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Emergency Medicine > Hypothermia > Flashcards

Hypothermia Flashcards

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1
Q

Types of cold injuries

A

Frostnip
Chilblains
Immersion foot
Frostbite
Hypothermia

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2
Q

Which cold injuries are Non-freezing vs Freezing?

  • Frostnip
  • Chilblains
  • Immersion foot
  • Frostbite
  • Hypothermia
A

Non-Freezing
Frostnip
Chilblains
Immersion foot

Freezing Injuries
Frostbite
Hypothermia

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3
Q

Frostnip?

A

Non-freezing injury
1st degreee variation of frostbite
The mildest cold injury
Affected areas are numb, swollen, red
Trmnt: rewarming -> hyperemia + pain/itching

(rare) Mild hypersensitivity to cold may persist for mo/yrs but there is no perm damage

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4
Q

Chilblains (Pernio)

A

ET: handling cold items a lot (repeat exposure to damp non-freezing cold)
SS: localized redness, swelling, pain, itchy,Blisters/ulcers
MC: fingers, pretibial areas
Tx: rewarming, Nifedipine (CCB), topical hydrocortisone

Unlike Frostnip, this has blisters/ulcers and can be treated with nifedipine, topical hydrocortisone (similat to reynauds trmnt)

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5
Q

Immersion foot

“TRENCH FOOT”

A

ET: repeat exposure to wet cold
SS: wrinkly like in bath too long, pale, red, clammy, cold, numb

Skin may ulcerate, or a black eschar may develop.

Autonomic dysfunction is common, with increased or decreased sweating, vasomotor changes, and local hypersensitivity to temperature change.

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6
Q

Immersion Foot trmnt

A
  • stop wearing tight boots, keep dry
  • rewarming in warm water (40-42C) followed by sterile dressings
  • NO nicotine
  • Elevate
  • Tetanus prophylaxis
  • NSAIDs/Opiods for painful hyperemic stage
  • Low grade fever common in first 12-36hrs
  • cellulitis -> ABX for staph, strep, pseudomonas
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7
Q

Frost Bite

A

injury due to freezing
SS: white skin, blisters, numb, +/- gangrene
Tx: rewarming in warm water, +/- amputation

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8
Q

Cause of Frost Bite (pathophys)

A
  1. Happens as a result of thermoregulation, posterior thalamus wants to maintain core temperature, thus vasoconstriction of extremities to shunt the blood to the core.
  2. shivering is a compensatory mech to help warm body
  3. ice crystals form within or b/w tissue cells -> freeze tissue -> cell death
  4. rewarming releases inflammatory cytokines (eg, thromboxanes, prostaglandins) are released, exacerbating tissue injury
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9
Q

Risk factors of frostbite

A
  • Poor Circulation
  • Alcohol Use
  • Smoking(Tobacco use inhibits Nitric Oxide)
  • PVD
  • Poor nutrition
  • Chronic Illness
  • Mental Illness
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10
Q

SS of frostbite

A
  • cold, hard, white, numb areas
  • Blisters with clear serum = superficial damage
  • Blood-filled blisters = deep damage -> tissue loss
  • May be painless bc it affects sensory nerve endings very early on
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11
Q

What does gangrene from frostbite look like?

A

Dry gangrene occurs when the blood supply to tissue is cut off. The area becomes dry, shrinks, and turns black.

Wet gangrene occurs if bacteria invade this tissue. The area is soft, edematous, and gray.

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12
Q

Severely damaged tissue may lead to _____ syndrome

A

Compartment Syndrome

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13
Q

how to rewarm?

A
  • rewarm rapidly by immersing in warm water
  • DONT use dry heat sources like fire or heating pad -> burn risk)
  • DONT rub -> further tissue damage
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14
Q

When would thawing the feet might be avoided?

A

if pt has to walk to receive care (lost outdoors)

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15
Q

pt is screaming in pain during rewarming process in the hospital. wdyd?

A

give pain meds and continue

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16
Q

If presenting within 24 hours, _____ may be given to reduce risk of amputation

A

tPA

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17
Q

If presenting within 48 hours consider ____ such as iloprost (vasodilator)

A

Prostacyclins
promotes VSMC relaxation (vasodilatation) and inhibits platelet aggregation (anti-thrombotic)
Ex. epoprostenol, iloprost, treprostinil

18
Q

Hyperthemia/cold injuries trmnt
(Hot mess to do later)

A
  • Patients are encouraged to move the affected part gently during thawing. Large, clear blisters are left intact or aspirated using sterile technique. Hemorrhagic blisters are left intact to avoid secondary desiccation of deep dermal layers. Broken vesicles are debrided.
  • Anti-inflammatory measures probably help.
  • Affected areas are left open to warm air, and extremities are elevated to decrease edema.
  • Phenoxybenzamine, a long-acting alpha-blocker, at a dosage of 10 to 60 mg orally once a day may theoretically decrease vasospasm and improve blood flow.
  • For severe injury presenting within 48 hours, infusion of a prostacyclin analog such as iloprost should be considered.
  • Preventing infection is fundamental; streptococcal prophylaxis (eg, with penicillin) is sometimes provided.
  • if wet gangrene is present, broad-spectrum antibiotics are used.
  • Tetanus toxoid is given if vaccination is not up to date.
  • If tissue damage is severe, tissue pressure is monitored.
  • Adequate nutrition is important to sustain metabolic heat production. Pre-thaw, consider using Doppler ultrasonography to assess pulses and tissue appearance.
  • Whirlpool baths at 37 °C 3x times a day followed by gentle drying, rest, and time are the best long-term management.
  • No totally effective treatment for the long-lasting symptoms of frostbite (eg, numbness, hypersensitivity to cold) is known, although chemical or surgical sympathectomy may be useful for late neuropathic symptoms.
  • Use of Hyperbaric oxygen treatment has been shown effective in improving function and recovery.
19
Q

