Accidental Hypothermia:
Cold, Dead, Both or Neither
Bill D. Hampton, DO, FACOEP
Emergency Physician
17 November 2016
Faculty Disclosures
Purpose: To discuss the pathophysiology, clinical presentation, and diagnosis of
accidental hypothermia and to give updated treatment recommendations
based on the best available evidence.
Conflicts of Interest: None.
Commercial Support: None.
Sponsorship: None.
Employer(s): Holy Family Memorial Medical Center, Manitowoc, Wisconsin
Lecture Outline
1.
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3.
4.
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6.
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8.
Terminology
Physiology: Heat Production & Loss
Acute vs. Chronic Hypothermia
Definitions:
Mild, Moderate, and Severe Hypothermia
Stage 1, Stage 2, Stage 3, Stage 4
Causes & Epidemiology
Organ Systems’ Response to Cold
Treatment
Cases, Summary, & Quiz
Terminology
Hypothermia is a core body temperature < 35°C
(95°F) due to any cause.
Primary hypothermia  exposure to cold, which
overwhelms the body’s compensatory
mechanisms to maintain physiologic temperature.
Secondary hypothermia  multiple causes (typically
metabolic), including sepsis, hypothyroidism,
burns, and hypothalamic disorders.
Poikilothermia is an inability to maintain one’s core
body temperature
Acute vs. Chronic
Hypothermia
The point at which your body
cannot overcome the cold any
longer and hypothermia begins.
x
Pathophysiology
Hypothermia
Heat loss exceeds body’s capacity to
generate or retain heat (insulation) leading
to a loss in core temperature
Heat loss occurs via four mechanisms:
Conduction (touch) 5%
• The transfer of heat
by direct physical
contact b/c temperature
gradient
• water is 25x greater
than air
Convection (wind chill) 15%
• The transfer of heat by the
movement of air / H20
Radiation (sunshine) 55%
• Heat transfer by particles
or waves (light).
Evaporation (sweating) 25%
• Conversion of a liquid to
the gaseous phase.
• Dominant cooling method
in hot conditions
Heat loss via Conduction
The transfer of heat by direct physical contact b/c
temperature gradient.
Normally only accounts for ~5% of total heat loss,
however…
Heat dissipation via conduction occurs
5 times faster in wet clothing
25 times faster in cold water
What about wind chill?
Wind Chill
• A measurement of the air temperature relative to convection (wind
speed), used as an indicator of discomfort / perceived temperature.
• Colder when high winds occur; warmer when low winds are present.
Cold Weather Acclimatization?
Acclimatization
A constellation of physiologic adaptations that appear
in a normal person as the result of repeated
exposures to temperature stress.
No evidence exists that there
is any significant physiologic
adaptation to the cold.
The discomfort of cold
can be reduced after long
periods of exposure.
Marx J, Hockberger R, Walls R. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 7th ed. Chap 138, “Accidental
Hypothermia,” New York, NY: Elsevier Health Sciences; 2009: 2236-2253.
Who gets hypothermia?
Epidemiology
Several die annually from accidental hypothermia.
2/3 are male.
About ½ are over age 49.
Majority?
– Urban setting due to environmental exposure
– Aggravated by homelessness, illicit drug use,
alcoholism, mental illness
Minority?
– Outdoor setting: hunters, swimmers, hikers, etc.
Hypothermia Epidemiology
http://activehistory.ca/2014/01/cold-comfort-firewood-ice-storms-and-hypothermia-in-canada/
How do we define the degree
of hypothermia?
Swiss Staging System
of Hypothermia
Mental Status
Alert
Alert
Drowsy
Unconscious
Unconscious
Core Body Temp
>35°C (>95°F)
32−35°C (89.6−95°F)
28−31.9°C (82.4−89.5°F)
24−27.9°C (75.2−82.3°F)
<24°C (<75.2°F)
Shivering?
Yes
Yes
No
No
No
Breathing?
Yes
Yes
Yes
Yes
No
Stage
HT 0
HT I
HT II
HT III
HT IV
Mild: 32 - 35°C (90 - 95°F)
Conscious: Stage I
LOC: Stage II
Moderate: 28 - 32°C (82Decreased
- 90°F)
Severe: < 28°C (< 82°F) Unconscious: Stage III
Cardiac Arrest: Stage IV
Brown DJA, Brugger H, “Accidental Hypothermia,” New England Journal of Medicine 2012;367:1930-8.
Circulation. 2005;112:IV-136-IV-138; originally published online November 28, 2005; doi: 10.1161/CIRCULATIONAHA.105.166566
What does hypothermia
present like?
