What are the indications for hemodialysis (HD) in patients with impaired renal function?

Indications for Hemodialysis

Hemodialysis should be initiated based on clinical symptoms and complications of uremia rather than a specific GFR threshold, with absolute indications including uremic symptoms (pericarditis, encephalopathy, bleeding), refractory volume overload, severe hyperkalemia unresponsive to medical therapy, severe metabolic acidosis, and protein-energy malnutrition that persists despite nutritional intervention. 1, 2

Clinical Indications (Not GFR-Based)

The decision to start dialysis must be driven by clinical manifestations rather than laboratory values alone. The following are absolute indications:

Uremic Symptoms

• Pericarditis (uremic pericardial friction rub or effusion) 2
• Encephalopathy (altered mental status, asterixis, seizures) 2
• Intractable nausea and vomiting unresponsive to antiemetics 2
• Uremic bleeding diathesis (platelet dysfunction causing bleeding) 2

Volume and Electrolyte Emergencies

• Refractory volume overload that does not respond to diuretic therapy, particularly with pulmonary edema 2, 3
• Severe hyperkalemia (typically >6.5-7.0 mEq/L) unresponsive to medical management 2, 3
• Severe metabolic acidosis (pH <7.1 or bicarbonate <10 mEq/L) refractory to bicarbonate therapy 2
• Uncontrolled hypertension despite maximal medical therapy 2

Nutritional Deterioration

• Protein-energy malnutrition that develops or persists despite vigorous nutritional optimization in patients with GFR 15-20 mL/min, when no other cause for malnutrition exists 1, 2

This nutritional indication is particularly important because malnutrition at dialysis initiation is associated with increased mortality and morbidity. 1

GFR Considerations (Secondary to Clinical Status)

While GFR alone should not dictate dialysis initiation, it provides context:

• Conservative management should continue until GFR <15 mL/min/1.73 m² unless specific clinical indications mandate earlier initiation 2
• GFR 10.5 mL/min has been associated with improved outcomes compared to delaying until GFR 5 mL/min when symptomatic uremia develops 1
• Early dialysis initiation in asymptomatic patients provides no survival benefit and may cause harm 2

Important Caveat for GFR Measurement

When considering dialysis initiation, obtain measured GFR using 24-hour urine collection for creatinine and urea clearance rather than relying on estimated GFR, as eGFR equations (including MDRD) are not interchangeable with measured GFR at low levels and may overestimate true kidney function. 2, 4

Special Populations

Diabetic Patients

Patients with diabetes should generally initiate dialysis at higher levels of residual kidney function than non-diabetic patients, though specific thresholds remain based on clinical symptoms rather than GFR alone. 1

Acute Kidney Injury

For chemotherapy-induced or other acute kidney injury, dialysis should be initiated for the same clinical indications (uremic symptoms, volume overload, severe metabolic derangements, malnutrition) rather than GFR alone. 2

Critical Pitfalls to Avoid

• Do not initiate dialysis based solely on a GFR threshold in asymptomatic patients, as this provides no survival benefit and may accelerate loss of residual kidney function 2
• Avoid aggressive first dialysis sessions, which can cause dialysis disequilibrium syndrome (cerebral edema, seizures) and cardiovascular instability 2
• Recognize that hemodialysis-related hypotension may accelerate loss of residual kidney function, which is particularly problematic in patients who may recover renal function (such as acute kidney injury) 2
• Remember that dialysis does not replace all kidney functions and imposes significant burden on patients 2

Initial Dialysis Protocol

When dialysis is indicated, use a "low and slow" approach for the first treatment: 2

• Session duration: 2-2.5 hours 2
• Blood flow rate: 200-250 mL/min (reduced from standard 300-400 mL/min) 2
• Minimal ultrafiltration during first session 2
• Frequent vital sign monitoring every 15-30 minutes 2
• Gradual dose escalation over subsequent sessions as tolerated 2

This cautious approach minimizes dialysis disequilibrium syndrome and hemodynamic instability. 2