What is dialysis?
Dialysis is a procedure that substitutes for many of the normal functions of the kidneys when their filtering function declines to a critical level or there are other complications. Dialysis allows persons with chronic kidney disease to lead a normal and productive life.

The leading causes for kidney failure needing dialysis are diabetes and hypertension. Other causes include glomerulonephritis and polycystic kidney disease

Types of Dialysis
Dialysis improves quality of and extends the life of many patients; in some patients it substitutes for the kidney function and buys time till a suitable donor can be found for consideration of transplant. The two main types of dialysis are

• Hemodialysis - Uses a machine into which patient’s blood is pumped and cleaned before being returned to the body
• Peritoneal dialysis - Peritoneal dialysis uses the lining of your abdomen (peritoneum) to filter your blood within the body (instead of using an external machine)

Hemodialysis Vs Peritoneal Dialysis
• Each method has merits and demerits
• Patients may choose the longterm dialysis type that suits their needs and convenience
• Hemodialysis is the more commonly employed method
• Peritoneal dialysis can be done at home but needs a reliable care provider and manual dexterity

About Hemodialysis
• During hemodialysis, patient’s blood passes into the dialysis machine via sterile tubing and into a filter (dialyser), called a dialysis membrane. The dialyser is otherwise termed “artificial” kidney
• The dialyser, or filter consists of two parts, one for blood and another for the washing fluid called dialysate. A thin membrane separates these two parts. Blood cells, protein and other important things remain in the blood because they are too big to pass through the membrane. Smaller waste products in the blood, such as urea, creatinine, potassium and excess fluid pass through the membrane and are washed away
• Prior to the procedure, the patient has a specialized vascular tube placed between an artery and a vein in the arm or leg (called a gortex graft).
• Sometimes, a direct connection can instead be made between an artery and a vein in the arm. This procedure is called a fistula formation.
• Needles are then placed in the graft or fistula, and blood passes to the dialysis machine, through the filter, and back to the patient.
• If the patient needs dialysis before a graft or a fistula is placed, a large diameter catheter (hemodialysis catheter) is placed directly into a large neck or leg vein to perform dialysis.
• Hemodialysis in a dialysis center is usually done 3 times per week for about 4 hours at a time. It can also be done at home

About Peritoneal Dialysis
• Peritoneal dialysis uses the lining membrane of the patient’s abdominal cavity to act as the filter.
• In peritoneal dialysis, a cleansing fluid flows through a tube (catheter) into the abdominal cavity and removes waste products the blood.
• An operation is necessary to insert the catheter that carries the cleansing fluid into and out of the abdomen
• Following the operation, dialysis will be started after an interval of at least two weeks to allow the surgical site to heal
• Once dialysis begins, the peritoneal membrane acts like a filter between the cleansing fluid and the blood stream
• After a prescribed period of time (four to six hours), the fluid with filtered waste products flows out of your abdomen and is discarded into a sterile collection bag

Peritoneal Dialysis Is Preferred In The Following Situations
• Patient desires minimal disruption of routine activities; can be done at home or while travelling
• Presence of residual kidney function
• Inability to tolerate rapid fluctuations in fluid balance due to hemodialysis

Contraindications To Peritoneal Dialysis
• Extensive surgical scars over abdomen
• History of weakened abdominal muscle (hernia)
• Limited ability for self-care or lack of dedicated caregiver
• History of inflammatory bowel disease or diverticulitis
• Protein malnutrition
• Presence of underlying critical illness

Types of Peritoneal Dialysis
The process of filling and then draining the abdomen is called an exchange. The two main types of peritoneal dialysis are

• Continuous ambulatory peritoneal dialysis (CAPD)
• Continuous cycling peritoneal dialysis (CCPD)

Continuous ambulatory peritoneal dialysis (CAPD)
The abdominal cavity is filled with dialysate fluid, stays there for a prescribed dwell time, and then drained out . Gravity pushes the fluid through the catheter and into and out of the abdomen.
With CAPD

• Three to five exchanges may be needed during the day and one with a longer dwell time while at night
• The exchanges can be performed at home, work or any clean place
• Normal activities can be carried out while the dialysate dwells in the abdomen

Continuous cycling peritoneal dialysis (CCPD)
Also known as automated peritoneal dialysis (APD), a machine (automated cycler) performs multiple exchanges at night time during sleep. The cycler automatically fills the abdomen with dialysate fluid, allows it to remain there and then drains it to a sterile bag which is emptied in the morning
With CCPD

• The patient should be attached to the machine for 10 to 12 hours at night
• The patient is not connected to the machine during the day. But in the morning you begin one exchange with a dwell time that lasts throughout the day
• CCPD is associated with a lower risk of peritonitis because connecting and disconnecting to the dialysis machine is done less frequently than with CAPD.

