Key Hemodialysis Parameters and Their Target Values
The most important hemodialysis parameters include dialysis adequacy (measured by Kt/V), treatment frequency, session duration, ultrafiltration, and residual kidney function monitoring, with specific targets established to optimize patient outcomes and reduce mortality. 1
Dialysis Adequacy Parameters
Kt/V - The Primary Measure of Dialysis Adequacy
- Target single pool Kt/V (spKt/V): 1.4 per hemodialysis session for patients treated thrice weekly 1
- Minimum delivered spKt/V: 1.2 (should never fall below this threshold) 1
- For schedules other than thrice weekly, target standard Kt/V of 2.3 volumes per week with minimum delivered dose of 2.1 1
- Kt/V represents fractional urea clearance and is the most precise measure of dialyzer effect on patient survival 1
Blood Urea Nitrogen (BUN) Sampling
- Proper BUN sampling techniques are crucial for accurate Kt/V calculation 1
- Common sampling errors to avoid:
Treatment Schedule Parameters
Frequency and Duration
- Standard schedule: Three times weekly 1
- Alternative schedules:
- Treatment time should be sufficient to achieve adequate fluid removal without excessive ultrafiltration rates 1
Residual Kidney Function (RKF)
- In patients with significant residual native kidney function (Kru), dialysis dose may be reduced 1
- Regular measurement of Kru is essential to avoid inadequate dialysis 1
- RKF contributes to total clearance and should be included in calculations for non-standard schedules 1
Fluid and Electrolyte Parameters
Ultrafiltration
- Ultrafiltration rate should be monitored to avoid rapid fluid removal 1
- Excessive ultrafiltration can lead to intradialytic hypotension and increased mortality 1
- Fluid removal should be individualized based on interdialytic weight gain and cardiovascular stability 1
Electrolyte Management
- Sodium: Target 1.8-2.5 g/day 1
- Potassium: Target 2000-2500 mg/day 1
- Phosphate: Target 800-1000 mg/day 1
- Fluid intake: 1000 ml plus urine volume 1
Nutritional Parameters
Protein and Energy Requirements
- Protein intake: 1.2-1.4 g/kg body weight/day (≥50% high biological value) 1
- Energy intake: 35 kcal/kg body weight/day for patients <60 years; 30 kcal/kg body weight/day for patients >60 years 1
- Nutritional status is an independent determinant of morbidity and mortality in hemodialysis patients 1
Monitoring Frequency
- Delivered dose of hemodialysis should be measured at least once monthly in all patients 1
- Increase measurement frequency when:
Common Pitfalls and How to Avoid Them
- Targeting minimum values as goals: Deliberately targeting just the minimum Kt/V of 1.2 will result in many sessions falling below this threshold; always target higher (1.4) 1
- Ignoring residual kidney function: Failing to account for RKF can lead to over-dialysis; measure periodically 1
- Inadequate sampling techniques: Improper blood sampling leads to inaccurate Kt/V calculations; follow standardized protocols 1
- Focus solely on small-solute clearance: While Kt/V is important, other aspects like fluid balance, blood pressure control, and nutritional status are equally critical 1
- Overlooking special populations: Certain groups (e.g., pregnant women) require more intensive dialysis regimens 3