Case #1 / 80-y/o ♂ NHR with AMS
CC: An 80-year-old man is brought in from a skilled
nursing facility with altered mental status.
VS: T = 34°C, HR 106, RR 28, BP 198/132, SaO2 85%
PE: The patient’s baseline mental status is unknown. He
has rales throughout and is obviously dyspneic. His
eyes are open. He moans, “Help me, help me” and
exhibits purposeful movements.
How would you most accurately describe this hypothermia?
Acute or Chronic?
Conscious
Stage I
Primary or Secondary?
 Conscious Unconscious Cardiac Arrest
Stage IV
Stage II
Stage III
Stage I Hypothermia
“Trying” Phase
32 - 35°C (90 - 95°F)
•
•
•
•
Excitation phase
Shivering, slurred speech, loss of coordination
Tachycardia,  Cardiac output
 Metabolic rate,  Heat production
Brown DJA, Brugger H, “Accidental Hypothermia,” New England Journal of Medicine 2012;367:1930-8.
Brown, DJA, Accidental Hypothermia, EM-RAP: Emergency Medicine Reviews and Perspectives, January 2014:14(1).
Case #2 / 30-y/o ♀ cross-country skier
CC: 30-year-old female who apparently got lost while
backcountry skiing, fortunately makes it to the roadside
before collapsing. It is unknown how long she is down
before being found by a passing motorist.
PE: The medics report she is breathing and has a pulse but is
slugishly responsive. They have an ETA of 15 minutes.
They have no thermometer available on their rig.
How would you most accurately describe this hypothermia?
Acute or Chronic?
Conscious
Stage I
Primary or Secondary?
 Conscious Unconscious Cardiac Arrest
Stage IV
Stage II
Stage III
Stage II Hypothermia
“Sighing” Phase (82°-90°F)
28 - 32°C (82 - 90°F)
• Adynamic phase
•  Respiratory rate,  Heart rate,
•  Metabolic rate, ↓ Cardiac output
• Loss of shivering
• Somnolence
Brown DJA, Brugger H, “Accidental Hypothermia,” New England Journal of Medicine 2012;367:1930-8.
Brown, DJA, Accidental Hypothermia, EM-RAP: Emergency Medicine Reviews and Perspectives, January 2014:14(1).
Case #3 / 50-y/o homeless etOH ♂
CC: On a busy, chilly Friday in late November, a John Doe
appearing to be in his 50’s is brought in by Good Samaritans after
being “found down” and apparently intoxicated.
PE: He has a slow pulse, is cold to touch, and unresponsive.
ED: The nurse places a Foley catheter and reports that his
temperature is 28°C (88°F). The cardiac monitor shows atrial
fibrillation with a slow ventricular response.
How would you most accurately describe this hypothermia?
Acute or Chronic?
Conscious
Stage I
Primary or Secondary?
 Conscious Unconscious Cardiac Arrest
Stage IV
Stage II
Stage III
Stage III Hypothermia
“Dying” Phase (< 82°F)
< 28°C (< 82°F)
•
•
•
•
•
Complete shutdown
Coma (limited to no cranial nerve reflexes)
Severe arrhythmias (A-fib, V-tach, V-fib, asystole)
The body no longer actively produces heat
Active re-warming is essential
Brown DJA, Brugger H, “Accidental Hypothermia,” New England Journal of Medicine 2012;367:1930-8.
Brown, DJA, Accidental Hypothermia, EM-RAP: Emergency Medicine Reviews and Perspectives, January 2014:14(1).
Case #4 / 57-y/o ♂ found floating in water
8:07 a.m. A 57-y/o ♂ is found adrift at sea at 8:07 a.m. Seawater
temperature is 12°C (54°F).
8:28 a.m. EMS confirms asystole. No signs of trauma.
8:51 a.m. He arrives at the ED pulseless and apneic, with fixed and
dilated pupils and a rectal temp of 22°C (72°F).
9:21 a.m. He is intubated, CPR is continued, and his repeat temp is
now 22.8°C (73°F). His downtime is almost 90 minutes.
9:24 a.m. “Gasping” respiratory effort is noted but still no pulse.
9:55 a.m. CPB is started. Shortly thereafter, the previous asystole
now becomes slow ventricular fibrillation.
10:22 a.m. V-fib spontaneously converts to NSR. Rectal temp is
now 26.7°C (80°F). Limb movement is then noted, his pupils
normalize & become reactive, and spontaneous respiratory effort
becomes adequate.
