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

From: Malignant hyperthermia: a review



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