see "Definition"). In this process, primarily low-molecular substances up to a molecular weight of 25,000 Daltons are eliminated via a semi-permeable membrane, while urinary substances diffuse from the blood along a concentration gradient into the isotonic or isoionic dialysate fluid. The concentration gradient between blood and dialysate is maintained by machine (Kuhlmann 2015). An osmotic or physical pressure gradient between the blood and the dialysate is required to remove water from the blood or body. As a result, water can be removed via a so-called ultrafiltration (Kuhlmann 2015).

Intermittent hemodialysis is usually performed 3 - 7 x / week for 3 - 4 hours up to a maximum of 7 days per week for 8 - 18 hours in cases of acute kidney failure and 6 - 7 x per week for 2 - 3 hours in cases of chronic kidney disease, mainly in dialysis centers, less frequently at home. Home hemodialysis for chronic kidney disease (this is performed in about 0.8 % of dialysis patients) is performed 3 x per week for 4 - 5 hours. Nocturnal HD in chronic kidney disease is performed 3 x a week for 8 hours (Kuhlmann 2015).

Complications of HD:

• on the shunt:
  • Infections
  • Stenoses
  • Bleeding
  • Thromboses
  • Aneurysms
  • steal syndrome
  • Heart failure with high output failure (caused by high shunt volume)
• Hypotension / hypotension (most frequent complication; can occur due to a too high filtration rate; is particularly common in diabetics)
• Hypertension (due to overhydration with uncontrolled fluid intake)
• Dysaquilibrium syndrome (can occur due to the rapid removal of urea and lead to cerebral edema with nausea, vomiting, headaches, visual disturbances)
• Heparin-induced thrombocytopenia type II
• Hypersensitivity reaction against e.g. materials of the membrane etc.
• Hyperkalemia (can become life-threatening)
• Muscle cramps
• Hepatitis B (early vaccination required)
• hepatitis C
• uremic polyneuropathy
• uremic encephalopathy
• Beta2- microglobulin- associated amyloidosis
• Cachexia
• psychological problems (Kasper 2015 / Herold 2020 / Kuhlmann 2015 / Bergmann 1993)

2. hemofiltration (HF, CAVH, CVVH)

A distinction is made between the following variants:

- continuous arteriovenous hemofiltration (CAVH). In this case, the physiological pressure gradient between artery and vein is used.

- continuous venous hemofiltration (CVVH). CVVH requires the use of a pump (Herold 2020).

Performance of the HF:

In HF - in contrast to haemodialysis - the dialysis fluid is not passed through a dialyser. Instead, a haemofiltration solution is injected i.v. and removed by the haemofilter using ultrafiltration . In the process, urinary substances are also removed from the blood by convection (see "Definition") (Kuhlmann 2015). Compared to HD, even larger molecules can be eliminated (Herold 2020). Usually, 14 - 18 l are exchanged 3 x / week for the HF (Kuhlmann 2015). The HF is considered to be equivalent to hemodialysis (HD). However, it has the advantage of a lower circulatory load (Herold 2020). Since HF requires large quantities of sterile substitution fluid, this method is very cost-intensive (Keller 2010). At < 5 %, pure hemofiltration is rarely used nowadays for patients with chronic kidney disease (Kasper 2015). However, it plays a role in patients with acute kidney failure. In these cases dialysis is performed 7 x per week for 24 hours (Kuhlmann 2015).

3. hemodiafiltration (HDF):

Hemodiafiltration combines the advantages of hemofiltration (HF) and hemodialysis (HD), using both diffusion (see "Definition") and convection (see "Definition") for detoxification. In this way, low and medium molecular weight substances can be eliminated (Kuhlmann 2015). In Germany, about 15 % of patients requiring dialysis receive HDF (Kasper 2015). For patients with chronic kidney disease, hemodiafiltration usually takes place three times a week for 4 - 5 hours (Kuhlmann 2015).

4. peritoneal dialysis (PD, CAPD, APD, CCPD, NIPD)

In peritoneal dialysis, a catheter is surgically, laparoscopically or percutaneously implanted into the abdominal cavity approximately 2 weeks before the start of dialysis using the Seldinger technique (Geberth 2011).

