Malignant Hyperthermia
Presented By: St. James Healthcare Education Collaborative
With the support of: Surgical Services Leadership Team
June 2012
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Target Audience & Objectives
• Target audience is all associates who care for surgical patients
undergoing general anesthesia and at risk for malignant
hyperthermia (MH).
• The goal is to be able to assess the patient preoperatively; be able
to recognize signs and symptoms of MH, institute prompt and
appropriate treatment, and provide appropriate treatment postcrisis.
• A MedELearn Test may be assigned to associates by the Education
Department. A pass score of 80 % is required.
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What is Malignant Hyperthermia
(MH)?
• It is a rare, genetic autosomial-dominate, life threatening disorder.
• A hypermetablolic disorder of the skeletal muscle, which left
untreated will result in death.
• Usually triggered through the use of commonly used general
inhalation anesthetics and succinylcholine.
• These triggering agents cause a series of chain reactions in the
body that increases intracellular calcium ion concentrations.
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Who Gets It?
Patients who have an autosomal mode of inheritance and of
these:
• Males more frequently than females.
• Highest incidence of MH is ages 18 years and under, with 52% of all
reactions occurring in kids under the age of 15.
• Patients who are obese or have muscular physiques have higher
occurrences.
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Perioperative Plan of care for
Malignant Hyperthermia Patients
• Assess the patient preoperatively.
• Be able to recognize signs and symptoms of MH.
• Institute prompt and appropriate treatment.
• Appropriate treatment post-crisis.
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Assess the Patient Preoperatively
• All patients should be interviewed for MH not only the patients
susceptible of MH.
• During the interview a risk assessment for MH should include
assessments on caffeine intolerance, personal history or family
history of MH, or prior complications form previous anesthetics.
• If the patient answers “yes” to your interview questions notify both
MD and Anesthesia.
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Patient’s Personal History
During the Interview be aware of any other personal history
such as:
• Any unexplained fever.
• Presence of Cola colored urine.
• History of muscle weakness or cramps or muscle group
hypertrophy.
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Pediatric population and Malignant
Hyperthermia prevalence
Perioperative nurses should be aware of MH being more
prevalent in the pediatric populations with these congenital
conditions at the fore front:
• Arthrogryposis – joint contractures
• Muscular dystrophys – (Becker’s, Duchenne’s)
• Kyphoscoliosis – abnormal spine curvature
• Osteogenesis – brittle bone disease
• Myotonia Congenita – neuromuscular disorder
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Preoperative Testing for Malignant
Hyperthermia
• Caffeine Halothane contracture test- only definitive diagnostic test.
• This test requires the removal of a muscle from the thigh. It is
expensive and not usually covered by insurers.
• DNA test-but not all patients susceptible to MH show DNA change
(mutation). This test can not yet replace the Caffeine Test.
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Clinical Manifestations
• Increased body temperature is a late sign.
• Unexplained tachycardia.
• Rapid rise of CO2 levels frequently
exceeding 80mmHg.
• Generalized muscle rigidity. Most prominent
is the masseter muscle of the jaw.
• Cyanotic or mottled skin.
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Differential Diagnosis or What
Mimics Malignant Hyperthermia
• Cocaine toxicity
• Hypoxic encephalitis
• Intracranial trauma
• Light anesthesia
• Sepsis
• Thyroid storm
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Known Triggering Anesthetic
Agents
• Halothane
• Enflurane
• Isoflurane
• Desflurane
• Sevoflurane
• Succinylcholine
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Required Equipment for Malignant
Hyperthermia
Designated Anesthesia Machine Required for MH Cases or if
Not Available Then:
• Before induction change out the lime soda.
• Flush the machine with 5000ml/minute of vapor free oxygen for 20
minutes.
• If detected during procedure then stop gases, change machine or
flush the CO2 line with 100%.
• May continue to administer nitrous oxide.
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Intraoperative Anesthesia
Medication Preparations
• Administer Dantrolene 2.5mg/kg IV given through a large bore
needle until crisis is resolved.
• Dantrolene is mixed with sterile water (no baterostatic agent) 60ml
with a 20mg vial, shake vigorously. Upper dosage is 10mg/kg, more
may be needed.
• Titrate Dantrolene as necessary until tachycardia, hyperthermia,
hypercarbia and rigidity is resolved.
• Dantrolene should be administered for 24hrs. Infusing 1mg/kg/hr.
