## Core Concept
Hyperkalemia is a condition characterized by elevated potassium levels in the blood, which can lead to serious cardiac arrhythmias. Management of hyperkalemia involves stabilizing cardiac membranes, shifting potassium into cells, and removing excess potassium from the body. ECG findings are crucial in guiding the immediate treatment.

## Why the Correct Answer is Right
The correct answer, **Calcium gluconate**, is used in the management of hyperkalemia to stabilize cardiac membranes but does not lower potassium levels. It is particularly useful when there are ECG changes. In the absence of ECG findings, the immediate need for calcium gluconate is less clear, but it does not address the root cause of hyperkalemia, which is the elevated potassium level itself.

## Why Each Wrong Option is Incorrect
* **Option A:** Insulin and dextrose can help shift potassium into cells, thereby lowering serum potassium levels. This is a valid treatment approach for hyperkalemia, especially when there are no ECG changes.
* **Option B:** Sodium bicarbonate can also help shift potassium into cells in exchange for hydrogen ions, particularly in the context of metabolic acidosis. It is considered in the management of hyperkalemia.
* **Option D:** Kayexalate (polystyrene sulfonate) is a potassium-binding resin that helps remove potassium from the body through the gastrointestinal tract. It is used for the longer-term management of hyperkalemia.

## Clinical Pearl / High-Yield Fact
A key point to remember is that in the absence of ECG changes, the focus in managing hyperkalemia shifts more towards methods that either shift potassium into cells (like insulin/dextrose, beta-2 agonists) or remove potassium from the body (like diuretics, kayexalate), rather than immediately stabilizing cardiac membranes with calcium.

## Correct Answer Line
**Correct Answer: C. Calcium gluconate**