Is lactated Ringer's (LR) solution suitable for patients with Acute Kidney Injury (AKI)?

Is Lactated Ringer's Good for AKI?

Yes, lactated Ringer's (LR) is appropriate and recommended for patients with acute kidney injury (AKI), with the critical exception of patients with severe traumatic brain injury or head trauma. 1, 2

Primary Recommendation

Balanced crystalloids like lactated Ringer's should be preferred over 0.9% normal saline for fluid resuscitation in AKI patients because they reduce the risk of adverse renal events and avoid hyperchloremic metabolic acidosis. 1 The 2022 European guidelines specifically recommend balanced crystalloids rather than normal saline as first-line fluid therapy to reduce mortality and adverse renal events, though this is a Grade 2+ recommendation acknowledging some uncertainty in the evidence. 1

Evidence Supporting LR in AKI

• Reduced mortality and AKI risk: A large retrospective analysis of 10,249 ICU patients found that higher percentages of LR (versus normal saline) were associated with significantly lower hospital mortality and less acute kidney injury, particularly when larger fluid volumes were administered. 3 For patients receiving >7L of fluid, using 75% LR versus 25% LR reduced mortality odds by 50% (OR 0.50,95% CI 0.32-0.79). 3

• Comparable renal outcomes with pre-existing CKD: In patients with prerenal AKI and chronic kidney disease stages III-V, LR and normal saline showed similar short and long-term kidney function recovery, but LR demonstrated superior acid-base balance improvement. 4

• No increased AKI risk with large volumes: The 2025 SOLAR trial analysis of 8,616 surgical patients found no evidence that large volumes of normal saline provoke more AKI than LR, though saline clearly causes volume-dependent hyperchloremia. 5 The original SOLAR trial showed no clinically meaningful difference in AKI rates between groups (6.6% LR vs 6.2% saline). 6

Metabolic Advantages of LR

• Avoids hyperchloremic acidosis: LR prevents the hyperchloremic metabolic acidosis associated with large volumes of normal saline, which can impair renal function and coagulation. 2

• Faster metabolic recovery: In diabetic ketoacidosis, LR was associated with faster resolution of high anion gap metabolic acidosis compared to normal saline (adjusted HR 1.325,95% CI 1.121-1.566, p<0.001). 7

• Physiologic electrolyte composition: LR has a sodium-to-chloride ratio closer to plasma (130:108 mmol/L) compared to normal saline's supraphysiologic chloride content. 2

Critical Contraindication: Severe Head Trauma

Avoid LR in patients with severe traumatic brain injury or increased intracranial pressure. 1, 2 LR has an osmolarity of 273-277 mOsm/L, making it hypotonic compared to plasma (275-295 mOsm/L), which can worsen cerebral edema. 2 In these patients, use 0.9% normal saline as the isotonic crystalloid of choice. 2

Other Specific Contraindications

• Rhabdomyolysis/crush syndrome: Avoid LR due to its potassium content (4 mmol/L), which poses additional risk when potassium levels may increase markedly following reperfusion of crushed tissue. 2

Common Pitfalls to Avoid

• Don't avoid LR due to mild hyperkalemia: The potassium content in LR (4 mmol/L) should not be considered a contraindication in patients with mild-to-moderate hyperkalemia or renal dysfunction, except in rhabdomyolysis/crush syndrome. 2 Large studies involving 30,000 patients found comparable plasma potassium concentrations between balanced fluids and saline. 2

• Don't avoid LR in liver disease: While the KDIGO guidelines suggest using bicarbonate rather than lactate buffers in dialysate for patients with liver failure during renal replacement therapy 1, this does not apply to standard IV fluid resuscitation with LR in AKI patients without severe liver failure.

• Consider total fluid volume: The beneficial effect of LR over saline becomes more pronounced with larger fluid volumes (>5-7L), where the metabolic consequences of hyperchloremia are more clinically significant. 1, 3

Practical Algorithm for Fluid Selection in AKI

1. Assess for severe TBI or head trauma: If present → use 0.9% normal saline 2
2. Assess for rhabdomyolysis/crush syndrome: If present → use 0.9% normal saline 2
3. For all other AKI patients: Use lactated Ringer's as first-line balanced crystalloid 1, 2
4. If large volumes anticipated (>5L): Strongly favor LR over saline to avoid hyperchloremic acidosis 1, 3