In PD, a distinction is made between

• 1. non-machine-assisted PD, such as continuous ambulatory PD (CAPD), where the abdominal cavity is constantly filled with dialysate A total of 4 dialysate changes per day are required, during the day every 4 hours, at night after 8 hours. CAPD is the most commonly used procedure (Geberth 2011).
• 2. machine-assisted PD such as: automated PD (APD), which uses higher volumes of dialysate than CAPD and the dialysate time is shorter. However, since higher molecular weight parts cannot be completely eliminated due to the short residence time, an additional dialysate fill / d with a long residence time is usually required (Geberth 2011).
  • continuous cyclic PD (CCPD), in which the abdominal cavity is also constantly filled with dialysate. The dialysate is changed at night, the last morning filling remains in the abdomen during the day (Geberth 2011).
  • nocturnal intermittent PD (NIPD), in which the dialysate change takes place at night and the abdominal cavity is completely emptied in the morning (Geberth 2011) The advantage of NIPD is that the patient is mobile during the day, there are hardly any cosmetic impairments, and there is the possibility to work or travel (Herold 2020).

In Germany, peritoneal dialysis is used for about 6 % of patients requiring dialysis (Kasper 2015), worldwide for about 10 % (Herold 2020). The majority of these patients today are children who require acute dialysis because of acute kidney failure. In this case, dialysis is performed on 7 days / week over 24 hours (Kuhlmann 2015). In recent years, the so-called concept of "integrated care" has been developed to reduce mortality, which has been confirmed in studies. Peritoneal dialysis is used initially and then switched to HD (see also mortality under "Prognosis") (Herold 2020).

Performing PD: In peritoneal dialysis, the dialysate is instilled into the abdominal cavity through a PD catheter. The dialysate itself often consists of glucose-containing solutions with a low concentration of glucose degradation products = GDPs. For automated PD, diabetics, obese patients and anuric patients, solutions containing icodextrin are generally used to reduce glucose intake (Herold 2020).
The peritoneum represents the semi-permeable membrane with an exchange surface of about 1m2. (Herold 2020). PD can be applied as continuous CAPD (see above) or as automated APD (see above), which usually performs the dialysate exchange with the help of a cycler (Kasper 2015). CAPD in chronic kidney disease is performed 7 days / week over 24 hours, NIPD in chronic kidney disease 7 nights per week and PD in acute kidney failure 7 x / week over 24 hours (Kuhlmann 2015).

Contraindications for PD are:

• existing diseases with an increased risk of peritonitis
• chronic inflammatory bowel disease (CED)
• COPD
• Hernias
• Protein deficiency
• Psychoses etc. (Herold 2020)

Complications of PD:

• PD- associated peritonitis
  • the contamination can be intraluminal, periluminal (along the catheter [Geberth 2011]) or gastrointestinal
  • mainly caused by gram-positive germs (especially staphylococci)
  • the patients complain of abdominal pain, cloudy dialysate; the dialysate contains a laboratory chemical detection of > 100 leukocytes / µg with > 50 % granulocytes and positive dialysate cultures
  • the therapy consists of broad-spectrum antibiotics according to an antibiogram, administration preferably intraperitoneal, otherwise i. v.
  • the dose should be adjusted to the residual renal function
  • Therapy duration at least 2 weeks, for S. aureus, enterococci, gram-negative pathogens at least 3 weeks
  • intraperitoneal heparin should be administered due to the risk of adhesion and catheter obstruction
• exit- side infections
  • this leads to a purulent secretion with or without redness, swelling and crusts
  • the diagnosis is made clinically
  • the systemic antibiosis should be carried out according to the smear or antibiogram (Kuhlmann 2015)
• Tunnel infections
  • In this case, infections of the abdominal wall in the area of the tissue surrounding the catheter occur with swelling, redness, pain and purulent secretion (Kuhlmann 2015)
  • the frequency of exit- side infections or tunnel infections varies between 0.1 % - 1 % episodes / year
  • the diagnosis is made sonographically (low-echo area around the catheter and / or the socket)
  • after a germ smear, antibiotic treatment adapted to the antibiogram
  • the follow-up should also be sonographic (Herold 2020)

Quality indices of PD treatment:

1. peritoneal equilibration test

The peritoneal transport properties should be checked regularly using the so-called combined modified peritoneal equilibration test (PET). According to the recommendation, this should be done for the first time 4 weeks after the start of therapy, then once a year (Herold 2020) and additionally after every case of peritonitis (Kasper 2015). The test is performed with a 3.68 % glucose solution. The ultrafiltration properties of the peritoneum, the sodium sieving and the free water transport are examined. A decrease in sodium sieving and free water transport are currently the best available parameters for early detection of encapsulating peritoneal sclerosis (EPS). A marker for peritoneal fibrosis is the decrease of free water transport (Haag- Weber 2017).

2. determination of the renal residual function

• In patients with existing urinary excretion, the residual renal function should be determined at least every six months (Herold 2020), as this contributes significantly to detoxification and drainage.

• Since residual renal function correlates inversely with patient mortality, all measures to maintain renal function should be taken. These include:

  • - Avoidance of higher doses of non-steroidal anti-inflammatory drugs.

