Introduction:
The kidneys are the excretory organs of the body. Their prime function is to filter blood and remove waste products and excess water in the form of urine. When this function goes down by 90 %, the kidneys cannot filter the blood and make urine. This leads to toxin buildup in the body. This is when renal replacement therapy or treatment that replaces the functioning of the kidneys is needed. One such renal replacement therapy is hemodialysis. Hemodialysis is a procedure that filters waste, removes excess fluid, and causes electrolytes (sodium, potassium, calcium, bicarbonate, magnesium, and phosphate) to balance, just like the kidneys, with the help of a machine.
Why Is Hemodialysis Performed?
A few factors that determine whether one needs hemodialysis:
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The overall health conditions.
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Kidney function.
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The various signs and symptoms of kidney failure.
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Quality of life.
The physician uses the estimated glomerular filtration rate (eGFR) to measure how well the kidneys function. eGFR is calculated using the blood creatinine test results, age, and sex of the individual. All these factors help in treatment planning and determining when to begin hemodialysis. Hemodialysis helps the body maintain blood pressure and electrolyte balance. Hemodialysis is carried out before the kidneys have stopped working altogether. The kidneys can shut down suddenly or after a severe illness, surgery, heart attack, or other problem.
How Is Hemodialysis Performed?
During hemodialysis, the blood is pulled out from the body, passed through a machine with a filter with a membrane known as a dialyzer, and returned to the body. The device works like the human kidney. During hemodialysis, around two cups of blood are out of the body at a time. Access or pathway is created to bring the blood out of the body to the machine and then back to the body. There are three types of access made for hemodialysis:-
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Arteriovenous (AV) fistula
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Arteriovenous (AV) Graft
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Central Venous Catheter.
Before the procedure starts, the individual's vitals and weight are checked. The increase in weight gives an idea of how much excess fluid the person has to remove during hemodialysis. After this, the person is put on the dialyzer. Two-needle sticks are placed in the access created (AV fistula or AV graft), one through which blood passes out of the body to the machine and the other through which the filtered blood returns back to the body. Individuals with a central venous catheter have two tubes from their access connected to the blood tubes going to the dialyzer and back to the body. The dialyzer is programmed, and the person is put on the machine for the treatment to begin.
The dialysis machine is like a giant computer with a pump. It tracks the blood flow, blood pressure, how much fluid is removed, and other vitals. It has a solution known as dialysate, like a fluid bath. The blood mixes with it where the fluid pulls out the toxins; then, the solution drains out along with the toxins. The dialysis machine has a pump that keeps the blood flowing by creating a pumping action on the blood tubes carrying the blood from the body to the dialyzer and back to the body. It also has several safety features.
How Does Hemodialysis Work?
The most important part of the dialysis machine is the dialyzer. It is known as the artificial kidney, which does the same job as the kidneys. The dialyzer is a hollow plastic tube, about one foot long, three inches in diameter, and contains many tiny filters. They are made in various sizes, and the physician chooses the appropriate one for the patient. The dialyzer has two sections, one for the dialysate solution and the other for the blood. Both these sections are divided by a semipermeable membrane, so they do not get mixed. A semipermeable membrane has small holes that allow only certain substances to pass through. Therefore, only water and waste are allowed to pass through it, not allowing the blood cells to mix with them.
Dialysate, also called dialysis fluid, is a dialysis solution of pure water, electrolytes, and salts like bicarbonate and sodium. The function of dialysate is to remove toxins from the blood into itself. This happens via the diffusion process. The patient's blood has a higher concentration of waste, whereas the dialysate solution has a lower concentration of garbage. Due to this variable concentration on either side of the semipermeable membrane, the waste moves from the blood towards the solution. The dialysis solution, which now has a higher waste concentration, is flushed out. The electrolytes in the dialysis solution are also used to balance the electrolytes in the individual's blood. Finally, the excess fluid is removed through the process of filtration.
How Often Is Hemodialysis Carried Out?
The doctor usually determines how long the treatments will undergo. The procedure takes around three to five hours to complete and is carried out three times a week.
What Are the Advantages of Hemodialysis?
Hemodialysis is effective for individuals with end-stage kidney failure. But it will not provide the complete treatment alone. Diet and fluid restrictions must be followed along with certain medications replacing other kidney functions, such as maintaining blood pressure and stimulating the production of red blood cells. People who opt for home dialysis can do things like reading, watching T.V., sleeping, etc., at their will and save time.
What Are the Disadvantages of Hemodialysis?
The disadvantages of hemodialysis are-
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Traveling three times a week to the dialysis center is cumbersome.
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Diet restrictions - Limiting the intake of foods containing phosphorus, potassium, and sodium.
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Drinking a limited amount of fluid.
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A feeling of being washed out after dialysis.
What Are the Risks Associated With Hemodialysis?
People requiring hemodialysis have a couple of health problems. While the treatment can be effective in replacing the lost kidney function, there could also be certain risks. Though not everyone undergoes similar experiences. The risks are:-
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Low Blood Pressure (Hypotension)- Low blood pressure is a common side-effect of the procedure. This might lead to shortness of breath, abdominal cramps, muscle cramps, nausea, or vomiting.
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Muscle Cramps- The muscle cramps during hemodialysis can be eased by adjusting the fluid and sodium intake between treatments.
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Itching- Itching of the skin might worsen during or after the procedure.
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Problems With Sleep- individuals undergoing hemodialysis often complain of trouble sleeping due to sleep apnea (break in breathing during sleep), aches and pains, or restless legs.
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Anemia- Anemia is a condition with less production of red blood cells. The kidneys reduce the production of a hormone that helps produce red blood cells. Diet restrictions, poor iron absorption, routine blood tests, and removal of iron and vitamins during the hemodialysis procedure can lead to anemia.
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Bone Diseases- Hemodialysis can remove too much or too little calcium from the body, making one prone to a few bone diseases.
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High Blood Pressure- If one consumes too much salt or drinks too much water during the procedure, it can increase blood pressure.
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Fluid Overload- During hemodialysis, fluid is removed, so drinking too many fluids between treatments may cause complications such as heart failure or fluid accumulation in the lungs.
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Pericarditis- This is an inflammation of the membranes surrounding the heart, interfering with the heart's ability to pump blood.
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Hyperkalemia or Hypokalemia- Hyperkalemia is the increased potassium level in the blood. In contrast, a decreased potassium level is called hypokalemia. If excess or too little potassium is removed from the body during hemodialysis, then these conditions arise.
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Access Site Complications- Infection, narrowing or ballooning of the blood vessels, or blockage can impact hemodialysis.
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Amyloidosis- This condition occurs when the proteins present in the blood are deposited on the joints and tendons, causing pain, stiffness, and fluid deposition in the joints.
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Depression- Individuals with kidney failure feel depressed after the hemodialysis procedure.
Conclusion:
Hemodialysis is a procedure that removes waste and excess water from the blood, just like a healthy kidney does. It also controls blood pressure and maintains the electrolyte balance. It is the treatment of choice when the kidneys do not function as they should. Hemodialysis can help one feel better and live longer. By eating the right food keeping in mind the restrictions, taking the prescribed medications on time without fail, and discussing concerns with the doctor, one can achieve the best outcomes from the procedure.