Case #4 / 57-y/o ♂ found floating in water
1:25 p.m. CPB is discontinued as he continues to show
hemodynamic stability.
Hospital Day #32 After neurological rehabilitation, he is discharged
to home, ambulatory, with no neurologic deficits.
How would you most accurately describe this hypothermia?
Conscious
Stage I
Unconscious
Stage III
 Conscious
Stage II
Cardiac Arrest
Stage IV
Sawamoto K, Tanno, K, et. al., “Successful treatment of severe accidental hypothermia with cardiac arrest for a long time using
cardiopulmonary bypass - report of a case,” International Journal of Emergency Medicine, 2012, 5:9:1-4.
Cardiac Arrest - HT IV
< 24°C (< 75°F)
•
•
•
•
•
Patient is cold and dead
Glasgow Coma Scale 3
Apnea
They may be rigid (e.g.: rigor mortis)
Transport to ECMO / CPB Center is essential!
Brown DJA, Brugger H, “Accidental Hypothermia,” New England Journal of Medicine 2012;367:1930-8.
Brown, DJA, Accidental Hypothermia, EM-RAP: Emergency Medicine Reviews and Perspectives, January 2014:14(1).
Why is categorizing the
hypothermia important?
The clinical presentation of the
hypothermia  the rewarming modality
Conscious
 Conscious
Unconscious
Cardiac
Arrest
CPB / ECMO
rewarming
Brown DJA, Brugger H, “Accidental Hypothermia,” New England Journal of Medicine 2012;367:1930-8.
HT Stage 1
Conscious
Passive External
Rewarming
• Remove wet clothing,
insulate, and protect from
the environment.
• Provides insulation for
patient’s own body heat
• Rate = 0.5°C - 2.0°C/hour
• Only effective if shivering
preserved
Becker, Joseph U., MD, Best Practices: Treating Hypothermic Patients. Medscape.com,
28 December 2012, last accessed 2 April 2013.
HT Stage 2
 Conscious
Active External
Rewarming
• External heat applied to skin
• Assumes intact circulation
• Heating blankets, forced air
blankets, radiant warmers,
heating pads, warm bath
immersion, etc.
• Keep warming temps at 40
to 45°C (104 - 113°F)
• Rate = 1°C - 2.5°C/hour
Becker, Joseph U., MD, Best Practices: Treating Hypothermic Patients. Medscape.com,
28 December 2012, last accessed 2 April 2013.
HT Stage 3
Unconscious
Active Internal
Rewarming
• Internal warmed fluids to body cavities (bladder, stomach,
thoracic cavity, peritoneum, mediastinum)
• Warming the exterior of internal organs
• Rate = variable (depending on method[s] used)
Non-invasive
Modalities
Invasive
Modalities
Becker, Joseph U., MD, Best Practices: Treating Hypothermic Patients. Medscape.com,
28 December 2012, last accessed 2 April 2013.
Active Internal Rewarming
Non-invasive Modalities
Invasive Modalities
• Warmed IV fluids
• Bladder lavage
• Humidified air via ETT
• Gastric lavage
X• Thoracic
X X lavage
XX
X• Peritoneal
X X Xlavage
X
Warmed inspired gases, warmed IV fluids, and bladder/gastric
lavage can raise the temperature by about 3°C/hour.
Is there a method to warm the patient more quickly?
Mulcahy, Allison R., MD; Watts, Melanie R., MD, “Accidental Hypothermia: An EvidenceBased Approach.” Emergency Medicine Practice. Vol. 11, No. 1, January 2001, 1-26.
Extracorporeal Rewarming
Warming the patient’s blood outside of the body.
• Hemodialysis
Extracorporeal Rewarming
X• Hemodialysis
XXXX
• Continuous arteriovenous
Xrewarming
XXX
XXXX
(CAVR)
Rate = 2 - 3C / hour
Rate = 3 - 4C / hour
XXXXXXXX
Rate = 2 - 3C / hour
• Extracorporeal membrane
oxygenation (ECMO)
Rate = 7C / hour
• Continuous venovenous
rewarming (CVVR)
• Cardiopulmonary bypass (CPB)
Rate = 18C / hour
Becker, Joseph U., MD, Best Practices: Treating Hypothermic Patients. Medscape.com, 28 December 2012, last
accessed 2 April 2013.
Mulcahy, Allison R., MD; Watts, Melanie R., MD, “Accidental Hypothermia: An Evidence-Based Approach.” Emergency
Medicine Practice. Vol. 11, No. 1, January 2001, 1-26.
