Is Lactated Ringer's (LR) solution preferred over Normal Saline (NS) in the setting of metabolic acidosis?

From the Guidelines

Lactated Ringer's (LR) solution is not preferred over Normal Saline (NS) in the setting of metabolic acidosis according to the provided evidence. The study 1 actually suggests that LR might potentially contribute to metabolic acidosis, and recommends considering a normal saline intravenous line for fluid replacement and venous access. This is because LR contains lactate, which may not be effectively metabolized in certain conditions, potentially worsening acidosis.

• Key points to consider when choosing between LR and NS in metabolic acidosis include:
  • The potential for LR to contribute to metabolic acidosis
  • The risk of hyperchloremic metabolic acidosis with NS, particularly with large volume administration
  • The importance of cautious use of LR in patients with severe liver dysfunction or hyperkalemia
• In the context of anaphylaxis, as discussed in the study 1, the primary focus is on epinephrine administration, fluid resuscitation, and management of hypoxemia and hypotension, rather than the specific choice between LR and NS for metabolic acidosis.
• The study 1 does provide guidance on fluid resuscitation in anaphylaxis, recommending up to 7 L of crystalloids (such as saline) for adults, and up to 30 mL/kg in the first hour for children, but it does not specifically address the preference between LR and NS in the setting of metabolic acidosis.

From the Research

Metabolic Acidosis Management

• The management of metabolic acidosis is crucial in various clinical settings, including diabetic ketoacidosis (DKA) and sepsis-induced hypotension.
• The choice of fluid for resuscitation is important, with lactated Ringer's (LR) and normal saline (NS) being two commonly used options.

Comparison of LR and NS

• A study published in 2024 2 found that LR was associated with faster time to high anion gap metabolic acidosis (HAGMA) resolution compared to NS in patients with DKA.
• Another study published in 2012 3 found no significant difference in the time to normalization of pH between LR and NS groups in patients with DKA.
• A study published in 2025 4 found that initial fluid resuscitation with LR was associated with improved survival and more hospital-free days at 28 days compared to NS in patients with sepsis-induced hypotension.

Strong Ion Difference-Related Metabolic Acidosis

• A study published in 2016 5 found that the use of LR did not eliminate the risk of strong ion difference-related metabolic acidosis following on-pump cardiac surgery.
• The study found that changes in the strong ion difference were primarily driven by changes in the serum sodium concentration.

Postoperative Respiratory Acidosis

• A study published in 2002 6 found that large intravascular volume infusion of LR during major spine surgery led to postoperative respiratory acidosis and mild hyponatremia.
• The study found that LR infusion did not cause hyperchloremic metabolic acidosis, but led to postoperative mild hyponatremia and respiratory acidosis.

Key Findings

• LR may be preferred over NS in the setting of metabolic acidosis due to its ability to resolve HAGMA faster and improve survival in certain clinical settings.
• However, the use of LR is not without risks, and its effects on serum sodium concentration and strong ion difference should be carefully considered.
• Further studies are needed to fully understand the benefits and risks of using LR versus NS in different clinical settings.