The type of peritoneal dialysis will be decided based on patient’s medical condition, lifestyle and
personal preferences.

Complications of Peritoneal Dialysis
• Peritonitis (peritoneal infection)
• Hernia - abdominal muscle strain due to holding large amounts of fluid
• Inadequate dialysis – following several years of dialysis. May need switching to hemodialysis
• Weight gain – due to the dextrose sugar in the dialysate fluid adding to the calories

Most people who begin with peritoneal dialysis will eventually suffer from decline in kidney function and will need hemodialysis or kidney transplant

General Precautions While On Dialysis
• Increasing protein in diet and limiting potassium, phosphorus, sodium, and fluid intake
• Patients with diabetes or other health conditions will need additional diet restrictions
• Avoiding certain drugs that can harm the kidneys eg painkillers
• The dialysis care team will monitor treatment with monthly lab tests to ensure that dialysis is adequate and dietary goals are being maintained

As to the dialysis, it is a common site in kerala, I cannot vouch for other states, the centres for dialysis are mushrooming in not only urban areas but also in semi urban and rural areas. Needless to say that these centres are not attached to a regular hospital where facilities are available to deal with any emergencies that may occur to patients on dialysis. Most important point I want to make in this connection is that intradialysis deaths are not uncommon and when they do occur it is presumed that such deaths are inevitable and they don’t make news. Patients relatives think that patients died due to chronic renal failure and nothing could have saved these patients. And they are ignorant that these had happened as common complications occurring during dialysis procedure. if these centres are attached to a regular hospital where ICU facilities are available, these patients may have been saved if attended to immediately without wasting time.
It is well recognized that the procedure of hemodialysis is associated with significant changes in blood pressure and systemic hemodynamics; 20-30% of treatments are complicated by intradialytic hypotension (IDH). There are now an increasing number of studies using electrocardiographic, isotopic and echocardiographic techniques that show that subclinical myocardial ischemia occurs during dialysis. This concept is supported by some studies showing that dialysis can induce acute rises in troponins and creatinine kinase MB. . Cardiovascular death is the biggest single cause of mortality in dialysis patients and of this sudden death comprises the largest proportion. As such, there is a large body of evidence examining whether dialysis is pro-arrhythmogenic. It is clear that dialysis can increase QTc interval and QT dispersion and is capable of inducing arrhythmias on Holter monitoring, likely due to the interaction of multiple factors, some of which prime for the development of arrhythmias (particularly the presence of preexisting cardiac disease), and some of which act as triggers .
It is being learnt now that compared with standard thrice-weekly hemodialysis, more frequent HD regimes are associated both with significant reductions in UF(Ultrafiltration) volume and rate and with abrogation of intradialytic hypotension. Furthermore, it is apparent that modification of these factors is associated with significant reductions in the occurrence of dialysis-induced myocardial stunning. More-frequent home-based therapies are associated with lower levels of markers for inflammation, myocardial cellular damage, and congestion. All of the above factors have been previously described as influencing survival in chronic HD patients.

https://www.ncbi.nlm.nih.gov/pubmed/17555488
https://www.ncbi.nlm.nih.gov/pubmed/19516249

UA Mohammed

Thank you for your very important comment Mohammed. It is true the procedure can cause significant drop in blood pressure which in turn can precipitate a cardiac arrest in an already compromised patient. Usually these dialysis units are well equipped with well trained staff to attend to emergencies. I do not know what the set up in India is like.

Dialysis although is becoming widespread and being used more and more in units around the world, it is a specialised invasive procedure. Therefore it requires careful monitoring with a lot of care and attention to prevent infection and spread of HIV and hepatitis. Whether it is peritoneal dialysis or haemodialysis extra care in sepsis must be observed. It is also necessary to take extra care of the access point - ie AV fistula created surgically for connecting the machine. Regulating and inspecting the units is usually done independently by the Dept of Health under the Govt. If the inspection is not done properly patients will suffer.