What would Grizzly Adams DO???? Hypothermia in the back 40

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What would Grizzly Adams DO????

• Hypothermia in the back 40!

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What we are going to talk about

• Hypothermia Pathophysiology
• Temperature measurement
• Hypothermia treatment
• Cold Injuries (frostbite)
• Prevention

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Hypothermia

• Definition of hypothermia
• Core temp below 35C or 95F
• Requires measurement of core temp

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Temperature Measurement

• CORE Temp
• Oral
• Rectal (4 cm)
• Axillary
• Esophageal
• Tympanic????

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A comment on Tympanic Thermometers

• Most units in the field are non contact
  thermometers.
• These are effected by facial cooling, ear
  infections, and ambient temperatures.
• Laboratory studies often use methods to eliminate
  these factors.
• These methods are not practical in the field.

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Incorrect Rectal Temperature Measurement
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Hypothermia Heat Loss

• Heat loss
• radiation - infrared loss (55-65)
• conduction - transfer by direct contact (15)
• convection - loss of surrounding heated air/water
  (15)
• evaporation - liquid to gas (15)

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Hypothermia Heat Loss
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Hypothermia physiology

• Thermoregulation
• Controlled by brain (Hypothalmus)
• Vasoconstriction
• squeezing of blood vessels in skin
• blood flow redirected away from surface
• hunting Response
• Increased muscle tone/shivering
• heat prod. increased 5Xlimited to a few hours

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Hypothermia risk factors

• Many risk factors, but most fall into one of
  three categories
• Decreased Heat production
• Increased Heat Loss
• Impaired Thermoregulation

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Hypothermia risk factors

• Immersion in water
• 25 to 30X increase in conductive loss
• Malnutrition, Dehydration
• Trauma (especially head injury)
• Alcohol and sedatives
• decrease shivering and awareness of cold
• Extremes of age (elderly, infants)
• Some diseases (diabetes, hypothyroidism

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Hypothermia stages

• Mild, Moderate, and Severe
• Most moderate and severe cases result from
• Cold water immersion
• Injury or illness in a cold environment
• Prolonged exposure with out adequate protective
  clothing
• Involve Alcohol or drug use.

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Hypothermia stages

• Mild hypothermia (34-35C / 93-95F)
• Maximum SHIVERING at 35C (95F)
• Cold, pale skin (vasoconstriction)
• Pulse and BP are normal or elevated
• Faster breathing
• Mild confusion, slurred speech, unsteady gait

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Hypothermia stages

• Moderate (30-34 C/86-93F) to severe hypothermia
  (lt/30C/86F)
• SHIVERING STOPS
• Pulse slows (bradycardia)
• Breathing slows
• Risk of cardiac arrhythmia
• Intense vasoconstriction - surface pooling
  (promotes afterdrop)
• Decreased LOC
• Increased mortality in major trauma by 40-50

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J-Wave/Osborn Wave

• The "hump" is present at the junction of the QRS
  complex and the ST-segment and can mimic acute
  myocardial injury (ST elevation).

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Hypothermia stages

• severe hypothermia (lt/30C/86F)
• Intense vasoconstriction - surface pooling
  (promotes afterdrop)
• As core temp drops the risk of V-Fib increases
  dramaticaly
• V-Fib or Bradycardia will degenerate into
  Asystole (flat line)

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Hypothermia Basic Care

• Recognize symptoms
• Handle gently
• Remove clothes
• Begin rewarming
• Immobilize neck (if diving injury)
• Rescue breathing (mouth to mouth)
• Start CPR?

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IN ORDER TO GET WARM THEY MUST BE DRY!!!
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Hypothermia re-warming
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HEAT Packs

• Use liberally
• Be prepared for short ½ life
• Use o warm IV tubing and fluid
• Porta-Warm mattress

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Warm Fluid And Air

• Warm Humidified O2 if possible (42-46C/108-115 F)
  
• If active heating is not possible, run tubing
  between body and hot pack to warm O2
• Consider use of a Mask or NRB to limit heat loss
  via respiration
• IV fluid heated to approx 43 degrees C/ 109
  degrees F (2 minutes per liter)
• Dont forget to warm tubing as well!
• NO LR
• Wrap around a hot pack
• Warm fluids may prevent AFTERDROP

