**Core Concept**
Malignant hyperthermia is a life-threatening medical emergency characterized by an abnormal increase in body temperature, metabolic acidosis, and muscle rigidity, often triggered by volatile anesthetics or succinylcholine. It results from an abnormal response of skeletal muscle cells to certain drugs, leading to an excessive release of calcium ions.

**Why the Correct Answer is Right**
The immediate treatment for malignant hyperthermia involves administering a dantrolene, a direct-acting skeletal muscle relaxant that inhibits calcium ion release from the sarcoplasmic reticulum. Dantrolene works by inhibiting the ryanodine receptor, which is responsible for the release of calcium ions from the sarcoplasmic reticulum. This action helps to reduce the excessive muscle contraction and heat production associated with malignant hyperthermia.

**Why Each Wrong Option is Incorrect**
**Option A:** Haloperidol is a dopamine antagonist that can actually worsen malignant hyperthermia by increasing muscle rigidity and heat production.
**Option B:** Fentanyl is a potent opioid analgesic that may be used in anesthesia but is not effective in treating malignant hyperthermia.
**Option C:** Sodium bicarbonate may be used to treat metabolic acidosis but does not address the underlying cause of malignant hyperthermia.

**Clinical Pearl / High-Yield Fact**
Dantrolene is the only FDA-approved treatment for malignant hyperthermia and should be administered promptly in cases where the diagnosis is suspected.

**Correct Answer: C. Sodium bicarbonate may be used to treat metabolic acidosis but does not address the underlying cause of malignant hyperthermia.