Download Malignant Hyperthermia

Malignant Hyperthermia
What is Malignant Hyperthermia?
 Malignant hyperthermia (MH) is an inherited
hypermetabolic syndrome, that when triggered,
causes sustained skeletal muscle contractions.
 Can lead to severe hyperthermia, left ventricular
failure, brain damage, organ failure, disseminated
intravascular coagulation (DIC), cardiac arrest,
and death.
 Usually triggered during or after administration of
commonly used general anesthetics
History of MH
 19th century – monitoring of patients minimal,
deaths with surgery not uncommon and often
unexplained.
 Early 20th century – first reports of fever and
tachycardia during or after anesthesia that ended
in death, cause unknown.
 1960’s- first documented case of MH
 Past mortality was 70%-80%, now with treatment
~5% within treatment hospital, 20% surgery
centers or transferring hospitals.
Incidences Of MH
 One in every 100,000 hospital discharges
complicated by MH
 500-600 cases in US each year
 Most common between ages 2 – 42
 2/3 cases are men
 More common in adults than children
 1st degree relative of someone who has had MH or
MH susceptible is at greater risk
 Higher risk in someone with a muscle disorder
Goal of Treatment
 Prevention
– Perioperative nurse includes risk assessment
during routine pre-op interview
 prior complications from previous surgery
 Personal history of muscle disorder
 Family history of complications with surgery
 Caffeine intolerance
 If MH occurs
– quickest response possible to prevent
complications and death
Triggers
 Known triggers:
– Volatile anesthetics - sevoflurane, isoflurane, and
desflurane
– Inhaled anesthetics (except nitrous oxide)
– Muscle relaxant – succinylcholine
 Do Not Trigger:
– All local anesthetics, barbiturates, Benzodiazepines,
etomidate, Ketamine, nitrous oxide, Nondepolarizing
muscle relaxants, propofol
Malignant Hyperthermia Screening
 Only definitive diagnostic test for MH is caffeine
halothane contracture test (CHCT).
– Done with thigh muscle biopsy
– Only 4 centers in the US perform test, 2 in Canada
– Patient must travel to testing centers, biopsy must be
fresh
– Cost $6,000 (not including travel), Cost usually not covered
by insurance

Can use DNA analysis but only 30% effective, cost
$200.
What’s Going ON
 A MH-susceptible person has an abnormal structure and
function of a calcium channel within their skeletal muscle
 When exposed to trigger drugs an abnormal release of
calcium inside the muscle cell occurs causing sustained
muscle contraction, abnormal increase in energy utilization
and heat production.
 The muscle cell eventually runs out of energy and dies
releasing large amounts of K and myoglobin into the
bloodstream leading to arrhythmias and kidney failure.
Signs & Symptoms
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Unexplained tachyarrhythmia (96% of cases)
Unexplained tachypnea (85% of cases)
Increased end-tidal CO2, hypoxemia
Acidosis (80%)
General muscle rigidity – one of earliest signs, especially in
masseter muscle of the jaw (80%)
 Cyanotic or mottled skin – generally starts with a
generalized flush (70%)
 Rapid, sustained increase in body temperature – late sign
only 30% of cases. Temperature can be as high as 110°
 Cola-colored urine due to rhabdomyolysis (later sign)
LABORATORY FINDINGS OF
ACUTE MH
 ABG
decreased pH
decreased PO2
increased PCO2
 Electrolytes
increased K
increased Ca
increased Mg
decreased Na
LABORATORY FINDINGS OF
ACUTE MH (cont.)
 Serum
increased Lactate
increased Pyruvate
increased CPK
increased LDH
increased Aldolase
increased Myoglobin
increased Glucose
increased Creatinine
decreased PT
decreased PTT
decreased Platelets
www.nursetoons.com
Responding to MH
 Stop procedure as soon as possible
 Discontinue all anesthetics, change soda lime canister,
change breathing circuit, and hyperventilate with 100% O2
 Initiates MH protocol, call for MH cart and additional help –
will need a minimum of 4 nurses and additional help
 Give 2.5 mg/kg Dantrolene Sodium rapid IV
 Monitor and Treat acidosis, hyperkalemia, arrhythmias,
hyperthermia, rhabdomyolysis and other symptoms
 Transfer to ICU – where the patient will remain for 24 hours
after symptoms have resolved.
Circulating Nurse (1)
 Calls immediately for additional help and
MH cart
 Assist anesthesia with anesthesia machine
and as needed
 Place additional IV lines
 Draws blood/ ABG’s
 Monitors patient including urine output
Dantrolene Nurse (2)
 Bring MH cart
 Start mixing Dantrolene ( will need up to 36
vials and 2 liters sterile water)
 Administer Dantrolene as soon as possible
Dantrolene
 The key to controlling a MH crisis is the
quick administration of Dantrolene.
