DIALYSIS

DIALYSIS


What is dialysis?
The kidneys are responsible for filtering waste products from the blood. Dialysis is a procedure that is a substitute for many of the normal duties of the kidneys. The kidneys are two organs located on either side of the back of the abdominal cavity. Dialysis can allow individuals to live productive and useful lives, even though their kidneys no longer work adequately. In the United States, there are over 200,000 people who use dialysis techniques on an ongoing basis.
Dialysis helps the body by performing the functions of failed kidneys. The kidney has many roles. An essential job of the kidney is to regulate the body's fluid balance. It does this by adjusting the amount of urine that is excreted on a daily basis. On hot days, the body sweats more. Thus, less water needs to be excreted through the kidneys. On cold days, the body sweats less. Thus, urine output needs to be greater in order to maintain the proper balance within the body. It is the kidney's job to regulate fluid balance by adjusting urine output.
Another major duty of the kidney is to remove the waste products that the body produces throughout the day. As the body functions, the cells use energy. The operation of the cells produces waste products that must be removed from the body. When these waste products are not removed adequately, they build up in the body. An elevation of waste products, as measured in the blood, is called "azotemia." When waste products accumulate they, cause a sick feeling throughout the body called "uremia."
When do patients require dialysis?

Patients usually require dialysis when the waste products in their body become so high that they start to become sick from them. The level of the waste products usually builds up slowly. Doctors measure several blood chemical levels to help decide when dialysis is necessary. The two major blood chemical levels that are measured are the "creatinine level" and the "blood urea nitrogen" (BUN) level. As these two levels rise, they are indicators of the decreasing ability of the kidneys to cleanse the body of waste products.
Doctors use a urine test, the "creatinine clearance," to measure the level of kidney function. The patient saves urine in a special container for one full day. The waste products in the urine and in the blood are estimated by measuring the creatinine. By comparing the blood and urine level of this substance, the doctor has an accurate idea of how well the kidneys are working. This result is called the creatinine clearance. Usually, when the creatinine clearance falls to 10-12 cc/minute, the patient needs dialysis.
The doctor uses other indicators of the patient's status to decide about the need for dialysis. If the patient is experiencing a major inability to rid the body of excess water, or is complaining of problems with the heart, lungs, or stomach, or difficulties with taste or sensation in their legs, dialysis may be indicated even though the creatinine clearance has not fallen to the 10-12 cc/minute level.

What types of dialysis are there?

There are two main types of dialysis: "hemodialysis" and "peritoneal dialysis." Hemodialysis uses a special type of filter to remove excess waste products and water from the body. Peritoneal dialysis uses a fluid that is placed into the patient's stomach cavity through a special plastic tube to remove excess waste products and fluid from the body.
During Hemodialysis, blood passes from the patient's body through a filter in the dialysis machine, called a "dialysis membrane." For this procedure, the patient has a specialized plastic tube placed between an artery and a vein in the arm or leg (called a "gortex graft"). Sometimes, a direct connection is made between an artery and a vein in the arm. This procedure is called a "Cimino fistula." Needles are then placed in the graft or fistula, and blood passes to the dialysis machine, through the filter, and back to the patient. In the dialysis machine, a solution on the other side of the filter receives the waste products from the patient.
Peritoneal dialysis uses the patients own body tissues inside of the belly (abdominal cavity) to act as the filter. The intestines lie in the abdominal cavity, the space between the abdominal wall and the spine. A plastic tube called a "dialysis catheter" is placed through the abdominal wall into the abdominal cavity. A special fluid is then flushed into the abdominal cavity and washes around the intestines. The intestinal walls act as a filter between this fluid and the blood stream. By using different types of solutions, waste products and excess water can be removed from the body through this process.

What does the patient do during dialysis?

