Burns, Hypothermia, and Hyperthermia

What are the 3 main layers of the skin?

- epidermis

- dermis

- subcutaneous

What are the functions of the skin?

- SHAPES

- sensation

- heat regulation

- absorption

- protection

- excretion

- secretion

- vitamin D production

What temperature does cell damage occur at?

>45°C (113°F)

What are the 3 zones of damage in a thermal burn?

- zone of coagulation: irreversible damage by thrombosis of blood vessels

- zone of stasis: stagnation of microcirculation

- zone of hyperemia: increase in circulation

What can injury to the skin result in?

- Disruption of Na+ pump

- Depression of myocardial contractility

- Increased systemic vascular resistance

- Metabolic acidosis

- Increased hematocrit, and blood viscosity

- Secondary anemia

- Tissue injury

What are 1st-degree burns?

- epidermis only

- tissue is red, painful, tender, "sunburn" appearance

- no blisters

- heals 7-14 days without scarring

What are superficial partial thickness 2nd-degree burns?

- into but not through dermis

- blisters, exposed dermis is red/moist

- very painful

- 14-21 days to heal with minimal scarring

What are deep partial thickness 2nd-degree burns?

- into but not through dermis

- possible blisters, but no blanching

- exposed dermis is dry, leathery, waxy, white

- pain with pressure

- heals in 3-8 weeks with scarring

- surgical debridement and skin grafting are needed

What is a 3rd degree burn?

- full-thickness

- damage to dermis and epidermis and adnexal structures

- waxy white to charred black

- painless

- surgical repair/skin grafting

What is a 4th degree burn?

- injury to SubQ fat, fascia, muscle, and bone

- charred & hard to the touch

- grafting required if the patient survives

- amputation & reconstruction needed

What needs to be done to calculate fluid replacement with a thermal burn?

Determine Total Body Surface Area (TBSA)

Describe the palmar rule?

- patient's palm is 1% of body surface area

- good for smaller burns

What is the rule of nines?

- division of body surface area in multiples of 9

- good for larger burns

What is the Lund and Browder chart?

gold standard age based assessment

How is the rule of nines calculated?

- for children over the age of one year, for each year above one, add 0.5% to each leg and subtract 1% for the head

- this formula should be used until the adult rule of nines values are reached

What is the initial management of thermal burns?

- Stop the burning process

- ABCs

- History (mechanism of injury, allergies, Td status)

- PE (extent/depth of the injury, calculations)

What is inpatient management of thermal burns?

establish IV access using body surface area, watch urinary output, NG tube (burns >25% TBSA), saline dressing, IV narcotics, labs

What is outpatient management of thermal burns?

- analgesics

- cleanse burn with mild soap and water

- topical antimicrobial: 1% silver sulfadiazine cream, Bacitracin, or triple antibiotic ointment

- sterile daily dressing changes

what is the secondary management of thermal burns if standard treatment fails?

escharotomy

What is an escharotomy?

- limb saving, purposeful cuts

- relieves compromise to distal circulation or mechanical restriction

What are the minor criteria for burns treated outpatient according to the American Burn Association?

- <10% TBSA in adult

- <5% in young/old

- <2% full thickness

What are the moderate criteria for burns treated in a hospital according to the American Burn Association?

- 10-20% TBSA in adult

- 5-10% in young/old

- 2-5% full thickness

- high-voltage injury

- suspected inhalation

- circumferential burn

- concomitant medical problem

What are the major criteria for burns treated in a burn center according to the American Burn Association?

- >20% TBSA in adult

- >10% in young/old

- >5% full thickness

- high-voltage burn

- known inhalation

- burn to face, eyes, ears, genitalia, or joint

- significant other injury

What are RF of inhalation burns?

- Enclosed smoke exposure

- Facial burns

- Increased size of burn area

- Old age

- Oropharyngeal inflammation

- Decreased mentation (overdose/substance abuse, head injury, loss of consciousness)

- Exposure to steam, particulate matter, or toxic gases

How does an inhalation burn occur (three diff ways)?

- particulate matter results from incomplete combustion of materials

- steam can burn deeper tissues below glottis

- toxic inhalants (CO, hydrogen cyanide, acrolein)

What is the most common toxic inhalant?

carbon monoxide

What are two other possible inhalants?

- hydrogen cyanide

- acrolein

What is the clinical presentation of an inhalation burn?

- facial burns

- singed nasal hair

- soot in mouth/nose

- carbonaceous sputum

- hoarseness

- dyspnea

- expiratory wheezing

- stridor

What is the management for inhalation burns?

- prophylactic antibiotics

- bronchodilators

- intubate early

- 100% O2

- Hyperbaric oxygen

What parts of the body are most affected by chemical burns?

- face

- eyes

- extremities

What are the different classifications of chemical burns?

- chemical activity

- acid

- base

- strength of agent

- duration on body

- quantity

What happens to the skin in an acid burn?

