Dialysis

35.5 million

This is the number of American adults living with chronic kidney disease (CKD)—1 in 7 US adults.

808,000

This is the number of people living with end-stage renal disease (ESRD) in the United States. Of these, 68% are on dialysis and 32% are living with a kidney transplant.

27,332

This is the number of kidney transplants that were completed in the United States in 2023 alone.

Kidney disease is a serious condition impacting millions of Americans and costing billions of dollars in Medicare and Medicare-related spending for beneficiaries with CKD and ESRD.

The lives of these patients depend on the skilled care provided by nephrology and dialysis healthcare professionals. Read on to learn more about this essential healthcare field.  

Dialysis guide: Modalities, procedures & patient management

End-stage renal disease represents a critical juncture in patient care, where the failure of native kidney function necessitates renal replacement therapy to sustain life. For a significant patient population worldwide, dialysis serves as the primary life-sustaining treatment, effectively managing uremia, fluid overload, and electrolyte imbalances. This intervention, a cornerstone of modern nephrology, bridges the gap for patients awaiting renal transplantation or provides definitive long-term therapy for those who are not transplant candidates.

Dialysis is a medical process involving the extracorporeal or intracorporeal removal of solutes and excess fluid from the blood. It artificially replicates the primary functions of the kidneys, including filtration and excretion. The fundamental principles of dialysis rely on the diffusion of solutes and convection of fluid across a semipermeable membrane, restoring physiological homeostasis.

The two principal modalities of dialysis are hemodialysis (HD) and peritoneal dialysis (PD), each with distinct procedures, advantages, and clinical considerations. 

This guide provides healthcare professionals with a detailed overview of dialysis, covering:

• Core principles
• Procedural specifics
• Management of common complications
• Essentials of patient care 

A thorough understanding of these elements is crucial for clinicians to optimize patient outcomes, provide effective education, and navigate the complexities of long-term renal replacement therapy.

What is dialysis, and what are its clinical indications?

To appreciate the necessity of dialysis, one must first understand the profound systemic impact of kidney failure. The kidneys are vital homeostatic organs responsible for:

• Excretion of metabolic waste: Filtering nitrogenous waste products like urea and creatinine from the blood
• Fluid and electrolyte homeostasis: Regulating blood volume, serum osmolality, and concentrations of critical electrolytes such as potassium, sodium, and phosphate
• Acid-base balance: Excreting hydrogen ions and regenerating bicarbonate to maintain blood pH
• Endocrine functions: Producing renin to regulate blood pressure, erythropoietin to stimulate erythropoiesis, and converting calcidiol to its active form, calcitriol, for calcium metabolism

In ESRD, the progressive loss of these functions leads to a toxic state known as uremia. Without intervention, this condition is fatal. Dialysis is a therapy designed to mitigate these consequences by providing artificial renal support.

The initiation of dialysis for kidney failure is a clinical decision based on a patient's glomerular filtration rate (GFR), symptomatology, and metabolic derangements. While there is no absolute GFR cutoff, dialysis is typically considered when GFR falls below 15 mL/min/1.73m². The most pressing clinical indications for emergent dialysis can be recalled with the mnemonic AEIOU:

• Acidosis: Severe metabolic acidosis (e.g., pH < 7.1) refractory to bicarbonate therapy
• Electrolytes: Persistent, severe hyperkalemia (e.g., K+ > 6.5 mEq/L) or hyperkalemia with EKG changes, unresponsive to medical management
• Intoxication: Acute poisoning with a dialyzable toxin, such as salicylates, lithium, or ethylene glycol
• Overload: Refractory volume overload leading to pulmonary edema
• Uremia: Symptomatic uremia, manifesting as uremic pericarditis, encephalopathy, or intractable nausea and vomiting

It is critical for healthcare professionals to recognize that dialysis is a supportive therapy, not a cure for kidney disease. It manages the sequelae of ESRD but does not restore the kidneys' endocrine or metabolic functions. For eligible candidates, the definitive treatment remains a kidney transplant. The decision between long-term dialysis vs. kidney transplant is a complex one, involving extensive patient evaluation and counseling.

Types of dialysis: A comparative clinical overview

The selection of a dialysis modality is a critical decision in a patient's care plan, influenced by clinical factors, patient lifestyle, psychosocial support systems, and individual preference. 

The primary modalities, hemodialysis and peritoneal dialysis, operate on the same principles of diffusion and ultrafiltration but differ significantly in their application.

Hemodialysis (HD)

Hemodialysis is the most prevalent form of dialysis, involving the circulation of blood through an extracorporeal circuit. 

