Burns, Hypothermia, Frostbite Flashcards
Frostbite
- Characterized by a cold-exposed area that is cyanotic, hard, waxy, and tender, with surrounding edema
- Dx is clinical. CT, angiography, MRI/MRA, bone scan to determine extent of nonviable tissue.
- Tx is with trunk warming, circulating warm water immersion. If tissue does not recover, it may need to be amputated. Analgesia and tetanus prophylaxis. Manage suspected infections aggressively.
Hypothermia
- Defined as core body temperature <35 C [95 F]
- Severe is < 28°C [82°F]
- Tx:
- Mild cases: Passive rewarming measures (e.g., warm clothing, blankets)
- Severe cases: Extracorporeal blood rewarming. Carries risks of stroke, hemorrhage.
Exam for suspected hypothermia should begin with. . .
. . . core temperature measurement and then ECG
This is often best done by rectal temperature
The most common cause of death in the case of hypothermia is. . .
. . . arrhythmia
Etiologies of hypothermia that don’t involve exposure
- Increased heat loss: Erythroderma (burns, psoriasis, pemphigus, etc), surgery, sepsis
- Decreased heat production: Endocrinopathy (hypothyroid, hypopituitarism, hypoadrenalism), severe malnutrition, neuromuscular insufficiency
- Impaired thermoregulation: Damage to the preoptic nucleus of the hypothalamus. Many mechanisms by which this can happen (trauma, strokes, toxic/metabolic, Parkinson’s, Wernicke’s, MS)
Stages of hypothermia and associated signs + symptoms
In hypothermia, what do you warm first: trunk or extremities?
TRUNK
The extremities will remain hypoperfused until the trunk is warm
What’s so bad about arrhythmias in a hypothermic patient?
They don’t respond to defibrillation
When a hypothermic patient has an arrhythmia, you have to continue CPR until their trunk is warm again (30–32°C / 86–90°F), THEN defibrillate.
Passive and active rewarming
- Passive: remove wet clothing, cover with blankets, warm room (preferably 28°C (82°F))
- Active: immerse affected extremity in a warm (preferably 37–39°C) circulating water bath
Differences between the Parkland Formula and the Modified Brooke Formula
Modified Brooke uses crystalloid during the first 24 hours and colloid (5% albumin in LR) solution during the second 24 hours. It also uses a range of 2-4 mL as the constant.
During the second 24 hours, fluids are given at 0.3-0.5 mL x % BSA x kg.
Both titrate to a urine output of >0.5 mL/kg/hr using the estimates as a base.
Silver sulfadiazine
- Most commonly applied topical agent for superficial burns
- Lacks the ability to penetrate eschars
- Not useful in infected burn wounds
Sulfamylon
- Topical agent used for full-thickness, infected burns
- Can penetrate eschars
- Painful w/ application
- May cause metabolic acidosis due to inhibition of carbonic anhydrase
Silver nitrate
- Topical burn wound agent
- Has limited eschar penetrance
- Turns tissue a black color
- Leads to leeching of salt from tissue, which may produce hyponatremia/hypochloremia, particularly if widely applied in children
“Major” burn wound
Arbitrarily defined as injuries with > 20% BSA involvement
Requires inpatient management
Three phases of burn management
- Phase 1: Evaluate extent of wound, administer fluids, secure airway if necessary
- Phase 2: Initial wound excision and biologic wound coverage to prevent/minimize wound sepsis, systemic inflammation, and generalized sepsis
- Phase 3: Definitive wound closure/coverage and treatment of injuries to complex anatomic regions (hand, face, genitalia). Rehabilitation and reconstruction.
The first two things you want to consider when evaluating a burn patient
- Is there respiratory involvement of the burn?
- Does this patient have carbon monoxide poisoning?
All victims rescued from the scene of closed-space fires should have. . .
. . . their carboxyhemoglobin measured
The carboxyhemoglobin symptom scale
- >5%: Respiratory changes
- >30%: CNS dysfunction
- >60%: Coma, death
When is it okay to fluid resuscitate a burn patient orally?
When <15% BSA is involved in 2nd/3rd degree burns
Why do we prefer LR over NS for burn patients?
They are going to need large-volume resuscitation, and large volumes of NS can cause hypochloremic metabolic acidosis
Target urine output in burns: Adults, kids, infants
Adult: 0.5 mL/kg/hr
Kid: 0.5-1 mL/kg/hr
Infant: 1-2 mL/kg/hr
How to assess for abdominal compartment syndrome
Measure the bladder pressure!
Bladder pressures > 20 mmHg plus evidence of at least one dysfunctional abdominal organ are indicative of abdominal compartment syndrome
This suggests the need for fasciotomy or escharotomy in a burn patient
Biologic wound dressing
- Preferred form of wound dressing for burns
- Should be applied as early as feasible following wound excision to second and third degree burn sites
- Optimal would be autologous skin graft
- Otherwise, porcine or bovine xenografts, cadaver skin, and acellular dermal matrix are possible tools.
- Improve time to epithelialization, reduce hypertrophic scarring, fluid and heat loss, and pain.
Neurologic burn complications
Transient delirium is quite common, usually due to anoxia or metabolic abnormalities
Immune dysfunction in burns
Often begins w/ SIRS due to high DAMP activity, but then is followed by a period of profound immunosuppression
GI complications of burns
-
Gatric and duodenal ulcers may develop due to decreased mucosal defense from low sphlanchnic bloodflow
- Ppx with early gatric feeding
- May also encounter acalculous cholecystitis, pancreatitis, hepatitis
Burns involving the face are an indication for an ___ consult
Burns involving the face are an indication for an Ophthalmology consult
Ophtho will do a fluorescein exam for corneal abrasions or ulcerations
Hypermetabolic state in burn injury