Cardiopulmonary Bypass
Rate: about 18°C/hour
Core Concepts
Treatment Modalities
Conscious
HT I
 Conscious Unconscious Cardiac Arrest
HT IV
HT II
HT III
(32°-35°C) (28°-32°C)
Passive
External
Rewarming
Insulation
Active
External
Rewarming
(< 28°C)
(< 24°C)
Active
Internal
Rewarming
Extracoporeal
Rewarming
Non-invasive
Heating pads
Forced air blankets Invasive
ECMO
CPB
Burke, David, “SSAR key in ‘miracle’ rescue Found ‘unresponsive’ near Elfin Lakes, patient revived after four hours of CPR,”
http://www.squamishchief.com /, April 9, 2014. Last accessed 17 September 2014.
Coppin, Rhiannon “Christine 'Tink' Newman's medical miracle: Revived from near death,” CBC News, April 07, 2014.
http://www.lifesaving.com/node/3286. Last accessed 17 September 2014.
http://www.deepsnowsafety.org/index.php/. Last accessed 17 September 2014.
McElroy, Justin, “Once you commit to CPR, you have to stick with it: The story of Christine Newman’s survival,” Global News, 6 April
2014.
Schneider, Katie, “Calgary-area entrepreneur Christine Newman recovering after miracle survival story in Whistler, B.C.” Calgary
Sun, April 06, 2014.
“Tink Newman Recovering After Medical Miracle,” The Huffington Post B.C., 04/07/2014.
http://www.huffingtonpost.ca/2014/04/07/tink-newman_n_5104979.html. Last accessed 17 September 2014.
Hypothermia duration ~ 7 hours
Core temp for EMS = 18°C (64°F)
Total duration of CPR > 4 hours
Isolated Hypothermia 
cardiac death
Brain is relatively protected
by the extreme cold, however
Complications of
hypothermia treatment?
Complications of Re-warming
Afterdrop Phenomenon
Peripheral
Vasoconstriction
Active External
Rewarming
Warming of
Extremities
Peripheral
Vasodilation
Cold blood
returns to core
Core temp drops
Becker, Joseph U., MD, Best Practices: Treating Hypothermic Patients. Medscape.com,
28 December 2012, last accessed 2 April 2013.
Afterdrop Phenomenon
Clinical Significance?
Afterdrop is real. Multiple physiology studies have
demonstrated it in vivo.
It is clinically irrelevant, however.
Re-warming hypothermic patients causes a core
temperature drop of ¼ to ¾ of a degree C.
This is (obviously) not clinically significant
Re-warm your hypothermic patients aggressively.
Becker, Joseph U., MD, Best Practices: Treating Hypothermic Patients. Medscape.com, 28 December 2012, last accessed 2 April
2013.
Brown, DJA, Accidental Hypothermia, EM-RAP: Emergency Medicine Reviews and Perspectives, January 2014:14(1).
“Complications” of Re-warming
Rescue Collapse
Rescue collapse occurs due to cardiac instability,
which is itself caused by the hypothermia.
It is predictable in core temperatures ≤ 28°C.
Re-warming hypothermic patients does not cause
rescue collapse.
Expect it to happen in the severely hypothermic
patient, and initiate CPR while simultaneously
arranging ECMO / CPB.
Brown DJA, Brugger H, “Accidental Hypothermia,” New England Journal of Medicine 2012;367:1930-8.
Brown, DJA, Accidental Hypothermia, EM-RAP: Emergency Medicine Reviews and Perspectives, January 2014:14(1).
Patient Management
in Hypothermia
Is your patient?
Cold and Alive
Patients with Vital Signs
Or are they?
Cold and Dead
Patients without Vital Signs
Is your patient?
Cold and Alive
Conscious
Stage I
 Consciousness
Stage II
Or are they possibly?
Cold and Dead
Unconscious
Stage III
Cardiac Arrest
Stage IV
Cold and Alive
Impaired Level of Consciousness?
Conscious
Stage I
NO
• Begin to re-warm on site
(if trauma also present)
• Warm, sweet beverages
• Encourage active movm’t.
Cold and Alive
Impaired Level of Consciousness?
 Consciousness
Stage II
Unstable?
YES
• SBP ≤ 90mm Hg
• Ventricular dysrhythmia
• Core temp < 28°C
ECMO / CPB Center
YES
Cold and Alive
Impaired Level of Consciousness?
 Consciousness
Stage II
NOT Unstable
YES
• Go to closest hospital
• Handle patient gently
• Prevent further heat loss
• Active external warming
• Non-invasive internal rewarming
YES
• Manage airway as needed
Cold and Dead
Severe (< 28°C)
Stage III
< 24°C
Stage IV
How do you know if the
patient is truly dead?
