Hemodialysis: Complete Guide to Kidney Dialysis Treatment

What Is Hemodialysis and How Does It Work?

Hemodialysis is a medical treatment that uses a dialysis machine to filter waste products, toxins, and excess fluid from your blood when your kidneys can no longer perform this vital function. Blood flows from your body through tubing to a dialyzer (artificial kidney), where it is cleaned and returned to your body. The process typically takes 3-5 hours and is performed 3 times per week.

Healthy kidneys filter approximately 120-150 liters of blood every day, removing waste products that are then eliminated through urine. When chronic kidney disease progresses to end-stage renal disease (ESRD), the kidneys function at less than 10-15% capacity and can no longer adequately filter blood. Without dialysis or a kidney transplant, waste products accumulate to dangerous levels, leading to serious illness and eventually death.

Hemodialysis works on the principles of diffusion and ultrafiltration. During diffusion, waste products and toxins move from areas of high concentration (your blood) to areas of low concentration (the dialysate solution) across a semipermeable membrane in the dialyzer. Ultrafiltration removes excess fluid by applying pressure to push water across the membrane. This process effectively mimics the filtering function of healthy kidneys.

The dialyzer, often called an artificial kidney, contains thousands of tiny hollow fibers made of a semipermeable membrane. Blood flows through these fibers while a special cleaning solution (dialysate) flows around them. The membrane allows small waste molecules like urea, creatinine, potassium, and excess water to pass through while keeping larger molecules like red blood cells and proteins in the blood.

Components of a Hemodialysis System

A complete hemodialysis system consists of several interconnected components that work together to clean your blood safely and effectively. Understanding these components can help you feel more comfortable and informed about your treatment.

• Dialysis machine: The main unit that controls blood flow, dialysate flow, and monitors the entire treatment process
• Dialyzer (artificial kidney): A cylindrical filter containing semipermeable membranes where actual blood cleaning occurs
• Blood tubing: Two sets of sterile tubing that carry blood from your body to the dialyzer and back
• Dialysate solution: A purified fluid containing electrolytes that helps remove waste from blood
• Vascular access: The point where blood is removed and returned, typically an AV fistula, graft, or catheter
• Blood pump: Ensures consistent blood flow through the system at 300-500 mL per minute

Who Needs Hemodialysis Treatment?

Hemodialysis is needed by people with end-stage renal disease (ESRD) whose kidneys function at less than 10-15% of normal capacity. The most common causes of kidney failure requiring dialysis are diabetes (accounting for about 44% of cases), high blood pressure (28%), and glomerulonephritis (7%). Dialysis may also be needed temporarily for acute kidney injury.

The decision to start dialysis is not based solely on kidney function tests but also considers symptoms and overall health. Many nephrologists recommend starting dialysis when the glomerular filtration rate (GFR) falls below 15 mL/min/1.73m2 and the patient experiences uremic symptoms. However, some patients may need to start earlier if they develop severe symptoms or complications.

Chronic kidney disease (CKD) progresses through five stages, with stage 5 representing kidney failure. During stages 1-4, treatment focuses on slowing disease progression through medication, diet, and lifestyle changes. When the kidneys fail completely, renal replacement therapy becomes necessary to sustain life. The three options are hemodialysis, peritoneal dialysis, and kidney transplantation.

While kidney transplantation offers the best long-term outcomes for most patients, the shortage of donor organs means that dialysis remains the primary treatment for most people with kidney failure. In many countries, wait times for a deceased donor kidney can exceed 5-7 years. During this time, hemodialysis maintains health and quality of life while patients wait for a suitable donor.

Signs That You May Need Dialysis

As kidney function declines, various symptoms appear that indicate the need for dialysis. These symptoms result from the buildup of waste products and fluid in the body. Recognizing these warning signs early allows for better treatment planning.

