Treatment of Acute Renal Failure
The cornerstone of acute renal failure treatment is fluid therapy with attention to oxygen supply, which must be implemented urgently to prevent progressive organ failure and improve survival outcomes. 1, 2
Initial Management
Fluid Resuscitation
- Immediate attention to volume status is critical as hypovolemia results in inadequate blood flow to meet tissue metabolic requirements 1, 3
- Fluid deficits can occur without obvious fluid loss due to vasodilation or alterations in capillary permeability 1
- Special attention to volume status is required in patients with or at risk for acute renal failure 1, 2
Hemodynamic Monitoring
- Maintain mean arterial pressure of at least 50-60 mmHg using vasopressors if fluid resuscitation is insufficient 2
- Volumetric parameters are more reliable for detecting intravascular volume changes, while pressure monitoring helps prevent pulmonary edema 1
- Clinical assessment tools include peripheral edema evaluation, body weight monitoring, and radiological evaluation 1
Fluid Management Considerations
Type of Fluid
- Evidence suggests physiological crystalloids (e.g., lactated Ringer's) may be preferable to 0.9% saline due to fewer biochemical abnormalities and adverse clinical outcomes 1
- Synthetic colloids should be avoided in critically ill patients, especially those with sepsis, due to increased incidence of kidney dysfunction and mortality 1
Fluid Administration Approach
- Goal-directed fluid therapy may be beneficial in perioperative patients but has shown lack of benefits for survival and kidney outcomes in early septic shock 1
- Dynamic indices for fluid therapy targets include passive leg-raising test, pulse/stroke volume variation, and ultrasound parameters 1
Renal Replacement Therapy (RRT)
Indications for RRT
- Severe electrolyte disturbances (hyperkalemia, metabolic acidosis)
- Fluid overload unresponsive to diuretics
- Uremic complications 2, 4
Modality Selection
- Continuous renal replacement therapy (CRRT) is preferred for hemodynamically unstable patients 2, 5
- CRRT is also recommended for patients with acute renal failure and concomitant liver failure 2
CRRT Modalities
- Hemofiltration venovenosa continua (CVVH): primarily convective clearance
- Hemodiálisis venovenosa continua (CVVHD): primarily diffusive clearance
- Hemodiafiltración venovenosa continua (CVVHDF): combines convective and diffusive clearance methods 2
- Recommended effluent volume for CRRT in acute renal failure is 20-25 mL/kg/h 2
Management of Complications
Electrolyte Imbalances
- Monitor and correct electrolyte abnormalities including hyperkalemia, hypocalcemia, and hyperphosphatemia 4
- Calcium gluconate may be administered for hypocalcemia, with careful monitoring in patients with renal impairment 6
- For patients with renal impairment receiving calcium gluconate, initiate at the lowest dose and monitor serum calcium levels every 4 hours 6
Diuretic Therapy
- Furosemide should be used cautiously in acute renal failure
- If increasing azotemia and oliguria occur during treatment of severe progressive renal disease, furosemide should be discontinued 7
- For high-dose parenteral therapy, controlled intravenous infusion is advisable (infusion rate not exceeding 4 mg furosemide per minute) 7
Monitoring and Follow-up
- Regular assessment of fluid status, electrolytes, acid-base balance, and renal function parameters
- Adjust fluid therapy based on repeated assessment of overall fluid and hemodynamic status 1
- Monitor for complications of therapy including fluid overload, electrolyte disturbances, and acid-base disorders 4, 5
Special Considerations
- In patients with hepatic cirrhosis and ascites, diuretic therapy should be initiated in the hospital setting 7
- Sudden alterations of fluid and electrolyte balance in patients with cirrhosis may precipitate hepatic coma 7
- Supplemental potassium chloride and aldosterone antagonists may help prevent hypokalemia and metabolic alkalosis in patients receiving diuretics 7