When to prefer 0.9% Normal Saline (NS) versus Lactated Ringer's (LR) solution?

From the Guidelines

Prefer Lactated Ringer's (LR) solution over 0.9% Normal Saline (NS) in most cases, especially when large volumes of fluid are required, as LR is associated with a lower risk of hyperchloraemia and metabolic acidosis 1.

Key Considerations

• Hyperchloraemia and metabolic acidosis: 0.9% NS is associated with a higher risk of these conditions, particularly in settings requiring large volumes of fluid, such as major surgery or ICU populations 1.
• Acute kidney injury: Patients receiving 0.9% NS have a higher incidence of acute kidney injury compared to those receiving balanced solutions like LR 1.
• Trauma patients: While there is no strong evidence to support the use of one crystalloid solution over another in trauma patients, balanced solutions like LR are favored due to their potential to reduce the risk of hyperchloraemia and metabolic acidosis 1.
• Severe acidosis: 0.9% NS should be avoided in cases of severe acidosis, especially when associated with hyperchloremia 1.
• Traumatic brain injury (TBI): Hypotonic solutions like Ringer's lactate should be avoided in patients with TBI to minimize fluid shift into the damaged cerebral tissue 1.

Specific Scenarios

• Haemorrhagic shock: Balanced solutions like LR may be preferred due to their potential to reduce the risk of hyperchloraemia and metabolic acidosis, although the evidence is not strong enough to support a definitive recommendation 1.
• Severe acute pancreatitis: Ringer's lactate may be associated with an anti-inflammatory effect, but the evidence for its superiority over 0.9% NS is weak 1.
• Major surgery: Balanced solutions like LR may be preferred due to their potential to reduce the risk of hyperchloraemia and metabolic acidosis, although the evidence is not strong enough to support a definitive recommendation 1.

From the Research

Comparison of 0.9% Normal Saline (NS) and Lactated Ringer's (LR) Solution

The choice between 0.9% Normal Saline (NS) and Lactated Ringer's (LR) solution depends on various factors, including the patient's condition, the type of surgery, and the risk of complications. Here are some key points to consider:

• Traumatic Brain Injury: A study published in 2016 2 found that LR was associated with higher adjusted mortality compared to NS in patients with traumatic brain injury.
• Abdominal Aortic Aneurysm Repair: A study published in 2001 3 found that NS patients developed hyperchloremic acidosis and received more bicarbonate therapy and blood products compared to LR patients.
• Elective Orthopedic and Colorectal Surgery: A study published in 2020 4 found no clinically meaningful difference in postoperative complications between LR and NS patients.
• Healthy Human Volunteers: A study published in 1999 5 found that large volumes of LR decreased serum osmolality, whereas NS resulted in lower pH and slower urinary output.
• Sepsis Patients: A retrospective analysis published in 2023 6 found no statistically significant difference in mortality rates, hospital length of stay, and ICU admission between sepsis patients receiving LR and NS as predominant resuscitation fluid.

Key Considerations

When deciding between NS and LR, consider the following:

• Risk of Acidosis: NS may increase the risk of hyperchloremic acidosis, particularly in patients undergoing major surgery or with traumatic brain injury.
• Risk of Cerebral Edema: LR may increase the risk of cerebral edema in neurosurgical patients due to its effect on serum osmolality.
• Fluid Requirements: The choice of fluid may depend on the patient's fluid requirements, with LR potentially being more suitable for patients requiring large volumes of fluid.
• Patient Characteristics: Patient characteristics, such as age, sex, and comorbidities, may influence the choice of fluid.

Fluid Management

Ultimately, the choice between NS and LR depends on the individual patient's needs and the clinical context. Consider the following:

• Balanced Crystalloids: The Surviving Sepsis Campaign recommends preferential resuscitation with balanced crystalloids, such as LR.
• Fluid Resuscitation: The choice of fluid should be guided by the patient's fluid requirements and the risk of complications.
• Monitoring and Adjustment: Close monitoring and adjustment of fluid management are crucial to ensure optimal patient outcomes.