Thermal Injury

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Thermal Injury
Mohan K. Rao MD FACS
Thermal Injury
• Objectives
– To identify types of burns and their causes
– To understand the pathogenesis of burn
injury
– To describe the principles of managing a
patient with burns
– To explain proper wound management
techniques for treating burns
Thermal Injury
• Introduction
• 2.2 million people per year sustain burns in
the U.S.A.
• 75-80% occur in homes
• Major causes: flames, scalds, heat,
chemicals and electricity
• Under age 6, major cause is scalding, In
adults, the major cause is flame
• 75% of burns could be avoided
Thermal Injury
• Introduction
– Extremely labor intensive patients
– Not enough burn beds available to
accommodate a major disaster
– Often a disease of persons with few means
– Very high cost of care
Thermal Injury
Thermal Injury
• Introduction
– 1st half of the 20th century
• Resignation to the inevitability of shock and
infection
• Treatment directed to the relief of complications
of skin injury and not to the repair of the skin
itself
• Therapies to hold the fort until the host
defenses allowed the patient to survive
Thermal Injury
• Introduction
– 2nd half of the 20th century
• Critical care expertise
• Understanding of the pathophysiology of burn
shock
– World Wars
– Coconut Grove fire
• Development of topical antimicrobial therapy
Thermal Injury
• Pathophysiology
– Multiple functions of skin
• Thermal regulation
• Prevention of fluid loss by evaporation
• Hermetic barrier against infection
• Contains sensory receptors that provide
information about environment
Thermal Injury
• Pathophysiology
– Histological assessment of the burn wound
• Zone of coagulation (necrosis)
• Zone of stasis (injury)
• Zone of hyperemia
Thermal Injury
• Pathophysiology
– Evaluation
• Depth
• Size
Thermal Injury
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Thermal Injury
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Thermal Injury
Burn Size
Rule of nines works well in
adults
Head size makes it work
less well in children
Palm of the hand is ~1%
of total body surface injury
1o burns do not count
Thermal Injury
Thermal Injury
•
Transfer Criteria
– 1. Partial thickness burns >= 20% TBSA in patients aged 10 - 50 years old.
– 2. Partial thickness burns >=10% TBSA in children aged 10 or adults aged
50 years old.
– 3. Full-thickness burns >= 5% TBSA in patients of any age.
– 4. Patients with partial or full-thickness burns of the hands, feet, face, eyes,
ears, perineum, and/or major joints.
– 5. Patients with high-voltage electrical injuries, including lightning injuries.
– 6. Patients with significant burns from caustic chemicals.
– 7. Patients with burns complicated by multiple trauma
– 8. Patients with burns who suffer inhalation injury.
– 9. Patients with significant ongoing medical disorders.
– 10. Hospitals without qualified personnel or equipment for the care of
children.
– 11. Burn Injury in patients who will require special social/emotional and /or
long-term rehabilitative support, including cases involving suspected child
abuse, substance abuse, etc.
Thermal Injury
• Don't be so intimidated by the burn
wound that you don't treat the
associated trauma.
Thermal Injury
Thermal Injury
• Management
– Primary survey
• Airway
• Breathing
• Circulation
• Disability
• Exposure/Enviornment
Thermal Injury
• Management
– Resuscitation phase
• 2 large bore peripheral IV’s
• Labs
– T/C, CBC, CMP, ABG’s, CO, Drug/EtOH
screen
• NG tube
• Foley catheter
• CXR, C-spine, Pelvis
• Fluid administration of LR
Thermal Injury
• Management
– Secondary survey (AMPLET)
•
•
•
•
•
A - Allergies
M - Medications
P - Past medical history/previous illness
L - Last meal or beverage consumed
E - Events preceding injury/history of present
illness
• T- Tetanus
Thermal Injury
• Airway management
– Statistically, more people will die from
inhalation injury than from the actual burns
– Any victim, burned in a closed area should
be presumed to have an inhalation injury
Thermal Injury
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
Thermal Injury
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
Thermal Injury
• Airway injury- carbon monoxide
– Most common type of airway injury is carbon
monoxide poisoning, which may often present with
very few symptoms.