The patient's blood is passed through a dialyzer, or "artificial kidney," which contains thousands of hollow fibers made of a semipermeable membrane. Waste products and excess electrolytes diffuse from the blood into a sterile solution called dialysate, while excess fluid is removed via hydrostatic pressure (ultrafiltration).

HD is most often performed in a dedicated outpatient dialysis center three times per week, with each session lasting 3-5 hours. This setting provides direct supervision by a team of nephrology nurses and technicians. For select patients who are stable and have adequate support, home dialysis with an HD machine is a viable alternative that offers greater scheduling flexibility.

Peritoneal dialysis (PD)

Peritoneal dialysis utilizes the patient's own peritoneal membrane as the physiological semipermeable membrane. 

A sterile dialysate solution is instilled into the peritoneal cavity via a surgically placed, permanent dialysis catheter. Solutes and fluid migrate from the capillaries in the peritoneal wall into the dialysate. After a specified "dwell time," the fluid is drained and replaced.

PD is a patient-centric home dialysis therapy, managed daily by the patient or a caregiver. The two main forms are:

1. Continuous ambulatory peritoneal dialysis (CAPD): A manual, gravity-based process where the patient performs 3-5 exchanges throughout the day
2. Automated peritoneal dialysis (APD): Multiple exchanges performed overnight with an automated cycler machine while the patient sleeps

Clinical comparison of hemodialysis and peritoneal dialysis

Healthcare providers must guide patients through the modality selection process by presenting a balanced view of the clinical and lifestyle implications of each option.

A specialized modality, continuous renal replacement therapy (CRRT), is employed in the intensive care unit (ICU) for hemodynamically unstable patients with acute kidney injury. It provides slow, continuous filtration over 24 hours, minimizing the risk of hypotension.

The dialysis procedure: A technical and clinical perspective

A comprehensive understanding of dialysis procedures is essential for nurses and other clinicians involved in the care of ESRD patients to ensure patient safety, manage the technical aspects of treatment, and provide ongoing assessment.

The hemodialysis procedure

An HD session is a highly controlled clinical process that requires a functional vascular dialysis access.

Vascular access 

The patient's lifeline for HD is a high-flow access point created surgically.

• Arteriovenous (AV) fistula: The preferred access, created by anastomosing an artery to a vein. It offers the best longevity and lowest infection rates.
• AV graft: A synthetic tube connects an artery to a vein, used when a patient's vasculature is unsuitable for a fistula.
• Central venous catheter (CVC): A catheter placed in a large central vein. CVCs are associated with high rates of infection and thrombosis and are generally reserved for temporary or urgent use.

Initiation and monitoring

The procedure begins with cannulation of the AV fistula or graft with two large-bore needles or by connecting the dialysis machine tubing to the CVC. One line draws blood to the dialyzer (the arterial line), and the other returns the purified blood (the venous line). 

Throughout the session, the dialysis nurse closely monitors the patient's vital signs, the extracorporeal circuit pressure, and signs of complications, such as clotting or hypotension. The machine's parameters, including the ultrafiltration rate and dialysate composition, are prescribed by a nephrologist and tailored to the patient's needs.

Mechanism of filtration 

Inside the dialyzer, two key processes occur:

• Diffusion: Waste products (urea, creatinine) move from the blood into the dialysate down their concentration gradient.
• Ultrafiltration: Excess water is removed from the blood by creating a transmembrane pressure gradient.

The peritoneal dialysis procedure

The PD procedure, or "exchange," is taught to patients by a specialized PD nurse.

Aseptic technique

The cornerstone of safe PD is strict aseptic technique to prevent peritonitis. This includes hand hygiene, wearing a mask, and using a sterile field for all connections.

The exchange cycle

• Drain: The effluent (used dialysate) is drained from the peritoneal cavity by gravity into a collection bag. The fluid should be inspected for clarity; cloudiness is a key sign of peritonitis.
• Fill: A new bag of sterile dialysate is infused into the peritoneal cavity. The volume is typically 1.5 to 2.5 liters.
• Dwell: The solution remains in the peritoneum for a prescribed duration (4-6 hours for CAPD, shorter cycles for APD) to allow for solute and fluid exchange. The dextrose concentration of the dialysate creates an osmotic gradient that drives ultrafiltration. Higher dextrose concentrations remove more fluid.

The clinical team is responsible for managing the patient's PD prescription, monitoring fluid balance and metabolic labs, and providing continuous support for this home-based therapy.