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Hypothermia re-warming

• Mild hypothermia (34-35C / 93-95F)
• Requires shivering/active heat production by the
  patient
• Passive external rewarming
• remove wet, cold clothes
• wrap with blankets
• AVOID hot liquids if confused

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Hypothermia re-warming

• Moderate (30-34 C/86-93F) to severe hypothermia
  (lt/30C/86F)
• Active external re-warming
• remove clothes and wrap in warm blankets
• place in sleeping bag with two other warm people
• Chem Paks
• warm bath (104-108F / 40-42C) arms and legs out
  of water
• Avoid AFTERDROP

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What is Afterdrop?

• Dubious phenomena caused by improper warming
  technique
• As extremities are warmed, they vasodiliate,
  allowing cold blood to rush to the core, causing
  rapid sudden cooling
• This vasodilitation also causes hypotension
• This can cause cardiac dysrhythmias and cardiac
  arrest.
• Questionable significance

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Hypothermia and Cardiac Arrest

• PER ACLS Guidelines
• CPR as normal
• 3 shocks/AED as normal
• Keep horizontal, avoid rough treatment but do not
  delay critical interventions
• Active re-warming
• Temp lt30 C/86 F with hold medications
• Temp gt30 C /86 F Increased intervals between
  meds (10 minutes ??)
• Hyperkalemia is a possibility

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Frostbite
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Frostbite

• Usually requires ambient temp -6C/20F6-12 hours
  exposure less if high wind-chillCrystal
  formation in tissues (-2C/28F)
• Vasoconstriction,
• sludging of blood
• Ext. appears waxy, white, yellow-white, mottled
  blue-white
• Ext. is cold, hard and insensitive or painful

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Frostbite
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Frostbite ( early )
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Frostbite
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Frostbite at risk

• Exposed areas and distal extremitiesears, nose,
  chin, cheeks, hands, and feetTight clothing,
  High altitude
• Diabetes/ heart disease
• Tobacco use
• Previous frostbite
• African-Americans
• Southerners
• Blood type O

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Frostbite to an exposed area
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Frostbite
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Frostbite field care

• First address core temp
• Rewarming the ext. first may cause afterdrop
• rewarm rapidly in 38-42C/ 104-108F water for 20
  to 40 minutes or until thawed
• Avoid mechanical stim. or dry heat
• Wrap in loose non-adherent dressing

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Frostbite field care

• Do not rewarm if the ext. is likely to re-freeze
  or if it has already thawed (will appear
  red/flushed, and relatively soft)
• It is better to walk out on a frozen extremity
  rather than risk refreezing feet.
• Leave blisters intact
• appear at 6 to 24 hours and last 5 - 10 days
• Stages of frostbite progress over weeks to months
  amputation is undergone after weeks

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Prevention of cold injury

• Dress appropriately for the coldC Keep
  clothing cleanbetter water resistance and air
  trappingO Avoid overheatingavoid sweatingL
  Wear clothing loose and in layersbetter blood
  flow and air trappingD Keep clothing
  drybetter air trapping and less evaporative or
  conductive heat loss

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Prevention of cold injury

• Appropriate clothingUnderwear wool, capilene,
  or polypropyleneIntermediate layers wool,
  polypropylene, or polyester (including
  socks)Outer layer (water repellent or
  resistant) Gore-tex, Thinsulate, other
  breathable waterproof shellsAccessories wool
  or synthetic insulated, water resistant/proof -
  mittens, boots, hat, and scarf or face mask

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Prevention of cold injury

• Avoid natural materials
• cotton and linen, down
• exception is wool (retains heat even when wet)
• Eat high calorie diet, drink water
• 75 of food energy used for heat production
• Malnutrition and dehydration increases risk of
  hypothermia
• Frequent stops with Buddy Aid and eval

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Good Choice of Clothes
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Poor Choice of Clothes
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Take Home Information

• Prevent hypothermia and frostbite with
  appropriate clothing and dietBe aware of signs
  of bothHandle patients gentlyRewarm hypothermia
  carefullyThaw frostbite rapidly, but NOT if
  re-freezing is possible

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