• Severe fatigue and weakness: Caused by anemia and toxin buildup
• Persistent nausea and vomiting: Results from uremia (elevated urea in blood)
• Swelling in legs, ankles, and feet: Due to fluid retention
• Shortness of breath: From fluid overload affecting the lungs
• Difficulty concentrating or confusion: Caused by toxin effects on the brain
• Severe itching: Related to phosphorus buildup
• Loss of appetite and metallic taste: Common uremic symptoms
• Muscle cramps: Often due to electrolyte imbalances

What Happens During a Hemodialysis Session?

During hemodialysis, you arrive at the dialysis center where staff check your weight, blood pressure, and vital signs. Two needles are inserted into your vascular access (or your catheter is connected), and blood flows through tubing to the dialysis machine where it is filtered and returned to your body. The session typically lasts 3-5 hours, during which staff monitor your condition continuously.

A typical hemodialysis session follows a well-established routine that ensures safety and effectiveness. Upon arrival at the dialysis center, you are weighed to determine how much fluid has accumulated since your last treatment. This "dry weight" measurement helps calculate the target fluid removal for the session. Staff also check your blood pressure, temperature, and pulse.

The vascular access site is carefully inspected and cleaned before needle insertion. For patients with an AV fistula or graft, two needles are placed - one to remove blood from the body (arterial needle) and one to return cleaned blood (venous needle). Patients with a central venous catheter have their catheter lines connected directly to the dialysis tubing. The initial needle insertion may cause brief discomfort, but most patients adapt over time.

Once connected, the dialysis machine begins pumping blood through the dialyzer at a rate of 300-500 mL per minute. The dialysate solution flows in the opposite direction at approximately 500-800 mL per minute. This counter-current flow maximizes the efficiency of waste removal. Throughout the treatment, the machine continuously monitors blood flow, dialysate temperature, and various safety parameters.

During the session, you can read, watch television, work on a laptop, sleep, or talk with other patients. Some people experience temporary symptoms such as low blood pressure, muscle cramps, nausea, or headaches. Dialysis staff are trained to manage these issues promptly. Snacks may be provided, though eating during dialysis varies by facility and individual needs.

Post-Treatment Recovery

After dialysis, the needles are removed (or catheter disconnected), and pressure is applied to the access site to prevent bleeding. Your blood pressure and weight are checked again to confirm appropriate fluid removal. Most patients feel tired after treatment and may need rest before resuming normal activities. Some people report feeling washed out on dialysis days but significantly better by the following day.

What Are the Types of Vascular Access for Hemodialysis?

There are three main types of vascular access for hemodialysis: arteriovenous (AV) fistula, AV graft, and central venous catheter. The AV fistula is preferred because it has the lowest infection and complication rates, provides excellent blood flow, and can last 10-20 years. AV grafts are used when fistulas are not possible, while catheters are typically reserved for urgent or temporary access.

Vascular access is literally your lifeline on hemodialysis. Without reliable access to the bloodstream, dialysis cannot be performed. The type of access used significantly affects treatment outcomes, complication rates, and quality of life. Planning for vascular access should ideally begin months before dialysis starts to allow time for the access to mature and heal.

Arteriovenous (AV) Fistula

An AV fistula is surgically created by connecting an artery directly to a vein, usually in the forearm or upper arm. This connection causes the vein to enlarge and strengthen over time, making it capable of handling repeated needle punctures and the high blood flow rates needed for dialysis. Creating a fistula is considered a minor surgical procedure performed under local anesthesia.

The fistula needs 2-4 months to mature before it can be used for dialysis. During this time, the vein grows larger and its walls thicken. Patients are often encouraged to exercise the arm to help the fistula develop. Once mature, a well-functioning fistula can last 10-20 years or longer with proper care. It has the lowest infection rate of all access types and provides the best blood flow for effective dialysis.

Arteriovenous (AV) Graft

When a patient's blood vessels are too small or damaged to create a fistula, an AV graft may be used instead. A graft is a synthetic tube surgically placed to connect an artery to a vein, usually in the arm. The graft provides a site for needle insertion during dialysis. Grafts can typically be used within 2-4 weeks after placement, which is faster than fistulas.

