Hemodialysis: Definition, Types, Procedure, Diagram, Treatments, Procedures

What Is Hemodialysis?

Hemodialysis is a medical process that removes waste, salts, and fluids from the blood if the kidneys can no longer perform this action naturally. It is very vital in patients with end-stage renal disease to maintain a good balance within the body to prevent further complications.

Overview Of Renal Function

The kidneys filter the blood and remove waste and excess substances to formulate urine. In renal failure, this accumulation builds up with toxins and fluid, leading to life-threatening conditions. Therefore, in such cases, interventions like hemodialysis become essential.

Hemodialysis: Step-by-Step Procedure

The process of hemodialysis involves several steps that are quite critical to effectively and safely treat patients with kidney failure.

Pre-Dialysis Assessment

• A detailed medical evaluation is carried out to determine the conditions or needs of a patient.

• Blood tests to determine waste products, electrolytes, and other relevant factors.

• The physical examination is to assess their general health and detect any possible complications.

Creation Of Vascular Access

• Fistula: An artery is joined to a vein, usually in the arm. A strong blood vessel is created that can be regularly pierced with a needle.

• Graft: In this, with the help of a synthetic tube, an artery is connected to a vein, in case it is not suitable to have a fistula.

• Catheter: A tube is placed in a large vein, typically in the neck or chest, for short-term or emergency access.

Hemodialysis Session

• The patient arrives at a dialysis centre, and gets weighed to assess fluid gain since the last session.

• Needles are inserted into vascular access and bloodlines are connected to the dialysis machine.

• The blood is drawn out of the patient's body into the dialyser.

• It flows through semi-permeable membranes that filter waste and excess fluid from the blood.

• A special fluid called dialysate flows counter to the blood to remove unwanted substances from it.

• The cleaned blood is returned to the patient's body.

• This process is continued till the recommended time for dialysis, which usually is 3-5 hours.

Monitoring During Hemodialysis

• Vital Monitoring Signs: Blood pressure, heart rate, and temperature are monitored at regular intervals.

• Blood Flow Rate: The correct rate of blood flow through the dialyzer.

• Dialysate Composition: The concentration of the electrolytes in the dialysate would be varied based on the patient's requirements.

• Ultrafiltration Rate: This is concerned with the volume of fluid that is removed from the patient's blood.

• Symptom Monitoring: Keep an eye on discomfort or complications, such as cramps, nausea, and hypotension, and act as appropriate.

Post-Dialysis Care

The care after hemodialysis includes the following:

Recovery and management post-treatment include:

• Vital Signs Check: The blood pressure and heart rate of the patient are checked once brought off the machine.

• Fluid Management: Advising fluid intake to prevent overloading between dialysis treatment sessions

• Nutritional Counseling: Dietary advice to ensure adequate balance and health.

Post-dialysis symptoms and their management include:

• Fatigue: Resting before suggesting a rebuilding of activity slowly

• Muscle Cramps: Stretching and hydration, other medications if needed

• Hypotension: Moving slowly, avoiding dizziness, and monitoring fluid intake.

• Nausea: Administer anti-nausea medications and provide dietary interventions that will prevent further problem behaviours.

Types Of Hemodialysis

There exist two main types of hemodialysis, each suited best for an individual patient's needs and conditions.

In-Center Hemodialysis

• Conducted at a dialysis clinic and managed by health care staff.

• Typically conducted 3 times a week, with each session lasting from 3 to 5 hours.

• Patients come, get attached to the dialysis machine by vascular access, and the treatment is performed.

Advantages

• Medical supervision continuously, with health care staff available at all times.

• Availability of specialised equipment and resources.

• Social interaction with other patients undergoing treatment.

Disadvantages

• The fixed schedule with a high frequency of visits to the centre.

• The daily routine is interfered with and flexibility is low.

• Possible risk of catching infections from a clinical setup.

Home Haemodialysis

• Under home conditions, it is performed after receiving extensive training.

• Requires a dedicated space for setting up dialysis equipment.

• These can be done more frequently with reduced periods.

• Good quality training by the health care team is linked to the operation of a dialysis machine, infection control measures, and response during emergencies.

• Caregiver training sessions, if required.

Advantages

• It offers flexibility in scheduling the periods of dialysis at times that best suit individual lifestyles.