 It is the first-line defense against reducing
MH mortality.
 Dantrolene is a muscle relaxant that
restores a healthy level of calcium in the
muscle and reduces high body temperature.
Dantrolene
 Mix:
– Mix each vial with 60cc sterile H20 (without
bacteriostatic agents) use IV spike transfer pins to
reconstitute
– Shake vigorously to reconstitute, mix until clear- this
may take several minutes
– Give rapid continuous IV push. Administer 2.5 mg/kg.
Repeat up to 10mg/kg or until symptoms subside
– When mixed keep from light and use within 6 hours
 Avoid use of calcium channel blockers with
dantrolene - may cause life-threatening
hyperkalemia and myocardial depression.
Dantrolene Dose Chart
2.5mg/kg initial dose
Weight (kg)
Dose
# Vials
15
37.5 mg
~2
30
75 mg
~4
45
112.5 mg
~5.5
60
150 mg
~7.5
75
187.5 mg
~9.5
90
225 mg
~11.25
105
262.5 mg
~13
120
300 mg
~15
135
337.5 mg
~17
150
375 mg
~18.75
These are approximate dose and vials used. Please
check your calculations.
New research
 Recent research revealed that
– intravenous administration of life-saving Dantrolene can occur
significantly faster by warming the diluent used in mixing
– Thirty seconds or more can be shaved off the process which
normally take at least two minutes
EVERY SECOND COUNTS WHEN TREATING A
PATIENT WITH MALIGNANT HYPERTHERMIA
This research indicates that it is possible to administer Dantrolene
faster, therefore increasing the chances of a successful patient
outcome.
Journal of the American Association of Nurse Anesthetist
April 2007
Medication Nurse (3)
 Brings crash cart into room
 Mix and administer drugs as needed:
– Sodium bicarbonate to correct metabolic acidosis
– IV glucose, insulin and calcium chloride to treat
hyperkalemia
– Antiarrhythmic agents to treat arrhythmias (Do not use
calcium channel blockers)
– Diuretics to prevent rhabdomyolysis
 Lasix, mannitol and IV NS to maintain urine output of 1-2
ml/kg/hr
Cooling Nurse (4)
 Obtains cooled IV solutions and ice
 Monitor patient’s temperature
 Cools the patient by :
–
–
–
–
–
–
–
Use of hypothermia blanket
Cooling room
Placing ice packs around patient
IV refrigerated solutions
Cold lavage through NG
Insert 3-way foley and irrigate with cool saline
If patient has open abdominal or thoracic cavity give scrub sterile
refrigerated saline for surgeon to use in cavity
STOP COOLING WHEN PATIENT’S TEMP IS 38° C (100° F) TO
PREVENT HYPOTHERMIA
Additional Help
 Help cooling nurse get ice from cafeteria
and cooled saline from anesthesia fridge
 Help make ice packs
 Bring other supplies as needed
 Run labs
 Limit excessive traffic in room
www.nursetoons.com
Post - Op
 MH is most likely to occur in the OR, however, it
can also occur in PACU within the first hour and
up to 24 hours post-op.
 MH may recur within hours of the initial episode
and temperature fluctuations may continue for
several days.
 Dantrolene should be continued at 1 mg/kg every
4-6 hours for 48 hours in the ICU to prevent
reappearance of symptoms.
Documentation
Documentation should include:
 All medications and times given
 Labs drawn and times
 Cooling methods used on patients
 Vitals including temp.
 All personal involved
 All procedures completed (foley, NG, IV’s)
Legalities
 Perioperative nurses should be aware of the
legal considerations of MH. Lawsuits have
been decided for the plaintiff when:
– Risk factors were not identified preoperatively
– Body temperature not monitored continuously
– Failure to recognize signs and symptoms of MH
– Failure to institute prompt and appropriate
treatment
In Conclusion:
EVERY SECOND COUNTS WHEN TREATING A PATIENT
WITH MALIGNANT HYPERTHERMIA
A malignant hyperthermia event is life-altering and can be deadly. But,
with proper preparation, training, and teamwork a MH crisis can be
managed without loss of life or serious adverse consequences.
The MH Association of the US (MHAUS), maintains a 24-hour hot line that
is staffed by anesthesiologists who are available to help those dealing
with a MH event. There is a 1-800 number posted on all phones in the
OR rooms, PACU and stage II.
References
 Malignant hyperthermia-the perioperative nurse’s role.
Ruth Hommertzheim, RN & Elaine Steinke, RN. AORN
January 2006 pg 151
 Standards, Recommended Practices, and Guidelines.
AORN, Inc. 2007 Ed. Pg 219-227.
 Journal of the American Association of Nurse Anesthetist
April 2007 Pg. 101-106
 Additional information also available on Malignant
Hyperthermia carts and the Malignant Hyperthermia
Association web site : www.mhaus.org