Hemodialysis

Treatment for hemodialysis takes place in a hemodialysis unit. This is a special building that is equipped with machines that perform the dialysis treatment. Special equipment adds the proper materials to purified water for the dialysis machines. The dialysis unit is also the place where patients can receive dietary counseling and help with social needs.
Patients generally go to the dialysis unit three times a week for treatment. For example, the schedule is either on Monday, Wednesday, and Friday or Tuesday, Thursday, and Saturday. Before treatment, patients weigh themselves so that excess fluid accumulated since the last dialysis session can be measured. Patients then go to assigned chairs that are like lounge chairs. The area of the graft or fistula (the connection between the artery and vein), is cleaned thoroughly. Two needles are then inserted into the graft or fistula. One takes the blood to the machine where it is cleaned. The other needle allows blood that is returning to the patient to go back into the patient's body.
Treatments last from 2 ½ to 4 ½ hours. During this time, the dialysis staff checks the patient's blood pressure frequently and adjusts the dialysis machine to ensure that the proper amount of fluid is being removed from the patients body. Patients can read, watch television, sleep, or do other work during treatment.
Peritoneal Dialysis

Peritoneal dialysis requires the patient to play a more active role in their dialysis treatment. Of primary importance is the patient's responsibility for maintaining a clean surface on the abdomen, where treatment is administered, in order to prevent infection.
In this process, the patient weighs herself/himself to determine the fluid to be used. The patient then puts on a mask and cleans the peritoneal catheter site. Fluid that has been allowed to stay in the peritoneal cavity is drained back into the plastic bag that originally contained the fluid. The patient then disconnects this bag and connects a new bag of solution that is allowed to drain into the peritoneal cavity. Once the fluid is in the body, the new bag is rolled up and placed in the patient's underwear until the next treatment. This procedure usually takes 30 minutes to accomplish and must be done four to five times a day.
As an alternative to this treatment, some patients on peritoneal dialysis use a machine called a "cycler." This cycler is used every night. Five to six bags of dialysis fluid is used on the cycler and the machine automatically changes the fluid while the patient sleeps.

What are the advantages of the different types of dialysis?

Each of the two types of dialysis, hemodialysis and peritoneal dialysis, has advantages and disadvantages. It is up to the patient to decide which of these procedures is best by considering her/his life style, other medical conditions, support systems, and how much responsibility and participation in the treatment program he/she desires. Each patient must view the two types of dialysis procedures from her/his own perspective.
Regardless of which type of dialysis is chosen , patients have certain responsibilities such as following a diet program, watching their fluid intake and taking special vitamins and other medicines to control blood pressure and calcium and phosphorus balance.
For many patients, the major advantage of hemodialysis is minimal participation in the treatment. However, patients are required to adhere to a specific schedule and travel to the dialysis unit. Hemodialysis also requires stricter diet control and fluid control than peritoneal dialysis.
For those patients preferring more independence, peritoneal dialysis allows for more flexible scheduling and can be performed at home. The patient still must undergo a certain amount of dialysis each day, but can alter the exact timing of the dialysis procedure. On the other hand, peritoneal dialysis must be done every day of the week.
The major problem with peritoneal dialysis is infection. The patient has a plastic tube that goes from the peritoneal cavity to the outside of the body and this is a potential site for the entry of bacteria into the body. Great emphasis is placed on cleanliness and technique during the training sessions.

Indications and contraindications of dialysis

Indications for Dialysis -In Chronic Renal Failure
In patients with chronic renal failure factors to be considered before initiating dialysis should include comorbid conditions and patient preference. Timing of therapy is dictated by serum chemistries and symptoms.
A) Absolute indications
Uremic Pericarditis
Uremic Encephalopathy or Neuropathy
Pulmonary edema (unresponsive to diuretics)
Severe Hypertension
Severe hyperkalemia
Intractable acidosis
Severe Bleeding diathesis
Persistent gastrointestinal symptoms
S.Creatinine more than 12 mg/dl, BUN more than 100 mg/dl
B) Relative indications
Mild encephalopathy or neuropathy
Severe edema (unresponsive to diuretics)
Progressive gastrointestinal symptoms
Recurrent GI “itis”: stomatitis, gastritis, dudenitis, pancreatitis
Ascitis without hepatic disease
Anemia refractor to Erythropoietin
Mild Bleeding diathesis
Pruritus
Infectious complications
Depression
C) Early indications
Decrease ideal body weight
Decrease in muscle mass (decrease s creatinine or its clearance)
Decrease in s.albumin to less than 4 g/l
GFR less than 15 ml/min (by I iothalamate)
S. Creatinine >10 mg/dl and bun >100 mg /dl
Decrease in s.transferrin
Low total cholesterol
Growth retardation in children
D) Specific indications for peritoneal dialysis
Patients with cardiovascular or hemodynamic instability
Hemodialysis patients with vascular access failure or can not be created (e.g. diabetic patients)
High risk of anti coagulation
Patients in the older age group (over 65) and small children
Severe hemodialysis-related symptoms or disequilibrium
Social reason
Indications for Dialysis other than chronic renal failure
1-Acute renal failure
2-Poisons and Drug intoxication
3-Hypercalcaemia
4-Hyperuricemia
5-Hypothermia
6-Metabolic alkalosis (special dialysis solution required)

