What is the electrolyte content of Lactated Ringer's (LR) solution?

Electrolyte Composition of Lactated Ringer's Solution

Lactated Ringer's solution contains sodium (130 mmol/L), potassium (4 mmol/L), chloride (109 mmol/L), calcium (1.4 mmol/L), and lactate (28 mmol/L), with an osmolarity of approximately 273-277 mOsm/L, making it slightly hypotonic compared to plasma. 1, 2

Detailed Composition

• Sodium: 130 mmol/L 1, 2
• Potassium: 4 mmol/L 1, 2
• Chloride: 108-109 mmol/L 1, 2
• Calcium: 0.9-1.4 mmol/L 1, 2
• Lactate: 27.6-28 mmol/L 1, 2
• Osmolarity: 273-277 mOsm/L 1, 2

Clinical Implications of Tonicity

• Lactated Ringer's solution is slightly hypotonic compared to plasma (which has an osmolarity of 275-295 mOsm/L) 1
• Due to its hypotonic nature, Lactated Ringer's should be avoided in patients with severe head trauma as it may increase cerebral edema 3, 1
• For brain-injured patients, 0.9% saline (osmolarity 308 mOsm/L) is the recommended crystalloid of choice as it is isotonic 1

Advantages of Lactated Ringer's Solution

• The balanced electrolyte composition of Lactated Ringer's makes it physiologically more similar to plasma than 0.9% sodium chloride 1
• Lactated Ringer's is recommended as a first-line balanced fluid resuscitation solution for many clinical scenarios, including burns victims 1
• The European guideline on management of major bleeding and coagulopathy following trauma recommends balanced crystalloid solutions like Lactated Ringer's for initial fluid therapy in hypotensive bleeding trauma patients 3

Important Clinical Considerations

• When administering additional electrolytes with Lactated Ringer's, remember that the solution already contains 4 mmol/L of potassium 1
• The presence of calcium (1.4 mmol/L) in Lactated Ringer's is important to consider when evaluating compatibility with other medications 2
• Despite concerns, research shows that infusion of Lactated Ringer's solution at resuscitation rates does not significantly increase circulating lactate concentrations in hemodynamically stable patients 4, 5
• Lactated Ringer's contains racemic lactate (a mixture of D- and L-stereoisomers), which is metabolized at nearly the same rate as L-lactate alone 6

Contraindications and Precautions

• Lactated Ringer's should be avoided in patients with severe head trauma due to its hypotonic nature 3, 1
• The European guideline specifically recommends against using Ringer's lactate in brain-injured patients 3
• For patients with traumatic brain injury or at risk for cerebral edema, 0.9% saline is preferred over Lactated Ringer's due to its isotonicity 1