What are the types of dialysis and their management?

Types of Dialysis and Their Management

For patients with end-stage renal disease (ESRD), there are two primary dialysis modalities—hemodialysis (HD) and peritoneal dialysis (PD)—with multiple variations within each type, and the choice should be guided by an individualized ESRD Life-Plan that considers patient preferences, lifestyle, clinical contraindications, and vascular access options rather than a one-size-fits-all approach. 1

Primary Dialysis Modalities

Hemodialysis (HD)

HD is the most commonly used dialysis therapy worldwide and involves extracorporeal blood purification. 1

Conventional Hemodialysis:

• Performed 3 times per week for 3-5 hours per session 1
• Can be delivered in-center (fully assisted by healthcare staff) or at home (with varying levels of assistance) 1
• Requires vascular access: arteriovenous fistula (AVF), arteriovenous graft (AVG), or central venous catheter (CVC) 1

Intensive Hemodialysis Regimens:

Short Daily Hemodialysis:

• 5 or more sessions per week, less than 3 hours per session 1
• May be offered as an alternative to conventional HD after considering patient preferences and potential benefits 1
• Patients must be informed about increased risk of vascular access procedures and potential for intradialytic hypotension 1
• Benefits include improved blood pressure control, reduced intradialytic hypotension, and enhanced clearance of uremic toxins 1

Long Hemodialysis:

• 3-4 sessions per week, ≥5.5 hours per session 1
• Consider for patients who prefer this therapy for lifestyle considerations 1

Long-Frequent (Nocturnal) Hemodialysis:

• ≥5.5 hours per session, 5 or more sessions per week (typically 6-8 hours, 3-6 nights per week at home) 1
• Patients must be informed about possible increased vascular access complications, potential for increased caregiver burden, and possible accelerated decline in residual kidney function 1
• Particularly recommended during pregnancy for women with ESRD 1

Peritoneal Dialysis (PD)

PD uses the peritoneal membrane as a filter, requiring regular exchanges of dialysis fluid into the peritoneal cavity. 1, 2

Continuous Ambulatory Peritoneal Dialysis (CAPD):

• Manual exchanges performed throughout the day 1, 3
• Most patients with residual renal function start with CAPD 3
• Requires regular dialysis fluid bag changes to maintain concentration gradient for waste removal 2

Automated Peritoneal Dialysis (APD):

• Uses a cycler machine to perform exchanges, typically overnight 1, 3
• Allows greater flexibility for daytime activities 1

Clinical Decision-Making Framework

Initial Modality Selection

Step 1: Assess for Absolute Contraindications

PD Contraindications:

• Inflammatory or ischemic bowel disease (increases risk of transmural contamination by enteric organisms) 4
• Frequent episodes of diverticulitis (significantly increases peritonitis risk) 4
• Inability to perform exchanges safely or maintain sterile technique 4

HD Contraindications:

• Inability to establish or maintain vascular access 1
• Severe hemodynamic instability precluding extracorporeal circulation 4

Step 2: Evaluate Relative Indications

Factors Favoring PD:

• Preservation of residual kidney function (PD may reduce risk of RKF loss: RR 0.55) 5
• Desire for home-based therapy and greater autonomy 4
• Better preservation of vascular access sites for future use 1
• Lower cost compared to in-center HD 6
• Potential survival advantage in first 1.5-2 years of dialysis 6, 5

Factors Favoring HD:

• Morbid obesity (challenges with catheter placement, wound healing, and achieving adequate clearance; risk of weight gain from dialysate glucose) 4
• Inability to achieve adequate clearance targets on PD 4
• Patient preference for in-center care with healthcare staff support 1

Step 3: Consider Patient-Specific Factors

• Patient schedule and quality of life preferences should be incorporated into the prescription 1
• Shared decision-making must involve the patient (or legal agent if lacking capacity), physician, and potentially family members 1
• All treatment options must be fully explained, including available dialysis modalities, conservative management, time-limited trial, and option to stop dialysis 1

Special Populations

Diabetic Patients:

• Both HD and PD are viable options; HD is most commonly used 3
• PD presents challenges with glucose absorption from dialysate affecting blood glucose control 3
• No definitive survival advantage of one modality over the other in most diabetic patients 7

Pediatric Patients:

• Little or no difference between HD and PD on all-cause death (RR 0.81) or cardiovascular death (RR 1.23) 5
• For acute hyperammonemia, intermittent HD and continuous kidney replacement therapy are more efficacious than PD 4

Pregnant Patients:

• Long frequent hemodialysis (either in-center or at home) should be provided during pregnancy 1

Management Principles by Modality

Hemodialysis Management

Vascular Access:

• Develop an ESRD Life-Plan that considers current access needs and plans for future access transitions 1
• Arteriovenous fistulas have nearly twofold higher survival rates compared to synthetic grafts 3
• Central venous catheters should be avoided for long-term access due to increased infection risk 6

Dialysis Adequacy:

• Target single pool Kt/V of at least 1.2 3
• Monitor for adequacy regularly to ensure prescribed regimen is sufficient 2

Intensive HD-Specific Considerations:

• Different approaches required for vascular access type, cannulation techniques, dialysate composition, and mineral metabolism management compared to conventional HD 1
• Enhanced clearance allows discontinuation of fluid, sodium, and phosphate restrictions (including phosphate binders) 1

Peritoneal Dialysis Management

Prescription Optimization:

• To optimize middle-molecule clearance in patients with minimal residual kidney function, prescribe dwells for the majority of the 24-hour day, even if small-molecule clearance is above target 1
• To optimize small-solute clearance and minimize cost, first increase instilled volume per exchange before increasing number of exchanges 1

Monitoring:

• Perform peritoneal equilibration test (PET) when clinically stable and at least 1 month after peritonitis resolution 1
• Monitor for declining peritoneal membrane function over time to identify need for transition to HD 4
• Consistent failure to achieve target Kt/Vurea and creatinine clearance despite optimal prescription adjustments is a mandatory indication for switching to HD 4

Infection Prevention:

• Peritonitis remains a major cause of PD discontinuation 3
• Patients must maintain proper technique during bag changes to prevent peritonitis 2
• No increased peritonitis risk in diabetic patients compared to non-diabetics 3

Dialysate Management:

• Regular fluid exchanges are essential to maintain effective clearance of uremic toxins 2
• Insufficient exchanges can lead to uremia, fluid overload, hypertension, and cardiovascular complications 2
• Patients should have emergency supply of dialysis fluid bags for disasters or supply disruptions 2

Common Pitfalls to Avoid

• Do not assume one modality is universally superior—survival is independent of modality for most patients, including those with diabetes 7
• Do not delay transition from PD to HD when adequacy targets cannot be met—sharp monitoring is necessary after a few years of PD to detect underdialysis promptly 8
• Do not ignore peritoneal transport characteristics—this can lead to inadequate dialysis prescription 4
• Do not calculate Kt/V using actual body weight in malnourished patients—this may falsely suggest adequate dialysis 4
• Do not impose arbitrary time limits on PD duration—transfer decisions should be based on clinical assessment, adequacy targets, and patient wishes 4
• Do not fail to obtain written advance directives from all dialysis patients 1

Ongoing Reassessment

• Life expectancy and quality of life should be discussed with patients or legal agents, with documentation of these conversations 1
• For patients encountering major complications that substantially reduce survival or quality of life, reassess treatment goals and consider withdrawing dialysis 1
• Implement systematic conflict resolution approach when disagreement exists regarding dialysis benefits 1
• If dialysis is indicated urgently, provide it while pursuing conflict resolution, provided the patient or legal agent requests dialysis 1