The patient appears diaphoretic. The rest of the physical examination is only notable for RLQ pain, which worsens with deep palpation, with no other abnormalities.

Standard American Society of Anesthesiologist monitors (non-invasive blood pressure cuff, pulse oximeter, EKG leads) are placed. Rapid sequence induction is performed, using intravenous propofol and fentanyl to induce general anesthesia and succinylcholine to facilitate tracheal intubation. The trachea is intubated using a MAC 3 blade and a 7.5 endotracheal tube (ETT). Correct ETT placement is confirmed by chest rise, auscultation, and capnography. An oropharyngeal temperature probe and an upper body forced air warming blanked are subsequently placed. Two grams of cefazolin are administered before surgical incision. General anesthesia is maintained with a mixture of sevoflurane, oxygen, and air. Six milligrams of intravenous morphine is administered, in two-milligram aliquots, for analgesia.

Half way through the case, the surgeon asks for additional muscle relaxation, as the abdomen “feels tight”. You notice that the patient is tachycardic (HR: 102 and regular) and has an elevated end-tidal carbon dioxide (E_TCO₂ 48 mmHg) despite no changes in minute ventilation.

You notify the surgeon and page your attending for additional help.

Malignant hyperthermia is a rare and potentially deadly pharmacogenetic disorder, which presents in susceptible individuals upon exposure to triggering agents [1].

Unregulated release of calcium from the sarcoplasmic reticulum into the myoplasm, secondary to a defect in ryanodine receptor protein (RYR1), leads to a hypermetabolic state characterized by uncontrolled muscle contraction (rigidity), heat production, excess carbon dioxide (CO₂) production, acidosis, hyperkalemia, rhabdomyolysis, and myoglobinuria.

Halogenated volatile anesthetics, non-depolarizing muscle relaxant succinylcholine, and in rare instances physical exertion in presence of high temperature.