– Carbon monoxide has a 200 times greater affinity
for hemoglobin than oxygen.
– As carbon monoxide binds to the hemoglobin
molecule, it prevents the red blood cell from
transporting oxygen, resulting in a shift of the
hemoglobin oxygen dissociation curve to the left.
Thermal Injury
– Airway injury-carbon monoxide
• As the levels of carboxyhemoglobin increase
the patient may develop myocardial and
cerebral hypoxia.
• The most common signs are central nervous
system complications: confusion, loss of
memory and headache.
• The skin may become cherry red.
• Anyone unconscious at the scene of a fire
should be presumed to have a carbon
monoxide injury.
Thermal Injury
• Airway injury-carbon monoxide
– The only way to treat a carbon monoxide
exposure is with immediate application of
high flow oxygen at the scene of the fire
– 1/2 life of carboxyhemoglobin is 30 minutes
– ? Use of hyperbaric chambers
Thermal Injury
• Airway injury- above the glottis
– Quite common due to the capacity of the
nasopharynx to dissipate heat to the nose,
throat and mouth.
– The resulting thermal injury can cause
edema which can present within minutes to
hours. These are the types of injuries that
can progress to airway obstructions.
Thermal Injury
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
Thermal Injury
• Airway injury- below the glottis
– Heat injury is less common due to the
effective heat removal of the upper airway
– Lower airways can be directly burned by
hot steam
– Injury to the lower airways can be caused
by the products of combustion in particular
the aldehydes
Thermal Injury
• Airway injury- tests
– ABG’s, CXR are often normal acutely
– Bronchoscopy
– Xenon I131 lung scan
Thermal Injury
Thermal Injury
• Airway injury- treatment
– Early intubation with positive pressure
ventilation
– High concentrations of oxygen
– Aggressive management of secretions
– THERE IS NO VALUE AND POTENTIAL
GREAT HARM THAT CAN OCCUR WITH
STEROID OR ANTIBIOTIC
ADMINISTRATION
Thermal Injury
• Fluid replacement
– Biphasic capillary leak to fluid, high density
molecular weight proteins (but not red
cells), electrolytes
– 1st phase is histamine dependent
– 2nd phase related to the release of TNF,
leukotrienes, interleukins
– Repair begins at 12 hours, complete at 24h
Thermal Injury
• Fluid replacement
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
Thermal Injury
• Fluid replacement
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
Thermal Injury
• Fluid replacement
– Example of fluid management
• A 70kg patient with 50% body surface area
burn would require:4 x 50 x 70 = 14000 mls of
Ringers Lactate solution over 24h
hours.Therefore 7 litres should be given in the
first 8 hours and 7 over the following 16 hours
• Initial IV rate should be ~900-1000 cc/hour
Thermal Injury
• Fluid replacement
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
Thermal Injury
• Fluid replacement
• Criteria to judge whether or not fluid
resuscitation is adequate is
measured by urine volume.
• Other criteria include appropriate
sensorium, pulse, and blood
pressure
Thermal Injury
• Fluid replacement
– Why Lactated Ringers solution?
