What are the recommended settings for blood flow rate, replacement fluid rate, and dialysate rate for pediatric patients undergoing Continuous Renal Replacement Therapy (CRRT)?

Pediatric CRRT Settings: Blood Flow, Replacement Fluid, and Dialysate Rate

For pediatric patients requiring Continuous Renal Replacement Therapy (CRRT), blood flow rates should be 3-6 mL/kg/min, replacement fluid rates 20-25 mL/kg/hr, and dialysate rates 20-25 mL/kg/hr, with adjustments based on patient size and hemodynamic stability.

Blood Flow Rate Settings

• Blood flow rates for pediatric CRRT should be tailored according to patient size 1:

  • Neonates and infants (<10 kg): 3-5 mL/kg/min (typically 30-50 mL/min) 2
  • Children (10-20 kg): 4-5 mL/kg/min (typically 50-100 mL/min) 2
  • Larger children (>20 kg): 5-6 mL/kg/min (typically 100-150 mL/min) 3

• Higher blood flow rates improve filter longevity but must be balanced against:

  • Hemodynamic stability of the patient 4
  • Access limitations (catheter size) 1
  • Risk of excessive hemoconcentration 4

Replacement Fluid Rate

• The recommended replacement fluid rate for pediatric CRRT is 20-25 mL/kg/hr 1

• For septic patients or those with high catabolic states, consider higher rates of 30-35 mL/kg/hr 4

• Pre-dilution fluid administration (before the filter) is preferred for:

  • Patients with frequent filter clotting 1
  • Situations where extracorporeal clearance is limited by achievable blood flow 1
  • Small infants where hemoconcentration is a concern 2

• For neonates and infants ≤5 kg, replacement fluid rates may need to be proportionally higher relative to body weight to achieve adequate clearance 2

Dialysate Rate

• For CVVHD or CVVHDF modalities, dialysate flow rates should be 20-25 mL/kg/hr 1

• Dialysate composition should use bicarbonate rather than lactate as buffer, especially in:

  • Patients with circulatory shock 1
  • Patients with liver failure 1
  • Patients with lactic acidemia 1

• For small children, the dialysate rate may need to be adjusted to maintain acid-base balance and electrolyte homeostasis 4

Fluid Removal Considerations

• Net ultrafiltration rates should be carefully controlled:

  • Optimal range for most pediatric patients is between -0.3 and -4.5 mL/kg/hr 5
  • More aggressive rates may be needed in fluid overloaded patients 6
  • Excessive ultrafiltration rates are associated with hemodynamic instability 5

• Fluid overload >10% at CRRT initiation is associated with increased mortality 6

• Target a gradual reduction in fluid overload status, especially in hemodynamically unstable patients 4

Special Considerations for Very Small Children

• For children ≤10 kg, mortality is significantly higher than larger children (57% vs 36%) 2

• Special circuit considerations for children ≤5 kg:

  • Blood priming of the circuit is typically required 2
  • Higher blood flows relative to body weight may be needed to prevent circuit clotting 2
  • More frequent monitoring of circuit pressures and filter performance 7

• For neonates, an instilled volume of at least 1,100 mL/m² is recommended 4

Monitoring Parameters

• Monitor delivered dose frequently to ensure prescribed dose is achieved 1

• Assess filter performance regularly and adjust prescription to achieve:

  • Electrolyte balance 1
  • Acid-base balance 1
  • Solute clearance 1
  • Fluid balance 1

• Monitor for common complications:

  • Electrolyte abnormalities (hypophosphatemia, hypokalemia, hypomagnesemia) 8
  • Filter clotting 3
  • Hemodynamic instability 4
  • Hypothermia (consider warming dialysate) 8

• Ensure accurate fluid balance monitoring, as errors in fluid balance can be potentially lethal in small children 7