Malignant Hyperthermia (MH)

Question 1

What is the first step in managing Malignant Hyperthermia (MH)?

Answer 1

Call for help and obtain the malignant hyperthermia cart.

Question 2

What should be done after calling for help in MH management?

Answer 2

Notify the surgeon.

Question 3

What anesthetic agents should be stopped in MH management?

Answer 3

Stop all inhalation anesthetic agents and succinylcholine administration.

Question 4

What should be continued during MH management?

Answer 4

Continue with non-MH triggering agents (e.g., propofol, nondepolarizing neuromuscular blocker).

Question 5

What is essential for maintaining the patient’s airway during MH?

Answer 5

Maintain a secure and patent airway.

Question 6

How should oxygenation and ventilation be provided in MH?

Answer 6

Provide adequate oxygenation and ventilation using a new breathing circuit and reservoir bag with high flow (≥ 10 L/min) and 100% oxygen.

Question 7

What should be applied to the anesthesia gas machine during MH?

Answer 7

Apply activated charcoal filters to the inspiratory and expiratory limbs.

Question 8

What medication should be administered for MH?

Answer 8

Administer dantrolene.

Question 9

What cooling measures are recommended for MH?

Answer 9

1. Forced air cooling. 2. Cooled IV fluids. 3. Intraperitoneal and/or intragastric lavage.

Question 10

What is the contact number for the Malignant Hyperthermia Association of the United States?

Answer 10

Consult the Malignant Hyperthermia Association of the United States (MHAUS) at 1-800-MH-HYPER (1-800-644-9737). Outside of North America: 001-209-417-3722.

Question 11

What are secondary actions in MH management?

Answer 11

Invasive monitoring (arterial line) and obtain a second large-bore IV catheter, IV fluid administration, increase minute ventilation, treat respiratory and metabolic acidosis, treat hyperkalemia if present.

Question 12

What is the reconstitution method for Dantrolene and Revonto formulations?

Answer 12

Reconstitute with 60 mL sterile water.

Question 13

What is the IV bolus dosage of Dantrolene for a 70-kg patient?

Answer 13

Administer 9 vials (180 mg) IV bolus.

Question 14

What is the reconstitution method for Ryanodex formulation?

Answer 14

Reconstituted with 5 mL sterile water.

Question 15

What is the IV bolus dosage of Ryanodex for a 70-kg patient?

Answer 15

Administer 3.5 mL (175 mg) IV bolus.

Question 16

What is the treatment for hyperkalemia in MH?

Answer 16

Regular insulin 5 Units IV bolus AND D50W (25 g/ampule) IV bolus.

Question 17

What is the calcium treatment for hyperkalemia?

Answer 17

10% Calcium chloride 0.5-1 g IV over 10 minutes or 10% calcium gluconate 1-2 g IV over 2-5 minutes.

Question 18

What is the treatment for metabolic acidosis in MH?

Answer 18

8.4% sodium bicarbonate 50 mEq (1 ampule) IV bolus over 5 minutes or alternatively, 150 mEq in 1 L of D5W over 2-4 hours.

Question 19

What are respiratory signs of Malignant Hyperthermia?

Answer 19

Decreased PaO₂, Increased PaCO₂, Unexplained increased EtCO₂ (most sensitive and specific initial clinical sign).

Question 20

What are cardiovascular signs of Malignant Hyperthermia?

Answer 20

Diaphoresis, Dysrhythmias, Hypertension, Mottled and cyanotic skin, Tachycardia (early sign but not specific).

Question 21

What are musculoskeletal signs of Malignant Hyperthermia?

Answer 21

Elevated CK (Creatine Kinase), Elevated urine and serum myoglobin, Generalized muscle rigidity, Masseter muscle spasm, Rhabdomyolysis.

Question 22

What are other considerations in Malignant Hyperthermia?

Answer 22

Disseminated intravascular coagulation, Hyperkalemia, Hyperthermia, Myoglobinuria, Respiratory and metabolic acidosis.

Question 23

What are some differential diagnoses for Malignant Hyperthermia?

Answer 23

Neurologic: Hypothalamic lesions, Neuroleptic malignant syndrome; Respiratory: Endobronchial intubation, Hypercarbia, Hypoventilation.

Question 24

What endocrine conditions can mimic Malignant Hyperthermia?

Answer 24

Carcinoid syndrome, Hypermetabolic syndromes (e.g., pheochromocytoma, thyroid storm).

Question 25

What pharmacologic conditions can mimic Malignant Hyperthermia?

Answer 25

Central anticholinergic syndrome (e.g., atropine overdose), Monoamine oxidase inhibitors, Opioid and/or alcohol withdrawal, Psychotropic medications causing neuroleptic malignant syndrome.

Question 26

What are some sympathomimetics that can mimic Malignant Hyperthermia?

Answer 26

Drug misuse (e.g., cocaine, methamphetamine), Therapeutic medications (e.g., epinephrine).

Question 27

What are other considerations that can mimic Malignant Hyperthermia?

Answer 27

Anaphylaxis, CO₂ rebreathing, CO₂ absorption, Exhausted CO₂ granules, Persistent hyperthermia despite cooling measures, Hypovolemia, Inadequate Depth of Anesthesia, Sepsis, Serotonin Syndrome.