Dialyzable drugs and Poisons (partial list)
a) Barbiturates : Phenobarbital -Pentobarbital -Amobarbital
b) Alcohol's : Methanol -Ethanol -Ethylene glycol -Isopropanol
c) Analgesics : Acetylsalicylic acid -Methylsalicylate
d) Metals : Calcium -Potassium -Sodium -Lithium
e) Endogenous toxins : Uric acid -Uremic toxins -Hyperosmolar state
f) Halides : Bromide
e) Miscellaneous : Theophylline -Mannitol -Radiocontrast -Thiocynate -
Boric acid -Aniline
NB 1) Dialysis for poisoning should be considered only when supportive measures are ineffective or there is impending irreversible organ toxicity.
2) Hemoperfusion is required in some cases

Factors to be considered in determine drug’s dialyzability:
1) Dialysis related factors:
Dialyzer membrane characteristics
Surface area
Blood flow rate
Dialysate flow rate
Degree of ultrafitration
Duration of dialysis

2) Drug related factors :
Availability of the drug in the plasma
Drug pharmacokinetic characteristics
Drug molecular weight (<500 cross the membrane more readily)
Drug solubility (water soluble are dialyzable than lipid soluble)

Factors Determinants for Dialysis
Factors determining the mode of chronic dialysis should include medical and non medical factors which have an impact on the treatment modality. Physicians have the responsibility to discuss the therapeutic options and offer their advice and recommendations about the choices. In general renal transplantation should be recommended as the preferred mode of renal replacement therapy in whom surgery and immunosupression is safe and feasible.
Medical Factors
1. Age
2. Comorbid medical illnesses
3. Patient survival
4. Patient rehabilitation
5. Quality of life
Non Medical Factors
1. Government-imposed Economic limitations
2. Physician and Patient bias
3. Resource availability
4. Social ,Religious ,Cultural mores
5. Availability of transplantation
6. Family support
7. Cost , race , sex , reimbursement

Contraindications of Dialysis therapy
Principally there is no absolute contraindication to dialysis therapy. Advanced age in and of itself is not a contraindication to dialysis therapy. Many elderly are physiologically equivalent to young patients.
Relative contraindications to dialysis therapy
1. Advanced malignancy (except multiple myeloma)
2. Alzheimer’s disease
3. Multi-infarct dementia
4. Hepatorenal syndrome
5. Advanced liver cirrhosis with encephalopathy
6. Hypotension unresponsive to pressors
7. Terminal illness
8. Organic brain syndrome
Contraindication for Peritoneal dialysis
Absolute
1. Peritoneal fibrosis
2. Pleuroperitoneal leak
Relative Major
1. Chronic Ostomies
2. Severe hypercatabolic state
3. Fresh aortic prosthesis
4. Recent Abdominal surgery
5. Recent Thoracic surgery
6. Extensive Abdominal adhesions
7. Quadriplegia
8. Blindness
9. Physical handicaps
10. Mental Retardation
Relative Minor
1. Polycystic Kidney disease
2. Diverticulosis
3. Obesity
4. Peripheral vascular disease
5. Hyperlipidemia
6. Social

