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Flashcards in Cold Injuries Deck (30)
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1
Q

Two common cold injuries & susceptible populations

A
  • Hypothermia & Frostbite
  • Populations - winter athletes, moutaineers, elderly, homeless, & employed in cold
2
Q

Causes of frostbite

A
  • Environmental exposure to cold
  • Direct exposure to freezing materials…ice packs
  • Inhalation of hydrocarbons (upper airway)
3
Q

Frostnip definition

Immersion Foot (“Trench Foot) definition

A
  • Frost = cold induced, local paresthesia that burns/tingles, resolve w/ rewarming
  • Immersion = injury to symp. nerves & vasculature, feet erythmatous, numb/pain, covered w/ hemorrhagic bullae
4
Q

What disease progression is this?

A

Immersion foot/Trench foot

5
Q

Perio definition and lesion descriptions

A
  • Def = acute or repetitive exposure to damp cold above freezing point
  • Edematous, red/purple, & may be pruritic and/or painful
6
Q

Frostbite def & what occurs when ice crystals form in tissues?

A
  • Def = tissue cooling w/ vasoconstriction & ischemia
  • Abnormal electrolytes; cell dehyd, lysis, & death
7
Q

What can thawing do to frostbite?

A
  • Initiate inflamm pathway = further tissue ischemia, emboli w/in vessels, & thrombi in larger vessel
  • Made worse if the injury re-freezes after initial thaw
8
Q

Common symptoms of frostbite

A
  • Cold, numbness, & clumsiness of area
  • skin insensate, white/grayish color, & hard or waxy to touch
  • Upon rewarming, bullae usually develop
9
Q

1st degree frostbite features

A
  • superficial
  • pallor and anesthesia surrounded by erythema
  • no tissue infarction
10
Q

2nd degree frosbite features

A
  • Large blisters w/ clear fluid, surrounded erythema & edema
  • Seen 24 hrs after rewarming
  • No tissue loss
11
Q

3rd degree frostbite features

A
  • Blisters hemorrhagic & more proximal
  • Black eschar 1+ week
12
Q

4th degree frostbit depth & extent damage to tissue

A
  • Extend to muscle & bone
  • Complete necrosis
13
Q

Should you rub a frostbit area to warm it?

A
  • No, may cause more tissue damage
14
Q

What is the preferred way to rewarm frostbit tissue?

When can you tell if frostbit tissue is thawed?

A
  • Rewarm by placing feet in water heated 37-39° C
  • Airdry tissues
  • Complete when tissue is red/purple & soft to touch
15
Q

How to care for frostbite wound?

A
  • Non-stick gauze & use pledgets between digits
  • elevate=reduce edema
  • Blisters
    • non hemorr may be debrided
    • hemmorr may be drained, not debrided
  • Give tetanus if due
  • Surgery if severe
  • Avoid Ab = may cause maceration (use if suspected infection however)
16
Q

Thrombolytic therapy to txt frosbite goal?

A
  • Save tissue from microvascular thrombus
  • Use tissue plasminogen activator (tPA), can add heparin joint (not by itself)
17
Q

Do you amputate frostbit tissue right away?

A

No, complete demarcation of necrosis may take 1-3 months

Only amputate right away if signs of sepsis/gangrene

18
Q

5 Ways body loses heat

A
  1. Radiation
  2. Conduction (body to object)
  3. Convection
  4. Evaporation
  5. Respiration
19
Q

Normal core body temp & bodies natural reaction to hypothermia

A
  • 37 C
  • Shivering & catecholamine production
  • Vasoconstriction vessels in periphery to shunt blood to organs & prevent heat loss
20
Q

Common causes of hypothermia

A
  • Metabolism (hypothyroid/-adrenalism)
  • Extreme age
  • Drug induced (ethanol/sedatives)
  • Environment
  • Aggressive fluid resuscitation or heat stroke txt
21
Q

Mild hypothermia: body reaction & signs

A
  • Rxn = HTN, shiver, tachycardia/pnea, vasoconstriction
  • Signs = apathy, ataxia, cold diuresis, & impaired judge.
22
Q

Temp ranges for normal, mild, moderate, and severe hypo

A
  • normal = 37° C
  • mild = 32.2-35° C
  • mod = 28-32.2° C
  • severe = <28° C
23
Q

Moderate hypothermia signs

A
  • Decreased HR/RR/BP
  • Dilated pupils
  • No shivering
  • J wave
  • Paradoxal undressing
24
Q

What is a J Wave?

A
  • Sign of moderate hypothermia
  • positive deflection
  • Height of deflection is proportionate to degree of hypothermia
25
Q

Severe hypo symptoms/signs

A
  • Apnea
  • Coma
  • Nonreactive pupils
  • Oliguria (no urine)
  • Pulm. edema
  • Little/no EEG
  • Ventricular dysrythmia
26
Q

Preferred thermometer when measuring hypothermia?

A

Rectal probe thermometer

27
Q

Definitions of methods of rewarming:

  1. Passive external
  2. Active external
  3. Active Internal (Core) Rewarming
A
  1. mild hypo, remove clothing & cover w/ blankets, patient must have intact thermoreg mech, endocrine f(x), & energy stores
  2. mod-sev, heat directly to skin, need intact circ, warm trunk before extremities
  3. severe
    1. Warm IV-saline w/ dextrose heat to 40-45° C
    2. Extracorporeal blood warming - take out blood, heat, then reintroduce, most effective method
28
Q

Most effective temperature reading in rewarming

A

Esophageal

29
Q

Risks in active external rewarming

A
  • Afterdrop - cold peripheral blood rapidly returns to heart
  • Rewarming acidosis - cold, acidemic blood returns to trunk = drops core temp & pH
30
Q

Lab values to check with hypothermia (2 main)

A
  • Glucose
  • EKG