Side effects, risks & complications: Assessment & management

Dialysis, while life-sustaining, is associated with a range of acute and chronic complications. Proactive monitoring and swift intervention by the healthcare team are crucial for minimizing morbidity.

Common dialysis side effects and management

Intradialytic hypotension is the most common complication of HD, caused by rapid volume removal. 

• Management: Decreasing the ultrafiltration rate, administering a normal saline bolus, and placing the patient in the Trendelenburg position

Muscle cramps are often associated with hypovolemia and electrolyte shifts. 

• Management: Saline or hypertonic glucose administration; preventative measures include profiling sodium and ultrafiltration rates

Fatigue is a near-universal symptom, particularly post-HD. 

• Management: Patient education on energy conservation, ensuring adequate nutrition, and managing anemia

Uremic pruritus is common and multifactorial. 

• Management: Optimizing phosphorus control, using emollients, and prescribing medications like gabapentin or antihistamines

Significant dialysis complications

Infection

Infection is a leading cause of hospitalization and mortality.

• HD: Vascular access infections are a major concern. CVCs carry the highest risk of bacteremia. Meticulous site care is paramount.
• PD: Peritonitis is the most significant complication, typically presenting with abdominal pain and cloudy effluent. Diagnosis is confirmed by fluid analysis (WBC count >100/µL with >50% neutrophils) and culture. Treatment involves intraperitoneal antibiotics.

Vascular access complications 

Thrombosis and stenosis are common in AV fistulas and grafts, threatening access viability. Regular surveillance (physical exam, access flow monitoring) is essential for early detection and intervention. Urologic surgery or vascular surgery is often involved in the creation and maintenance of these access sites.

Cardiovascular disease 

This is the leading cause of death in dialysis patients. Chronic volume overload, hypertension, inflammation, and disordered mineral metabolism contribute to accelerated atherosclerosis and left ventricular hypertrophy.

Anemia 

Anemia is caused by erythropoietin deficiency and managed with erythropoiesis-stimulating agents (ESAs) and intravenous iron.

Mineral and bone disorder (MBD) 

This is a systemic disorder characterized by abnormalities in calcium, phosphorus, PTH, and vitamin D metabolism, leading to renal osteodystrophy and vascular calcification. Management requires phosphate binders, vitamin D analogs, and calcimimetics.

Healthcare professionals at dialysis centers and hospitals must be adept at recognizing and managing these complex issues to improve patient outcomes.

Diet, lifestyle, and patient counseling

Effective management of ESRD extends beyond the dialysis procedure itself; it requires comprehensive patient education and psychosocial support. The healthcare team, including nurses, dietitians, and social workers, plays a pivotal role in empowering patients to manage their condition.

The dialysis diet: Key counseling points

A renal dietitian is essential for creating an individualized dialysis diet. Key areas of education include:

Fluid restriction 

Healthcare professionals must counsel patients on managing thirst and accurately tracking fluid intake to prevent volume overload between HD sessions. The typical allowance is 1 liter plus the patient's 24-hour urine output.

Sodium, potassium, and phosphorus control

• Sodium: Educating on reading food labels and avoiding high-sodium processed foods to control thirst and blood pressure
• Potassium: Providing lists of high- and low-potassium foods to prevent life-threatening hyperkalemia
• Phosphorus: Emphasizing the importance of avoiding high-phosphorus foods (dairy, nuts, dark sodas) and adhering to a phosphate binder regimen with every meal

Protein intake 

Renal dietitians recommend an adequate intake of high-biological-value protein to counteract catabolism and losses that occur during dialysis.

Lifestyle management and psychosocial support

Living with dialysis is a significant psychosocial stressor. Clinicians should:

• Encourage physical activity by promoting light to moderate exercise as tolerated to improve cardiovascular health, energy levels, and overall mood.
• Address mental health by screening for depression and anxiety, which are highly prevalent in this population. Referrals to social workers or mental health professionals are often necessary.
• Facilitate normalcy by providing resources for dialysis and travel. Social workers can coordinate treatments at other dialysis centers, allowing patients to travel for vacation or family events. Patients with PD often have more flexibility but require logistical support for shipping supplies.

The goal is to integrate the treatment into the patient's life, rather than letting the treatment dominate it.

Preparing for dialysis and access management

Optimal patient outcomes are often achieved through proactive, pre-dialysis care. Timely education and preparation can ease the transition to renal replacement therapy.

