**Question:** Content of Na+ in ringer lactate is ……………… meq/l-

**Core Concept:** Ringer's lactate is a commonly used intravenous fluid for fluid resuscitation in clinical practice. It contains various electrolytes to maintain electrolyte balance and physiological function.

**Why the Correct Answer is Right:** Ringer's lactate solution is a balanced electrolyte solution, which means it has equal concentrations of sodium, potassium, and calcium ions. In this case, the correct answer represents the concentration of sodium ions in millimoles per liter (mmol/L).

**Why Each Wrong Option is Incorrect:**

A. This option is not related to the question, as it refers to another electrolyte (calcium) rather than sodium.
B. This option represents the concentration of potassium ions (K+) in mmol/L, which is incorrect for sodium (Na+) concentration.
C. This option represents the concentration of chloride ions (Cl-) in mmol/L, which is irrelevant to sodium concentration.
D. This option represents the concentration of calcium ions (Ca2+) in mmol/L, again incorrect for sodium concentration.

**Why the Correct Answer is Right (again):**

The correct answer (145 mmol/L) represents the concentration of sodium ions (Na+) in Ringer's lactate solution, ensuring its use remains safe and effective in maintaining electrolyte balance and preventing complications such as hypernatremia or hyponatremia.

**Clinical Pearl:** Ringer's lactate solution is advantageous in situations where normal saline (0.9% NaCl) is unsuitable, e.g., in patients with hyponatremia or renal failure, as lactate does not contribute to fluid volume expansion as much as chloride ions in normal saline.

**Correct Answer:** 145 mmol/L