Download Wet, cold and injured

Wet, cold and injured
Mikael S Mikaelsson,
ED registrar Christchurch
We are the sum of our past
Overview
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A few general words
Hypothermia
Near Drowning
Avalanche survival
Questions
5 minute breather
Chris Hill
A warning
• Very little randomised
research
• Mostly anecdotal,
case series and
animal research
• “Truth” is derived from
consensus, the
application of basic
principles and maybe
a little common sense
Hypothermia
• Text book definition:
– a state in which the body's mechanism for
temperature regulation is overwhelmed in the
face of a cold stressor
• A shorter definition:
– when core temperature is lower then 35 C
History
• Immobility
• Age
– Young and Old at risk
• Increased heat loss;
– Cold, Wet, Wind
• Fatigue and starved
• Medical co
morbidities
• Drug effects
Mechanisms of Heat Loss
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Radiation
Conduction
Convection
Respiration
Evaporation
Prehospital a not so perfect world
• First keep your self
safe
• Avoid further
harm/stabilise
• Approximate and
adapt
– and as for the rest just
do the best you know
how
You can’t always get what you
want….
• Darkness
• Poor weather
• Lack of equipment
and resources
• Minimal back up
Prehospital
• Goals in hypothermia
– To prevent further heat
loss, to start core
rewarming and to
avoid precipitating
malignant cardiac
rhythms
Prehospital
• Specifically
– Gentle handling
– Move to a warm/protected
environment
– Warm and dry clothing
– If possible horizontal
extraction and transfer,
especially from cold water
– Start active core rewarming
– Be prepared for extended
CPR if significant
hypothermia
Not just an outdoor disease
• Patients presenting to
ED from home are
commonly
hypothermic.
• It’s generally a poor
prognostic sign as
often secondary to
extended immobility
and underlying
disease
Cold, Colder, Coldest
• Hypothermia is
subclassified into
(core temperature):
– Mild
• 32-35 C
– Moderate
• 28-32 C
– Severe
• below 28 C
Not every one is made the same
• We can give thanks
for that
Adriana Iliescu
Mild hypothermia
• Patients are generally are stable
haemodynamically and able to
compensate for the symptoms
• 34 C - 35 C
– most people shiver vigorously
• Below 34 C,
– altered judgment, amnesia, and
dysarthria. Respiratory rate may
increase.
• At approximately 33 C
– ataxia and apathy may be seen
• The following may also be observed:
– hyperventilation, tachypnea,
tachycardia, and cold diuresis as renal
concentrating ability is compromised
Moderate
• The body starts to shut down and compensatory
mechanisms fail
• Most patients with temperatures of 32 C or
lower present in stupor.
• At 30 C, patients develop a higher risk for
arrhythmias.
– The pulse slows and Atrial as well as Ventricular
rythms are seen. A J wave starts to be seen.
• Between 28 C and 30 C, pupils can become
markedly dilated and minimally responsive to
light.
• Some patients have paradoxical undressing
Severe
• < 28 C, the body becomes
very susceptible to VF
• <27 º C, 83% of patients are
comatose.
• Can appear dead
• Pulmonary oedema,
depressed cardiac output,
oliguria, coma, hypotension,
rigidity, apnoea,
pulselessness, areflexia,
unresponsiveness, fixed
pupils, and decreased or
absent activity on EEG
At Hospital
• Assess ABC
• Measure core
temperature
• Monitor
• Assess cardiac rhythm
• Assess patient for other
problems and injuries
• Don’t forget the basics
Rhythm abnormalities
• Common in moderate
and severe
• Bradycardia
• Slowing of conduction
• J (Osborne) waves
• Atrial arrhythmias
• Ventricular arrhythmias
J waves (Osborne)
Best rewarming strategy?
• Disputed, but always start with the basics
of a warm dry shelter and clothing.
• For mildly hypothermic patients, pick any
gentle warming method that is practical
• For the profoundly hypothermic
– If stable warm fluids, warm air and warming
blankets
– If unstable or in resuscitation, invasive
warming
Invasive rewarming
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Peritoneal lavage
Bladder lavage
Thoracic lavage
Cardiopulmonary
bypass
Cardiac Arrest
• Optimal ratio of compression vs ventilation
unknown
• Defibrillation and medications have
minimal to no effect on a cold heart
• Give warm fluids to minimise rewarming
shock and to increase drug effect
• Bretylium may work on arrhythmia
• Warm patient to 33 C
• Have faith
Bretylium Tosylate
• Antidysrhythmic (Class
III)
• Can be used both
prophylactically and to
treat VT and VF in
hypothermia
• Initial dose 5mg/kg,
subsequent doses
10mg/kg
• Bretylium has been
discontinued by all
manufacturers
Mortality
• Survival in mild
hypothermia is
excellent
• Mortality in moderate
hypothermia 21%
• Mortality in severe
hypothermia 40%
• Very dependant on
comorbidities
The luckiest
• World record holders:
– 9º C - Lowest reported
survivor from
therapeutic exposure.
