GuidelinesOther guideline
Malignant Hyperthermia Crisis
AAGBI Safety Guideline This guideline is not a standard of medical care. The ultimate judgement with regard to a particular clinical procedure or treatment plan must be made by the clinician in the light of the clinical data presented an d the diagnostic and treatment options available.
Successful management of malignant hyperthermia depends upon early diagnosis and treatment; onset can be within minutes of induction or may be insidious. Previous uneventful anaesthesia does not rule out the possibility of MH.
The standard operating procedure below is intended to ease the burden of managing this rare but life threatening emergency.
| 1. Recognition | • Unexplained increase in ETCO2 AND • Unexplained tachycardia AND • Unexplained increase in oxygen requirement • Temperature changes are a late sign |
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| 2. Immediate management | • STOP all trigger agents • CALL FOR HELP. Allocate specific tasks • Install clean breathing system and HYPERVENTILATE with 100% O2 high flow • Maintain anaesthesia with intravenous agent • ABANDON/FINISH surgery as soon as possible • Muscle relaxation with non-depolarising neuromuscular blocking drug |
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| 3. Monitoring & treatment | • Give Dantrolene • Initiate active cooling avoiding vasoconstriction • TREAT: • Hyperkalaemia: calcium chloride, glucose/insulin, NaHCO3 • Arrhythmias: magnesium/ amiodarone/ metoprolol AVOID calcium channel blockers - interaction with dantrolene • Metabolic acidosis: hyperventilate, NaHCO3 • Myoglobinaemia: forced alkaline diuresis (mannitol/furosemide + NaHCO3); may require renal replacement therapy later • DIC: FFP, cryoprecipitiate, platelets • Check plasma CK as soon as able |
DANTROLENE 2.5mg/kg immediate iv bolus. Repeat 1mg/kg boluses as required to max 10mg/kg For a 70kg adult • Initial bolus: 9 vials dantrolene 20mg (each vial mixed with 60ml sterile water) • Further boluses of 4 vials dantrolene 20mg repeated up to 7 times. Continuous monitoring Core & peripheral temperature ETCO2 SpO2 ECG Invasive blood pressure CVP Repeated bloods ABG U&Es (potassium) FBC (haematocrit/platelets) Coagulation |
| 4. Follow-up | • Continue monitoring in ICU, repeat dantrolene as necessary • Monitor for acute kidney injury and compartment syndrome • Repeat CK • Consider alternative diagnoses (sepsis, phaeochromocytoma, thyroid storm, myopathy) • Counsel patient & family members Complete Critical Incident Form |
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