Introduction
Background
Chronic renal failure (CRF) requiring dialysis or transplantation is known as end-stage renal disease (ESRD). In the United States, diabetic nephropathy is the most common and hypertension the second most common cause. Along with glomerulonephritis, these cause approximately 75% of all adult cases. Certain geographic areas have a high incidence of HIV nephropathy. Genetic kidney disease such as polycystic kidney disease is a common cause in young adults.1
Patients with end-stage renal disease (ESRD) are commonly encountered in the ED with problems related to the metabolic complications of their renal disease or dialysis complications. Various problems related to vascular access in patients on hemodialysis and to abdominal catheters in patients using continuous ambulatory peritoneal dialysis (CAPD) are also common. Patients who have undergone renal transplantation may experience a variety of transplant-related conditions.
Patients with chronic renal failure often present to the ED with an unrelated condition. In these cases, the level of renal function may have important implications for diagnosis and treatment.
Pathophysiology
All major organ systems are affected by renal failure. Prevalence of symptoms is a function of the glomerular filtration rate (GFR), which averages 120 mL/min in a healthy adult. As the GFR falls to less than approximately 20% of normal, symptoms of uremia may begin to occur. They almost are invariably present when the GFR decreases to less than 10% of normal. Measuring GFR requires a timed urine collection as well as measurement of serum creatinine. However, it can be accurately estimated from a patient's age, weight, gender, and serum creatinine level. Online calculators are available to automate the calculation.2

Signs and symptoms of renal failure are due to overt metabolic derangements resulting from inability of failed kidneys to regulate electrolyte, fluid, and acid-base balance; they are also due to accumulation of toxic products of amino acid metabolism in the serum. Signs and symptoms include the following:
Systemic signs

Malaise, weakness, and fatigue are very common.
Gastrointestinal signs

GI disturbances include anorexia, nausea, vomiting, and hiccups. Peptic ulcer disease and symptomatic diverticular disease are common in patients with CRF.
Neurological signs

Peripheral neuropathy and restless legs syndrome are the most common neurologic complications of CRF. Seizures may occur due to uremia, and the prevalence of stroke is increased.
Hematologic signs

Anemia is inevitable in CRF because of loss of erythropoietin production. Abnormalities in white cell and platelet functions lead to increased susceptibility to infection and easy bruising.
Dermatologic signs

Pruritus is a common dermatologic complication assumed to be secondary to accumulation of toxic pigments (urochromes) in the dermis.
Metabolic/endocrine signs

Volume overload occurs when salt and water intake exceeds losses and excretion. This causes congestive heart failure (CHF) and exacerbates hypertension. Hyperkalemia is the most common immediately life-threatening metabolic complication of renal failure and may develop suddenly when GFR is severely reduced. Anion gap acidosis results from decreased hydrogen ion excretion and may exacerbate hyperkalemia. Hypocalcemia is potentially life threatening and results from loss of vitamin D and increased parathyroid hormone levels. Hypermagnesemia also may occur.

Cardiac signs

Volume overload may cause CHF and pulmonary edema. Hypertension contributes to cardiovascular disease. Dyslipidemia is a primary risk factor for cardiovascular disease and a common complication of ESRD. Uremia may also lead to pericardial effusion and, in rare cases, pericardial tamponade. Cardiovascular mortality is 10-20 times higher in dialysis patients than in the normal population.

Vascular signs

Vascular access complications are similar to those seen in any patient with a vascular surgical procedure (eg, bleeding, local or disseminated intravascular infections, vessel [graft] occlusion).
Dialysis catheters

A peritoneal dialysis catheter subjects patients to the risks of peritonitis and local infection. The catheter acts as a foreign body and provides a portal of entry for pathogens from the external environment.
Infection/immunologic

Patients who have received renal transplants may experience recurrent renal failure due to rejection or other graft complications. In addition, chronic immunosuppression makes them prone to infection.
Frequency
United States
The government of the United States funds treatment of end-stage renal disease (ESRD) universally for US citizens. As a consequence, the population of patients receiving dialysis or who have had a renal transplant in the United States is large. During 2004, the last year with complete data availability, 104,364 patients (approximately 0.03% of the US population) began renal replacement therapy, an adjusted incidence rate of 339 per 1,000,000. As of 2005, more than 485,000 patients were receiving treatment for ESRD in the United States. As a result, patients with ESRD are encountered on a regular basis in US emergency departments.
International
Resources allocated for treatment of ESRD vary throughout the world, and the treatments are expensive. Untreated ESRD is rapidly fatal, and treatment is too expensive for most individuals to purchase privately. Consequently, very few patients with ESRD are encountered in countries where ESRD treatment is not funded by the government.

