Malignant Hyperthermia: Treatment
Basic, Clinical Sciences: Anesthesia Procedures, Methods, and Techniques
Once acute MH is suspected (hypercarbia not resolving to hyperventilation, generalized rigidity, PVCs, tachycardia, unstable arterial pressure, masseter spasm, unexplained metabolic acidosis), the MH Protocol should be initiated. The Malignant Hyperthermia Association of the United States (MHAUS) identifies the following actions that the anesthesiologist should immediately take:
After completing these steps, further management is guided by the persistence of hypercarbia, the degree of acidosis present, any electrolyte abnormalities, urine output, coagulation studies, and other tests as indicated. Vital signs, core temperature, ETCO2, minute ventilation, blood gases, electrolytes, CK, urine myoglobin, and coagulation studies as warranted by the clinical severity of the patient should be followed. Sodium bicarbonate should be considered for severe metabolic acidosis, especially for base excesses greater then -8. Active cooling should be initiated for patient core temperatures > 39°C and stopped once < 38°C. Hyperkalemia should be treated aggressively with calcium chloride and sodium bicarbonate (or ECMO if cardiac arrest occurs). Dysrhythmias should be treated with standard antiarrhythmics, but calcium channel blockers should be avoided. Diuretics should be titrated to > 1 mL/kg/hr urine output. Once the patient is stable, he or she should be transferred to the ICU for at least 24 hours to further assess, evaluate, and/or treat hypercarbia, dysrhythmias, hyperthermia, and generalized muscular rigidity.