Skip to main content

Table 1 Criteria used in the Clinical Grading Scale for Malignant Hyperthermia

From: Malignant hyperthermia: a review

Process Indicator
I: Rigidity a. Generalized muscular rigidity (in absence of shivering due to hypothermia, or during or immediately following emergence from inhalational anesthesia)
b. Masseter spasm shortly following succinylcholine administration
II: Muscle Breakdown a. Elevated creatine kinase >20,000 IU after anesthetic that included succinylcholine
b. Elevated creatine kinase >10,000 IU after anesthetic without succinylcholine
c. Cola colored urine in perioperative period
d. Myoglobin in urine >60 μg/L
e. Myoglobin in serum >170 μg/L
f. Blood/plasma/serum K+ > 6 mEq/L (in absence of renal failure)
III: Respiratory Acidosis a. PETCO2 > 55 mmHg with appropriately controlled ventilation
b. Arterial PaCO2 > 60 mmHg with appropriately controlled ventilation
c. PETCO2 > 60 mmHg with spontaneous ventilation
d. Arterial PaCO2 > 65 mmHg with spontaneous ventilation
e. Inappropriate hypercarbia (in anesthesiologist’s judgment)
f. Inappropriate tachypnea
IV: Temperature Increase a. Inappropriately rapid increase in temperature (in anesthesiologist’s judgement)
b. Inappropriately increased temperature > 38.8 °C (101.8 °F) in the perioperative period (in anesthesiologist’s judgment)
V: Cardiac Involvement a. Inappropriate sinus tachycardia
b. Ventricular tachycardia or ventricular fibrillation