“They’re not dead until they
are warm and dead.”
Warm and Dead
Warm adults to 32°C (90° F) before pronouncing.
Warm children to 35°C (95° F) before pronouncing.
Signs of Irreversible Death
A potassium (K+) level > 12 mEq/L
Nose
Obvious
A rigid,
or mouth
non-compressible
lethal
occluded
injurieswith
is a ice
Frozen
or clotted
a sign are
that
Ammonia
(NH3) blood
> 250 is
mmol/L
(preventing
thorax is
reason
also
ventilation)
atoreason
ceaseortoastop
core
the
resuscitation
be stopped.
both
reasons to should
stop resuscitation
a hypothermic
temp
resuscitative
< 15°C
resuscitation.
(59°
efforts.
F).
regardless of core temperature.
Historical Clues to Irreversible Death
Historical Clues to Irreversible Death
Historical Clues to Irreversible Death
Hypothermia: Children vs. Adults
• Infant BSA 3x adult
• Child BSA 2x adult
• The large surface-area to
body-mass ratio results in
quicker heat loss for infants
and children
• Faster cooling  cerebral
protection from hypoxia-even in submersion injury
Blackburn ST, Maternal, Fetal, & Neonatal Physiology: A Clinical Perspective, 3e (Maternal Fetal and Neonatal Physiology),
Saunders; 3rd edition (March 14, 2007): 800 pgs.
Historical Clues to Irreversible Death
Historical Clues to Irreversible Death
Avalanche Burial
< 35 min. burial  NOT hypothermia
> 35 min. burial  possibly hypothermia
In hypothermia, these signs  death!
Cold and Dead
Severe (< 28°C)
Stage III
< 24°C
Hx or Signs
Stage IV of irreversible
death?
YES!
Cold and Dead
Severe (< 28°C)
Stage III
< 24°C
Hx or Signs
Stage IV of irreversible
death?
NO
• Immediate CPR
• Prevent further
heat loss
• Manage airway
• 1mg Epi x 3 doses
• Defibrillate PRN
Cold and Dead
Severe (< 28°C)
Stage III
< 24°C
Stage IV
Anticipate and expect
Rescue Collapse
ECMO / CPB Center
• Continuous CPR
• Intubate & warm O2
• Warm IVF (38-42°C)
• Stop addtl. heat loss
• Look for occult trauma
Hypothermia patients with cardiac arrest who
are treated at an ECMO/CPB Center have a
50% survival rate.
Hypothermia patients with cardiac arrest
who are treated without ECMO / CPB have a
10% survival rate.
Brown DJA, Brugger H, “Accidental Hypothermia,” New England Journal of Medicine 2012;367:1930-8.
Brown, DJA, Accidental Hypothermia, EM-RAP: Emergency Medicine Reviews and Perspectives, January 2014:14(1).
A
B
CD
E
Airway
Breathing
Circulation
D.O.N.T.
Environment
Exposure
Endotracheal intubation
does not cause or increase
the likelihood of ventricular
dysrhythmias.
All patients with AMS and
hypothermia should be
intubated for airway
protection and re-warming.
Airway
Danzl, DF, Pozos RS, Auerbach PS, et al. Multicenter hypothermia survey. Annals of Emergency Medicine. September
1987;16(9):1042-1055.
Breathing
Warmed humidified oxygen (38-40° C) via ETT or
nasal canula (depending on patient).
Remember, CAB resuscitation—CPR is imperative!
Duration of CPR is NOT predictive of patient
outcome in hypothermia.
Mulcahy, Allison R., MD; Watts, Melanie R., MD, “Accidental Hypothermia: An Evidence-Based Approach.” Emergency
Medicine Practice. Vol. 11, No. 1, January 2001, 1-26.
CPR provides ~50% normal cerebral blood flow.
At temperatures < 28°C, neurologic outcome may be
independent of CPR duration.
Brown, DA, “Accidental Hypothermia Teaching Slides,” http://drdougbrown.ca/. Last accessed 9/15/14.
Circulation
Bradycardia, A-fib, and/or mild hypotension (SBP > 90mm) are
normal in hypothermia and should resolve with warming.
With very low core temps (< 28°C), anticipate and expect: cardiac
arrest, ventricular dysrhythmias, and severe hypotension.
Defibrillation, pacing, and traditional ACLS medications are likely
to be unsuccessful at temps < 30°C (86° F).