• Travel time is reduced hence the ease of treatment at home.

• More frequent treatments may mean better outcomes.

Disadvantages

• Initial set-up costs of equipment and adapting the home.

• The burden of daytime treatments and adherence to rigorous protocols.

• Social isolation compared with that in-center dialysis.

Indications for Hemodialysis

Hemodialysis needs careful medical consideration. Before hemodialysis is initiated, it has to be determined that it would be a suitable treatment for the patient.

• End-stage renal disease (ESRD) with kidney function below 10-15%.

• Severe electrolyte imbalance, for example, hyperkalemia.

• Fluid overload uncontrolled by medical management.

• Uremic symptoms: nausea, weakness, dyspnea

Complications During/After Hemodialysis

Complications during and after hemodialysis are:

During Dialysis

• Hypotension during rapid fluid removal by ultrafiltration

• Muscle cramps

• Nausea

• Arrhythmias

• Infection in the site of vascular access

Long-Term Complications

• Cardiovascular complications, such as heart disease or stroke.

• Access site problems, including fistula or graft failure

• Bone and mineral disorders, including osteoporosis.

Advances In Hemodialysis

Hemodialysis is an ever-evolving and rapidly changing field, with new technologies and research emerging incessantly.

Technological Advancements

• More efficient dialysis machines with improved filtration capacity.

• Wearable and portable devices for dialysis provide more mobility and ease to the patient.

Future Directions

• Nanotechnology applications in enhancing membrane efficiency in dialysis.

• Bioengineering solutions towards artificial kidneys.

• Gene therapy approaches the treatment of underlying genetic causes of kidney diseases.

• Research in the field of stem cells to regenerate a kidney for use in tissue engineering applications.

Hemodialysis NEET MCQs (With Answers & Explanations)

Important questions asked in NEET from this topic are:

• Procedure of Hemodialysis

• Complications during hemodialysis

Practice Questions for NEET

Q1. Dialysing unit (artificial kidney) contains a fluid which is almost same as plasma except that it has

1. High glucose

2. High urea

3. No urea

4. High uric acid

Correct answer: 3) No urea

Explanation:

A haemodialysis equipment that removes toxins from a person's blood when their kidneys are totally damaged is called an artificial kidney.
Diffusion across a semipermeable barrier is how undesirable compounds are eliminated from the circulation and desired ones are added.
Some chemicals can enter through the membrane's pores, while others cannot.
A tube that is connected to an artery—typically the radial artery—connects the patient to the machine.
A tube that passes through the dialyzer receives pumped blood from the artery.
Dialyzing fluid, which is used to fill the dialyzer, has the same amounts of nutrients and electrolytes as regular plasma but no waste.

Hence, the correct answer is option 3) No urea.

Q2. Which of the following is a key feature of an artificial kidney?

1. Produces urine

2. Requires a continuous supply of water

3. Filters waste products from the blood

4. Requires a donor for transplant

Correct answer: 3) Filters waste products from the blood

Explanation:

An artificial kidney also known as a hemodialysis machine is a medical device used to filter waste products and excess fluids from the blood of patients with kidney failure. It does not produce urine like a natural kidney but rather helps to maintain the body's fluid and electrolyte balance. The machine uses a semi-permeable membrane to remove waste and excess fluid and requires a supply of clean water for the process. It does not require a donor for transplant, as it is a mechanical device rather than a biological organ.

Hence, the correct answer is option 4) Filters waste products from the blood.

Q3. In a dialysing unit, the dialysing fluid has a similar composition as the plasma except

1. Proteins

2. Electrolytes

3. Hormones

4. Nitrogenous wastes

Correct answer: 4) Nitrogenous wastes

Explanation:

An adult human excretes, on average, 1 to 1.5 litres of urine per day. The urine formed is a light yellow-coloured watery fluid which is slightly acidic (pH-6.0) and has a characteristic odour. The pH of urine is 6.0 which is acidic due to secretion of H+ ions. H+ is proportional to 1/pH (low pH -> High H+).

Hence, the correct answer is option 3) hydrogen ions are actively secreted into the filtrate.

Also Read:

• MCQs on Hemodialysis

• Glomerular Filtration Rate

• Ammonotelism

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