However, grafts have higher complication rates than fistulas. They are more prone to infection, clotting, and narrowing (stenosis). The average lifespan of a graft is 3-5 years, though some last longer with good care. Regular monitoring and prompt treatment of problems can extend graft function.

Central Venous Catheter

A central venous catheter is a flexible tube inserted into a large vein in the neck, chest, or groin. Catheters can be used immediately, making them essential for patients who need urgent dialysis or whose permanent access is not yet ready. They are also used temporarily while a fistula or graft matures or heals.

Catheters carry the highest risk of infection and bloodstream complications among all access types. They also provide lower blood flow rates, which may result in less efficient dialysis. For these reasons, catheters are generally considered a temporary solution while working toward a permanent access. Long-term catheter use should be avoided when possible.

What Diet and Lifestyle Changes Are Needed on Hemodialysis?

Hemodialysis patients typically need to limit potassium (bananas, oranges, potatoes), phosphorus (dairy, nuts, colas), sodium (processed foods, salt), and fluids. Adequate protein intake is important, especially on dialysis days. A renal dietitian can create a personalized meal plan. Lifestyle adjustments include medication management, regular exercise as tolerated, and planning travel around dialysis schedules.

Diet plays a crucial role in managing health between dialysis treatments. Because hemodialysis only removes waste products intermittently (rather than continuously like healthy kidneys), dietary restrictions help prevent dangerous buildups between sessions. The specific restrictions vary based on individual lab values, residual kidney function, and other health conditions.

Unlike people with healthy kidneys, dialysis patients cannot simply "drink more water" to flush out excess potassium or phosphorus. These substances can only be removed during dialysis sessions. Eating too much of restricted foods between treatments can cause dangerous elevations that may lead to heart rhythm problems (high potassium), bone disease (high phosphorus), or fluid overload.

Key Dietary Restrictions

Potassium: High potassium levels can cause dangerous heart arrhythmias. Foods high in potassium include bananas, oranges, potatoes, tomatoes, spinach, and dried fruits. Leaching vegetables by soaking them in water before cooking can reduce potassium content. Your dietitian will guide you on which foods to limit based on your blood tests.

Phosphorus: Elevated phosphorus leads to bone disease and blood vessel calcification. Phosphorus is found in dairy products, nuts, seeds, beans, colas, and many processed foods. Most dialysis patients take phosphate binders with meals to help control levels. Reading food labels for phosphate additives becomes an important skill.

Sodium: Limiting sodium helps control thirst and fluid retention. Processed foods, restaurant meals, canned soups, and salty snacks are major sources. Cooking at home with fresh ingredients and using herbs and spices instead of salt can make a significant difference.

Fluids: Because the kidneys cannot remove excess fluid, most hemodialysis patients must limit fluid intake to 1-1.5 liters per day (including water, ice, soups, and foods that melt like ice cream). Managing thirst by sucking on ice chips, keeping the mouth moist, and avoiding salty foods helps with fluid restriction.

Protein and Calories

Adequate protein intake is important for dialysis patients because the dialysis process removes some amino acids and proteins. Most nephrologists recommend 1.0-1.2 grams of protein per kilogram of body weight daily. High-quality protein sources include eggs, fish, poultry, and lean meats. Getting enough calories prevents muscle wasting and malnutrition.

What Are the Potential Complications of Hemodialysis?

Common complications during hemodialysis include low blood pressure (hypotension), muscle cramps, nausea, and headaches. Long-term complications may include infections (especially with catheters), vascular access problems, anemia, bone disease, and cardiovascular issues. Most complications can be managed or prevented with proper care, monitoring, and treatment adjustments.

While hemodialysis is life-sustaining, it is not a perfect replacement for natural kidney function and carries certain risks. Understanding potential complications helps patients recognize warning signs early and take steps to prevent problems. Open communication with your dialysis care team is essential for managing complications effectively.

