From the Guidelines
Lactated Ringer's (LR) solution is generally preferred over Normal Saline (NS) in the setting of metabolic acidosis. LR contains lactate which is metabolized to bicarbonate in the liver, helping to buffer excess acid and improve pH balance in patients with metabolic acidosis 1. Normal Saline, in contrast, contains a high chloride content (154 mEq/L) which can worsen acidosis by causing hyperchloremic metabolic acidosis, particularly when administered in large volumes.
When treating patients with metabolic acidosis, LR should be infused at rates appropriate for the clinical situation, typically 10-20 mL/kg/hr for initial resuscitation, then adjusted based on patient response and hemodynamic parameters. The lactate in LR (28 mEq/L) is particularly beneficial because it's metabolized by the liver and kidneys into bicarbonate, providing an alkalinizing effect that directly counteracts acidosis. Additionally, LR more closely resembles human plasma in electrolyte composition than NS, making it less likely to disrupt electrolyte balance.
However, LR should be used cautiously in patients with liver dysfunction who may not effectively metabolize lactate, and in hyperkalemic patients since LR contains 4 mEq/L of potassium. The use of crystalloids, such as LR, is recommended over colloids for initial management of expansion of intravascular volume in patients at risk for acute kidney injury (AKI) or with AKI 1. It is essential to maintain optimal kidney function, and the choice of intravenous fluid can significantly impact patient outcomes.
Some key points to consider when using LR in patients with metabolic acidosis include:
- Monitoring patient response and adjusting infusion rates as needed
- Being cautious in patients with liver dysfunction or hyperkalemia
- Using LR as part of a comprehensive treatment plan to manage metabolic acidosis
- Considering the potential benefits of LR in improving pH balance and reducing the risk of hyperchloremic metabolic acidosis.
From the Research
Comparison of Lactated Ringer's and Normal Saline in Metabolic Acidosis
- Lactated Ringer's (LR) is preferred over Normal Saline (NS) in the setting of metabolic acidosis due to its ability to reduce the risk of hyperchloremic metabolic acidosis and acute kidney injury 2.
- A study comparing LR and NS in the management of acute diabetic ketoacidosis found that LR was associated with faster time to high anion gap metabolic acidosis resolution compared to NS (adjusted hazard ratio 1.325; 95% confidence interval 1.121-1.566; p < 0.001) 2.
- Another study found that initial fluid resuscitation with lactated Ringer's solution, compared with 0.9% saline, might be associated with improved survival in patients with sepsis-induced hypotension (adjusted hazard ratio of 0.71; 95% CI, 0.51-0.99; p = 0.043) 3.
- However, a study on the use of lactated Ringer's solution in on-pump cardiac surgery found that it did not eliminate the risk of strong ion difference-related metabolic acidosis, and that changes in the strong ion difference were primarily driven by changes in the serum sodium concentration 4.
- A meta-analysis comparing LR and NS in the management of acute pancreatitis found that LR may be superior to NS due to its potential advantage in decreasing the incidence of pancreatic necrosis and intensive care unit admission (RR=0.39,95% CI=0.18-0.85; P=0.02) 5.
Key Findings
- LR is associated with faster resolution of metabolic acidosis compared to NS 2, 3.
- LR may reduce the risk of hyperchloremic metabolic acidosis and acute kidney injury 2.
- LR may be superior to NS in managing patients with acute pancreatitis due to its potential advantage in decreasing the incidence of pancreatic necrosis and intensive care unit admission 5.
- The use of LR does not eliminate the risk of strong ion difference-related metabolic acidosis in on-pump cardiac surgery, and changes in the strong ion difference are primarily driven by changes in the serum sodium concentration 4.