Management Parameters for Acute Kidney Injury (AKI)
The management of AKI requires prompt identification using standardized diagnostic criteria, removal of nephrotoxic agents, appropriate fluid management, and consideration of renal replacement therapy based on specific clinical parameters. 1, 2
Diagnostic Parameters for AKI
Definition and Staging
- AKI is defined by any of the following:
- Increase in serum creatinine ≥0.3 mg/dL within 48 hours
- Increase in serum creatinine ≥50% from baseline within 7 days
- Urine output <0.5 mL/kg/h for >6 hours 2
| Stage | Creatinine Criterion | Urine Output Criterion |
|---|---|---|
| 1 | Increase ≥0.3 mg/dL in 48h or 1.5-1.9 times baseline | <0.5 mL/kg/h for 6-12h |
| 2 | 2.0-2.9 times baseline | <0.5 mL/kg/h for ≥12h |
| 3 | ≥3.0 times baseline or increase to ≥4.0 mg/dL or initiation of RRT | <0.3 mL/kg/h for ≥24h or anuria for ≥12h |
Essential Diagnostic Tests
- Urinalysis with microscopy (casts, cells, crystals)
- Urine electrolytes and osmolality in selected cases
- Additional labs based on suspected etiology (complement levels, ANCA, anti-GBM) 2
- Furosemide stress test to predict AKI progression 2
Immediate Management Parameters
Medication Management
Discontinue nephrotoxic medications:
Medication dosage adjustment:
- Adjust all medications based on kidney function
- Monitor aminoglycoside levels when treatment exceeds 24 hours
- Administer aminoglycosides as single daily dose when possible 2
Fluid Management
Volume assessment and correction:
- Use isotonic crystalloids rather than colloids for initial volume expansion
- Initial bolus of 500-1000 mL for hypovolemic patients, then reassess
- For cirrhosis with ascites: albumin 1 g/kg/day (maximum 100g) for two consecutive days 2, 1
- Avoid excessive fluid administration in euvolemic or hypervolemic patients 2
Monitor for fluid overload:
- Define fluid overload thresholds to guide management decisions
- Determine optimal method for fluid removal including rate, targets, and monitoring 1
Nutritional Support
- Provide 20-30 kcal/kg/day total energy intake
- Do not restrict protein intake to delay RRT initiation
- Protein requirements:
- 0.8-1.0 g/kg/day in non-catabolic AKI patients without dialysis
- 1.0-1.5 g/kg/day for patients on RRT
- Up to 1.7 g/kg/day for patients on continuous RRT and hypercatabolic patients 2
- Target blood glucose: 110-149 mg/dL (6.1-8.3 mmol/L) 2
Hemodynamic Support Parameters
- Determine optimal vasopressor in the context of AKI 1
- Avoid using low-dose dopamine, fenoldopam, atrial natriuretic peptide, or recombinant human IGF-1 2
- Consider sodium bicarbonate in patients with AKI and metabolic acidosis 1
Renal Replacement Therapy (RRT) Parameters
Consider RRT when any of the following are present:
- Severe metabolic acidosis
- Hyperkalemia
- Volume overload unresponsive to diuretics
- Uremic symptoms 2
The optimal timing of RRT initiation remains controversial, but should be determined on an individualized basis 1, 2
Monitoring Parameters
- Daily monitoring of:
- Serum creatinine
- BUN
- Electrolytes
- Urinalysis 2
- Schedule follow-up within 3 months to assess for development of chronic kidney disease
- More frequent monitoring for high-risk patients 2
Special Considerations for AKI in Cirrhosis
- Follow specific algorithm for AKI in cirrhosis:
- Withdraw diuretics and nephrotoxic drugs
- Volume expansion with albumin (1 g/kg) for 2 days
- If no response and meets criteria for hepatorenal syndrome, consider vasoconstrictors plus albumin 1
Risk Factors to Monitor
- Dehydration or volume depletion
- Advanced age
- Female gender
- Black race
- Chronic kidney disease
- Chronic diseases of the heart, lung, or liver
- Diabetes mellitus
- Cancer
- Anemia 1
By following these parameters systematically, clinicians can optimize outcomes for patients with AKI and reduce the risk of progression to chronic kidney disease and mortality.