The morbidity and mortality of dialysis patients is much higher in the United States compared with most other countries. This is probably a consequence of selection bias. Due to liberal criteria for receiving government-funded dialysis in the United States and rationing (both medical and economic) in most other countries, US patients receiving dialysis are on the average older and sicker than those in other countries.
Mortality/Morbidity
Patients in renal failure are prone to all of the complications of any underlying condition, such as diabetes and hypertension. In addition, renal failure causes a variety of metabolic and physiologic derangements.
• The most common cause of sudden death in patients with end-stage renal disease (ESRD) is hyperkalemia, which is often encountered in patients after missed dialysis or dietary indiscretion. Serum potassium also rises when the serum is acidemic, even though total body potassium is unchanged. Hyperkalemia is usually asymptomatic and should be treated empirically when suspected and when arrhythmia or cardiovascular compromise is present.
• Iatrogenic complications related to fluid administration (fluid overload) or medications are frequently encountered in patients in renal failure.
• Cardiovascular mortality is 10-20 times higher in dialysis patients than in the normal population.
• Anemia results in fatigue, reduced exercise capacity, decreased cognition, and impaired immunity.
• Renal transplant patients are prone to infection, especially in the immediate post-transplant period.
Race
Etiology of end-stage renal disease (ESRD) differs among racial groups primarily because of the prevalence of predisposing conditions, such as diabetes and hypertension. In populations with problematic access and utilization of primary medical care for treatment of predisposing conditions, ESRD often is encountered in relatively young patients. While the costs of treatment for ESRD are borne by the entire population (through government funding), relatively inexpensive preventive treatments often are funded poorly. Diseases such as diabetes and hypertension are much less likely to lead to renal failure when appropriately treated. The cost of primary care for these conditions is far lower than for dialysis or transplantation, yet primary care remains poorly funded, while ESRD treatment is reimbursed completely by the government. This conundrum is reflective of the often illogical and capricious nature of health care spending in the United States.

