Kidney diseases occur when there is a loss of normal kidney functions. These kidney diseases can occur suddenly or over a longer period of time. Of all kidney diseases, chronic kidney disease (CKD - when the kidneys have become damaged over time, for at least three months, and have a hard time doing all their important jobs) remains the most common. According to the International Society of Nephrology, approximately 850 million people worldwide were affected by CKD last year (2023).

In Sri Lanka, CKD is the leading kidney disease, affecting more than 150,000 people, while the actual value is much higher. In addition, genetic and familial kidney diseases, glomerular diseases (a condition that can damage the kidneys. The disease attacks tiny filters in the kidneys, called glomeruli, where the blood is cleaned. Damaged glomeruli can allow proteins and sometimes red blood cells to leak into the urine. One of the proteins in the blood is albumin. If too much albumin leaks into the urine, fluid can build up in the body, leading to swelling in the face, hands, feet, or legs. In some cases, glomerular disease can also prevent the kidneys from properly removing waste products, causing wastes to build up in the blood), renal vascular diseases (affects the blood flow into and out of the kidneys), and renal carcinomas (cancers) account for a much lesser extent.

Causes for CKD

The most common causes of CKD are diabetes and high blood pressure. Over the past few decades, a new disease entity called CKD of unknown aetiology (CKDu) has emerged in some parts Sri Lanka, where it is believed to be caused by polluted water and environmental toxins. Cigarette smoking, exposure to certain chemicals and medicines, infections (viruses and bacteria), a low water intake, and obesity are the other leading causes of kidney diseases.

However, following a severe illness, major surgery, heart attack, or other issue, the kidneys may suddenly stop working (acute renal failure). Kidney damage may also be caused by certain drugs as well.

When is haemodialysis needed?

When the estimated glomerular filtration rate (eGFR – used to determine if one has kidney disease, and if so, what stage it is in. eGFR measures the kidneys' ability to filter toxins or waste from the blood. A very low number may indicate kidney failure, which requires dialysis or a kidney transplant) is less than six, dialysis is mandatory. But, dialysis may be needed earlier than that if the remaining kidneys are unable to remove excess water and waste products.

What is haemodialysis?

Haemodialysis is the process of filtering wastes, salts, and liquids from the blood by a machine when the kidneys are no longer healthy enough to perform this function well. 

Dialysis has two categories, haemodialysis and peritoneal dialysis. In haemodialysis, excess water and waste products are removed from the blood by a machine. This method is more efficient, but costs a lot. Haemodialysis is needed once every two to three days. In peritoneal dialysis (which is less efficient), the fluid inside the peritoneal cavity (belly) is used to clean the blood. But, this method is needed on a daily basis.

Haemodialysis therapy may be effective in restoring some lost kidney function. Although many individuals benefit from haemodialysis, those who undergo it still have a lower life expectancy than the healthy population. Haemodialysis will not cure the kidney disease, and the only permanent cure is a kidney transplant. 

How is it done?

One will be connected to the haemodialysis machine through an arteriovenous (AV) fistula (abnormal connections between arteries and veins. AVFs can be surgically created, can occur as a result of a congenital or genetic anomaly, or be secondary to iatrogenic [relating to illness caused by medical examination or treatment] injury or trauma) or a vascular line (vascular catheterisation [a test or treatment for certain heart or blood vessel problems. It uses a thin, hollow tube called a catheter. The tube is guided through a blood vessel to the heart] - a thin, flexible tube that is placed into an artery. It helps to check the blood pressure and take blood samples). An AV fistula is a connection that is made between an artery and a vein for dialysis access. If the blood vessels are too thin, an AV graft will be created. The vas cath for dialysis is a large bore central venous catheter line placed in the jugular vein (any of the several large veins in the neck, carrying blood from the head and face) or femoral vein (a large blood vessel in the thigh. This vein collects deoxygenated blood from tissues in the lower leg and helps move it to the heart.)

The dialysis machine receives blood that is pumped out of the body. Then, in the machine, inside the ‘artificial kidney’ or ‘dialyser’, blood is sent via several small tubes. Inside these small tubes, waste products and fluid in the blood may travel through a unique membrane. In the other way, a clear liquid known as ‘dialysate’ is transferred outside the tubes. Waste products and extra water enter the dialysate as the blood flows in one direction and the dialysate flows in the other way. The dialysate is then pushed out of the machine, with the waste going down the drain and the cleansed blood being pumped back into the body.

With every dialysis treatment, the blood flows through the dialysis machine, constantly removing waste products and excess fluid. The normal duration for dialysis treatments is around four hours.

Problems associated with haemodialysis

During haemodialysis, one will not feel any pain. But, one may encounter any related symptoms as mentioned below, during or after the haemodialysis. One’s dialysis staff can support one in managing them.

Hypotension, or low blood pressure, is one of the most common side effects. Muscle cramps are prevalent during haemodialysis. Many haemodialysis patients experience itchy skin, which often worsens during or after treatment. In addition, patients can get low sugar levels (hypoglycemia) during haemodialysis.

In between haemodialysis sessions, patients are advised to restrict fluid and certain food.

There are different haemodialysis centres around the country where haemodialysis is given free of charge depending on the availability.

(The writer is attached to the National Institute for Nephrology, Dialysis and Transplantation) 

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The views and opinions expressed in this article are those of the author, and do not necessarily reflect those of this publication.