Complications During Treatment

Hypotension (low blood pressure): The most common complication during dialysis, occurring in 20-30% of sessions. Symptoms include dizziness, nausea, and feeling faint. It typically happens when fluid is removed too quickly or when too much fluid is removed. Treatment includes lowering the dialysis chair, reducing ultrafiltration rate, and giving saline solution.

Muscle cramps: Often occur toward the end of treatment, especially with rapid fluid removal or electrolyte shifts. Cramping typically affects the legs, feet, or hands. Stretching, massage, and adjusting dialysis parameters can help. Some patients benefit from quinine or other medications.

Nausea and vomiting: May result from hypotension, dialysis disequilibrium (in new patients), or other factors. Eating a light snack before dialysis and avoiding large meals may help. Anti-nausea medications can be given if needed.

Long-term Complications

Infections: Particularly common with central venous catheters but can occur at any access site. Signs include fever, redness, swelling, or discharge at the access site. Prompt treatment with antibiotics is essential. Good hygiene and proper access care reduce infection risk.

Cardiovascular disease: Heart disease is the leading cause of death in dialysis patients. The combination of fluid overload, high blood pressure, abnormal calcium-phosphorus metabolism, and other factors accelerates cardiovascular problems. Regular monitoring and aggressive management of risk factors are crucial.

Anemia: Reduced production of erythropoietin by failing kidneys leads to anemia. Most dialysis patients require erythropoiesis-stimulating agents (ESAs) and iron supplementation to maintain adequate hemoglobin levels.

Bone and mineral disorders: Abnormal calcium, phosphorus, and parathyroid hormone levels lead to bone disease. Dietary phosphorus restriction, phosphate binders, vitamin D supplements, and sometimes calcimimetics are used to manage this condition.

Can You Do Hemodialysis at Home?

Yes, home hemodialysis (HHD) is an option for many patients who want more flexibility and independence. Home dialysis can be performed more frequently (4-6 times per week) with shorter sessions, or overnight while sleeping (nocturnal hemodialysis). Studies show home hemodialysis may offer better blood pressure control, improved quality of life, and potentially better survival compared to in-center dialysis.

Home hemodialysis has been available for decades but has seen renewed interest as technology has improved. Modern home dialysis machines are smaller, easier to use, and have advanced safety features. Patients who perform home hemodialysis report greater flexibility in scheduling, more control over their treatment, and improved quality of life.

To qualify for home hemodialysis, patients typically need a suitable vascular access (preferably an AV fistula), adequate space at home for the machine and supplies, access to clean water, and a willing care partner for most programs (though some programs allow self-dialysis). Patients must complete extensive training that typically takes 4-8 weeks before starting home treatment.

Types of Home Hemodialysis

Short daily hemodialysis: Shorter sessions (2-3 hours) performed 5-6 times per week. More frequent dialysis provides gentler fluid removal and better waste clearance, often resulting in fewer dietary restrictions and better symptom control.

Nocturnal hemodialysis: Longer, slower sessions (6-8 hours) performed overnight while sleeping, typically 3-6 nights per week. This schedule allows for very gentle dialysis and often provides excellent clearance and blood pressure control.

Conventional home hemodialysis: Similar to in-center schedules (3 times per week for 3-5 hours), but performed at home. This option appeals to patients who want the convenience of home treatment without changing to a more intensive schedule.

Benefits and Challenges of Home Dialysis

Home hemodialysis offers several potential benefits: flexible scheduling that accommodates work and family life, no travel to a dialysis center, more frequent or longer treatments for better clearance, and greater independence and control. Research suggests that more frequent home dialysis may improve blood pressure, reduce medication needs, improve phosphorus control, and potentially extend survival.

However, home dialysis also presents challenges. Patients must take on more responsibility for their treatment, including setting up and cleaning the machine, monitoring themselves during treatment, and troubleshooting problems. The training commitment is significant, and not all patients are suitable candidates. Supply storage requires space, and some patients feel anxiety about dialyzing without professional staff nearby.

How Can You Maintain Quality of Life on Dialysis?

