What is better, normal saline (0.9% sodium chloride solution) or Ringer's lactate (lactated Ringer's solution)?

From the Guidelines

Ringer's lactate is generally preferred over normal saline for fluid resuscitation in most clinical situations, particularly in trauma, burns, and sepsis, due to its more physiologic composition and lower risk of hyperchloremic metabolic acidosis, as supported by recent studies such as the SMART study 1.

Key Considerations

• Normal saline (0.9% NaCl) can cause hyperchloremic metabolic acidosis with large volumes, which may be detrimental in critically ill patients 1.
• Ringer's lactate contains lactate which converts to bicarbonate, helping prevent acidosis, and its electrolyte composition more closely resembles plasma 1.
• The SMART study, which included 15,802 ICU patients, found a reduced incidence of major adverse kidney events in patients receiving balanced solutions like Ringer's lactate compared to normal saline 1.
• While some studies have reported no difference in mortality or acute renal failure between normal saline and balanced solutions, the potentially deleterious effects of high-volume chloride-rich solutions should orient treatment choices toward balanced solutions 1.

Clinical Implications

• For most routine fluid replacement, Ringer's lactate may be preferable due to its more physiologic composition, but the choice should be individualized based on the patient's specific electrolyte status, acid-base balance, and clinical condition.
• Patients with liver dysfunction, hyperkalemia, or severe metabolic alkalosis may require alternative fluid choices, such as normal saline, due to the potential risks associated with Ringer's lactate 1.
• The choice between normal saline and Ringer's lactate should be guided by the patient's specific clinical situation, taking into account the potential benefits and risks of each fluid type, as well as the latest evidence from studies like the SMART study 1.

From the Research

Comparison of Normal Saline and Ringer Lactate

• Normal saline and Ringer lactate are two commonly used fluids for resuscitation and fluid management in various medical settings.
• The choice between these two fluids has been a topic of debate, with some studies suggesting that Ringer lactate may be associated with better outcomes in certain situations.

Metabolic Acidosis and Hyperchloremia

• A study published in 1999 found that infusion of 0.9% saline, but not lactated Ringer's solution, caused a metabolic acidosis with hyperchloremia and a concomitant decrease in the strong ion difference 2.
• Another study published in 2001 found that patients who received normal saline developed a hyperchloremic acidosis and required more bicarbonate therapy compared to those who received lactated Ringer's solution 3.
• A study published in 2005 found that normal saline was associated with higher levels of serum chloride and decreased levels of serum bicarbonate, while lactated Ringer's solution was associated with less hyperkalemia and acidosis 4.

Clinical Outcomes

• A study published in 2025 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 5.
• A study published in 2015 found that there were no significant differences in clinical outcomes, including mortality and duration of hospital stay, between patients who received lactated Ringer's solution and those who received normal saline for fluid resuscitation in acute pancreatitis 6.
• A study published in 2001 found that the use of normal saline as the primary intraoperative solution was associated with increased perioperative blood loss, but did not affect outcome as assessed by duration of mechanical ventilation, intensive care unit stay, hospital stay, and postoperative complications 3.

Fluid Management

• The choice of fluid for resuscitation and fluid management should be based on the individual patient's needs and the specific clinical situation.
• Lactated Ringer's solution may be a better choice than normal saline in certain situations, such as in patients with sepsis-induced hypotension or those undergoing major surgery with extensive blood loss.
• However, more research is needed to fully understand the effects of different fluids on clinical outcomes and to determine the best fluid management strategies for various medical conditions.