🩺 Renal Replacement Therapy in AKI

KDIGO 2026 Guidelines — Initiation, Modality, Dose, Access & Discontinuation

🏅 KDIGO 2026 AKI/AKD Guideline — Chapter 5: Renal Replacement Therapy

⏱️ RRT Initiation — Deferred Strategy

Rec 5.1.1 (1C): We suggest a deferred timing strategy for RRT initiation over an early/pre-emptive strategy in critically ill adults with AKI.

This recommendation is grounded in three landmark trials demonstrating no benefit (and potential harm) from early RRT initiation:

STARRT-AKI (2020)

N=2,927. No mortality benefit with accelerated vs. standard strategy. More adverse events with early RRT.

AKIKI (2016)

N=620. Delayed strategy: 49% of patients never needed RRT. No mortality difference.

IDEAL-ICU (2018)

N=488. Early RRT in septic shock: no mortality benefit. Stopped early for futility.

PP 5.1.1: Shared decision-making with patients and families regarding RRT initiation, goals, and potential outcomes should be incorporated into clinical practice.
PP 5.1.2: For patients with a high probability of needing RRT, plan BEFORE absolute indications are met — including transfer to centers with nephrology services if needed.

🚨 Indications for RRT Initiation (Deferred Strategy)

🔴 Absolute Indications

  • Refractory fluid overload
  • Refractory hyperkalemia
  • Severe metabolic acidosis (refractory to medical therapy)
  • Uremic complications — encephalopathy, pericarditis, bleeding

⚠️ Special Situations

  • Consider CRRT for hepatic encephalopathy ≥grade 2 with hyperammonemia even without conventional AKI indications
  • Time-limited trial of RRT can be started if uremic/metabolic complications are plausibly confounding neurological evaluation (PP 5.1.5)

🔄 RRT Modality Selection

Feature CRRT IRRT (IHD) PIRRT (SLED) Acute PD
Hemodynamic Stability Best Worst Good Good
Solute Clearance Continuous Intermittent high Intermediate Lower
Preferred For Unstable, brain injury, liver failure Stable patients Alternative to CRRT Resource-limited, select peds
Anticoagulation Citrate preferred UFH / LMWH UFH / LMWH None

📋 Key Modality Recommendations

Rec 5.2.1 (2C): We suggest CRRT or acute PD over conventional IRRT for hemodynamically unstable patients.
PP 5.2.2: CRRT is preferred in patients with acute brain injury or increased ICP (avoids rapid osmotic shifts).
PP 5.2.4: Prolonged intermittent RRT (PIRRT / SLED) is an acceptable alternative to CRRT where resources or expertise favor it.
PP 5.2.5: Transition from CRRT → IRRT when the patient is hemodynamically stable and ICP risks have resolved.

💉 RRT Dose-Intensity

CRRT Dose (Rec 5.3.1, 1B)

20–25 mL/kg/h

Effluent volume target

Use ideal or adjusted body weight for BMI ≥30

IRRT / PIRRT Dose (Rec 5.3.1, 1B)

Kt/V 3.9/week

Minimum delivered dose target

Review adequacy before each IRRT session

Acute Peritoneal Dialysis

Kt/V 2.2/week

18–24 L PD fluid per day

Review adequacy daily for CRRT, before each IRRT session

🚫 AGAINST High-Volume Hemofiltration (HVHF) in Sepsis (Rec 5.3.2, 1B)

KDIGO 2026 recommends against high-volume hemofiltration (>35–45 mL/kg/h) in sepsis and septic shock.

Rationale:
  • HVHF was proposed to remove inflammatory cytokines in sepsis
  • Evidence does NOT support a mortality benefit
Key Trials:
  • IVOIRE trial: No survival benefit with HVHF vs. standard dose
  • ATN trial: Intensive dose (35 mL/kg/h) = standard dose (20 mL/kg/h)
  • RENAL trial: Higher intensity CRRT did not reduce mortality
Harms of HVHF:
  • Increased electrolyte losses (hypokalemia, hypophosphatemia)
  • Enhanced antibiotic clearance → subtherapeutic levels
  • Greater nursing workload and cost
Bottom Line: Standard dose (20–25 mL/kg/h) is the evidence-based target. More is NOT better.

🩸 Vascular Access for RRT

📋 Catheter Management

  • Use standardized care bundles for catheter insertion and maintenance
  • No routine or scheduled catheter changes
  • Replace poorly performing catheters via new venipuncture or guidewire exchange (individualize decision)

🔌 AV Fistula / Graft Use

  • Existing AV fistulas and grafts are suitable for IRRT
  • AVOID using AV access for CRRT — dislodgement risk with continuous use

🔄 Tunneled Catheter Transition

  • Transition to tunneled dialysis catheter if low probability of AKI resolution
  • Also consider when preparing for discharge with ongoing RRT need

💊 Anticoagulation for RRT

Rec 5.5.1 (1B): We recommend regional citrate anticoagulation over heparin for CRRT in patients without contraindications to citrate.

