Hemodialysis is a life-sustaining treatment for people whose kidneys can no longer properly filter waste and excess fluids. Understanding how does hemodialysis work helps explain how it replaces part of kidney function by cleaning the blood through a dialysis machine.
This guide explains the full process of how hemodialysis works, what happens during treatment, and what patients can expect before, during, and after each session at NephroPlus dialysis care centers in Makati City.
What is Hemodialysis?
Hemodialysis is a form of dialysis treatment that performs the function of healthy kidneys when they are no longer working properly. It works by intermittently removing blood from the body, passing it through an artificial kidney (dialyzer), and then returning the cleaned blood to circulation. This process helps remove waste products such as urea and creatinine, balances electrolytes, and removes excess fluid from the bloodstream.
According to the National Kidney Foundation (2024), dialysis helps control blood pressure and maintain safe levels of minerals such as potassium and sodium when kidney function declines to critical levels.
Hemodialysis is most commonly used for patients with end-stage kidney disease (ESKD) or severe chronic kidney disease (CKD). Treatment is typically performed on a scheduled basis, ranging from about three hours per session three times a week to longer or more frequent sessions, such as eight to nine hours per session six to seven times a week, depending on the patient’s medical needs and prescribed dialysis plan.
https://www.kidney.org/kidney-topics/hemodialysis
https://www.ajkd.org/article/S0272-6386(24)00654-1/fulltext
How Does Hemodialysis Work?
Hemodialysis works by circulating blood outside the body, filtering it through a special device called a dialyzer, and then returning the cleaned blood to the bloodstream. This process helps replace key functions of the kidneys when they are no longer able to remove waste and excess fluid effectively.
The dialyzer acts as an artificial kidney. It uses a semipermeable membrane that allows waste products and extra fluids to pass out of the blood while keeping red blood cells and essential proteins inside. This balance helps maintain safer levels of electrolytes and fluids in the body during kidney failure.
Step 1: Vascular access creation and access management
Before hemodialysis can begin, a vascular access is created to allow safe and repeated blood flow between the body and the dialysis machine. This access is essential because it provides a reliable pathway for blood to be removed, filtered, and returned safely.
There are three main types of access:
Arteriovenous (AV) fistula – considered the best long-term option, created through a small surgery that connects an artery and a vein
AV graft – a synthetic tube used when veins are not suitable for a fistula
Central venous catheter – used temporarily when immediate dialysis is needed
Healthcare professionals provide access management support, ensuring patients understand how to care for their access site. Proper cleaning and monitoring are emphasized to reduce infection risk and support better long-term outcomes. All catheters require careful handling, as they are more prone to infection than fistulas.
http://niddk.nih.gov/health-information/kidney-disease/kidney-failure/hemodialysis?utm_
Step 2: Blood is drawn from the body
Once access is ready, blood is gently drawn from the body through the vascular access and directed into the dialysis machine using a pump system. This process is carefully controlled to maintain safety and stability throughout treatment.
The dialysis machine continuously regulates:
Blood flow rate
Pressure levels
Air detection and safety alarms
These safeguards ensure that blood circulates smoothly through the system without clotting or complications. Patients are closely observed throughout this phase to ensure comfort and safety.
https://www.kidney.org/kidney-topics/hemodialysis
Step 3: Blood filtration inside the dialyzer
Inside the dialyzer, blood flows through thousands of tiny hollow fibers while a special cleansing fluid called dialysate flows around them. This structure allows waste and excess substances to diffuse out of the blood.
As explained by leading kidney care references such as the Cleveland Clinic, this filtration process removes toxins and extra fluids while preserving essential blood components.
Key substances removed during dialysis include:
Urea and creatinine (waste products)
Excess potassium
Phosphorus
Extra water
This process helps restore chemical balance in the blood and reduces strain on the body caused by kidney failure.
https://my.clevelandclinic.org/health/treatments/14618-dialysis
Step 4: Clean blood is returned to the body
After filtration, the cleaned blood is safely returned to the body through the same vascular access point. This continuous circulation process ensures that blood is filtered multiple times during a single session.
While hemodialysis performs many functions of healthy kidneys, it does not fully replace all kidney activities, such as hormone production. However, it plays a critical role in maintaining stability in patients with advanced kidney disease.
