Transcript Objectives - Silver Cross Emergency Medical Services System

Erika Ball, RN, BSN
* Objectives:
* Understand the
physiology of
hypothermia
* EMS considerations for
the hypothermic
patient
* Mechanisms of heat
loss
Bledsoe, 2013.
* Clinical indications of
hypothermia
* Degrees of
hypothermia
* Treatment and
rewarming
* Other considerations in
hypothermia
* Temperature regulation:
* Happens in the hypothalamus
* The hypothalamus is the body’s
“thermostat”
* The body has thermo sensors in the skin
the mucosa, and in certain deeper
structures in the body
* The hypothalamus works as a regulator for
shivering and sweating, depending on the
environmental stimulus (excessive cold or
heat).
Bledsoe, 2013.
*There are two rates the temperature
regulation system effects:
*Basal Rate- the normal resting rate
for the CORE of the body (deep
internal temperature)
*Metabolic Rate- reactive
adjustment to the environment to
maintain a continual core
temperature
Bledsoe, 2013.
*Normal body temperature is 98.6
o
o
F or 37 C
*Hypothermia definition:
*Decrease (unintentionally) in CORE
temperature greater than 3.5 degrees
from the basal temperature
Bledsoe, 2013.
*
*Conduction
*Convection
*Radiation
*Evaporation
*Respiration
Bledsoe, 2013.
*Conduction:
*Direct contact with a cooler object
*Heat loss happens in the direction of the
high temperature to the low
temperature
Bledsoe, 2013.
*Convection:
*Air temperature causes heat loss
*Radiation:
* Infrared rays cause heat loss
* Infrared heat loss is always happening until
temperatures reach molecular standstill (called
absolute zero)
Bledsoe, 2013.
*Evaporation:
* Water evaporation causes heat loss
* This phenomenon can happen from the skin or
water evaporating in the air as we breathe
Bledsoe, 2013.
*Respiration:
* A combination of convection, radiation, and
evaporation occurs during the respiratory
process, causing further heat loss
Bledsoe, 2013.
*
* Body composition
* Thermoregulatory response (shivering ability/ heat
production)
* Clothing/insulation
* Water or air temp and conditions
* Medications or intoxication
* Age
* Health
* Extended exposure
* Associated Injury
Bledsoe, 2013.
* Mechanisms for heat conservation:
* Vasoconstriction of peripheral blood vessels
* Skin becomes pale and cool
* Goose bumps (unknown why this truly happens,
some speculate this is an evolutionary remnant*)
Bledsoe, 2013.
* Hypothermia results from:
*Insufficient heating mechanisms
*Severe cold stress (exertion with cold
exposure)
Bledsoe, 2013.
* Degrees of hypothermia:
* MILD: 95- 89.6 F
* Thermoregulatory mechanisms are still operating
fully
* MODERATE: 89.6- 82.4 F
* Effectiveness of thermoregulatory mechanisms
diminish until they fail
* SEVERE: Lower than 82.4 F
* Loss of consciousness
* No more shivering
* pH balance disrupted
* Susceptible to V Fib or asystole
Bledsoe, 2013.
*
Bledsoe, 2013.
*
1.Short-term
(Cold shock response)
2. Midterm
(Loss of performance)
3. Long-term
(development of hypothermia)
Bledsoe, 2013.
*
Bledsoe, 2013.
*
* Generally in water
* First 3-4 minutes of immersion (with head out of
the water)
* Peripheral vasoconstriction
* Panic
* Gasp reflex
* Hyperventilation
* Tachypnea
* Vagal cardiac arrest and subsequent drowning
(Polar bear plunge!!)
Bledsoe, 2013.
* IF they survive the cold-shock, this is the next 30
minutes of progression
*
Neuromuscular activity and loss of motor control
* If the neuromuscular mechanisms fail, individual
can not execute survival procedures (grabbing life
preserver) and individual will drown
*
Bledsoe, 2013.
* Development of hypothermia process
* Mild
* Moderate
* Severe
*
Bledsoe, 2013.
* Shivering
* Lethargy
* Lack of coordination
* Pale cool skin
* Early stages witness rise in BP, heart rate, and
respiration
*
Bledsoe, 2013.
* Shivering ceases
* Arrhythmias can occur
* Cardiac arrest
* Voluntary muscle control loss
* Hypotension
* Pulse and respirations become undetectable
*
Bledsoe, 2013.
* Initial treatment:
* Remove any wet clothing
* Stop cooling process with blankets and elements
* Keep patient in supine to prevent further
hypotension
* Handle patient gently (skin is fragile)
* Establish cardiac rhythm
*
Bledsoe, 2013.
* PR interval can become longer (1st degree
heart block)
* This progresses to a prolonged QRS and QT
* “J” waves, or Osborne waves, can occur under
a core temperature of 90 F
O
*
Bledsoe, 2013.
* J waves are most frequent in leads II and V6
* These waves become larger in size as the patient’s
core temperature decreases
*
Bledsoe, 2013.
*
Bledsoe, 2013.
* Active rewarming:
* Mild hypothermia- external methods
* Blankets
* Heat packs (in axilla and groin)
* Mild Hypothermia- internal rewarming
* Warm IV fluids
* If the patient is still shivering, rewarming should
occur quickly
*
Bledsoe, 2013.
* External:
* Warm blankets
* Heat packs (again, groin and axilla)
* Internal
* Warmed IV Fluid
* Warm, humidified oxygen
* Best done in the ER, where protocol exists for
slowly rewarming the patient
*
Bledsoe, 2013.
* EMS should use caution in rewarming the
patient due to peripheral reflex dilation
* Patient’s rewarming sometimes causes a
hypotension and can precipitate V Fib
* This is why warm packs in the groin and axilla
warm the core rather than the extremities
*
Bledsoe, 2013.
*
Bledsoe, 2013.
Please Review!
* DO NOT give any drugs to these patients!
* Assess the pulse for a full 30-45 seconds
* May attempt defibrillation x1
*
Bledsoe, 2013.
*
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*
* Morphine
* Binds with opioid receptors to produce narcotic
analgesia
* CNS depressant
* Causes peripheral vasodilation
* May be given in 5 mg increments for severe pain
(blood pressure permitting) for a dose of 5-10 mg
in hypothermia, at the discretion of the ECRN/
MD.
* Contraindications:
* Respiratory depression, shock, hypotension, known
sensitivity or allergy. Use with caution in bronchial
asthma, respiratory insufficiency, head trauma
Bledsoe, 2013.
* Thank you for your time and attention!
* The 2014 CE calendar will be available early in
December!
* We welcome your suggestions!
Bledsoe, 2013.
References
Bledsoe, B. 2013Prehospital management in the 21st
century.
Giesbrecht, G., 2013. Prehospital treatment of
hypothermia. Expedition Medicine.
Region VII Emergency Medical Service Systems
Standing Medical Orders, 2011
Bledsoe, 2013.