Which of the following is the most common initial manifestation of malignant hypehermia?

Increased PETCO2 is the most common initial manifestation of malignant hypehermia. Malignant hypehermia (MH) may occur either in the operating room (OR) or in the early postoperative period. The earliest sign is an increase in end-tidal carbon dioxide. A fulminant reaction is obvious, with very high end-tidal carbon dioxide (>100 mm Hg), a low pH with a metabolic component, tachycardia and dysrhythmias, rigidity (in some cases), rapidly increasing temperature, a mottled skin color, hyperkalemia, myoglobinuria, muscle edema, sympathetic hyperactivity with eventual metabolic exhaustion, increased cellular permeability, whole body edema, disseminated intravascular coagulopathy (DIC), and cardiac and renal failure. Early diagnosis and treatment with dantrolene can improve the outcome.