What is the sodium concentration in lactated Ringer's solution?

• A. 130 mEq/L
• B. 154 mEq/L
• C. 109 mEq/L
• D. 77 mEq/L

Answer: (A)

The sodium concentration in lactated Ringer's solution is 130 mEq/L. This makes lactated Ringer's a balanced crystalloid that more closely mirrors extracellular fluid than normal saline, which has a higher sodium content (154 mEq/L). The lower sodium helps avoid hypernatremia during fluid resuscitation, while the solution also contains chloride at about 109 mEq/L, potassium around 4 mEq/L, calcium about 2 mEq/L, and lactate about 28 mEq/L (lactate serves as a bicarbonate precursor). The other numbered options do not fit because they represent either the sodium level of normal saline or non-sodium components of LR.