- pH <2.0

- coagulation necrosis

- superficial deep tissue burns

What happens to the skin in a basic burn?

- pH >12.0

- liquefaction necrosis

- deeper tissue damage

What is the management of chemical burns?

- flush

- cardiac monitor

- BMP

- Tetanus

- fluids/analgesics

What are the exceptions to not flush a chemical burn?

- powders: brush off prior to irrigation

- hydrofluoric acid: tx with calcium gluconate to bind the fluoride iron

- sodium metal burns: may ignite spontaneously --> use sand/class D fire extinguisher

How do you treat ocular injuries related to chemical burns?

- irrigate: minimum of 1L NS for a minimum of 20-30 minutes

- check acuity

- check pH via sclera

What are the 2 etiologies of electrical burns?

- AC (alternating current)

- DC (direct current)

Where is AC found normally, and what do the entrance and exit wounds look like?

- household electricity

- entrance and exit wounds are same size

Where is DC found normally, and what do the entrance and exit wounds look like?

- industrial injuries, batteries, and lightning

- small entrance wound, large exit wound

- resistance varies based on tissue type

What are S/S of electrical burns?

- loss of consciousness

- confusion to coma

- Seizures

- Headache

- Tinnitus

- Stroke

- Spinal cord-like injury

- Vascular problems

- trauma

What is the management of electrical burns?

- ABCs (assume spinal injury)

- IV Fluids (vigorous lactated ringers)

-ECG/cardiac monitors

- thorough examination of all major organs and for any sign of vessel thrombosis

What is a flashover?

a high voltage electric short circuit made through the air between exposed conductors

What are the 4 types of lightning exposures and which is the most common?

- direct strike

- side flash

- contact strike

- ground strike (MC)

What is the presentation of lightning injuries?

- Lichtenberg figures

- star cataracts

- tympanic membrane rupture

- cardiac damage

- internal organ contusion

- visual problems

What is the management of lightning injuries?

- O2

- tetanus status

- cardiac monitoring

- seizure prevention

- assess for additional injury/internal injury

What are 4 ways heat is lost?

- conduction

- convection

- radiation

- evaporation

What are 5 ways heat is gained/conserved?

- controlled by hypothalamus

- shivering

- thyroid-mediated increase in metabolic rate

- peripheral vasoconstriction

- behavioral response

What temperature does hypothermia occur at?

less than 35 degrees C (95°F)

How is core body temp measured?

- rectal

- tympanic

- esophageal

- intravascular

- bladder

What are some causes of hypothermia?

- Accidental environmental exposure

- Metabolic disorders

- Hypothalamic/CNS dysfunction (head trauma, tumors, stroke)

- Drugs

- Sepsis

- Dermal Disease

- Acute incapacitating illness

- Massive fluid/blood resuscitation

What are the predisposing factors to decreased heat production?

1. hypoglycemia

2. malnutrition

3. hypopituitarism

4. extreme age

What are the predisposing factors of increased heat loss?

1. alcohol abuse

2. DM

3. Drug OD

4. burns

What is the presentation of someone who has mild hypothermia (CBT 32°C - 35°C)?

- Tachycardia

- Tachypnea

- Hypertension

- Shivering

- Impaired coordination

- Poor judgment

- Apathy

- Pale, cold, numb skin

- Dysarthria

things are FAST

What is the presentation of someone who has moderate-severe hypothermia (28°C - 32°C)?

- Shivering stops

- Bradycardia

- Dilated pupils

- Slowed/absent DTR

- Cold diuresis

- Loss of voluntary muscle control

- Confusion

- Lethargy

- Loss of consciousness

everything is SLOOOOOW

What kinds of cardiac dysfunction occur in hypothermia?

- sinus bradycardia to }slow atrial fibrillation to ventricular fibrillation to asystole

- Increased cardiac muscle irritability

What ECG changes are present in hypothermia?

- prolonged p wave & QRS duration

- T wave inversion

- Muscle tremor artifact

- Osborne (J wave): delayed ventricular depolarization and early repolarization

What are methods of passive rewarming for mild hypothermia?

- Transport from cold

- Adequate shelter/heat

- Remove wet garments

- Layer clothes/blankets

- Warm, sweet beverage

What are methods of active external rewarming for mild hypothermia?

- Heated blankets

- Warm bedding/blankets

- Warm packs to trunk

- Immersion into a 40°C bath

What are methods of active internal rewarming for moderate and severe hypothermia?

- Heated humidified O2

- Heated IV fluids (43°C)

- Warm lavage to bladder or stomach

- Peritoneal dialysis or hemodialysis

- Open cardiac massage

- Esophageal or endovascular rewarming

If CBT < 30C, what is done immediately?

- active rewarming + CPR

- one defibrillation attempt

- once CBT reaches 30oC cardiac medication can be given

- continue active rewarming to 32oC

What is the temperature frostbite occurs at?

-20°C (-4°F)

What groups of people are at increased risk for frostbite?