Pre-dialysis education and planning

Preparing for dialysis should begin when a patient enters Stage 4 CKD (GFR <30). This involves:

• Modality education: A multidisciplinary team should provide unbiased education on all renal replacement options, including HD, PD, and transplantation.
• Vascular access planning: The mantra "fistula first, catheter last" emphasizes the importance of early referral to a vascular surgeon. Timely placement of an AV fistula allows it to mature, thereby avoiding the need for a high-risk CVC when dialysis is initiated. For patients choosing PD, surgical consultation for catheter placement should be arranged.

Clinical management of dialysis access

The dialysis access is the patient's lifeline, and its preservation is a primary nursing responsibility. The dialysis nurse's role includes:

• Assessment: Performing a routine "look, listen, feel" assessment of AV fistulas and grafts before each cannulation to check for signs of infection, stenosis (absent thrill, high-pitched bruit), or thrombosis
• Aseptic technique: Using strict sterile technique during cannulation and CVC connection/disconnection to prevent bloodstream infections
• Patient education: Teaching patients how to self-monitor their access at home and to protect it from trauma or compression (e.g., no blood pressures or tight clothing on the access arm)

Cost, insurance, and resource navigation

The financial burden of ESRD is substantial. The cost of dialysis and associated care is a major concern that can impact treatment adherence. Healthcare professionals, particularly case managers and social workers, are instrumental in helping patients navigate this complex system.

In the United States, patients with ESRD are uniquely eligible for Medicare, regardless of age, after a 3-month waiting period. Medicare Part B covers 80% of dialysis services. The role of the clinical team includes:

• Facilitating insurance enrollment: Assisting patients with applications for Medicare, Medicaid, and other programs
• Connecting to financial assistance: Referring patients to non-profits like the American Kidney Fund, which can provide grants to help cover insurance premiums and other costs
• Addressing barriers to care: Identifying and addressing logistical challenges, such as transportation to and from the dialysis center, which can be a significant hidden cost

By taking a proactive role in resource navigation, the healthcare team can mitigate financial toxicity and support uninterrupted access to life-sustaining care.

Dialysis vs. kidney transplant: Guiding long-term strategy

While dialysis effectively manages ESRD, a successful kidney transplant is the treatment of choice for eligible patients, offering superior survival rates and quality of life. A key responsibility of the nephrology team is to provide ongoing education about the dialysis vs. kidney transplant pathways.

Dialysis as a bridge or destination therapy

For many patients, dialysis is a bridge to transplantation. They remain on HD or PD while undergoing a transplant evaluation and waiting for a suitable donor organ. 

For others, due to advanced age, severe comorbidities (e.g., active cancer, severe cardiovascular disease), or personal choice, dialysis serves as destination therapy.

The kidney transplant option

A kidney transplant is a surgical procedure to implant a healthy kidney from a living or deceased donor. The field of transplant surgery has evolved significantly, making it a safe and effective option for many.

• Clinical advantages: Restores near-normal kidney function, eliminates the need for dialysis, liberalizes diet and fluid restrictions, and is associated with a longer life expectancy
• Clinical challenges: Involves the risks of major surgery, requires a lifelong regimen of immunosuppressive drugs to prevent rejection (which increases infection and malignancy risk), and is limited by organ availability

The role of the healthcare provider is to identify potential transplant candidates early, refer them for evaluation, and support them through the complex waiting and post-operative process. This discussion is a crucial part of shared decision-making, ensuring the patient's long-term treatment plan aligns with their medical profile and personal goals.

The integral role of dialysis in modern nephrology

Dialysis remains a cornerstone of treatment for patients with end-stage renal disease, serving as a life-sustaining therapy that requires a profound level of clinical skill and interdisciplinary collaboration. 

From managing the technical intricacies of hemodialysis and peritoneal dialysis to addressing the complex web of potential complications like intradialytic hypotension, infections, and long-term cardiovascular disease, the role of the healthcare professional is multifaceted and critical. Effective patient care extends far beyond the procedure itself, encompassing meticulous access management, individualized dietary counseling, and robust psychosocial support.

Ultimately, successful dialysis management hinges on a holistic and proactive approach. It involves not only mastering the clinical protocols but also empowering patients through education and shared decision-making, whether the therapy serves as a long-term destination or a vital bridge to kidney transplantation. The continuous advancements in technology and care models further underscore the dynamic and demanding nature of this field.

The field of nephrology is dedicated to managing these complex conditions and improving the lives of patients with kidney disease. For healthcare professionals looking to specialize in this vital area, a deeper understanding of renal science and therapies is the next step.

Learn more about the rewarding career path and clinical challenges in the field of nephrology.

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