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Additional Medication
• Sodium bicarb to correct acidosis with initial dose 1 to 2 mEq/kg
and repeat as indicated.
• To treat hyperkalemia in adults use 10U Regular insulin IV and 50ml
50% glucose. Kids then 0.1 U Regular insulin/kg 50% glucose.
• Life threatening Hyperkalemia then adults give calcium chloride
10mg/kg or 10 to 50mg/kg calcium gluconate and check glucose
hourly.
• Administer standard antiarrhythmic agents for the treatment of
acidosis and hyperkalemia.
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The Medications Not to Give
• Bacteriostatic Water
• Calcium Channel Blockers - may increase hyperkalemia and react to
the dantrolene causing death.
• Avoid solutions containing potassium such as LR which may
contribute to the hyperkalemia and acidosis. Delegate extra
personnel for both meds, labs and cooling needs.
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Implementing Thermoregulation
• Apply cooling blanket.
• Infuse cold saline IV.
• Apply ice packs to the head, axillae, groin and underneath the
patient.
• Maintain basins of ice water and apply cold wash cloths exposed
body parts.
• Discontinue cooling measures when body temperature reaches 38 C
or 100.4 F .
• If an open procedure then apply cold irrigation solution to the body
cavity.
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Monitoring Thermoregulation
• Standard Monitors include EKG, cardiac output, HR ,BP, O2 SAT,
Arterial Line, and End Title CO2.
• Core temperature done through esophageal, tympanic, axillary,
rectally and bladder.
• Esophageal and rectal lavage.
• Inspect skin integrity and apply protective measures to the skin.
Preop assessment of tissue perfusion.
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Monitor Renal Function
• Muscle breakdown caused elevations in creatine kinase (CK) which
may cause renal insufficiency.
• Monitor CK and know that it may be normal at first and may not
peak until 16hrs after the crisis.
• If urine is less than 1mg/kg/hr give lasix to prevent myoglobin
induced renal failure
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Laboratory Studies
Malignant Hyperthermia Order Set Entry – lab tests performed
to detect the following imbalances:
• Increased Potassium, Calcium, Magnesium and Sodium
• Prolonged PTT & PT
• Decreased Platelets
• Increased CPK (measure every 6hrs until decreased), Creatine and
Lactate
• Increased Glucose
• ABGs
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Primary RN Role:
The primary or lead RN will delegate duties as follows:
• Notify Charge Nurse / Supervisors / Pharmacy.
• Have two to four RNs for Dantrolene Administration.
• RN to document/record (lab results, urine output and color, fluid intake,
types of irrigation and amounts, line placements).
• RN to lavage.
• Care Aids / Anesthesia Tech / Housekeeping to run for cold supplies,
running for lab, and running for invasive equipment
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Delegation of Duties
Specific Duties During The MH Crisis That Will Be Delegated To
Associates:
• Running for supplies not on the MH cart: Insulin in the fridge, Iced
IV bags, cold IV solutions, cold irrigations.
• Equipment for art. lines and 2 - 4 infusion pumps.
• Bringing deliberator into the room.
• Changing the anesthesia machine if directed by MD Anesthesia or
CRNA
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Patient Susceptibility Without a
Reaction: Post Acute Phases
In the Post Acute Phases for a patient who was susceptible to MH but
did not react, the following is required:
• All these patients should be observed for at least 12 hours.
• Sets up monitors including a chance for invasive monitors and
assures crash cart is close.
• Prepares containers of ice for the possible need.
• Counsel patient and family on MH and further precautions. Refer
them to MHAUS (Malignant Hyperthermia Association of the United
States); the MHAUS Hotline Number (800) 644-9737 (the Malignant
Hyperthermia Association of the United States) can be reached 24
hours a day.
• Educate patient on muscle biopsy follow-up.
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Post Acute Malignant Hyperthermia
Phase
• Observe in ICU for at least 24hours due to the risk of
recrudescence.
• Maintenance dantrolene 1mg/kg or 0.25mg/kg/hr by infusion for at
least 24hrs. Further doses may be indicated.
• Frequent ABGs, and CK every 6hrs.
• Monitor serum and urine pH
• Physician follow-up with education on MHAUS as well as muscle bx.
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References:
1.
2.
American Society of Anesthesiologits (2012).
http://www.asahq.org/.
Malignant Hyperthermia Association of the United States (2012).
http://www.mhaus.org/.
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