The process helps control fluid buildup, reduce toxin levels, and support overall body function between treatments.
https://www.mayoclinic.org/tests-procedures/hemodialysis/about/pac-20384824
Step 5: Continuous monitoring during treatment
Throughout the entire dialysis session, healthcare professionals closely monitor the patient’s condition to ensure safety and treatment effectiveness. Adjustments are made in real time based on the patient’s response and clinical needs.
Key parameters monitored include:
Blood pressure
Heart rate
Fluid removal rate
Patient comfort and symptoms
Treatment is personalized using clinical data and ongoing assessment. The care team ensures that each session is adjusted appropriately to maintain stability and reduce complications.
https://pmc.ncbi.nlm.nih.gov/articles/PMC7460937/
Healthy Approach To Living On Dialysis
Living with dialysis is not only about treatment sessions but also about maintaining a balanced lifestyle. Patients are encouraged to see dialysis as part of life, not the center of it, so they can continue their daily routines with confidence.
A structured routine helps maintain physical and emotional well-being. Many patients continue working, pursuing hobbies, and spending time with family. Staying active supports mental health and helps maintain a sense of normalcy during long-term care.
Plan Your Routine
Maintaining a consistent routine is important for patients undergoing hemodialysis. Regular schedules for treatment, rest, meals, and medications help the body adjust better to dialysis care.
Many patients can continue working or engaging in daily activities with proper planning. Organizing dialysis sessions around personal responsibilities helps maintain independence and improve quality of life.
https://www.nhs.uk/tests-and-treatments/dialysis/
Eat Well With Kidney Disease
Nutrition plays a key role in supporting patients on dialysis. A kidney-friendly diet helps manage fluid balance and reduces strain on the body between sessions.
A dietitian typically recommends controlled intake of sodium, potassium, phosphorus, and fluids. Personalized meal planning ensures patients can still enjoy food while maintaining health stability during treatment.
https://www.kidney.org/kidney-topics/hemodialysis-and-your-diet
Consider Your Treatment Options
Different dialysis options may be available depending on medical condition and lifestyle needs. Hemodialysis is commonly performed in centers, while other modalities may be considered in specific cases.
Choosing the right treatment method allows patients to align care with their daily routine. Healthcare professionals help guide this decision based on medical evaluation and lifestyle suitability.
Explore new places
Travel is possible for many dialysis patients with proper planning and coordination. Treatment continuity can be maintained by arranging dialysis sessions in advance at available centers in different locations.
Continuity of care across locations helps patients maintain treatment schedules even while away from home. This allows greater flexibility and improves overall quality of life.
Stay Informed, Stay Confident in Your Kidney Care Journey
Access to clear and reliable information helps patients and families better understand kidney disease and dialysis care. Learning about treatment options, daily management, and health changes can make each step of the journey easier to navigate.
Nephro Reads offers helpful resources on the stages of chronic kidney disease, dialysis treatments, and kidney-friendly nutrition. Staying informed supports better decisions, improved daily care, and greater confidence in long-term kidney health management.
https://www.kidney.org/kidney-topics
Kidney Health Assessment
Understanding kidney health status early can help guide treatment decisions. Regular evaluation by healthcare professionals ensures timely care and better management of kidney conditions.
Assessment tools and clinical evaluations help identify kidney function levels and determine the appropriate treatment pathway for each patient.
https://www.kidney.org/kidney-topics/estimated-glomerular-filtration-rate-egfr
What to expect during hemodialysis
Before the session
Before dialysis begins, several important checks are performed to ensure the treatment is safe and well-planned. These include measuring the patient’s weight to assess fluid buildup, monitoring blood pressure, examining the vascular access site, and reviewing the prescribed treatment plan. These steps help determine the correct amount of fluid and waste that needs to be removed during the session. Patients are also encouraged to wear comfortable clothing and arrive on time to avoid delays and ensure a smooth start to their dialysis treatment.
https://www.kidney.org/kidney-topics/hemodialysis
During the session
During a typical hemodialysis session, treatment usually lasts around 3 to 5 hours and is performed about three times per week, depending on the patient’s medical condition and the doctor’s recommendation. Throughout the session, the patient sits or reclines comfortably in a chair while blood continuously circulates through the dialysis machine for filtering.
