Fluid Management in Acute Kidney Injury

Primary Recommendation

The Kidney Disease: Improving Global Outcomes (KDIGO) guidelines recommend using isotonic crystalloids rather than colloids for initial management and expansion of intravascular volume in patients at risk for AKI or with established AKI (Grade 2B) 1
The KDIGO guidelines suggest that isotonic crystalloids are preferred over colloids due to no mortality benefit from colloids, increased cost, and documented harm from synthetic colloids including increased renal replacement therapy requirements and bleeding complications 1

Emerging evidence strongly favors balanced crystalloids (Lactated Ringer's, Plasmalyte) over 0.9% saline due to reduced risk of hyperchloremic metabolic acidosis and potentially lower rates of AKI 2
Balanced solutions maintain acid-base balance better and have electrolyte composition closer to plasma 2
Two large multicenter RCTs examining the question of crystalloid selection were ongoing as of 2020, with accumulating evidence of biochemical abnormalities and adverse clinical outcomes associated with 0.9% saline 2

Synthetic colloids (hydroxyethyl starch, gelatin) are contraindicated in critically ill patients, especially those with sepsis, due to increased mortality and renal dysfunction 2
The 6S Trial demonstrated that HES 130/0.42 resulted in more deaths, increased need for renal replacement therapy, and severe bleeding compared to Ringer's acetate 1
Albumin showed no benefit over crystalloids in the SAFE trial for general ICU patients, though specific subpopulations may differ 1

Volume overload >10-15% body weight is associated with adverse outcomes 2
Target adequate perfusion (MAP, urine output, lactate clearance) without fluid overload 2
Consider early vasopressor support rather than excessive fluid administration for persistent hypotension 2

IV volume expansion with either isotonic sodium chloride or sodium bicarbonate solutions is recommended over no IV expansion (Grade 1A) for contrast-induced AKI prevention 6
In resource-limited settings, where balanced crystalloids are unavailable or cost-prohibitive, 0.9% saline remains acceptable, though risks of hyperchloremia should be monitored 2