Can Lactated Ringer's (LR) solution be used in patients with impaired renal function?

Use of Lactated Ringer's Solution in Patients with Impaired Renal Function

Lactated Ringer's (LR) solution can be safely used in patients with impaired renal function and is not contraindicated based on renal status. Despite containing potassium (4 mmol/L), LR does not increase the risk of hyperkalemia in patients with reduced kidney function 1, 2.

Evidence Supporting LR Use in Renal Impairment

Safety Profile

• A recent study specifically examining LR in patients with reduced kidney function (eGFR <30 ml/min/1.73m²) found no significant correlation between LR administration and development of hyperkalemia 2
• Only 5% of patients developed de-novo hyperkalemia following LR use, and this was not associated with the volume of LR administered 2
• Pre-existing serum potassium level was the strongest predictor of post-LR potassium levels, not the administration of LR itself 2

Comparison with Normal Saline

• When comparing LR to normal saline (NS) in patients with prerenal acute kidney injury and pre-established CKD (stages III-V), both fluids showed similar effects on kidney function improvement 3
• However, LR demonstrated a better acid-base balance profile and less chloride overload compared to NS 3
• In kidney transplant recipients, LR was associated with less hyperkalemia and metabolic acidosis compared to NS 4

Clinical Applications and Recommendations

Fluid Selection Principles

1. LR is a balanced crystalloid solution with a composition (Na+ 130 mmol/L, K+ 4 mmol/L, Cl- 108 mmol/L) that closely resembles human plasma 1
2. The American Society of Anesthesiologists supports the use of balanced crystalloids like LR as first-line IV fluid therapy due to their lower risk of adverse renal events 1
3. The potassium content in LR (4 mmol/L) is physiologic and does not pose a significant risk even in patients with impaired renal function 1, 2

When to Consider Alternatives to LR

While LR is generally safe in renal impairment, consider alternatives in these specific situations:

• Patients with severe hyperkalemia (K+ >6.0 mmol/L) 1
• Patients with traumatic brain injury (TBI) where hypotonic solutions should be avoided 5

Practical Approach to Fluid Selection in Renal Impairment

1. Assess baseline potassium level:

   • If normal or mildly elevated: LR is appropriate
   • If severely elevated (>6.0 mmol/L): Consider 0.9% NS initially

2. Monitor during administration:

   • Regular assessment of electrolytes, acid-base status, and fluid balance
   • Target urine output of 0.5-1 mL/kg/hr when appropriate 1

3. Consider clinical context:

   • In crush injuries or rhabdomyolysis with renal impairment, avoid potassium-containing fluids initially 5
   • For most other scenarios involving renal impairment, LR is appropriate and may be preferred over NS

Clinical Pearls

• The concern about LR causing hyperkalemia in renal impairment is largely theoretical and not supported by clinical evidence 2
• The balanced electrolyte composition of LR may actually be beneficial in preventing hyperchloremic metabolic acidosis, which can occur with large volumes of NS 1, 3
• Recent evidence suggests that balanced crystalloids like LR may be associated with better outcomes compared to NS in critically ill patients, including those with kidney dysfunction 1, 6

In conclusion, LR is a safe and appropriate fluid choice for most patients with impaired renal function, with the exception of those with severe hyperkalemia or specific clinical scenarios like crush injury during the initial resuscitation phase.