What are the guidelines for initiating and managing hemodialysis in patients with impaired renal function?

Hemodialysis Initiation and Management

Timing of Dialysis Initiation

Dialysis should be initiated based on clinical symptoms and complications of kidney failure, not solely on a specific GFR threshold, with conservative management continuing until GFR falls below 15 mL/min/1.73 m² unless urgent clinical indications are present. 1

GFR-Based Thresholds

• Target GFR for initiation is approximately 10 mL/min/1.73 m² based on theoretical considerations, with mean actual initiation occurring at 9.8 mL/min/1.73 m² 1, 2
• Young and middle-aged adults typically initiate at lower GFR (7-9 mL/min/1.73 m²), while children and elderly patients initiate at higher GFR (10-10.5 mL/min/1.73 m²) 1, 2
• Early initiation at GFR >10 mL/min/1.73 m² in asymptomatic patients provides no survival benefit and may cause harm 2
• When corrected for lead-time bias, there is no clear survival advantage to starting dialysis at higher GFR levels 1, 2

Mandatory Clinical Indications for Earlier Initiation (Override GFR)

Initiate dialysis immediately when any of the following are present, regardless of GFR:

• Uremic symptoms: Pericarditis, encephalopathy, intractable nausea/vomiting, bleeding diathesis 1, 2
• Protein-energy malnutrition that persists despite vigorous dietary optimization, with no apparent cause other than low nutrient intake 1, 2
• Volume overload refractory to diuretic therapy 2
• Uncontrolled hypertension despite maximal medical management 2
• Severe metabolic acidosis or hyperkalemia unresponsive to medical therapy 2
• Progressive nutritional deterioration: Declining edema-free body weight, falling serum albumin, lean body mass <63% 1, 2

Conditions Permitting Delayed Initiation

Dialysis may be safely deferred even when GFR <10 mL/min/1.73 m² if ALL of the following criteria are met:

• Stable or increased edema-free body weight 1, 2
• Serum albumin above lower limit of normal and stable or rising 1
• Subjective global assessment score indicating adequate nutrition 1
• Complete absence of uremic symptoms 1, 2

Pre-Dialysis Preparation

Patient Education (CKD Stage 4)

Begin comprehensive education when patients reach CKD stage 4 (GFR <30 mL/min/1.73 m²) to allow adequate time for decision-making and access planning 1

Education must cover:

• Kidney transplantation (including preemptive living donor options) 1
• Peritoneal dialysis 1
• Hemodialysis (home or in-center) 1
• Conservative management without dialysis 1

GFR Estimation Methods

Use validated estimating equations (MDRD or CKD-EPI), not serum creatinine alone 1

Special circumstances requiring measured GFR (24-hour urine collection for creatinine and urea clearance):

• Unusually low creatinine generation: Malnutrition, amputation, muscle wasting diseases, vegetarian diet 1
• Unusually high creatinine generation: Bodybuilders, high muscle mass 1
• Altered tubular creatinine secretion: Trimethoprim, cimetidine, advanced liver disease 1

Initial Dialysis Prescription: "Low and Slow" Approach

The first hemodialysis treatment must use reduced parameters to prevent dialysis disequilibrium syndrome and hemodynamic instability 2, 3

First Session Parameters

• Duration: 2-2.5 hours (not full 4 hours) 2, 3
• Blood flow rate: 200-250 mL/min 2, 3
• Ultrafiltration: Minimal, focusing on clearance rather than fluid removal 2, 3
• Monitoring: Vital signs every 15-30 minutes 3

Rationale for Low and Slow Approach

• Rapid urea removal creates osmotic gradient causing cerebral edema (dialysis disequilibrium syndrome) 3
• Symptoms include headache, nausea, vomiting, restlessness, seizures, and potentially coma 3
• Risk is highest in patients with very high BUN levels at initiation 3
• Rapid fluid removal causes hypotension, myocardial stunning, and arrhythmias, especially in elderly patients with cardiovascular comorbidities 3

Dose Escalation

Gradually increase dialysis dose over subsequent sessions as patient tolerates treatment 2, 3

Ongoing Hemodialysis Adequacy

Dose Measurement and Targets

• Measure delivered dose monthly at minimum using Kt/V (where K = dialyzer urea clearance, t = time, V = urea distribution volume) 1
• Preferred method: Formal urea kinetic modeling 1
• Include frequency of treatments in dose expression 1

Critical Pitfalls and Caveats

Risks of Dialysis Itself

• Hemodialysis is not innocuous and does not replace all kidney functions 1
• HD-related hypotension may accelerate loss of residual kidney function 1, 2
• Vascular access complications represent significant morbidity 1, 2
• Dialysis imposes substantial burden on patient, family, and healthcare system 1, 2

Patient Selection Bias in Observational Data

Frailer patients with more comorbidities tend to start dialysis at higher GFR levels but do not live as long as healthier patients who start later—this reflects patient selection bias, not benefit from early initiation 1, 2

Conservative Management Option

For patients choosing not to pursue dialysis, provide comprehensive conservative management including low-protein diets, keto-analogs of essential amino acids, loop diuretics, sodium polystyrene sulfonate, and palliative care 1

Multidisciplinary Planning

When GFR <30 mL/min/1.73 m², planning should include access to dietary counseling, education about RRT modalities, transplant evaluation, vascular access surgery consultation, and psychological/social support 1