Many people on dialysis maintain fulfilling, active lives by working with their care team to optimize treatment, staying physically active as tolerated, maintaining social connections, managing mental health, and planning ahead for travel or special events. Proper adherence to diet, fluid restrictions, and medications helps prevent complications that can reduce quality of life.

Being diagnosed with kidney failure and starting dialysis is a significant life change that affects every aspect of daily life. However, with time, support, and proper self-care, many patients adapt well and continue to enjoy meaningful activities. The key is finding a balance between the demands of treatment and the activities that bring joy and purpose to life.

Physical activity is important for dialysis patients. Exercise improves cardiovascular health, muscle strength, mood, and sleep quality. Most patients can safely engage in walking, swimming, cycling, or light resistance training. Consult your healthcare team before starting a new exercise program. Many dialysis centers offer exercise programs designed specifically for their patients.

Working While on Dialysis

Many dialysis patients continue to work, especially those with flexible jobs or who can arrange their dialysis schedule around work hours. Some countries have laws protecting the employment rights of people with chronic conditions. Talk to your employer about possible accommodations, such as schedule flexibility for dialysis appointments. Home hemodialysis may offer more scheduling flexibility for working patients.

Traveling on Dialysis

Travel is possible for dialysis patients with advance planning. Dialysis centers exist in most major cities worldwide, and many will accept visiting patients with prior arrangement. Your dialysis center can help coordinate treatment at your destination. Some cruise ships even offer onboard dialysis services. Allow extra time for planning, and always carry essential medications and supplies in your carry-on luggage.

Emotional and Mental Health

Depression and anxiety are common among dialysis patients. The stress of chronic illness, treatment demands, dietary restrictions, and uncertainty about the future can take an emotional toll. Seeking support from mental health professionals, joining patient support groups, and staying connected with friends and family can help. Many dialysis centers offer social work services to help patients cope.

What Are the Alternatives to Hemodialysis?

The main alternatives to hemodialysis are peritoneal dialysis and kidney transplantation. Peritoneal dialysis uses the lining of your abdomen to filter blood and can be done at home daily. Kidney transplantation offers the best long-term outcomes for suitable candidates but requires finding a donor kidney and taking lifelong immunosuppressant medications.

When kidneys fail, there are three main options for renal replacement therapy: hemodialysis, peritoneal dialysis, and kidney transplantation. The best choice depends on individual factors including overall health, lifestyle preferences, medical history, and availability of resources. Many patients use multiple modalities over their lifetime, switching based on changing circumstances.

Peritoneal Dialysis

Peritoneal dialysis (PD) uses the peritoneum (the membrane lining the abdominal cavity) as a natural filter. A catheter is surgically placed in the abdomen, and dialysis solution is infused into the peritoneal cavity. Waste products and excess fluid pass from blood vessels in the peritoneum into the solution, which is then drained and discarded. This process is called an exchange.

There are two main types of peritoneal dialysis. Continuous ambulatory peritoneal dialysis (CAPD) involves manual exchanges 4-5 times daily. Automated peritoneal dialysis (APD) uses a machine to perform exchanges overnight while you sleep. PD offers advantages including home-based treatment, no needles, more dietary flexibility, and preservation of residual kidney function for a longer time.

Kidney Transplantation

Kidney transplantation offers the best long-term survival and quality of life for suitable candidates. A transplanted kidney can restore near-normal kidney function, eliminating the need for dialysis and most dietary restrictions. Kidneys can come from living donors (related or unrelated) or deceased donors.

However, transplantation requires major surgery and lifelong immunosuppressant medications to prevent rejection. Not everyone is a suitable candidate due to age, other health conditions, or personal factors. The shortage of donor organs means many patients wait years for a transplant, during which time they continue dialysis.

Conservative Management

For some patients, particularly elderly individuals with multiple serious health conditions, conservative management without dialysis may be an appropriate choice. This approach focuses on managing symptoms and maintaining quality of life through medications and supportive care. The decision to forego dialysis is deeply personal and should be made after thorough discussion with the healthcare team and family.