What should be done for a patient with acute impaired renal function?

Management of Acute Impaired Renal Function

For patients with acute kidney injury (AKI), immediate management should include discontinuation of nephrotoxic medications, optimization of fluid status with isotonic crystalloids, and close monitoring of renal function with regular creatinine measurements. 1

Initial Assessment and Classification

• AKI is defined as an increase in serum creatinine by ≥0.3 mg/dL within 48 hours or ≥50% within 7 days, or urine output <0.5 mL/kg/h for 6 hours 1
• The rise in creatinine from 1.2 to a higher value the next day indicates possible Stage 1 AKI, requiring prompt intervention 1
• Traditional classification of AKI as pre-renal, renal, and post-renal is less helpful than distinguishing between conditions that reduce glomerular function, cause tubular/glomerular injury, or both 1
• Staging AKI severity (Stages 1-3) helps guide management intensity and predicts outcomes 1

Immediate Management Steps

1. Fluid Management

• Use isotonic crystalloids rather than colloids (albumin or starches) for initial intravascular volume expansion 1
• Balanced crystalloids (e.g., lactated Ringer's) may be preferable to 0.9% saline due to emerging evidence of fewer adverse outcomes 1
• Fluid administration should be guided by hemodynamic assessment and reassessed frequently to avoid volume overload 1
• In patients with cirrhosis and AKI, albumin at 1 g/kg (maximum 100 g/day) may be considered after discontinuing diuretics 1

2. Medication Management

• Discontinue all nephrotoxic medications including NSAIDs, ACE inhibitors, ARBs, and aminoglycosides 1
• Adjust dosages of all medications according to current renal function 1
• If patient is on diuretics, these should be temporarily held 1
• If on beta-blockers and has cirrhosis, consider temporarily discontinuing these medications 1

3. Identify and Treat Underlying Causes

• Evaluate for infections and treat promptly if present 1
• Consider intra-abdominal pressure measurement if abdominal compartment syndrome is suspected 2
• Assess for contrast-induced nephropathy if recent contrast exposure 3
• Evaluate for potential obstruction with renal ultrasound 1

Monitoring and Follow-up

• Monitor serum creatinine daily until stabilization 1
• Monitor urine output hourly in critically ill patients 1
• Assess fluid status regularly to avoid both hypovolemia and fluid overload 1
• Consider more intensive monitoring for patients with pre-existing CKD, heart failure, cirrhosis, or malignancy 1

Indications for Nephrology Consultation

• Stage 2 or 3 AKI (creatinine 2.0-2.9 times baseline or ≥3.0 times baseline) 1
• Persistent AKI despite initial management 1
• Severe electrolyte abnormalities 1
• Acid-base disturbances 1, 4
• Consideration for renal replacement therapy 1

Renal Replacement Therapy Considerations

• Consider RRT for refractory volume overload, severe metabolic acidosis, uremic symptoms, or refractory hyperkalemia 1
• Decision for RRT should be individualized based on clinical context and overall patient condition 1
• Early involvement of nephrology for potential RRT planning is recommended 1

Post-AKI Care

• AKI increases risk for future CKD, cardiovascular disease, and mortality even after apparent recovery 1
• Follow-up of renal function at regular intervals after discharge is essential 1
• Patients with residual renal damage should be managed according to CKD guidelines 1
• Avoid nephrotoxic medications and maintain appropriate hydration after AKI episode 1
• The severity of AKI should determine the frequency and intensity of follow-up care 1

Special Considerations

• In patients with cirrhosis, AKI may progress to hepatorenal syndrome requiring vasoconstrictors plus albumin 1
• Patients with diabetes who develop contrast-induced nephropathy have particularly poor prognosis 3
• Even recommended doses of supplements like creatine monohydrate may rarely cause kidney damage 5
• Careful attention to drug dosing is required during and after AKI 1