What is the first-line management step for malignant hyperthermia in the operating room?

• A. Stop offending agents
• B. Stop all medications
• C. Dantrolene administration
• D. Rapid cooling and supportive care

Answer: (C)

Malignant hyperthermia management centers on stopping the crisis by reversing the abnormal calcium handling in skeletal muscle. Dantrolene administration is the best first-line step because it directly counteracts the underlying mechanism: it inhibits calcium release from the sarcoplasmic reticulum, which rapidly halts sustained muscle contraction, lowers metabolic rate, and reduces heat production, acidosis, and electrolyte disturbances. Prompt IV dosing (typically 2.5 mg/kg, with repeat doses up to a total of about 10 mg/kg as needed) is lifesaving and should be given as soon as MH is suspected.

Stopping triggering agents remains essential and should be done immediately, but it does not by itself reverse the crisis; dantrolene is what directly halts the pathophysiology. While preparing and administering dantrolene, provide 100% oxygen, hyperventilate to normalize CO2, begin cooling measures, and manage fluids, acidosis, and electrolyte disturbances to support the patient through the crisis.