2. Clinical grading scale for malignant hyperthermia.
| Process | Indicator | Score |
| #These indicators should be used only for determining malignant hyperthermia (MH) susceptible. | ||
| Ⅰ. Rigidity | ·Generalized muscular rigidity (in absence of shivering due to hypothermia, or
during or immediately following emergence from inhalational anesthesia) |
15 |
| ·Masseter spasm shortly following succinylcholine administration | 15 | |
| Ⅱ. Muscle breakdown | ·Elevated creatine kinase >20 000 IU after anesthetic that included succinylcholine | 15 |
| ·Elevated creatine kinase >10 000 IU after anesthetic without succinylcholine | 15 | |
| ·Cola colored urine in perioperative period | 10 | |
| ·Myoglobin in urine >60 μg/L | 5 | |
| ·Myoglobin in serum >170 μg/L | 5 | |
| ·Blood/plasma/serum K+>6 mEq/L (in absence of renal failure) | 3 | |
| Ⅲ. Respiratory acidosis | ·PETCO2 >55 mmHg with appropriately controlled ventilation | 15 |
| ·Arterial PaCO2 >60 mmHg with appropriately controlled ventilation | 15 | |
| ·PETCO2 >60 mmHg with spontaneous ventilation | 15 | |
| ·Arterial PaCO2 >65 mmHg with spontaneous ventilation | 15 | |
| ·Inappropriate hypercarbia (in anesthesiologist's judgment) | 15 | |
| ·Inappropriate tachypnea | 10 | |
| Ⅳ. Temperature increase | ·Inappropriately rapid increase in temperature | 15 |
| ·Inappropriately increased temperature >38.8 °C (101.8 °F) in the perioperative period | 10 | |
| Ⅴ. Cardiac involvement | ·Inappropriate sinus tachycardia | 3 |
| ·Ventricular tachycardia or ventricular fibrillation | 3 | |
| Ⅵ: Family history (used for MH susceptible) | ·Positive MH family history in relative of first degree# | 15 |
| ·Positive MH family history in relative not of first degree# | 5 | |
| Ⅶ. Other indicators that are not part of a single process | ·Arterial base excess more negative than −8 mEq/L | 10 |
| ·Arterial pH <7.25 | 10 | |
| ·Rapid reversal of MH signs of metabolic and/or respiratory acidosis with intravenous dantrolene | 5 | |
| ·Positive MH family history together with another indicator from the patient's own
anesthetic experience other than elevated resting serum creatine kinase# |
10 | |
| ·Resting elevated serum creatine kinase in patient with a family history of MH# | 10 | |