From the Guidelines
0.9% sodium chloride (normal saline) is preferred over lactated Ringer's solution in patients with severe head trauma, as it avoids the potential for cerebral edema associated with hypotonic solutions like Ringer’s lactate. According to the European guideline on management of major bleeding and coagulopathy following trauma: sixth edition 1, normal saline is recommended for fluid therapy in hypotensive bleeding trauma patients, and hypotonic solutions like Ringer’s lactate should be avoided in patients with severe head trauma.
Key Considerations
- Normal saline provides sodium without calcium or bicarbonate precursors, making it suitable for patients with metabolic alkalosis, hyponatremia, or hypercalcemia.
- It is indicated for patients with severe renal impairment, diabetic ketoacidosis (especially initially), and those receiving blood transfusions, as calcium in lactated Ringer's can promote clotting in stored blood.
- Normal saline is preferred when administering certain medications, particularly amphotericin B and mannitol, which may be incompatible with calcium-containing fluids.
- The higher chloride content in normal saline creates a mild acidifying effect, which can be beneficial in alkalotic states but may worsen acidosis if used in large volumes.
Clinical Scenarios
- Neurosurgical procedures: normal saline is often used to avoid potential cerebral edema that might occur with more hypotonic solutions.
- Traumatic brain injury: normal saline is preferred to avoid potential cerebral edema associated with hypotonic solutions like Ringer’s lactate.
- Severe head trauma: normal saline is recommended to avoid the potential for cerebral edema associated with hypotonic solutions like Ringer’s lactate, as stated in the European guideline on management of major bleeding and coagulopathy following trauma: sixth edition 1.
Monitoring and Precautions
- Monitor for hyperchloremic metabolic acidosis, especially during high-volume resuscitation, as this is the most common adverse effect of large-volume normal saline administration.
- Be cautious when using normal saline in patients with severe metabolic acidosis, as it may worsen the condition.
The most recent and highest quality study, the European guideline on management of major bleeding and coagulopathy following trauma: sixth edition 1, provides the basis for the recommendation to use normal saline in patients with severe head trauma.
From the FDA Drug Label
INDICATIONS AND USAGE: ... Isotonic Sodium Chloride Injection should be limited to cases in which the chloride loss is greater than the sodium loss, as in vomiting from pyloric obstruction, or in which the loss is about equal, as in vomiting from duodenal, jejunal or ileal obstruction and in the replacement of aspirated gastrointestinal fluids
- 0.9% sodium chloride (normal saline) is preferred over lactated Ringer's (LR) solution in cases where:
- Chloride loss is greater than sodium loss, such as vomiting from pyloric obstruction
- Chloride loss is about equal to sodium loss, such as vomiting from duodenal, jejunal or ileal obstruction
- Replacement of aspirated gastrointestinal fluids is needed 2
From the Research
Preferred Use of 0.9% Sodium Chloride
0.9% sodium chloride (normal saline) is preferred over lactated Ringer's (LR) solution in certain situations:
- In patients with severe metabolic alkalosis, as lactated Ringer's can exacerbate the condition 3
- In patients with lactic acidosis with decreased lactate clearance, as lactated Ringer's contains lactate 3
- In patients with severe hyperkalemia, as lactated Ringer's contains potassium 3
- In patients with traumatic brain injury or at risk of increased intracranial pressure, as the optimal fluid choice in these situations is still debated and may depend on individual patient factors 3
- During renal transplantation, normal saline is often used to avoid the risk of hyperkalemia associated with potassium-containing fluids, although some studies suggest that lactated Ringer's may be a safe alternative 4
Key Considerations
When choosing between normal saline and lactated Ringer's, clinicians should consider the following factors:
- The cause of hypovolemia
- The cardiovascular state of the patient
- Renal function
- Serum osmolality
- Coexisting acid-base and electrolyte disorders 3
- The potential risks and benefits of each fluid, including the risk of hyperchloremic metabolic acidosis and renal vasoconstriction associated with normal saline 3