Haemodialysis

HAEMODIALYSIS

The Problem

Kidneys play a major role in intoxicating the body. Damage of the kidneys is irreversible and has no known cure thus can only be treated to sustain life. If you develop kidney failure, there is an interruption in the excretion and osmoregulation process which results your body in experiencing a build up of harmful wastes, rise in blood pressure and retaining of excess fluids. [7] Your kidneys also produce hormones and balance chemicals in your system thus; failure may cause you problems with anaemia and conditions that affect your bones, nerves, and skin. Common sign and symptoms of renal failure include fatigue, bone problems, joint problems, itching, and restless legs. [11]

Haemodialysis; a Treatment Option

Dialysis treatments help you feel better and live longer, but does not cure kidney failure. Treating renal failure is not secluded to one type of treatment which is not often known by the general public, previously including myself. It is crucial in selecting the correct treatment as the choice made will highly affect ones day-to-day lifestyle with each treatment having their pros and cons. However, treatments are interchangeable if a patient feels uncomfortable or experiences difficulties in what they currently undergo.

Haemodialysis is a primarily diffusion-based therapy in which solute from the patient's blood crosses a semipermeable membrane (the dialyzer) into the dialysate at a location outside the body. [5] Its extracorporeal location [6] distinguishes haemodialysis from other treatments such as peritoneal dialysis. Removal of excess fluid is attained by ultrafiltration, in which hydrostatic pressure causes the bulk flow of plasma water through the membrane. With advances in vascular access, anticoagulation, and the production of reliable and efficient dialyzers, haemodialysis has become the predominant method of treatment for acute and chronic renal failure.

How it Works

Blood and dialysate are flowed on opposite sides of the semipermeable membrane in a counter current direction for maximal efficiency of solute removal. [3] Dialysate composition, the characteristics and size of the membrane in the dialyzer, and blood and solute flow rates all affect solute removal. The electrolyte composition of the dialysate is chosen meticulously [3] because ion fluxes (particularly potassium) can induce arrhythmias. The standard glucose concentration of dialysate is 200mg/dl. [6]

Arm with an arteriovenous fistula.Vascular Access

Before starting haemodialysis, an important step is preparing a vascular access i.e. a site on your body from which your blood is removed and returned. [13] It needs to be prepared either weeks or months before the actual procedure starts [13] and must be able to deliver blood flow rates as high as 400 to 500ml/min through the dialyzer. [6] There are two general types available; catheters placed in a central vein which is often used by patients with acute renal failure and more permanent arteriovenous shunts placed peripherally [6], usually in the forearm or upper arm and occasionally in the leg or on the chest.

The standard duration for each haemodialysis treatment is three dialyses per week for 3 to 5 hours per treatment depending on patient size, residual renal function, and access blood flow. It is done on alternate days as a routine with either a choice of Monday, Wednesday, Friday or Tuesday, Thursday, Saturday commonly referred as 1,3,5 and 2,4,6 respectively. [7] The large-bore needles required for haemodialysis are inserted into the A-V fistula or graft under local anaesthesia. There is no pain with initiation of dialysis if catheter access is used. The procedure itself is very safe, having been administered in many centres over a million times each without any serious complications.

Anticoagulation

During haemodialysis, blood clotting can happen due to initiation of the cascade of events in the intrinsic clotting pathway resulting from exposure of fresh blood to an artificial surface. [6] If unchecked, this would normally lead to clotting in the dialyzer and tubing within only a few minutes after starting the blood pump. For every extracorporeal device, a method for inhibiting this clotting process is essential. Most centres inhibit blood clotting both in the patient and in the dialyzer temporarily by injecting heparin intravenously in small to moderate doses during dialysis. [4] In some centres, a low dose of heparin is also infused continuously directly into the dialyzer to enhance the effect locally. [6]

Factors Influencing the Prognosis of Kidney Patients on Haemodialysis

Haemodialysis is a life saving treatment modality. However, the prognosis for renal patients may differ according to the following factors.

Good prognosis means higher chance of cure for the patients but in this case of no cure, it refers to higher chances of survival.

