Volume replacement in critically ill patients with acute renal failure

Area of Science:

• Critical Care Medicine
• Nephrology
• Hemodynamics

Background:

• Intravascular volume maintenance is vital for organ function in critically ill patients.
• Acute renal failure often results from inadequate intravascular volume and impaired renal perfusion.
• Crystalloid solutions are primary for fluid deficits, but colloids are needed for major hypovolemia and increased capillary permeability.

Purpose of the Study:

• To evaluate the role of colloid solutions in restoring intravascular volume and improving tissue perfusion in critically ill patients.
• To compare the efficacy and safety of different colloid solutions, particularly synthetic colloids like hydroxyethyl starch (HES).
• To provide guidance on colloid use in patients with acute renal dysfunction and during kidney transplantation.

Main Methods:

• Review of the literature on fluid management strategies in critical care.
• Comparison of crystalloid and colloid solutions for intravascular volume restoration.
• Analysis of the risk/benefit ratio of synthetic colloids, focusing on hydroxyethyl starch (HES) 200/0.5.
• Consideration of colloid administration in specific patient populations, including those with renal dysfunction and kidney transplant recipients.

Main Results:

• Synthetic colloids, unlike albumin, effectively restore intravascular volume, stabilize hemodynamics, and improve microcirculation.
• Hydroxyethyl starch (HES) solutions with low molecular weight (e.g., HES 200/0.5) offer the best risk/benefit ratio among synthetic colloids.
• HES solutions are safe regarding coagulation, platelets, reticuloendothelial system, and renal function when used within dosage limits.
• In patients with renal dysfunction, careful monitoring of renal function, colloidal osmotic pressure, and adequate crystalloid use are essential. Gelatin and low molecular weight HES are preferred colloids.
• Colloid administration should be restricted in kidney donors and recipients.

Conclusions:

• Synthetic colloid solutions are superior to albumin for correcting major hypovolemia and improving tissue perfusion in critically ill patients.
• Low molecular weight hydroxyethyl starch (HES) solutions provide effective and safe intravascular volume restoration with a favorable risk/benefit profile.
• Specific precautions and monitoring are necessary when using colloids in patients with renal dysfunction or undergoing kidney transplantation.