🧪 Regional Citrate (Preferred for CRRT)

  • Chelates calcium in the circuit → prevents clotting
  • Calcium infused separately to patient
  • Longer circuit life vs. heparin
  • Lower bleeding risk
  • Also preferred in HIT (PP 5.5.5)

💉 Alternatives When Citrate Contraindicated

  • Unfractionated heparin (UFH)
  • Epoprostenol (prostacyclin)
  • Nafamostat (serine protease inhibitor)
PP 5.5.2: Regional citrate + systemic anticoagulation may be combined for hypercoagulable states

🩸 Heparin-Induced Thrombocytopenia (HIT)

  • Argatroban (direct thrombin inhibitor)
  • Danaparoid
  • Bivalirudin
  • Regional citrate also preferred in HIT (PP 5.5.5)
IHD / PIRRT Anticoagulation: UFH or LMWH are standard for patients without increased bleeding risk. Regional citrate is not typically used for intermittent modalities.

🧫 Hemofilters & Solutions

🧬 Membrane Selection

  • Use biocompatible membranes
  • Synthetic membranes (polysulfone, polyethersulfone) preferred

⏳ Maximize Circuit Life (Non-Pharmacologic)

  • Optimal catheter tip position — right atrium
  • Use predilution mode when possible
  • Prefer CVVHD or CVVHDF over CVVH (convection-only modes clot faster)

🧪 Solution Specifications

  • Bicarbonate buffer (not lactate) in shock, liver failure, lactic acidemia
  • Use sterile CRRT solutions
  • Use AAMI-compliant solutions for IRRT

✅ RRT Discontinuation

Discontinue RRT when kidney function is adequate for clinical needs, or per patient/family preference aligned with goals of care.

📊 Predictors of Successful Discontinuation

>450 mL/24h
UOP without diuretics
>2300 mL/24h
UOP with diuretics
≥23 mL/min
2-hour timed creatinine clearance

💊 Diuretics Around Discontinuation

  • Diuretics may augment urine output
  • However, diuretics are NOT proven to facilitate AKI resolution
  • Use for volume management, not to "kick-start" kidneys
Clinical Pearl: A rising urine output trend — especially if sustained for 24–48 hours — is more meaningful than any single measurement.

🎯 Key Learning Points — RRT in AKI

⏱️ Timing

  • Deferred strategy preferred (STARRT-AKI, AKIKI, IDEAL-ICU)
  • Initiate for refractory complications, not arbitrary thresholds
  • Plan ahead if RRT likely needed
  • Shared decision-making essential

🔄 Modality

  • CRRT for hemodynamic instability, brain injury, liver failure
  • PIRRT is acceptable alternative to CRRT
  • Transition CRRT → IRRT when stable
  • PD for resource-limited settings

💉 Dose & Anticoagulation

  • CRRT: 20–25 mL/kg/h (standard, not high-volume)
  • HVHF does NOT improve outcomes in sepsis
  • Regional citrate preferred for CRRT
  • Bicarbonate buffer in shock and liver failure

✅ Discontinuation

  • UOP >450 mL/24h (no diuretics) predicts success
  • 2h CrCl ≥23 mL/min also predictive
  • Diuretics augment UOP but don't resolve AKI
  • Tunneled catheter if prolonged need expected

📚 Verified Sources

RRT initiation timing and modality evidence anchored to STARRT-AKI, AKIKI, IDEAL-ICU, and KDIGO. [Bibliography added 2026-05-04]

  1. STARRT-AKI Investigators; Bagshaw SM, Wald R, Adhikari NKJ, et al. Timing of Initiation of Renal-Replacement Therapy in Acute Kidney Injury. N Engl J Med. 2020;383(3):240-251. PMID: 32668114. — Accelerated vs standard KRT initiation; no mortality benefit, more dialysis dependence with accelerated.
  2. Gaudry S, Hajage D, Schortgen F, et al; AKIKI Study Group. Initiation Strategies for Renal-Replacement Therapy in the Intensive Care Unit. N Engl J Med. 2016;375(2):122-133. PMID: 27181456. — Early vs delayed RRT in ICU AKI; no difference in mortality.
  3. Barbar SD, Clere-Jehl R, Bourredjem A, et al; IDEAL-ICU Trial Investigators. Timing of Renal-Replacement Therapy in Patients with Acute Kidney Injury and Sepsis. N Engl J Med. 2018;379(15):1431-1442. PMID: 30304656. — Early vs delayed RRT in septic AKI; no mortality benefit; trial stopped early for futility.
  4. RENAL Replacement Therapy Study Investigators; Bellomo R, Cass A, Cole L, et al. Intensity of continuous renal-replacement therapy in critically ill patients. N Engl J Med. 2009;361(17):1627-1638. PMID: 19846848. — RENAL trial — high-intensity (40 mL/kg/hr) vs standard (25 mL/kg/hr) CRRT; no difference in mortality.
  5. VA/NIH Acute Renal Failure Trial Network; Palevsky PM, Zhang JH, O'Connor TZ, et al. Intensity of renal support in critically ill patients with acute kidney injury (ATN). N Engl J Med. 2008;359(1):7-20. PMID: 18492867. — ATN trial — intensive vs less-intensive RRT; no mortality benefit.
  6. KDIGO Acute Kidney Injury Work Group. KDIGO Clinical Practice Guideline for Acute Kidney Injury. Kidney Int Suppl. 2012;2:1-138. KDIGO 2012 AKI Guideline (PDF). — RRT initiation criteria, modality selection, dosing.

📚 For Educational Purposes Only — KDIGO 2026 AKI/AKD Guideline Recommendations

© 2025 Andrew Bland MD - All Rights Reserved

Also on this topic

The same subject at other levels of depth.