**Question:** Animal and clinical studies have shown that administration of lactated Ringer's solution to patients with hypovolemic shock may

A. Improve cardiac output
B. Increase blood pH
C. Cause renal dysfunction
D. Result in hypernatremia

**Correct Answer:**

**Core Concept:** Hypovolemic shock occurs when there is a reduction in circulating blood volume, leading to inadequate organ perfusion and potentially organ failure. Lactated Ringer's solution is a crystalloid intravenous fluid commonly used in clinical settings to replace fluid deficits and maintain tissue perfusion.

**Why the Correct Answer is Right:** The correct answer, A. Improve cardiac output, relates to lactated Ringer's solution's primary function in treating hypovolemic shock. By restoring blood volume and pressure, this solution helps to increase the amount of blood pumped by the heart (cardiac output) and deliver oxygen and nutrients to tissues, thereby improving overall organ function.

**Why Each Wrong Option is Incorrect:**

B. Increase blood pH (Option B): While lactated Ringer's solution does not significantly alter blood pH, it does not cause a significant change in pH compared to normal saline.

C. Cause renal dysfunction (Option C): Although some studies have suggested potential nephrotoxicity with long-term use, lactated Ringer's solution does not directly cause renal dysfunction when used for short-term resuscitation in hypovolemic shock.

D. Result in hypernatremia (Option D): Lactated Ringer's solution contains sodium chloride, but its sodium concentration is similar to that of plasma, making it less likely to cause hypernatremia compared to other fluids like normal saline. However, excessive fluid administration may lead to hypernatremia, so it is essential to use this solution judiciously.

**Clinical Pearl:** When using lactated Ringer's solution for fluid resuscitation in hypovolemic shock, ensure that the fluid is given cautiously and in accordance with the patient's fluid balance and clinical response. Overhydration can lead to complications, so monitoring and adjusting fluid administration is crucial.