  • - Avoidance of nephrotoxic antibiotics such as cephalosporins, penicillamine, sulfonamides, etc. [Weckmann 2019])

  • - Avoidance of large doses of contrast medium (Haag- Weber et al. were able to prove in a study that small amounts of contrast medium do not lead to any significant impairment of residual renal function) (Kuhlmann 2015)

5. sustained low efficiency dialysis e.g. Genius Dialysis (SLED)

• The SLED is generally used in acute renal failure. The principle is based on diffusion (see "Definition"). The blood flow is between 100 - 200 ml / min for a patient weighing approx. 70 kg, the dialysate flow between 200 - 500 ml / min. The SLED is used 7 days / week for 8 - 12 hours (Kuhlmann 2015).

6. continuous veno-venous hemofiltration (CVVHD)

• The CVVHD is also used for acute renal failure. The principle is also based on diffusion (see "Definition"). Continuous hemodialysis with citrate anticoagulation is used for 24 hours over 8 days / week (Kuhlmann 2015).

7. kidney transplantation see "Surgical therapy

Anticoagulation: As the coagulation system is activated when the blood comes into contact with an artificial surface, the patient requires anticoagulation during dialysis (Kuhlmann 2015). Fractionated and unfractionated heparin can be used as medication. If heparin is intolerant, substances such as argatroban, danaparoid or recombinant hirudin can be used (Geberth 2011).

• For intermittent dialysis the standard therapy is: Recommended dosage: initial dose 2,500 - 5,000 I. E. Heparin, then 500 - 1,000 I. E. Heparin / hour (Kuhlmann 2015). Antidote: The antidote to heparin is protamine sulphate. 1 ml protamine sulfate neutralizes approx. 1,000 - 1,4000 I. E. Heparin (Geberth 2011).
• Anticoagulation in heparin-induced thrombocytopenia: In heparin-induced thrombocytopenia, a distinction is made between Type I and Type II.
• HIT type I: HIP type I occurs in the first 5 days after the start of therapy and is not immunologically caused. The platelet count remains > 100,000 / µl (Kuhlmann 2015). It is not necessary to discontinue heparin therapy (Herold 2020).
• HIT Type II: HIT II manifests itself approx. 5 - 10 days after the start of treatment (in already sensitized patients the symptoms appear only a few hours after the first heparin injection). This is an immunological antibody induced HIT (also known as "immune mediated HIT" or "white clod syndrome" [Kuhlmann 2015]). One should always consider a HIT II if the platelets drop by 50% from the highest value from the 4th day after the start of treatment, even if the number of platelets is still in the range of ≥ 150 x 10 9/ l (Geberth 2011). HIT II results in antibody formation against the platelet factor- 4-heparin complex with a drop in platelet count with increased thrombin formation and the associated risk of vessel occlusion (Herold 2020). Both the amputation rate and the mortality rate are high (20 % each) [Geberth 2011]. The antibody test is sufficiently sensitive but not specific (many dialysis patients are positive without having HIT type II). For this reason, if thrombocytopenia occurs, heparin treatment should be discontinued immediately rather than waiting for the test result (Kuhlmann 2015).

The following drugs are available as an alternative to heparin:

1. argatroban (Argatra®). The degradation takes place in the liver, the half-life is short with 39 - 51 min (Kuhlmann 2015). Contraindication: Patients with bleeding tendency (in this case citrate [see below] can be used [Geberth 2011]). Dosage recommendation: Initially as a bolus 250 µg / kg bw, then 2 µg / kg bw / min or 0.5 µg / kg bw / min in patients with liver dysfunction (Geberth 2011). The ACT value should be 170 - 230 s during treatment (Kuhlmann 2015)

2nd citrate: In patients at risk of bleeding, treatment with extracorporeal sodium citrate can be avoided. Since citrate is metabolised to bicarbonate, there is a risk of metabolic alkalosis during treatment. The bicarbonate value of the dialysis solution should therefore be reduced accordingly (e.g. - 4 mmol / l) (Kuhlmann 2015). Extracorporeal calcium losses should be compensated for by additional doses of calcium, as well as magnesium, as this is also lost through complex formation with citrate. The postfilter calcium level should be 0.2 - 0.4 mmol / l (Schubert 2018). Dosage recommendation: Citrate 50 mmol / h, parallel to this calcium 17.5 mmol / l and magnesium 0.5 mmol / l (Kuhlmann 2015).

Danaparoid (trade name Orgaran®) The half-life is 25 hours for healthy kidney patients and longer for dialysis patients. Cross-allergies to heparin are found in about 10 %. Dosage recommendation: The system should be filled with 750 I. E. The system should be flushed.