- Military

- Outdoor workers

- Elderly

- Homeless

- Drug/ETOH

- Psych

Describe 1st-degree frostbite and its prognosis?

- numbness, erythema, swelling, dysesthesia, white plaques, no loss of tissue

- excellent prognosis

Describe 2nd-degree frostbite and its prognosis?

- edema, erythema, blister formation in 6-12 hours

- good prognosis

Describe 3rd-degree frostbite and its prognosis?

- tissue loss involving the entire thickness

- hemorrhagic blisters

- Blue-gray discoloration

- "block of wood" then burning, throbbing pain

- poor prognosis

Describe 4th-degree frostbite and its prognosis?

- freezing of tissue, muscle, bone, tendon

- little edema, skin is mottled with non-blanching cyanosis

- deep, dry black mummified eschar

- very poor prognosis

What is the management of frostbite?

- Cover and protect

- Remove wet/constrictive clothing

- Constant warmth without rubbing

- rapid rewarming for full-thickness frostbite

- IV fluids/analgesics

- local wound care

When is surgery done for frostbite?

not until definite tissue necrosis (3-5 weeks after injury)

What is hyperthermia?

elevation of core body temperature above the normal diurnal range of 36 to 37.5ºC due to failure of thermoregulation

What is the main etiology of hyperthermia?

Imbalance between metabolic heat production/environmental heat load and normal heat capacity/loss heating

What are 3 other etiologies of hyperthermia?

- Serotonin Syndrome

- Malignant Neuroleptic syndrome

- Malignant hyperthermia of anesthesia

What is M&M related for hyperthermia?

duration of core temperature elevation

What are the 4 predisposing factors for hyperthermia?

1. age (young or old)

2. drugs (anticholinergics, tricyclic antidepressants, diuretics, cocaine)

3. occupational hazards

4. chronic disease

What does the clinical presentation, pathophys, and treatment look like for heat edema?

- mild severity

- lower extremity edema

- normal temp, BP, CNS

- sweating present

- cutaneous vasodilation and pooling of interstitial fluid in dependent areas

- treatment is symptomatic

What does the clinical presentation, pathophys, and treatment look like for heat cramps?

- mild severity

- painful muscle contractions

- normal temp, BP, CNS

- profuse sweating

- dilution hyponatremia

- treatment is symptomatic

What does the clinical presentation, pathophys, and treatment look like for heat exhaustion?

- moderate severity

- syncope, N/V, HA

- temp nL-104oF

- orthostatic BP

- profuse sweating

- decrease PVR, decreased volume, respiratory alkalosis/hyperventilation

- IV saline, evaporative cooling, electrolyte replacement

What does the clinical presentation, pathophys, and treatment look like for heat stroke?

- severe

- HA/MS changes

- temp >105 F

- abnormal CNS

- failure of thermoregulation

- rapid cooling, fluid and electrolyte management

What is the other management of heat exhaustion?

- move to shaded area

- lay supine

- feet above head

- fluids

- avoid sudden or prolonged standing until fully recovered

What are 2 types of heat stroke?

1. Classic/nonexertional

2. Exertional

What is the presentation of classic/non-exertional heat stroke?

- elderly

- no exercise

- sweating absent

- volume contracted: mild/moderate

- respiratory alkalosis

- underlying illness

What is the presentation of exertional heat stroke?

- young

- exercising

- sweating present

- volume contracted: severe

- metabolic acidosis

- no underlying illness

What is the evaluation and management of classic heat stroke?

- ABCs

- manage airway, ventilation, and circulation

- Rapid cooling until goal rectal temp of 38 to 39ºC (100.4 to 102.2ºF)

- assess volume status & give fluids

- CHECK EVERY LAB LIKE FR

What are prehospital treatments for exertional heat stroke?

- ABCs

- remove equipment and excess clothing

- rapid cooling

- stop cooling when rectal temp is 102.2

What are hospital treatments for exertional heat stroke?

- protect airway and maintain adequate oxygenation, ventilation, and circulation

- monitor vitals

- fluid resuscitation

- correct electrolyte issues

What is the pathophysiology of malignant hyperthermia?

- some patients have genetic skeletal mm receptor anomalies which allow for excess Ca2+ accumulation in the presence of certain agents

- this leads to sustained mm contraction, breakdown, metabolism, and acidosis causing more heat generation than the body can get rid of

- presents as marked hyperthermia minutes to hours past initial onset of sx

What are early signs of malignant hyperthermia?

- Hypercarbia

- Sinus tachycardia

- Masseter muscle rigidity

- Generalized muscle rigidity

What are late signs of malignant hyperthermia?

- Hyperthermia

- ECG changes w/ hyperkalemia

- Ventricular ectopy/ bigeminy/ tach/ fib

- Myoglobinuria

- Excessive bleeding

What is the treatment of malignant hyperthermia?

- Dantrolene

- supportive measures & remove causative agent