Survival of Haemodialysis Patients

Widespread data of dialysis patient survival is found in annual reports of the European Dialysis and Transplant Association. [2] For the entire series based on 650 patients treated over 3 months at Necker Hospital and associated centres, the overall cumulative actuarial survival rate reaches 92.7% at 1 year, 84.3% at 3 years and 75.7% at 5 years (a mean annual mortality of about 5% after the first year). [2] From the graph, survival of patients under 50 is higher than that of above 50 years of age. Despite that, overall mortality in patients is low showing the reliability of performing haemodialysis. [14]

Complications of Haemodialysis

Hypotension is the most frequent complication faced during haemodialysis. For patients dialyzed following the usual schedule of three treatments per week, hypotension must be anticipated with a treatment plan in advance. Prevention can be achieved by monitoring dry weight, precise ultrafiltration, stabilizing body temperature, careful choice of dialysate sodium and calcium concentrations, and reduction of medications for hypertension immediately before dialysis. [5]

Muscle Cramps happen as a result of plasma volume contraction and rapid sodium fluxes usually during ultrafiltration. Restriction in fluid intake to ensure weight gain of not more than 2kg between treatments, stretching exercises, and hypertonic saline injections are among the preventive measures that are taken. [5]

Hypoxemia is a deficiency in oxygen which is important to take note during dialysis in patients with compromised cardiopulmonary function. Predisposed patients need to be given supplemental oxygen and dialyzed with synthetic copolymer membranes using bicarbonate dialysate. [5]

Arrhythmias in predisposed patients are contributed by hypoxemia, hypotension, removal of arrhythmic agents during dialysis and rapid changes in serum bicarbonate, calcium, magnesium and potassium. It is a disturbance in the normal rhythm of the heart making it necessary for continuous electrocardiogram monitoring in high-risk patients. [5]

Acquired Renal Cystic Disease. Up to 80% of dialysis patients treated over 3 years develop multiple renal cysts. It is recommended that screening of haemodialysis patients by ultrasonography or computed tomography be carried out after 3 years of dialysis treatment to detect any malignant changes. [5]

Bleeding. Despite uremia causing platelet dysfunction which can be assessed by measuring bleeding time, anticoagulants must still be given to the patient to prevent clotting of the extracorporeal circuit. The dose of heparin as a drug of choice can be adjusted according to the clotting time. [4] Nevertheless, in suitable cases dialysis without heparin may be conducted. [4]

Through personal observations of haemodialysis patients, I found that there are patients who are incompatible with certain types of treatment modalities. This may be attributed to fine and narrow veins or other diseases experienced by the patient.

Alternative Treatments

Peritoneal dialysis differs from haemodialysis as cleansing happens inside the body. It uses the lining of your abdomen called the peritoneal membrane to filter blood. The dialysis solution is inserted through a catheter initially placed surgically into your abdomen 2 or 3 weeks beforehand. [9] Waste, chemicals and extra water diffuses into the dialysis solution which is drawn out of the body after several hours. [9] The cycle is repeated by refilling the abdomen with fresh dialysis solution.

Illustration of a patient receiving peritoneal dialysis.

Illustration of a kidney transplantation.Kidney transplant is surgically placing a normal functioning kidney belonging to another person into your body. The new kidney is positioned inside your lower abdomen and its artery and vein is connected to your own. [10] Notice that the diseased kidneys do not have to be removed. The new kidney can be used soon after surgery or may take up a few weeks to function like your own kidneys when undamaged.

The above is quoted from a published book so the information should be factual unless it has become out of date since being published. Newer discoveries would not be available.

Transplantation is closest to cure but despite the best match available there is still a tendency of rejection by the body. In my opinion, the elderly should not opt for this treatment.

Social, Psychological and Economic Implications

Patients can live normally for a long time despite renal failure but gradually activities will start to get limited due to increasing weakness and anaemia. Strict diets must be followed and frustration often develops especially in young children and adolescents. Feelings of weakness, discouragement and even anxiety greatly affect the patients and a few suicides have been reported to support this. [1]

The cognitive capability of the patient is also gradually lowered, more so to the elderly. Having to deal with these patients prove to be quite challenging. To give more comfort to elderly patients, I personally feel that instead of undergoing peritoneal dialysis every day, haemodialysis is a better option. After going through dialysis, the patient feels exhausted and this can prolong the whole day. As haemodialysis is done on alternate days, the patient is able to rest a day without the treatment giving more quality of life. This can also help reduce depression experienced by the patient.