– 14.4 C – Lowest
reported infant survival
from accidental
exposure.
– 13.7º C – Lowest
reported adult survival
from accidental
exposure.
Dr Anna Bågenholm
No one is dead, unless warm and
dead or…..
• K >10?
• Core temp under
12 C?
• Obvious fatal injury
• Submersion >1hr?
• A chest that is so
frozen that CPR is
impossible
• Rescuers at risk
Paradoxical undress and burrowing
• 69 cases of death due to
lethal hypothermia
• 25% showed signs of
undress of partial or
complete undress
• All of those had moved
into an smaller space
Terminal burrowing
behaviour M. A. Rothschild,
Arch Kriminol. 1991 JanFeb;187(2):47-56
Submersion injury
Drowning
• NZ death toll 114 per
year on average
• 60% recreational
• NZ has one of the highest
drowning rates of any
developed nation
• It is consistently the third
highest cause of
unintentional death,
surpassed only by road
vehicle crashes and
accidental falls
Near Drowning
• Defined as survival
for 24hours after
submersion
• For every death 4
hospitalizations and
14 ED visits are due
to submersion injuries
Some arbitrary distinctions
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Warm >20
Cold <20
Very cold <5
Possibly some small
benefit of very cold water
for young children as
anecdotal stories of
paediatric survival with
extended submersion
• Adults in cold water
submersion, no increase
in survival
Not Hollywood
• Most people are
found submerged for
an unobserved period
of time and often
unclear cause
Prognosis
• The prognosis is directly related to the duration
and magnitude of hypoxia.
• The most significant impact on morbidity and
mortality occurs before the patient arrives at the
hospital.
• Poor survival is associated with the need for
continued cardiopulmonary resuscitation efforts
on arrival to the hospital.
– Of these patients, 35-60% die in the ED.
– Of the survivors, 60-100% have long-term neurologic
sequelae.
The good news
• If your patient is
awake with minimal
symptoms from lungs
on arrival to hospital
then they generally do
very well
Orlowski score
• Orlowski score has been found
to identify the likelihood of
neurologically intact survival.
• 2 items or less a 90%
• 3 items or more have only a
5%
• Age 3 years or older
• Submersion time of more than
5 minutes
• No resuscitative efforts for
more than 10 minutes after
rescue
• Comatose on admission to the
emergency department
• Arterial pH of less than 7.10
“benefits” of very cold water
• The neuroprotective
effects of cold-water
drowning are poorly
understood.
– Hypothermia profoundly
decreases the cerebral
metabolic rate.
– Neuroprotective effects
seem to occur only if the
hypothermia occurs at the
time of submersion and
only if very rapid cooling
occurs in water with a
temperature of less than
5 C.
Wim Hof, world record holder for
longest swim under ice
“Cold” water
• Thermal conduction of water is
25-30 times that of air.
• Physical exertion increases
heat loss up to 35-50%
• A significant risk of
hypothermia usually develops
in water temperatures less
than 25 C
• During immersion in very cold
water,
– hypothermic in approximately
30 minutes
– life-threatening in
approximately 60 minutes
Prehospital resuscitation
• Standard advanced life
support
• But remember
– Safety first, don’t be
another statistic
– Trauma, especially in
diving accidents
– First focus is ventilation
– Start ventilation in the
water if necessary
– Hi flow O2 if any pulmonary
concerns
Just a reminder
• Treat cold water
submersions gently
• Hypothermia is
common
• Arrhythmias at rescue
well known and have
a poor prognosis
In hospital
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CNS 2 to asphyxia
Trauma from event
Hypothermia
ARDS – even small
aspirations
problematic
• Observe for
pulmonary
complications
A few words…
• Salt vs fresh water
aspiration is an
academic distinction
• No benefit in
prophylactic
antibiotics
– (Unless they drowned
in a sewer pond)
• Never forget the Cspine
Avalanches
Simple in theory
• Get patients free fast
• Treat for
– Asphyxia
– Hypothermia
– Multi trauma
Dismal survival curve
Quick as they can..
• Discounting initial
trauma deaths,
survival is then
dependant on
– Being found quickly
– Being dug out
efficiently
– Initial resuscitation
• But best of all don’t
get caught in one
Just belabouring the point
• The impact of avalanche
transceivers on mortality
from avalanche accidents
– High Alt Med Biol. 2005
Spring;6(1):72-7
• 278 totally buried victims
• reduction in mortality from
68.0% to 53.8%
(p=0.011)
• reduction in median burial
time from 102 to 20 min
(p < 0.001)
Not all made the same
• 23:00,11th of March,
1984 a small fishing
vessel capsized 6km
off Iceland
• The air temperature
was -2 C, and the
sea a frigid 5-6 C
• Guðlaugur survived 6
hours swimming and
the 3 hour climb/walk
to safety
Guðlaugur_Friðþórsson
Determination!
Questions?
Be Safe