Renal Replacement Therapy in Children

Indications for RRT in Children - RRT SOS Signals

📌 AEIOU Mnemonic:

• Acidosis: Severe metabolic (pH < 7.1-7.2), refractory to therapy.
• Electrolytes (refractory):
  • Hyperkalemia (K⁺ > 6.5-7 mEq/L or ECG changes).
  • Symptomatic Na⁺ imbalance.
  • Severe hyperphosphatemia.
• Intoxications: Dialyzable drugs/toxins (e.g., salicylates, methanol, lithium).
• Overload: Fluid overload refractory to diuretics, causing respiratory compromise.
• Uremia: Symptomatic (encephalopathy, pericarditis, uremic bleeding).

⭐ Early RRT is crucial in pediatric AKI with severe fluid overload (>15-20% body weight).

RRT Modalities Overview - The Pediatric Toolkit

Peritoneal Dialysis (PD) Deep Dive - Belly Bath Method

• Mechanism: Peritoneal membrane as filter for solute & water exchange.

• Catheter: Tenckhoff common; surgically placed.

• Solutions: Dextrose (1.5%, 2.5%, 4.25%); Icodextrin for long dwells.
• Cycles: Fill (infuse), Dwell (exchange), Drain (remove).
• Types:
  • CAPD: Manual, 3-5 exchanges/day.
  • APD/CCPD: Automated cycler, overnight.
• Parameters:
  • Fill volume: 800-1100 mL/m² or 30-40 mL/kg.
  • Dwell: CAPD 4-6 hrs; APD 1-2 hrs.
• Complications: Peritonitis (cloudy fluid, pain), exit-site/tunnel infections, leaks, hernias.

⭐ Peritonitis is the most common serious PD complication; often S. epidermidis or S. aureus.

Hemodialysis (HD) & CRRT - Blood Purifying Power

• Hemodialysis (HD): Efficiently clears toxins & excess fluid via diffusion/convection.
  • Access: AV fistula/graft, CVC.
  • Anticoagulation: Heparin. BFR: 5-7 ml/kg/min. DFR: ~2x BFR.
  • Adequacy: $Kt/V > extbf{1.2}$. $URR = ((Pre_{BUN} - Post_{BUN}) / Pre_{BUN}) \times 100%$.
  • Key risks: Hypotension, disequilibrium syndrome.
• CRRT (Continuous Renal Replacement Therapy): For unstable AKI; maintains physiologic balance.
  • Modes: CVVH (convection), CVVHD (diffusion), CVVHDF.
  • Anticoagulation: Regional citrate preferred.
  • Effluent dose: 20-25 ml/kg/hr for optimal clearance.

⭐ CRRT is preferred in hemodynamically unstable children with AKI due to better fluid balance control and cardiovascular stability.

Complications & Special Issues - Navigating RRT Challenges

• Infections: Peritonitis (PD), CRBSI (HD/CRRT).
• Cardiovascular: Hypertension, LVH, arrhythmias.
• Nutrition & Growth: Malnutrition, growth failure (critical).
• Anemia: ↓EPO, blood loss; manage with ESA, iron.
• Mineral Bone Disorder (MBD): Monitor Ca, P, PTH, Vit D.
• Access Issues: Thrombosis, stenosis, infection.
• Psychosocial: Schooling, adherence, family stress.
• Fluid/Electrolyte Imbalance: HyperK, hypoCa, acidosis.

⭐ Growth failure is a major long-term complication in children on RRT, impacting final adult height and quality of life.

High‑Yield Points - ⚡ Biggest Takeaways

• Peritoneal dialysis (PD) is preferred in neonates/infants; easier access.
• Hemodialysis (HD) needs good vascular access; AV fistula ideal but challenging.
• CRRT for hemodynamically unstable children, mainly in PICU.
• Indications: AKI with fluid overload, severe electrolyte imbalance, uremia, intoxications.
• Complications: Peritonitis (PD), hypotension (HD), access issues, electrolyte disturbances.
• Dialysis dose calculation is critical, based on pediatric body size.
• Growth failure is a major concern with chronic RRT.