A recent study finds that the more pills taken by kidney dialysis patients, the more side effects they suffer. [12]

MedlinePlus works to update people with current health information. It is a service provided by the U.S NATIONAL LIBRARY OF MEDICINE and the NATIONAL INSTITUTES OF HEALTH which are well established sources making it reliable. Moreover, the study is referred to the Clinical Journal of the American Society of Nephrology ensuring its validity. A limitation would be lack in variation as sources focus on the US instead of the whole world. I feel that the issue above should be looked upon seriously as researchers say that increase in prescribed pills do not improve phosphorus levels instead jeopardizes their quality of life.

Different statistical studies indicate that a minimum of 40-50 patients per million citizens annually enter the fatal phase of kidney failure requiring haemodialysis. [1] These studies have been confirmed by data from countries that have successfully succeeded in treating all their chronic uremic patients such as Sweden and Australia, making it very reliable. [1] Haemodialysis creates a financial problem for the national budget due to its high cost. The high cost treatment for a small number of patients strikes an imbalance in the general budget for the entire population. To reduce the financial burden, home dialysis and renal transplantation is promoted.

Future Development

Haemodialysis therapy has been in clinical practice for over 60 years. A review of treatment options to intensify haemodialysis is being continuously carried out to improve the efficacy and safety of the procedure. Although it is not without risk, by far I feel that it has proven to be life sustaining for majority of patients with end-stage renal disease.

Bibliography

[1] Hamburger, Crosnier, Grunfield (1979) Treatment of Terminal Renal Failure: General Concepts of Supportive Therapy, Nephrology, USA: Wiley Medical Publication

[2] Hamburger, Crosnier, Grunfield (1979) Results and Limitations of Long-term Dialysis Treatment, Nephrology, USA: Wiley Medical Publication

[3] Paul Glynne, Andrew Allen, Charles Pusey (2002) Basic Principles of Haemodialysis, Acute Renal Failure In Practice, London: Imperial College Press

[4] Allen R. Nissenson, Richard N. Fine (2008) Methods of Haemodialysis Anticoagulation, Handbook of Dialysis Therapy 4th Edition, USA: Saunders Elsevier

[5] Christopher S. Wilcox, C. Craig Tisher (2005) Hemodialysis and Continuous Therapies, Handbook of Nephrology & Hypertension 5th Edition, USA: LIPPINCOTT WILLIAM & WILKINS

[6] Francesco P. Schena, Alexander M. Davidson, Hein A. Koomans, Jean-Pierre Grunfeld, Fernando Valderrabano, Fokko J. Van der Woude (2001) Hemodialysis, Clinical Medicine Series, Nephrology, England: Mc Graw - Hill

[7] Treatment Methods for Kidney Failure: Hemodialysis-http://kidney.niddk.nih.gov/kudiseases /pubs/hemodialysis/index.htm: retrieved on December 21, 2008

[8] Hemodialysis-en.svg-http://en.wikipedia.org/wiki/File:Hemodialysis-en.svg : retrieved on June 20, 2009

[9] How PD Works- http://www.kidney.niddk.nih.gov/kudiseases/pubs/peritoneal/: retrieved on December 25, 2008

[10] Treatment Choice: Kidney Transplantation-http://www.kidney.niddk.nih.gov/kudiseases/ pubs/choosingtreatment/index.htm: retrieved on December 25, 2008

[11] Conditions Related to Kidney Failure and Their Treatments-http://www.kidney.niddk.nih.gov /kudiseases/pubs/peritoneal/: retrieved on December 25, 2008

[12] For Dialysis Patients, More Pills = Lower Quality of Life-http://www.nlm.nih.gov/medlineplus /news/fullstory_84219.html: retrieved on June 3, 2009

[13] Vascular Access for Haemodialysis-http://kidney.niddk.nih.gov/kudiseases/pubs/hemodialysi s/index.htm: retrieved on December 21, 2008

[14] Domenico Santoro, Giampiero Mazzaglia, Vincenzo Savica, Maurizio Li Vecchi, Guido Bellinghieri (2009) Hepatitis Status and Mortality in Haemodialysis Population, Informa Healthcare, Renal Failure 31:6-12