What is the difference between Lactated Ringer's (LR) solution and Normal Saline (NS) solution?

From the Guidelines

For most fluid resuscitation needs, Lactated Ringer's (LR) solution is generally preferred over Normal Saline (NS) due to its association with reduced mortality in critically ill patients, as evidenced by a recent meta-analysis 1. When considering the choice between LR and NS, it's essential to understand their composition and how they affect the body. LR is more physiologically similar to human plasma, containing lactate, which the liver converts to bicarbonate, helping to maintain acid-base balance. In contrast, NS has a higher chloride content, which can increase the risk of hyperchloremic acidosis.

Some key differences between LR and NS include:

• LR contains lactate, potassium, and calcium, whereas NS only contains sodium and chloride
• LR has a lower chloride content than NS, reducing the risk of hyperchloremic acidosis
• LR is more effective in maintaining acid-base balance due to its lactate content, which is converted to bicarbonate by the liver

According to a recent meta-analysis 1, using balanced crystalloids like LR is associated with reduced mortality in the general population of critically ill patients without cirrhosis. This suggests that LR should be the preferred choice for initial fluid resuscitation in most cases of hypovolemia, shock, or mild to moderate dehydration. However, NS may still be preferred in certain situations, such as patients with severe hyperkalemia or increased intracranial pressure.

In terms of specific clinical scenarios:

• Use LR for patients with diabetic ketoacidosis or other acidotic states, as it can help maintain acid-base balance
• Use NS for patients with severe hyperkalemia, as LR contains a small amount of potassium
• Use NS for patients with increased intracranial pressure, due to its slightly higher osmolarity
• Monitor the patient's response to fluid therapy and adjust as needed, taking into account their specific clinical condition, electrolyte status, and acid-base balance.

From the Research

Comparison of Lactated Ringer's (LR) and Normal Saline (NS) Solutions

• Lactated Ringer's (LR) solution is a buffered crystalloid that has been shown to have possible advantages over normal saline (NS) in certain medical conditions, such as acute pancreatitis 2 and diabetic ketoacidosis 3.
• Normal Saline (NS) solution, on the other hand, is an unbalanced crystalloid that can lead to hyperchloremia and renal injury when used in large volumes 3.
• The main difference between LR and NS solutions is their electrolyte composition, with LR containing lactate, potassium, calcium, and chloride, while NS contains only sodium and chloride.
• Studies have shown that LR can help mediate beneficial effects on acid-base balance compared to NS 4, and may be associated with lower mortality rates in certain patient populations, such as those with acute pancreatitis 2.
• However, other studies have found no significant difference in outcomes between LR and NS in certain conditions, such as sepsis 5 and trauma patients in the surgical intensive care unit 6.

Key Findings

• LR may be associated with lower 1-year mortality compared to NS in patients with acute pancreatitis 2.
• LR may reduce the incidence of iatrogenic hyperchloremia and support renal recovery in patients with diabetic ketoacidosis 3.
• NS may be associated with increased risk of hyperchloremia and renal injury when used in large volumes 3.
• There is no significant difference in mortality rates or hospital length of stay between LR and NS in sepsis patients 5.
• Plasma-Lyte (PL) may not demonstrate mortality benefit compared to LR in trauma patients in the surgical intensive care unit, but may be associated with prolonged hospital and SICU length of stay 6.