## **Core Concept**
Hartmann's solution, also known as Ringer's lactate solution, is a type of isotonic crystalloid fluid used for fluid resuscitation and maintenance. It contains sodium, potassium, calcium, chloride, and lactate ions.

## **Why the Correct Answer is Right**
Hartmann's solution is isotonic, meaning it has the same osmolality as blood, and is commonly used for intravenous administration to replenish fluids and electrolytes. The composition of Hartmann's solution includes sodium (131 mEq/L), potassium (5 mEq/L), calcium (2 mEq/L), chloride (109 mEq/L), and lactate (28 mEq/L).

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is not provided, so we cannot assess its accuracy.
- **Option B:** This option is not provided, so we cannot assess its accuracy.
- **Option C:** This option is not provided, so we cannot assess its accuracy.
- **Option D:** This option is not provided, so we cannot assess its accuracy.

## **Clinical Pearl / High-Yield Fact**
A key point to remember about Hartmann's solution is that it contains lactate, which is metabolized by the liver into bicarbonate, providing some buffering capacity to help correct metabolic acidosis.

## **Correct Answer: D.**