The most sensitive early sign of malignant hyperthermia during general anesthesia is which of the following?

The most sensitive early sign of malignant hyperthermia during general anesthesia is which of the following?

• A. Tachycardia
• B. Hypertension
• C. Fever
• D. Increased end-expiratory CO2 tension (PECO2)

Answer: (D)

In malignant hyperthermia, triggering anesthetics provoke an uncontrolled, hypermetabolic response in skeletal muscle, driven by excess calcium release. The earliest and most sensitive sign during anesthesia is a sudden rise in end-tidal CO2 tension (PECO2). This happens because CO2 production accelerates dramatically from the hypermetabolic state, and the capnography trace reflects this rapid increase even before other signs become evident. Tachycardia and hypertension can occur but are nonspecific and common to many intraoperative stresses, so they’re less reliable as early indicators. Fever develops later as heat production and muscle breakdown continue, not as an immediate sign.

In malignant hyperthermia, triggering anesthetics provoke an uncontrolled, hypermetabolic response in skeletal muscle, driven by excess calcium release. The earliest and most sensitive sign during anesthesia is a sudden rise in end-tidal CO2 tension (PECO2). This happens because CO2 production accelerates dramatically from the hypermetabolic state, and the capnography trace reflects this rapid increase even before other signs become evident. Tachycardia and hypertension can occur but are nonspecific and common to many intraoperative stresses, so they’re less reliable as early indicators. Fever develops later as heat production and muscle breakdown continue, not as an immediate sign.