Patients < 50 kg receive:

• 1. HD 2.500 I. E.
• 2. HD 2,000 I. E.
• for further HDs depending on the anti-Xa level before dialysis:
• Anti- Xa < 0.3: 2,000 I. E.
• Anti- Xa 0,3 - 0,35: 2.000 I. U.
• Anti- Xa > 0,35: 1.500 I. E.
• Patients > 50 kg receive:
  • 1. HD 3,750 I. E.
  • 2. HD 3,750 I. E. E.
  • for further HDs depending on the Anti- Xa- level before dialysis:
  • Anti- Xa < 0.3: 3,000 I. E.
  • Anti- Xa 0,3 - 0,35: 2.500 I. E.
  • Anti- Xa > 0,35: 2.000 I. E. (Kuhlmann 2015)

Another form of renal replacement treatment is kidney transplantation(NTX). It is clearly superior to all other forms of renal replacement therapy in terms of quality of life. The transplantation ability of a patient should be evaluated from a GFR of < 15 ml / min / 173m2 KOF and the patient should be prepared accordingly. In addition, the patient should also be made aware of the possibility of preemptive transplantation (transplantation before initiation of dialysis treatment) (Kuhlmann 2015).

Indication for kidney transplantation is a:

• terminal CKD

Vaccinations: Preoperatively, patients should have sufficient vaccination protection or have it refreshed regularly, e.g.:

- polio

- Diphtheria

- Tetanus

- hepatitis B

- Pneumococci

- Influenza

Postoperatively, no vaccinations should be given for the first 6 months (except the flu vaccination) and afterwards only vaccinations with inactive inactivated vaccines (live vaccines are contraindicated because of the lifelong immunosuppression) (Herold 2020)

• Donation of corpses: The waiting period for a corpse donation is about 5 - 6 years (Herold 2020).
• Living donation: Donors are close relatives or people from the immediate environment of the affected person. In the case of living donation, there is the possibility of an AB0-incompatible transplant (Herold 2020).

Note: Postoperative: Transplanted patients require lifelong immunosuppression (Herold 2020).

The progression of chronic kidney disease (CKD) up to the need for renal replacement therapy is particularly responsible:

• Non-influenceable factors such as
  • male sex
  • higher age
  • positive family history
  • genetic factors
• Influensible factors such as
  • arterial hypertension
  • Tobacco consumption
  • Dyslipidemia
  • Albumin excretion rate
  • increased BMI (Wolf 2020)

Early dialysis or kidney transplantation (NTX) improves the prognosis (Woolliscroft 2013).

For dialysis patients between the ages of 20 and 40, a kidney transplantation prolongs the life expectancy by about 17 years compared to dialysis treatment.

The prognosis after NTX is better for patients with living donation than for patients with cadaver donation due to the short ischemia time and the possibly more motivated postoperative compliance (Herold 2020)

• Mortality: In dialysis patients, the occurrence of alkalosis (> 27 mmol HCO3) is associated with increased mortality (Kuhlmann 2015).

Peritoneal dialysis (PD) has a lower mortality in the first 2-3 years compared to haemodialysis (HD), but with long-term PD, mortality is higher compared to HD. In order to reduce mortality, the so-called "integrated care" concept has been developed, in which peritoneal dialysis is initially used and later switched to HD (Herold 2020).

The 5-year mortality rate for dialysis patients with a low risk profile (especially no diabetes mellitus and no coronary heart disease) is about 10 % and can be > 80 % at high risk (Kuhlmann 2015). Compared to dialysis, the life expectancy of a transplanted patient is 2 - 3 times higher (Kuhlmann 2015). After a kidney transplantation the 5-year survival rate is 77 % for cadaveric donations and 85% for living donations (Herold 2020). The best long-term results have preemptive transplantation (transplantation before initiation of dialysis treatment) (Kuhlmann 2015).

Although lifelong immunosuppression according to NTX leads to an accumulation of specific infections and the tumor risk is 4 times higher under immunosuppression (Kuhlmann 2015), cardiovascular diseases are the main cause of death in dialysed patients (Kasper 2015).

follow-up: patients on haemodialysis should be monitored regularly:

• Nutritional status
• Weight curve
• overall wellbeing
• Blood pressure
• Assessment of the dialysis shunt
• Determination of the following laboratory values in particular:
  • Serum phosphate
  • Serum calcium
  • Serum potassium (danger of hyperkalemia)
  • Parathyroid hormone
  • Degree of anaemia (Herold 2020)

No more blood must be taken from the affected arm before the shunt is placed.

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