A 20-year-old woman is brought to the emergency department after being struck by a car while crossing the street. Vital signs are within normal limits. X-ray of the lower extremity shows a mid-shaft femur fracture. The patient is taken to the operating room for surgical repair of the fracture. As the surgeon begins the internal fixation, the patient shows diffuse muscle stiffness and profuse diaphoresis. Her temperature is 39°C (102.2°F), pulse is 130/min, respirations are 24/min, and the ECG tracing shows sinus tachycardia Hg. Inhibition of which of the following is most likely to improve this patient's condition?

Question

Quizplus · Accepted Answer

Eductional Objective: The features of malignant hyperthermia (e.g., fever, muscle rigidity, tachycardia, tachypnea, increased CO₂ production) are caused by severe, generalized muscle contraction due to increased Ca²⁺+ release from the sarcoplasmic reticulum via the RYR channels. Dantrolene, an RYR antagonist, would prevent this Ca²⁺+ release.

A 20-Year-Old Woman Is Brought to the Emergency Department After