Is it safe to use Ringer's (lactated Ringer's solution) in patients with Acute Kidney Injury (AKI)?

Use of Ringer's Lactate in Acute Kidney Injury

Ringer's lactate solution is generally safe to use in patients with acute kidney injury (AKI), except in specific situations such as circulatory shock, liver failure, or lactic acidemia where bicarbonate-based solutions are preferred.

Fluid Selection in AKI

General Recommendations

• The KDIGO guidelines suggest using bicarbonate rather than lactate as a buffer in dialysate and replacement fluid for renal replacement therapy (RRT) in patients with AKI (2C recommendation) 1
• For patients with AKI and circulatory shock, the guidelines strongly recommend using bicarbonate rather than lactate as a buffer (1B recommendation) 1
• For patients with AKI and liver failure and/or lactic acidemia, bicarbonate is suggested over lactate as a buffer (2B recommendation) 1

Specific Clinical Scenarios

Safe to Use Ringer's Lactate:

• In patients with prerenal AKI and pre-existing CKD (stages III-V), Ringer's lactate showed no significant difference in short or long-term kidney function compared to normal saline 2
• Ringer's lactate demonstrated a better profile in acid-base balance improvement and reduced chloride overload compared to normal saline in AKI patients 2
• Higher percentage of Lactated Ringer's solution during the first 2 days of ICU admission was associated with less AKI and reduced hospital mortality 3

Avoid Ringer's Lactate:

• In patients with AKI and circulatory shock (use bicarbonate-based solutions instead) 1
• In patients with AKI and liver failure or lactic acidemia (use bicarbonate-based solutions instead) 1
• In patients with traumatic brain injury (use normal saline instead) 4

Balanced vs. Non-Balanced Crystalloids

• In patients with hemorrhagic shock, balanced crystalloids (like Ringer's lactate) are probably recommended over 0.9% NaCl as first-line fluid therapy to reduce mortality and adverse renal events (GRADE 2+ recommendation) 1
• Balanced solutions may have advantages in preventing hyperchloremic metabolic acidosis, which can occur with large volumes of normal saline 1
• Recent evidence suggests that balanced crystalloids may be associated with better outcomes in critically ill patients compared to 0.9% saline 1

Monitoring and Considerations

When using Ringer's lactate in AKI patients:

1. Monitor lactate levels, especially in patients with impaired lactate clearance
2. Assess acid-base status regularly
3. Consider switching to bicarbonate-based solutions if:
   • Patient develops circulatory shock
   • Liver function deteriorates
   • Lactic acidemia develops
4. Be cautious with the potassium content (4 mEq/L) in Ringer's lactate for patients with or at risk for hyperkalemia

Practical Algorithm for Fluid Selection in AKI

1. First assessment: Determine if patient has any contraindications to Ringer's lactate:

   • Circulatory shock → Use bicarbonate-based solutions
   • Liver failure → Use bicarbonate-based solutions
   • Lactic acidemia → Use bicarbonate-based solutions
   • Traumatic brain injury → Use normal saline
   • Severe hyperkalemia → Use normal saline

2. If no contraindications:

   • Ringer's lactate is generally safe and may be preferred over normal saline
   • Monitor for changes in clinical status that might necessitate switching fluids

3. For patients requiring RRT:

   • Use bicarbonate as buffer in dialysate and replacement fluid rather than lactate 1

Cautions and Pitfalls

• Don't assume all AKI patients need to avoid lactate-containing solutions
• Avoid large volumes of normal saline in AKI patients without specific indications, as it may worsen hyperchloremic metabolic acidosis
• Remember that fluid selection should be reassessed as the patient's condition changes
• Consider that lactate metabolism may be altered in AKI, potentially affecting clearance 5