What are the guidelines for managing Acute Kidney Injury (AKI)?

Management of Acute Kidney Injury (AKI)

The management of acute kidney injury requires immediate identification of risk factors, discontinuation of nephrotoxic medications, optimization of fluid status, and implementation of stage-based interventions to prevent progression and reduce mortality. 1

Definition and Staging

AKI is defined according to the KDIGO criteria:

Stage	Serum Creatinine Criteria	Urine Output Criteria
1	1.5–1.9× baseline or ≥0.3 mg/dL (≥26 μmol/L) increase within 48h	<0.5 mL/kg/h for 6–12h
2	2.0–2.9× baseline	<0.5 mL/kg/h for ≥12h
3	3.0× baseline or increase to ≥4.0 mg/dL (354 μmol/L) or initiation of RRT	<0.3 mL/kg/h for ≥24h or anuria for ≥12h

Initial Management

1. Risk Factor Identification and Removal

   • Immediately review all medications and discontinue nephrotoxic drugs (NSAIDs, aminoglycosides, contrast agents) 1
   • Ask a pharmacist for advice about optimizing medication choices and dosages 1
   • Identify and treat underlying causes (sepsis, hypovolemia, obstruction) 1

2. Fluid Management

   • Use isotonic crystalloids rather than colloids for volume expansion 1
   • Avoid hydroxyethyl starches due to increased risk of AKI 1
   • Maintain euvolemia through careful fluid assessment 1
   • In patients with cirrhosis and AKI, administer albumin at 1 g/kg/day for two consecutive days 1, 2

3. Hemodynamic Support

   • Maintain mean arterial pressure ≥65 mmHg (higher targets may be needed in patients with pre-existing hypertension) 1
   • Use vasopressors if fluid resuscitation fails to restore blood pressure 1
   • Avoid dopamine for renal protection (Level 1A evidence against its use) 1

Monitoring and Assessment

1. Laboratory Monitoring

   • Measure serum urea, creatinine, and electrolytes at least every 48 hours or more frequently in high-risk patients 1
   • Monitor fluid balance daily 1
   • Use early warning scores (e.g., NEWS2) for deteriorating patients 1

2. Diagnostic Evaluation

   • Renal ultrasound to rule out obstruction 2
   • Urinalysis and microscopy to help determine etiology 3
   • Consider specific tests based on suspected cause (e.g., paracentesis in cirrhotic patients) 2

Stage-Based Management

Stage 1 AKI

• Close monitoring of renal function and urine output
• Optimization of volume status
• Discontinuation of nephrotoxic agents
• Treatment of underlying causes

Stage 2-3 AKI

• More intensive monitoring
• Consider nephrology consultation
• Prepare for possible renal replacement therapy
• Careful management of electrolyte abnormalities

Special Considerations

AKI in Cirrhosis

• Follow International Club of Ascites guidelines 1, 2
• Withdraw diuretics and nephrotoxic drugs
• Administer albumin (1 g/kg/day for two days)
• Consider vasoconstrictors (terlipressin, noradrenaline) for hepatorenal syndrome 2

COVID-19 Associated AKI

• AKI is common in COVID-19 patients, especially those requiring mechanical ventilation 1
• Causes include hypovolemia, cytokine-mediated injury, thrombotic vascular processes, and direct viral injury 1
• Management principles remain the same, with attention to fluid balance and avoidance of nephrotoxins 1

Prevention of AKI

1. Pre-procedure Strategies

   • Ensure adequate hydration before contrast procedures 1
   • Consider oral hydration regimens for lower-risk outpatients 1
   • N-acetylcysteine with IV isotonic crystalloids may be considered in high-risk patients, though evidence is debatable 1

2. Medication Management

   • Implement electronic clinical decision support systems to identify drug-related risks 1
   • Therapeutic drug monitoring during aminoglycoside use 1
   • Temporary withholding of ACE inhibitors/ARBs in high-risk situations 1, 2

Post-AKI Follow-up

• Monitor for development or progression of chronic kidney disease (CKD) 1
• Target follow-up to highest risk populations (baseline CKD, severe AKI, incomplete recovery) 1
• Pediatric patients with AKI warrant early follow-up due to potential long-term consequences 1

Common Pitfalls to Avoid

• Delaying recognition of drug-induced nephrotoxicity 2
• Continuing nephrotoxic medications despite worsening renal function 2
• Inadequate monitoring of renal function in high-risk patients 2
• Excessive fluid administration leading to volume overload 4
• Assuming all AKI is due to hypovolemia 5

By following these guidelines, clinicians can effectively manage AKI, potentially reducing mortality and preventing progression to chronic kidney disease.