Many patients use this time to read, rest, sleep, or listen to music to stay relaxed during treatment. Some may experience mild side effects such as feeling cold, fatigue, or light muscle cramps, but these are closely monitored and managed by the healthcare team to ensure safety and comfort throughout the procedure.
https://www.mayoclinic.org/tests-procedures/hemodialysis/about/pac-20384824
After the session
After dialysis, patients may feel slightly tired as the body recovers from the treatment process. Many also notice improved breathing due to the removal of excess fluid, along with relief from swelling in the hands, legs, or other parts of the body. Rest is often recommended after each session, especially during the early stages of dialysis, as the body gradually adjusts to regular treatment.
https://www.kidney.org/kidney-topics/hemodialysis
Why is Hemodialysis Needed
Hemodialysis is needed when the kidneys are no longer able to properly remove waste products and excess fluid from the body. When this happens, toxins begin to build up in the bloodstream, which can lead to serious and life-threatening health complications. Without proper treatment, this buildup can affect vital organs such as the heart, brain, and lungs, making everyday body functions harder to maintain.
Hemodialysis helps by removing toxins from the blood, balancing important electrolytes, controlling blood pressure, and reducing swelling caused by fluid overload. This process supports overall body stability and helps reduce the risk of kidney failure when natural kidney function is no longer sufficient.
https://www.kidney.org/kidney-topics/kidney-failure
Lifestyle during hemodialysis
Living with hemodialysis requires some adjustments, but many patients are still able to maintain active, meaningful lives with proper care and routine. Adapting to treatment becomes easier when daily habits are aligned with medical guidance and personal health needs.
Key lifestyle considerations include following a kidney-friendly diet, managing fluid intake, taking prescribed medications consistently, and attending all scheduled dialysis sessions. These habits help support overall stability, improve well-being, and reduce complications related to kidney disease over time.
https://www.cdc.gov/kidney-disease/
Possible Side Effects
Some patients undergoing hemodialysis may experience mild side effects such as low blood pressure, muscle cramps, headaches, or fatigue during or after treatment. These reactions can vary depending on individual health conditions, fluid status, and the body's response to dialysis. In most cases, these effects are temporary and closely monitored by the healthcare team.
They are effectively managed by adjusting fluid removal rates, treatment duration, and dialysis settings to ensure patient comfort and safety throughout the session. In some cases, supportive care strategies such as nutritional guidance and antioxidant therapy may also be considered by the healthcare team to help support overall wellness during long-term dialysis treatment.
Tips to prepare for dialysis
Preparing for a dialysis session can help make the experience more comfortable and smooth. It is generally recommended to eat light meals before treatment, depending on medical advice, to avoid discomfort during the session. Wearing loose, comfortable clothing also helps with easy access to the treatment area and allows for better relaxation throughout the procedure.
It is also helpful to bring something to entertain yourself, such as a book, headphones, or music, since sessions can last several hours. Keeping track of symptoms before and after treatment and reporting changes to the healthcare team helps ensure care can be adjusted as needed for better safety and comfort.
FAQs
1. How does a dialysis machine clean blood?
It filters blood through a dialyzer membrane that removes waste and excess fluid while keeping blood cells.
2. Is hemodialysis painful?
The process is not painful, but needle insertion may cause brief discomfort.
3. How long is a dialysis session?
Typically, 3–5 hours per session, depending on medical needs.
4. Can patients live normally on dialysis?
Yes, many patients continue work and daily activities with proper care and scheduling.
5. What are common side effects?
Fatigue, low blood pressure, and muscle cramps are the most common and manageable effects.
Conclusion
Understanding how does hemodialysis work helps patients feel more prepared and confident about treatment. With proper care, monitoring, and lifestyle adjustments, dialysis can support a stable and healthier life.
For guided kidney care and structured dialysis treatment in Makati City, NephroPlus offers patient-centered support at every stage of the kidney care journey.
Learn more: https://nephroplus.ph/
917 875 0001 / 917 875 0002 / 917 875 0003