Hypothermia  profound vasoconstriction & cardiac irritability;
Vaspopressors have  dysrhythmia risk with  benefit.
The best therapy for cardiac arrest  hypothermia is ECMO / CPB
Brown, DA, “Accidental Hypothermia Teaching Slides,” http://drdougbrown.ca/. Last accessed 9/15/14.
Cardiovascular Hypothermia
In hypothermia, the patient will usually be
tachycardic until the temperature drops
below 29°C (84° F).
< 25°C: Asystole / V-fib are common
Mulcahy, Allison R., MD; Watts, Melanie R., MD, “Accidental Hypothermia: An Evidence-Based Approach.” Emergency
Medicine Practice. Vol. 11, No. 1, January 2001, 1-26.
Osborn or J-wave
• The Osborn J-wave is often noted when the temperature
declines to < 32°C (90° F).
• The amplitude of the J wave is proportional to the degree of
hypothermia.
• It is thought to result from abnormal depolarization and
repolarization of ventricular tissue.
Becker, Joseph U., MD, Best Practices: Treating Hypothermic Patients. Medscape.com, 28 December 2012,
last accessed 2 April 2013.
Osborne or J-wave
• Best seen in leads aVL, aVF, and the lateral chest leads.
• Presence suggests (but is not pathognomonic for) hypothermia.
Becker, Joseph U., MD, Best Practices: Treating Hypothermic Patients. Medscape.com, 28 December 2012,
last accessed 2 April 2013.
Disability /
D.O.N.T.
Dextrose should be assessed in all patients with AMS.
Hyperglycemia in acute hypothermia
Hypoglycemia in chronic or secondary hypothermia
Ethanol is metabolized more slowly in hypothermia.
Mulcahy, Allison R., MD; Watts, Melanie R., MD, “Accidental Hypothermia: An Evidence-Based Approach.” Emergency
Medicine Practice. Vol. 11, No. 1, January 2001, 1-26.
Exposure
Remove wet clothing and insulate immediately.
Children are more vulnerable to hypothermia due to higher
surface area to body mass ratio.
Assume injury in the hypothermic patient. Immobilize and
image (x-ray and CT) liberally.
Remember good trauma care; cover and warm your patient
after the secondary survey.
Marx J, Hockberger R, Walls R. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 7th ed. Chap 138, “Accidental
Hypothermia,” New York, NY: Elsevier Health Sciences; 2009: 2236-2253.
How do we re-assess
temperature in hypothermia?
Case #5 / 2 ½-y/o ♀ fell into a creek
Time zero: On June 10, 1986, a 2 ½-y/o ♀ playing near a creek in
Salt Lake City, Utah, falls into the water. A sibling sees this and
immediately notifies their mother.
8 minutes: EMS arrives on scene. The child cannot be found.
62 minutes: The resevoir outflow is reduced, and the child’s arm can
be seen approximately 20 yards from where she initially fell in.
64 minutes: She is pulled from the water, where she had been
wedged against the upstream side of a rock. She is blue, apneic,
asystolic, with fixed & dilated pupils. Water temp is 5°C.
65 minutes: CPR is initiated, and she is transferred to Primary
Children’s Medical Center, Salt Lake City.
70 minutes: Initial rectal temp is 22.4°C. She is intubated and
warmed via oxygen, IVF, and gastric lavage. Still in asystole.
Case #5 / 2 ½-y/o ♀ fell into a creek
175 minutes: She is taken to the OR, CPR is stopped, and extracorporeal re-warming is initiated. Her esophageal/rectal temp in
the OR measures 19°C.
185 minutes: Core temperature reaches 25°C, and the patient
gasps. Fine V-fib is noted on the cardiac monitor.
192 minutes: Coarse V-fib is now seen, which spontaneously
converts to NSR.
213 minutes: Core temperature is now 37°C. ECR is discontinued,
and she is transferred to the ICU.
Next 6 days: Intubated and ventilated due to severe non-cardiogenic
pulmonary edema.
2 weeks: Responsive smile is noted. She appears to be blind,
however.
3 weeks: Whispers a few words.
Case #5 / 2 ½-y/o ♀ fell into a creek
4 weeks: Speaks in 4-word sentences and can sit up for 10 seconds.
7 weeks: Cortical blindness appears to resolve.
8 weeks: Receptive and expressive language skills are at the level
of a 3-year-old child. She is discharged to home. Fine motor skills
are appropriate, but she has a tremor.
1 year later: She is 3 ½-years-old and functioning at age level.
Her tremor has shown progressive improvement.