In the United States, racial and ethnic discrepancies in ESRD exist, with 2006 rates in the African American and Native American populations 3.6 and 1.8 times greater, respectively, than the rate among whites, and the rate in the Hispanic population 1.5 times higher than that of non-Hispanics.3
Sex
Presentation and treatment of chronic renal failure (CRF) and end-stage renal disease (ESRD) do not differ significantly between men and women. Differences in causes of renal failure are related to the types of underlying conditions prevalent in men and women.
Age
While the etiology of CRF differs among age groups, the presentations and nature of complications are similar. Young children with ESRD often are treated with transplantation rather than dialysis because of a relatively greater long-term benefit compared to that of adults, and due to difficulties related to vascular access for dialysis.
Clinical
History
Renal failure produces no symptoms early in the course of the disease. At this stage, symptoms of the underlying illness may bring the patient to medical attention and renal insufficiency is noted on laboratory testing.
• Chronic renal failure (CRF) potentially affects all organ systems. History for the presenting disorder is similar to that encountered when the same disorder exists in patients without renal failure.
• The following presentations are seen frequently in CRF. Moreover, some problems are unique to patients with CRF/ESRD; many of these are related to treatments, such as dialysis or transplantation.
• Electrolyte abnormalities include life-threatening hyperkalemia, which is usually asymptomatic.
o Dilutional hyponatremia may cause mental status changes or seizures.
o Hypocalcemia or hypermagnesemia may cause weakness and life-threatening dysrhythmias.
o Neuromuscular irritability is seen with hypocalcemia and may present as tetany or paresthesia.
o Hypermagnesemia causes neuromuscular depression with weakness and loss of reflexes.
o Acidosis may present as shortness of breath due to the work of breathing from compensatory hyperpnea.
• Pericarditis and asymptomatic pericardial effusion are common in patients with ESRD. Cardiac tamponade may occur but is rare. Presentation of pericarditis and tamponade are typical, with pleuritic chest pain being the most common presentation.
o Tamponade presents as fatigue, weakness, syncope, or dyspnea.
o Hypotension is usually present, and, if advanced, frank shock and cardiovascular collapse occur.
• Hypotension with postural weakness or syncope may occur as a complication of fluid shifts from dialysis or from any other cause. Sepsis is a serious cause of hypotension.
• Myocardial ischemia or infarction is common in patients with ESRD; consider this diagnosis in hypotensive patients along with other conditions, such as GI bleeding.
• Dialysis dysequilibrium syndrome is a common neurologic complication seen in dialysis patients.
o Syndrome is characterized by weakness, dizziness, headache, and in severe cases, mental status changes. Diagnosis is one of exclusion.
o A prime characteristic of the syndrome is that it is nonfocal.
• Peritonitis is common in patients being treated with continuous ambulatory peritoneal dialysis (CAPD), occurring approximately once per patient year. Patients present with abdominal pain, which may be mild, or complain of a cloudy effluent. Fever often is absent.
• Infection at the catheter exit site manifests as expected local pain, erythema, warmth, and/or fluctuance.
• Other abdominal conditions, such as appendicitis, pancreatitis, or diverticulitis, should be considered when patients present with abdominal pain, especially if signs and symptoms are localized.
• Vascular access problems include infections, which are usually manifest with typical signs and symptoms such as local pain, redness, warmth, or fluctuance. Fever may be present without local signs.
o Clotting of the vascular access presents as loss of normal bruit or thrill. There may be signs or symptoms of distal limb ischemia.
o Patients may present after dialysis or minor trauma with bleeding from their vascular access. Bleeding usually can be controlled with elevation and firm but nonocclusive pressure. In the immediate postdialysis period, protamine may be needed to reverse the effect of heparin (routinely used in dialysis to prevent clotting). Life-threatening bleeding may occur.
Physical
• Chronic renal failure (CRF) produces no specific physical findings.
• Patients with an arteriovenous fistula or graft should have the site examined regularly. Abnormal findings include loss of palpable thrill, overlying erythema, or active bleeding from the incisional wound of a newly placed fistula or graft.
• Physical findings of chronic renal failure complications generally are those expected with the specific complication and do not differ from those encountered when the condition occurs in patients with normal renal function.
• Certain complications are very common in renal failure.
• CAPD-associated peritonitis
o Abdominal pain and tenderness usually are generalized and relatively mild.
o Localized pain and tenderness suggest a local process, such as incarcerated hernia or appendicitis.
o Severe generalized peritonitis may be due to a perforated viscus as in any other patient.
• Transplant-related problems: Pain and tenderness over a transplanted kidney may be due to infection (pyelonephritis), obstruction (stone or extrinsic compression), or graft rejection.
• Vascular access aneurysms or pseudoaneurysms : These present as localized swelling, which may be pulsatile, and are often chronic. A rapid increase in size may indicate active bleeding.
Causes
Once chronic renal failure (CRF) has occurred, treatment options and complications are largely independent of the cause.
• In terms of broad categories of disease, glomerulonephritis and interstitial nephritis are the most common causes of CRF in adults and children.
• Chronic upper urinary tract infection causes CRF in all age groups.
• CRF also is encountered in children because of congenital anomalies such as chronic hydronephrosis, which is caused by anatomic defects that obstruct urine flow or allow reflux from the bladder (vesicoureteral reflux).
• Kidneys may be congenitally hypoplastic.
• Hereditary nephropathies also exist.
• In adults, diabetic and hypertensive nephropathies are the most common specific causes of CRF.
• Polycystic disease, renal vascular disease, and analgesic nephropathy also are common.
• In certain geographic areas, HIV-related renal disease is becoming common.
• Certain diseases such as some of the types of glomerulonephritis tend to recur in transplanted kidneys. In these cases, dialysis is the preferred treatment option.
• Consider renal transplant patients to be mildly to moderately immunosuppressed.
o In the immediate posttransplant period or during a rejection episode, intensive immunosuppression puts patients at considerable risk of infection, including disseminated viral infections such as herpes zoster.
o Degree of immunosuppression is less late in the posttransplant course when corticosteroids alone may be used.