Frostbite Complications

A
  • Throbbing pain for days or months afterward
  • Intermittent Paresthesias for several months
  • Sensations of “electric shock”
  • Hyperhidrosis common
  • Decreased proprioception
  • Peds epiphyseal plate trauma -> growth abnorm
  • Recommended to avoid cold exposure 6 to 12 months after injury
20
Q

leves of frostbite

A
21
Q

Hypothermia is defined as a core body temp of <________

A

< 35°C (95°F)

temp below what is req for normal cell metab!

22
Q

What temps are mild, mod, and severe hyothermia?

A

Mild (32-35 C) (90-95F)
Moderate (28-32C) (82-90F)
Severe <28C (<82F)

(35, 32, 28)

23
Q

Systemic SS of hypothermia

A
  • shivering stops once temp drops below 31C (falls even quicker after this)
  • CNS dysfn - cant feel the cold
  • lethargy, clumsiness, confusion, irritability, hallucinations, coma
  • unreactive pupils
  • resp and HR slow
  • Sinus bradycardia -> slow Afib -> Vfib or Asystole
  • Cold diuresis
  • Coagulopathy
  • Rhabdomyoloysis
24
Q

What is the chronological progression of arrhythmias due to hypothermia?

A

Sinus bradycardia -> slow Afib -> Vfib or Asystole

25
Q

Dx of hypothermia is made by ___ temp

core or oral?

A

core
rectal and esophageal probes are most accurate

26
Q

EKG may show _____ waves.

A

J (Osborn)

27
Q

lab orders for hypothermia

A

CBC
Glucose (including bedside measurement)
Electrolytes
BUN
Creatinine
ABGs

28
Q

“Patient isn’t dead until they are ____ and dead”

A

WARM

29
Q

1st priority in hypothermia trmnt

A

remove wet clothes and insulate to prevent further heat loss

30
Q

For hypothermia, how fast do you rewarm stable patients?
____°C/hour

A

1°C / hour

31
Q

Fluids for hypothermia

A

Fluid resuscitation for hypovolemia
1-2L of 0.9% NS (20 mL/kg for children) IV.
if possible, the solution is heated to 40 - 42° C
More fluid is given as needed to maintain perfusion.

32
Q

Indications for active rewarming?

A

Any of the following
< 32.2° C
Cardiovascular instability
hormone insufficiency
hypothermia 2ndary to trauma, toxins, or predisposing disorders

33
Q

Active core rewarming options

A

Inhalation
IV infusion
Lavage
Extracorporeal core rewarming (ECR)

*There are 5 types of ECR: hemodialysis, venovenous, continuous arteriovenous, cardiopulmonary bypass, and extracorporeal membrane oxygenation.

34
Q

How might CPR harm a hypothermia pt?

A

chest compressiosn may convert perfusing rhythm to nonperfusing one

BUT IF THERES NO PULSE GET ON THE CHEST! DONT WAIT FOR A DOPPLER

35
Q

POINTS TO REMEMBER

A
  • dont treat the bradycardia if they have adequate BP. treating it could make it worse! TREAT THE COLD.
  • Measure core temperature in the rectum or esophagus using an electronic thermometer or probe.
  • Above about 32° C, heated or forced-air blankets and warm drinks are adequate treatment.
  • Below about 32° C, active rewarming should be done, typically using forced-air hot air enclosures; heated, humidified oxygen; warm IV fluid; and sometimes heated lavage or extracorporeal methods (eg, cardiopulmonary bypass, hemodialysis).
  • At lower temperatures, patients are hypovolemic and require fluid resuscitation.
  • CPR is not done if there is a perfusing rhythm.
  • When CPR is done in patients with a nonperfusing rhythm, defibrillation is deferred (after one initial attempt) until temperature reaches about 30° C.
  • Advanced cardiac life-support drugs are usually not given.
36
Q

Other causes of hypothermia

A
  • Massive transfusion
  • Dialysis
  • Sx
  • Distributive Shock
  • Pancreatitis
  • Alcohol
  • Lithium toxicity
  • Hypoglycemia
  • DKA
  • Hypothyroidism (Myxedema Coma)
  • Adrenal Insufficiency
  • CO poisoning
  • Thalamic (midbrain) stroke (posterior thalamus is respon for thermal reg)

just know cold exposure isnt the only reason ppl can get hypothermia!

37
Q

Active rewarming trmnts: Moderate vs Severe

A

Moderate hypothermia(32-28° C) -> external rewarming with forced hot air enclosures.

Severe hypothermia (< 28° C), particularly those with low blood pressure or cardiac arrest -> req active internal core rewarming.

38
Q

Hypothermia with temps <____°C require active warming

A

32°C

39
Q

Trmnt for mild hypothermia (35-32° C) with intact thermoregulation (indicated by shivering)

A

insulation with heated blankets and warm fluids to drink are adequate.

40
Q

Blisters filled with clear serum indicate ______
Blood-filled, proximal blisters indicate ____

A

Clear serum = superficial damage
Blood/filled = deep damage & tissue loss

Emergency Medicine (11 decks)

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