Summary

KDIGO’s 2012 guideline establishes a unified definition and staging system for acute kidney injury (AKI) by merging RIFLE and AKIN criteria, and provides evidence-graded recommendations for risk assessment, prevention, pharmacologic management, contrast-induced AKI (CI-AKI), and renal replacement therapy (RRT). It emphasizes early recognition, hemodynamic optimization with crystalloids, avoidance of nephrotoxins, and stage-based management. Specific guidance is given for RRT timing, modality, anticoagulation, vascular access, dose, and buffer choice.

Key Recommendations

Diagnose AKI by any of: SCr rise ≥0.3 mg/dL within 48 h, SCr ≥1.5× baseline within 7 days, or urine output <0.5 mL/kg/h for 6 h.
Use isotonic crystalloids rather than colloids (albumin or starches) for initial volume expansion in patients at risk for or with AKI, except in hemorrhagic shock (2B).
Use vasopressors with fluids in vasomotor shock with or at risk for AKI (1C); apply protocol-based hemodynamic management in perioperative and septic shock patients (2C).
Target plasma glucose 110–149 mg/dL with insulin in critically ill patients; avoid tight control <110 mg/dL due to hypoglycemia risk (2C).
Do not use diuretics to prevent AKI (1B); use only to manage volume overload, not to treat AKI itself (2C).
Do not use low-dose dopamine (1A), fenoldopam (2C), ANP (2C/2B), or recombinant IGF-1 (1B) to prevent or treat AKI.
Avoid aminoglycosides unless no less-nephrotoxic alternative exists (2A); when used, dose once-daily and monitor levels (1A for multi-daily, 2C for single-daily >48 h).
Prefer lipid formulations of amphotericin B (2A) or azoles/echinocandins over conventional amphotericin B (1A).
For CI-AKI prevention: use lowest possible contrast dose, iso-osmolar or low-osmolar contrast (1B), IV isotonic saline or bicarbonate volume expansion (1A); do not use oral fluids alone (1C) or fenoldopam (1B); consider oral NAC with IV crystalloids (2D).
Do not use NAC for prevention of postsurgical AKI (1A) or in critically ill hypotensive patients (2D).
Initiate RRT emergently for life-threatening fluid, electrolyte, or acid-base disturbances; otherwise weigh broader clinical context rather than single BUN/creatinine thresholds.
Use CRRT rather than intermittent RRT for hemodynamically unstable patients (2B) and for patients with acute brain injury or raised intracranial pressure (2B).
For RRT anticoagulation in patients without bleeding risk: use heparin (unfractionated or LMWH) for IHD (1C), regional citrate for CRRT (2B); for HIT, use direct thrombin or Factor Xa inhibitors (1A).
Insert dialysis catheter preferentially in right internal jugular vein under ultrasound guidance (1A); avoid subclavian if possible; obtain post-placement chest radiograph (1B).
Use bicarbonate rather than lactate as RRT buffer, especially in circulatory shock (1B) or liver failure/lactic acidemia (2B); comply with AAMI standards for dialysate purity (1B).
Deliver Kt/V of 3.9 per week for intermittent/extended RRT (1A) and effluent volume 20–25 mL/kg/h for CRRT (1A), with frequent assessment of delivered vs prescribed dose.

Thresholds & Doses

AKI Stage 1: SCr 1.5–1.9× baseline or ≥0.3 mg/dL increase; UO <0.5 mL/kg/h for 6–12 h.
AKI Stage 2: SCr 2.0–2.9× baseline; UO <0.5 mL/kg/h for ≥12 h.
AKI Stage 3: SCr ≥3× baseline, or SCr ≥4.0 mg/dL (≥353.6 µmol/L), or initiation of RRT, or eGFR <35 mL/min/1.73 m² in patients <18 y; UO <0.3 mL/kg/h for ≥24 h or anuria ≥12 h.
Glycemic target in critically ill: plasma glucose 110–149 mg/dL (6.1–8.3 mmol/L).
Energy intake in AKI: 20–30 kcal/kg/d.
Protein intake: 0.8–1.0 g/kg/d (non-catabolic, no dialysis); 1.0–1.5 g/kg/d (on RRT); up to 1.7 g/kg/d (on CRRT or hypercatabolic).
Aminoglycoside dosing (normal renal function): gentamicin/tobramycin 5 mg/kg/d once daily; netilmicin 6 mg/kg/d; amikacin 15 mg/kg/d.
Monitor aminoglycoside levels if multi-daily dosing >24 h; if single daily dosing >48 h.
CI-AKI risk threshold: eGFR <60 mL/min/1.73 m² (some evidence supports <45 mL/min/1.73 m²); SCr ≥1.3 mg/dL (men) or ≥1.0 mg/dL (women).
Gadolinium NSF risk: contraindicated if GFR <30 mL/min/1.73 m²; caution if GFR 30–60 mL/min/1.73 m².
IV fluid for CI-AKI prevention: 1.0–1.5 mL/kg/h for 3–12 h before and 6–12 h after contrast; target urine output ≥150 mL/h.
RRT dose: Kt/V 3.9/week (intermittent/extended); CRRT effluent 20–25 mL/kg/h delivered (prescribe 25–30 mL/kg/h).
Pediatric fluid overload: mortality risk increases substantially at >10–20% fluid accumulation at CRRT initiation.
Vascular access order: 1st right IJ; 2nd femoral; 3rd left IJ; last subclavian (dominant side).
Catheter sizing pediatrics: neonate 7F double-lumen; 6–30 kg 8F; >30 kg 10F double-lumen or 12F triple-lumen.
Dialysate microbial standards (AAMI/ISO): water and dialysate bacteria <100 CFU/mL, endotoxin <0.5 EU/mL; substitution fluid sterile.

Citations

Section 2.1 (Recommendations 2.1.1–2.1.2) — AKI definition and staging criteria based on combined RIFLE/AKIN.
Section 3.1 (Recommendations 3.1.1–3.1.3) — Fluid resuscitation with isotonic crystalloids, vasopressor use, and protocolized hemodynamic management.
Section 3.3 (Recommendations 3.3.1–3.3.5) — Glycemic control target 110–149 mg/dL and nutritional support (energy 20–30 kcal/kg/d; protein 0.8–1.7 g/kg/d).
Section 3.4–3.5 (Recommendations 3.4.1–3.5.3) — Recommendations against diuretics, low-dose dopamine, fenoldopam, and ANP for AKI prevention/treatment.
Section 3.8 (Recommendations 3.8.1–3.8.7) — Aminoglycoside and amphotericin B nephrotoxicity prevention.
Section 4 (Recommendations 4.1–4.5.1) — CI-AKI definition, risk assessment, contrast choice, IV volume expansion, and NAC use.
Section 5.1–5.2 — Timing of RRT initiation and discontinuation criteria.
Section 5.3–5.8 (Recommendations 5.3.1.1–5.8.4) — RRT anticoagulation, vascular access, dialyzer membranes, modality (CRRT vs IHD), buffer choice, and dose targets (Kt/V 3.9/week; effluent 20–25 mL/kg/h).