Hypothermia

Question 1

Types of cold injuries

Answer 1

Frostnip
Chilblains
Immersion foot
Frostbite
Hypothermia

Question 2

Which cold injuries are Non-freezing vs Freezing?

• Frostnip
• Chilblains
• Immersion foot
• Frostbite
• Hypothermia

Answer 2

Non-Freezing
Frostnip
Chilblains
Immersion foot

Freezing Injuries
Frostbite
Hypothermia

Question 3

Frostnip?

Answer 3

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

Question 4

Chilblains (Pernio)

Answer 4

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)

Question 5

Immersion foot

“TRENCH FOOT”

Answer 5

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.

Question 6

Immersion Foot trmnt

Answer 6

• 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

Question 7

Frost Bite

Answer 7

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

Question 8

Cause of Frost Bite (pathophys)

Answer 8

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

Question 9

Risk factors of frostbite

Answer 9

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

Question 10

SS of frostbite

Answer 10

• 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

Question 11

What does gangrene from frostbite look like?

Answer 11

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.

Question 12

Severely damaged tissue may lead to _____ syndrome

Answer 12

Compartment Syndrome

Question 13

how to rewarm?

Answer 13

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

Question 14

When would thawing the feet might be avoided?

Answer 14

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

Question 15

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

Answer 15

give pain meds and continue

Question 16

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

Answer 16

tPA

Question 17

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

Answer 17

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

Question 18

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

Answer 18

• 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.

Question 19

Frostbite Complications

Answer 19

• 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

Question 20

leves of frostbite

Answer 20

Question 21

Hypothermia is defined as a core body temp of <________

Answer 21

< 35°C (95°F)

temp below what is req for normal cell metab!

Question 22

What temps are mild, mod, and severe hyothermia?

Answer 22

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

(35, 32, 28)

Question 23

Systemic SS of hypothermia

Answer 23

• 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

Question 24

What is the chronological progression of arrhythmias due to hypothermia?

Answer 24

Sinus bradycardia -> slow Afib -> Vfib or Asystole

Question 25

Dx of hypothermia is made by ___ temp | core or oral?

Answer 25

core rectal and esophageal probes are most accurate

Question 26

EKG may show _____ waves.

Answer 26

J (Osborn)

Question 27

lab orders for hypothermia

Answer 27

CBC Glucose (including bedside measurement) Electrolytes BUN Creatinine ABGs

Question 28

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

Answer 28

**WARM**

Question 29

1st priority in hypothermia trmnt

Answer 29

remove wet clothes and insulate to prevent further heat loss

Question 30

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

Answer 30

1°C / hour

Question 31

Fluids for hypothermia

Answer 31

_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.

Question 32

Indications for active rewarming?

Answer 32

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

Question 33

Active core rewarming options

Answer 33

Inhalation IV infusion Lavage Extracorporeal core rewarming (ECR) ## Footnote *There are 5 types of ECR: hemodialysis, venovenous, continuous arteriovenous, cardiopulmonary bypass, and extracorporeal membrane oxygenation.

Question 34

How might CPR harm a hypothermia pt?

Answer 34

chest compressiosn may convert perfusing rhythm to nonperfusing one BUT IF THERES NO PULSE GET ON THE CHEST! DONT WAIT FOR A DOPPLER

Question 35

POINTS TO REMEMBER

Answer 35

* 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.

Question 36

Other causes of hypothermia

Answer 36

* 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) ## Footnote just know cold exposure isnt the only reason ppl can get hypothermia!

Question 37

Active rewarming trmnts: Moderate vs Severe

Answer 37

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.

Question 38

Hypothermia with temps <____°C require active warming

Answer 38

32°C

Question 39

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

Answer 39

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

Question 40

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

Answer 40

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