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

Hemodialysis Guidelines: Initiation and Management

Timing of Dialysis Initiation

Dialysis should NOT be initiated based on GFR alone; instead, conservative management should continue until GFR falls below 15 mL/min/1.73 m², unless specific clinical indications mandate earlier initiation. 1, 2

GFR Thresholds for Initiation

• Target GFR for initiation is approximately 10 mL/min/1.73 m² based on theoretical considerations and historical practice patterns 1, 2
• The mean GFR at dialysis initiation in 2003 was 9.8 mL/min/1.73 m², with lower values (7-9 mL/min/1.73 m²) for young and middle-aged adults and higher values (10-10.5 mL/min/1.73 m²) for children and elderly patients 1, 2
• Early dialysis initiation (GFR >10 mL/min/1.73 m²) in asymptomatic patients provides no survival benefit and may cause harm 2, 3
• When corrected for lead-time bias, there is no clear survival advantage to starting dialysis at higher GFR levels 1, 2

Absolute Clinical Indications for Dialysis (Override GFR)

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

• Uremic symptoms: pericarditis, encephalopathy, intractable nausea/vomiting, bleeding diathesis 4, 2
• Volume overload refractory to diuretic therapy 4, 2
• Uncontrolled hypertension despite maximal medical management 4, 2
• Severe metabolic derangements: hyperkalemia unresponsive to medical therapy, severe metabolic acidosis 4, 2
• Protein-energy malnutrition that develops or persists despite vigorous attempts to optimize intake, with no apparent cause other than low nutrient intake 1, 4, 2

Pre-Dialysis Preparation (Stage 4 CKD)

Patient Education Requirements

• Begin comprehensive dialysis education when patients reach Stage 4 CKD (GFR 15-29 mL/min/1.73 m²) to allow adequate time for decision-making and access planning 1
• Education must cover: treatment modality options (hemodialysis vs peritoneal dialysis vs transplantation), vascular access timing, home dialysis eligibility, and conservative management options 1
• Include family members, close friends, and primary care providers in education sessions, as their understanding critically influences patient decisions 1

Access Planning

• Timely vascular access creation is essential to avoid catheter-dependent dialysis initiation, which increases morbidity 1
• Planning should account for variable success rates and healing times of access procedures, which may take weeks to months 1

GFR Measurement Accuracy

When to Use Measured GFR Instead of Estimated GFR

In patients with unusual creatinine generation or altered tubular secretion, obtain measured GFR using 24-hour urine collection for creatinine and urea clearance rather than relying on estimated GFR. 1, 4

Conditions with Low Creatinine Generation (eGFR overestimates true GFR):

• Malnutrition, muscle wasting, amputation, advanced age, vegetarian diet 1

Conditions with High Creatinine Generation (eGFR underestimates true GFR):

• Unusually muscular habitus, high meat intake 1

Altered Tubular Creatinine Secretion:

• Drugs competing for tubular secretion (trimethoprim, cimetidine) cause artifactually low GFR estimates 1
• Advanced liver disease increases tubular secretion, causing overestimation of GFR 1

The MDRD equation is not interchangeable with measured GFR when GFR <15 mL/min/1.73 m²; for a true GFR of 15 mL/min/1.73 m², MDRD will provide a value of approximately 19.7 mL/min/1.73 m² 5

Initial Dialysis Prescription: "Low and Slow" Approach

The first hemodialysis treatment MUST use a "low and slow" approach to minimize dialysis disequilibrium syndrome and hemodynamic instability. 4, 2

First Session Parameters:

• Duration: 2-2.5 hours (NOT full 4 hours) 4, 2
• Blood flow rate: 200-250 mL/min (reduced from standard 300-400 mL/min) 4, 2
• Ultrafiltration: Minimal during first session; focus on solute clearance rather than fluid removal 4, 2
• Monitoring: Vital signs every 15-30 minutes with close observation for neurological symptoms 4
• Dose escalation: Gradual increase over subsequent sessions as tolerated 4, 2

Hemodialysis Adequacy Monitoring

Dose Measurement Requirements

• Delivered hemodialysis dose must be measured at regular intervals no less than monthly 1
• Express dose as Kt/V, where K = effective dialyzer urea clearance (mL/min), t = time (minutes), V = patient's urea distribution volume (mL) 1
• The preferred method is formal urea kinetic modeling 1
• A weekly Kt/V of 2.0 approximates a kidney urea clearance of 7 mL/min and creatinine clearance of 9-14 mL/min/1.73 m² 2

Critical Pitfalls to Avoid

Do NOT Initiate Dialysis Based on GFR Alone

• Early dialysis initiation in asymptomatic patients provides no survival benefit and may cause harm 2, 3
• Observational data showing earlier initiation in sicker patients reflects selection bias, not benefit from early start 1, 2

Recognize Dialysis-Related Risks

• Hemodialysis-related hypotension may accelerate loss of residual kidney function, which is particularly problematic as residual function contributes significantly to overall clearance 1, 4, 2
• Dialysis does not replace all kidney functions (erythropoietin production, vitamin D activation, acid-base regulation) 1, 2
• Vascular access complications and dialysate-related complications impose significant morbidity 1
• Dialysis imposes substantial burden on patient, family, and healthcare system 1, 2

Avoid Aggressive First Dialysis Sessions

• Rapid removal of uremic toxins can cause cerebral edema, seizures, and cardiovascular instability (dialysis disequilibrium syndrome) 4

Consider Conservative Management

• For older, frailer patients with multiple comorbidities, conservative management without dialysis may be appropriate and should be discussed as part of shared decision-making 1, 3
• Conservative management includes low-protein diets, ketoanalogs of essential amino acids, loop diuretics, and sodium polystyrene sulfonate 1

Conditions Allowing Safe Delay of Dialysis (Even with GFR <10)

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

• Stable or increased edema-free body weight 2
• Adequate nutritional parameters (serum albumin stable, lean body mass >63%) 2
• Complete absence of clinical signs or symptoms attributable to uremia 2
• Careful clinical follow-up with monthly monitoring 6, 3

In asymptomatic patients with Stage 5 CKD, dialysis may be safely delayed until eGFR is as low as 5-7 mL/min/1.73 m² with adequate patient education and close monitoring 3