Renal Dialysis FAQ

Q1. What is a Renal Dialysis?

Renal Dialysis is the medical process carried out to remove excess water and waste from the blood stream. This process is mainly carried out on patients suffering from renal failure, a condition that leads to loss of kidney function, resulting in the blood stream not being purified.

Renal Dialysis can also be used for disturbances in the kidney function, which may be caused by any injury or external damage, and chronic kidney diseases.

Q2. What happens during Renal Dialysis?

This process involves filtration of fluids and diffusion of solutes across a semi-permeable membrane. A specialized fluid, dialysate is used for the process. This fluid is used to promote the diffusion activity of waste and excess water from the blood.

The waste and water are accumulated in the dialysate, which can be easily drained out. Dialysate comprises minerals like potassium and calcium, present in a concentration corresponding with the natural concentration in the blood. The concentration levels of these minerals are adjusted as per every individual's blood composition.

Q3. What are the Types of Renal Dialysis?

There are five different types of renal dialysis, of which 3 are primary and 2 are secondary processes. The primary processes include:

1. Hemodialysis: This type of dialysis involves the removal of water and wastes from the blood by the process of circulating it through a filter outside the body. This filter is called a dialyzer and contains a semi-permeable membrane. Blood and dialysate, the fluid used for the process, flow in opposite directions of the membrane, while diffusion properties ensure that maximum concentration of urea and other wastes are removed from the blood. This dialysis procedure is the most effective amongst all renal dialysis processes.
2. Peritoneal Dialysis: Waste and excess water are filtered from the blood stream inside the body using a peritoneal membrane, also called the peritoneum. The water and waste move through this semi permeable membrane to the dialysate which is then removed from the body. Peritoneal dialysis can be easily carried out at home.
3. Hemofiltration: Like the hemodialysis process, this dialysis procedure too involves the pumping of blood through the dialyzer. The difference between the two procedures is that that hemofiltration does not require any dialysate during the process. Pressure is used to enhance the flow of water across the semi-permeable membrane, with the dissolvable impurities moving along with the water.

The secondary processes carried out in cases of renal failure are:

1. Hemodiafiltraton: This procedure combines the principles of hemodialysis and hemofiltration, ensuring an efficient process.
2. Intestinal Dialysis: The process of intestinal dialysis involves the intake of high quantities of soluble fibres or non-absorbable solutions at regular intervals. This promotes bacterial growth along the colon, which in turn leads to an increase in the amount of nitrogen to be eliminated in fecal waste. This procedure is also used for patients suffering from renal calculi (kidney stones).

Q4. What are the indications for Renal Dialysis?

The indications required for the specialists to decide that the patient needs to undergo this artificial renal transplant process can be divided into chronic indications and acute indications. The chronic indications include the patient displaying signs of symptomatic renal failure and low GFR (Glomerular Filtration Rate).

Acute indications can be summarized as AEIOU. These include:

• Acidemia (Low blood pH) resulting from metabolic acidosis in the cases where treatment with sodium bicarbonate may result in fluid overload
• Electrolytes, such as potassium or calcium, rising to abnormal levels
• Intoxication, a condition arising from acute poisoning due to some dialyzable substance
• Overloading of fluids not likely to have the desired effect on the patient
• Uremia complications, which include gastrointestinal bleeding, encephalopathy (Brain damage) and pericarditis (inflammation of the fibrous sac surrounding the heart)

Q5. What all preparation is needed for Dialysis?

A patient can increase the effectiveness of the dialysis procedure by following a few simple steps before undergoing the process.

• Regular consultations with the doctor and following the prescribed medication and diet strictly to make sure that the body is well prepared for dialysis.
• Patients are generally advised to go on a renal diet, which has low concentrations of protein and potassium. One should consider limiting the intake of milk, bananas, pulses and other food items that may lead to an increase in the potassium and protein levels present in the blood.
• The medication prescribed before the dialysis process is usually aimed at helping the fluid retention and normalizing the blood pressure. This medication course needs to be followed throughout the preparation period.
• Patients also need to make sure they get an adequate amount of rest before the dialysis procedure, in order to make sure that the body is completely relaxed during the process.

Q6. Long Term Precautions, if any?

One of the risks of long term dialysis is Hepatitis B. This viral infection that can lead to liver diseases may be contracted during the dialysis process. The chances of getting this disease are quite low in today's times, but it is advised to consult a doctor at the first sign of Hepatitis B. The symptoms include nausea, fever and body pains. Other precautions to be taken during long-term dialysis include maintaining complete hygiene, following a suitable diet along with the prescribed course of medication.

Q7. What are Dialyzable substances?

Dialyzable substances have a few common characteristics which include high water solubility, low molecular mass, small volume distribution, prolonged elimination and low protein binding. Several substances having these characteristics include ethanol, methanol, lithium, acetone, ethylene glycol, barbiturates, chloral hydrates, salicylates, bromide, theophylline, procainamide, isopropylalcohol and sotalol.

Q8. Does one need to get admitted for Renal Dialysis or Is Renal Transplant a day care procedure?

When starting with hemodialysis, patients are admitted to a hospital. The first stage of this artificial renal transplant procedure usually involves 3 sessions over a three day period, during which the patient is required to stay in the hospital. Once the patient's body has settled into the fixed dialysis pattern, this process can be arranged as per the convenience and time schedules of the patient without the need to get admitted. In the case of peritoneal dialysis, the patients can perform the procedure themselves at home. After receiving the PD catheter, one should remain in constant contact with the peritoneal dialysis nurse and should get the catheter changed at the prescribed intervals.

Q9. Who does Renal Dialysis?

Renal Dialysis is usually performed by trained patient care technicians under the supervision of nurses in the dialysis center. In some special cases nephrologists carry out the procedure. Peritoneal dialysis can be performed by the patient without any external assistance.

Q10. What are the types of Renal Dialysis Machine?

There are 3 types of renal dialysis machines:

1. Coil Dialyzer: This dialyzer comprises long membrane tubes placed between support screens and wound around a plastic core.
2. Parallel Plate Dialyzer: Membrane sheets are mounted on plastic support screens in this dialyzer. The arrangement is then stacked in multiple layers, resulting in parallel channels for flow of blood and dialysate.
3. Hollow Fiber Dialyzer: Several fibres make up this dialyzer with polyurethane used at the ends to provide support. This machine ensures low resistance to the flow of fluids and provides high efficiency.

Q11. What is dialysis catheter used for? What are its types?

A dialysis catheter is a thin tube used to exchange blood between the hemodialysis machine and the patient's body. The dialysis catheter comprises two lumens, namely Venous and Arterial. The arterial lumen is used to withdraw the blood from the patient's body to the dialyzer and the venous lumen carries the blood back to the patient's body after purification in the dialyzer. Dialysis catheters are of two types:

• Non-tunneled: This catheter is used in cases in which there is an immediate need for dialysis
• Tunneled: This type of catheter is used for the patients who need a longer dialysis procedure. Tunneled catheters can also be used for patients suffering from chronic kidney diseases or renal failure.