Malignant hyperthermia crisis
Unexplained increase in ETCO2 AND tachycardia AND increased oxygen consumption. Temperature rise is a late sign. MH is rare. Always consider other, more common causes of hyperthermia (see 2-8 Peri-operative hyperthermia).
Turn off vaporisers and remove from anaesthesia workstation.
Set fresh gas flow to 100% oxygen, maximum flow.
Hyperventilate (2–3 × normal minute ventilation).
Place activated charcoal filters on both limbs of the breathing circuit.
Change soda lime and breathing circuit if/when feasible (not a priority).
Delegate mixing – it is time and labour intensive.
2–3 mg.kg⁻¹ immediate i.v. bolus (Adult approx. 200 mg).
Repeat 1 mg.kg⁻¹ every 5 min, until ETCO2 <6 kPa and temp <38.5 °C.
Pause and observe.
Repeat 1 mg.kg⁻¹ to maintain ETCO2 <6 kPa and temp <38.5 °C, even if exceeds 'maximum' dose 10 mg.kg⁻¹.
Turn off active warming.
Apply ice to axillae and groins.
Use cold i.v. fluids.
Consider cold peritoneal lavage.
Other cooling methods according to need and availability: surface cooling devices, intravascular devices, extracorporeal heat exchange.
Metabolic acidosis: Sodium bicarbonate 50 mmol (50 ml of 8.4% solution) if pH <7.2 despite hyperventilation.
Hyperkalaemia: Sodium bicarbonate 50 mmol (50 ml of 8.4% solution); Glucose (50 ml of 50%) with insulin 10 IU; Calcium 0.1 mmol.kg⁻¹ (in extremis).
Myoglobinuria: Forced alkaline diuresis (aim UOP >2 ml.kg⁻¹; urine pH >7).
DIC: FFP, cryoprecipitate, platelets.
Tachyarrhythmias: Amiodarone, β-blockers.
Compartment syndrome: surgical decompression.
AVOID Calcium channel blockers (interaction with dantrolene).
Emergency hotline 07947 609601 or 0113 243 3144
UK MH Registry website: www.ukmhr.ac.uk