Bolte RG, Black PG, et. al., “The Use of Extracorporeal Rewarming in a Child Submerged for 66 minutes,” Journal of the American
Medical Association, 15 July 1988:260(3):377-379.
Giddy-up
Case #6 / 21-y/o ♂ stranded in blizzard
CC: 21-y/o ♂ brought by friends after being stranded
outside in a blizzard. Patient was seen by a snowplow
driver shortly after 3:00 a.m.
EMS: HR 42, RR 6, BP 97/66, SaO2 ??%
ED: On arrival the patient is dressed in t-shirt, jeans,
and tennis shoes with no socks. He was apparently
going to run out for supplies when his car slid off the
road and he was stranded for several hours. Gas ran
out about 6 hours ago.
What are your initial treatment priorities?
Case #6 / 21-y/o ♂ found in snowbank
• Remove wet clothing and cover with warm
blankets (active external re-warming)
• Perform procedures gently
• Assume injury and immobilize C-spine
Case #6 / 21-y/o ♂ found in snowbank
ED (cont): Patient is placed on a cardiac monitor.
PE: Bradycardia rate of 42 bpm is seen with a widened QRS,
but no pulse can be palpated. Slow, shallow breaths are
seen. Nursing staff reports to you a temporal thermometer
reading of 88 F. SaO2 cannot capture a waveform.
Which of the following are TRUE statements?
1. Atropine should be given to treat the bradycardia
and/or external pacing should be attempted.
2. CPR should be started immediately.
3. Supplemental O2 is unnecessary because he is breathing
4. Temporal thermometry gives a true core temp.
1. Atropine / external pacing should be tried for the bradycardia.
FALSE. Bradycardia is due to d spontaneous depolarization of
pacemaker cells. Atropine will be ineffective. Cold
myocardium is irritable, and external pacing may convert an
organized rhythm into V-fib.
2. CPR should be started immediately.
TRUE. Rescue collapse should be anticipated in this unconscious
patient, CPR will perfuse the brain until ECMO / CPB is available.
3. Additional O2 is unnecessary because he is breathing.
FALSE. Hypothermic patients will benefit from humidified /
warmed O2. It is a form of non-invasive active re-warming.
4. Temporal thermometry gives a true core temp reading.
FALSE. Temporal thermometry “should not be used…in the
setting of suspected hypothermia.” Rectal, Esophageal, or a
Foley catheter thermister is recommended.
Marx J, Hockberger R, Walls R. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 7th ed. Chap 138, “Accidental
Hypothermia,” New York, NY: Elsevier Health Sciences; 2009: 2236-2253.
Case #6 / 21-y/o ♂ found in snowbank
PE: HR still shows wide QRS at rate in 40s. Patient is being
administered humidified warmed air. IV access cannot be
established and IO is unavailable to you. A rectal temp
shows a temperature of 28C (82 F). The SaO2 monitor
is still not reading.
Which of the following are TRUE statements?
4. A forced warm air device should NOT be used as this
patient requires more invasive active re-warming.
5. ACLS Medications should be given IM or
administered through the ET tube.
6. IV fluids are probably not necessary and should be
withheld until labs are available.
Case #6 / 21-y/o ♂ found in snowbank
4. Forced warm-air device should not be used.
FALSE. All available re-warming modalities should be started,
especially non-invasive ones such as forced warm air.
5. ACLS medications either IM or ET.
FALSE. ACLS meds will likely be ineffective at core temperatures
< 30 C and will not circulate due to  GI motility and peripheral
vasoconstriction. Re-warm the patient  cardiac recovery.
6. IV fluids are probably unnecessary.
FALSE. Hypothermic patients are usually dehydrated due to cold
diuresis. Rapid volume expansion is a critical action; anticipate
2 to 5 Liters in severe hypothermia. D5NS or 0.9NS are
preferred. LR should be avoided b/c cold liver ineffectively
metabolizes lactate.
Marx J, Hockberger R, Walls R. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 7th ed. Chap 138, “Accidental
Hypothermia,” New York, NY: Elsevier Health Sciences; 2009: 2236-2253.
Case #6 / 21-y/o ♂ found in snowbank
PE: IV access is finally established, but no fluid warmer is
available. Cardiology stops by and inquires whether you
want him to float a transvenous pacer in case of V-fib.
General surgery also pokes her head in and asks if you
want her to pull out a DPL kit to lavage the peritoneum or
place a pair of chest tubes in the thorax.
Which of the following are TRUE statements?
