Download Triggers of Malignant Hyperthermia

MALIGNANT HYPERTHERMIA
GATEWAY SURGERY
CENTER
This program about Malignant
Hyperthermia will review:
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Definition
Etiology and Pathogenesis
Clinical Picture and Diagnosis
Therapy
Prevention
Imposters
Malignant Hyperthermia
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A chain reaction event (syndrome) triggered
in susceptible individuals by commonly used
anesthetics
An autosomal-dominant disorder
Life threatening
Causes of Malignant Hyperthermia
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Triggering agents release calcium for storage
sites in muscles leading to elevated calcium
concentrations in the muscles
High calcium levels increase metabolism
causing the muscles to contract and become
rigid
The process results in heat production,
acidosis and muscle cell breakdown
Triggers of Malignant Hyperthermia
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Volatile inhalation agents
Succinylcholine
Clinical Picture of MH
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Masseter spasms
Tachycardia
Increased end tidal CO2
Hypoxemia
Flushing of the skin
Hypotension
Metabolism acidosis
Hyperthermia
Body rigidity
Treatment of MH
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Stop triggering agents
100% Oxygen
Stop surgery ASAP
Deepen anesthesia with opiods, sedatives and
relaxation with non depolarizing relaxant
Dantrolene 2.5 mg/kg bolus IV, repeat until
hypermetabolism stops. May need more than
Dantrolene 10 mg/kg. Give 1 mg/kg every 6 hours
after control of the episode for 24 hours.
Sodium Bicarb according to ABG
Treatment of MH continued…
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Antiarrhythmic therapy with beta blocker or lidocaine
Cooling measures
Additional monitors…A-line, CVP, urinary catheter
Force diuresis
Check renal function, coagulation, electrolytes,
creatin kinase and temperature
Inform patient and relatives…Test for MH
Test for Malignant Hyperthermia
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No simple test available for screening
Requires skeletal muscle biopsy from thigh
Perform caffeine halothane contracture test
Prevention of MH
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Pre-op visit -- family history
Good anxiolysis
Monitors…EKG, CO2, SaO2
Dantrolene
Persistent elevated creatin kinase
Avoid triggering agents…flush anesthesia
machine with O2 10 liters/min for 20
minutes…change soda lime
MH patients in the ASC?
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Yes, use non-triggering agents
Observe for 3-5 hours
Imposter: Sudden Unexpected Cardiac
Arrest
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Sudden Unexpected Cardiac Arrest occurs in
young males soon after succinylcholine
usually with an undiagnosed myopathy.
Measure potassium ASAP and treat with
calcium, hyperventilation, glucose and insulin
Imposter: Neuroleptic Malignant
Syndrome
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Neuroleptic Malignant Syndrome is reported in
patients that receive neuroleptics for a range of
psychiatric illnesses as well as medical patients who
receive neuroleptics as antiemetics or sedatives.
Clinical characteristics include rigidity, mental status
changes and hyperthermia
NMS is a self-limiting disorder when the neuroleptics
are withdrawn. Recovery time has been estimated
at 7-10 days.