7. Room temp IV fluids are the only option if no fluid warmer.
8. A transvenous pacer is a good idea as external
pacing is likely to be ineffective.
9. Peritoneal lavage is preferred to thoracic lavage.
Case #6 / 21-y/o ♂ found in snowbank
7. Room temp IV fluids are only option if no fluid warmer.
FALSE. Microwave 1 Liter of 0.9 NS on high for 2 minutes.
Shake bag to distribute warmth. Test on wrist before infusing.
8. Transvenous pacing can/should be used.
FALSE. Transvenous intracardiac pacing is extremely hazardous
for hypothermia-induced dysrhythmias. Any organized rhythm
should be assumed sufficient for perfusion and not manipulated.
9. Peritoneal lavage is preferred to thoracic lavage.
FALSE. Peritoneal & thoracic lavage rewarming should NOT be
routinely selected for stable patients. Transport to ECMO /
CPB Center is the priority for HT III and HT IV patients; do not
delay for unnecessary procedures (thoracic / peritoneal lavage).
Marx J, Hockberger R, Walls R. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 7th ed. Chap 138, “Accidental
Hypothermia,” New York, NY: Elsevier Health Sciences; 2009: 2236-2253.
Case #6 / 21-y/o ♂ found in snowbank
ED (cont): Microwaved IV fluids, humidified warmed air, forced
warm air blankets, and continuous bladder & gastric
irrigation are being done.
PE (cont): Core temp by bladder thermometer now reads
32C (90 F). Heart rate is sinus brady in the 60s; BP is
90/50, and the patient is becoming more responsive. Pupils
remain sluggishly reactive to light at 5mm bilaterally.
Which of the following are TRUE statements?
10. Given his initial temperature of 28 C, this
unresponsiveness will likely continue for several hours.
11. If the patient is intoxicated with alcohol, his hypothermiainduced cold diuresis will help him become sober faster.
12. The patient should be left hypothermic as it has
protective effects for head injury, cardiac arrest, and shock.
Case #6 / 21-y/o ♂ found in snowbank
10. The initial temp is a predictor of ongoing unresponsiveness.
FALSE. A patient warmed to 32C with ongoing AMS needs
further workup as to why: intoxication, trauma, infection, etc.
11. Hypothermia-induced diuresis speeds etOH elimination.
FALSE. Ethanol is metabolized at a slower rate in hypothermia.
It is the most common cause of heat loss in urban settings.
12. Leave the patient hypothermic for trauma, cardiac, or shock.
FALSE. While therapeutic hypothermia is used in cardiac arrest
with ROSC, hypothermia is associated with poor outcomes in
trauma patients. The optimal rate of re-warming (delayed vs.
rapid) has not been determined.
Marx J, Hockberger R, Walls R. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 7th ed. Chap 138, “Accidental
Hypothermia,” New York, NY: Elsevier Health Sciences; 2009: 2236-2253.
Summary – Hypothermia
Hypothermia Summary
Accidental hypothermia can occur in mild climates, and even indoors,
especially among high-risk populations such as the elderly, the
homeless, or in the setting of acute intoxication or trauma.
Standard thermometers do not read below 34°C (93.2°F). Diagnosis of
hypothermia must be taken with a rectal, bladder, or esophageal
probe) and requires a low-reading thermometer.
The initial focus in a very cold patient is to prevent additional heat loss
by removing wet clothing and insulating the patient from further
exposure.
Active external rewarming, such as a forced air re-warming device,
warmed humidified air, and warm IV fluids is sufficient for most
hypothermic patients.
If a hypothermic patient has been re-warmed to > 32°C (89.6°F) but
continues to have an altered mental status, look for other underlying
etiologies such as trauma, infection, or toxic ingestion.
Hypothermia Summary
If a patient is resistant to re-warming techniques, consider other causes
such as hypoglycemia, infection, myxedema coma, or adrenal
insufficiency.
“A patient is not dead until they are warm and dead.” Continue
resuscitation in the adult patient to 32°C (90° F) or to 35C (95 F) in
children.
Resuscitation may be withheld only if the patient is frozen solid, there is
an ice-occluded airway, there is a clear “Do Not Resuscitate” order,
there are other obvious lethal injuries, or the patient had a history of
cardiopulmonary arrest prior to becoming hypothermic.
CPR duration does not predict neurologic outcome in the patient with
hypothermic arrest; continuous CPR is recommended with expedited
transfer to ECMO / CPB center.
If a patient in asystole or ventricular fibrillation does not respond to initial
vasoactive medication or defibrillation, hold further rounds and
actively re-warm the patient.
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