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
Thermal Injury
• Complications of edema formation
– Airway edema
– Extremity edema limiting circulation
• 6 p’s of circulatory insufficiency
– Torso edema limiting ventilation
• High peak ventilatory pressures
Thermal Injury
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
Thermal Injury
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
Thermal Injury
• Wound care
– Goals
• If the patient is to be transferred,
then simply cover the wounds with
a clean dressing
• Burn creams are unnecessary in
this circumstance
Thermal Injury
• Wound care
– Goals
• Cosmesis
• Comfort
• Decrease wound flora to less than
105 organisms/gram of tissue
Thermal Injury
• Wound care
– Topical antibiotics
Agent
Advantages
0.5% AgNO3 Broad spectrum
Silvadene
Broader spectrum
(silver sulfadiazine)
Sulfamylon Broadest spectrum
(mafenide)
Disadvantages
Electrolyte abn’s,
inconvenient
Leukopenia
Painful,metabolic
acidosis
Thermal Injury
• Wound care
– 1st degree• Keep clean, moisturize
– 2nd degree
• Debride blisters
• Keep clean
• Topical antibiotic cream
• Biologic dressings
• Grafting if no healing in 3 weeks
Thermal Injury
• Wound care
– 3rd degree
• Topical antibiotic cream
• Will need skin grafting
• Aggressive vs. non- aggressive treatment
– Prompt excision and immediate physiologic
wound closure decreases morbidity and
hospital stay but increases the likelihood of
blood transfusion
Thermal Injury
• Wound care
– Skin grafting
• In general, desirous to graft areas of function
first
• Split thickness vs. full thickness grafts
– Epidermis and variable depths of dermis
– The thinner the graft, the greater likelihood of
graft take but the greater risk of contraction.
– The thicker the graft, the less the likelihood of
graft take but the less the risk of contraction.
Thermal Injury
• Complications
– Curling’s ulcers
• 85% of all major burn victims have
stomach or duodenal inflammation at
endoscopy
• Best treated with prevention
• Complications
–Perforation, obstruction, hemorrhage
Thermal Injury
• Complications
– Pneumonia
– Infection of thermally injured cartilage
– Invasive catheter infection
– Invasive burn wound infections
Thermal Injury
• Complications
– Pneumonia
• More likely in intubated patients, especially
those with inhalation injury
• Need to distinguish between pneumonia and
colonization
Thermal Injury
• Complications
– Infection of thermally injured cartilage
• Often requires cartilage removal
• Very disfiguring
Thermal Injury
• Complications
– Invasive catheter infections
• Frequent line changes necessary
• Gram + or Gram - possible
Thermal Injury
• Complications
– Invasive burn wound infections
• More likely if >105 organisms/gram of tissue
• Ecthyma gangrenosum indicates metastatic
pseudomonas
• Treatment with IV antibiotics and burn
debridement
• Gram + (staph or strep) or Gram (pseudomonas)
Thermal Injury
Electrical injury
• With high voltage current, the
skin resistance is lowered and the
victim can get profound injuries
from the electricity.
• Electricity does not travel over the
surface of the skin, because the
surface tension of the skin is very
high.
• The current tends to enter the
body through a relatively small
opening, travels deep through the
body then exits through a small
opening.
Thermal Injury
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Thermal Injury
• Electrical injury
– Early complications
• Cardiac dysrhythmia
• Spine fractures
• Bowel necrosis
• Seizures
• Renal failure
Thermal Injury
• Electrical injury
– Late complications
• Cataracts
• Gallstones
• Neuropsychiatric changes
Thermal Injury
• Electrical injury
Thermal Injury
• Electrical injury
– Renal failure secondary to myonecrosis
and the release of myoglobin
– Myoglobin causes renal failure by two
mechanisms
• Direct nephrotoxin
• Causes an obstructive uropathy due to
the precipitation of myoglobin in the
tubules
Thermal Injury
Thermal Injury
• Electrical injury
– Compartment syndrome
•The muscles of the lower leg are
wrapped with fascia that divides
them into four groups called
compartments. Two such
compartments exist in the forearm.
•These fascial envelopes are unable
to stretch to accommodate swollen
muscles.
Thermal Injury
• Electrical injury
•Severe fractures, trauma, vascular
injuries and electrical injuries can
all produce muscle damage.
•As the injured muscle swells the
internal pressure rises so high that
local circulation is disrupted and
the affected muscle dies
Thermal Injury
• Electrical injury- management
– Primary survey, resuscitation, secondary
survey
– Cardiac monitoring
– Fluid replacement to assure greater than
100 cc/hour of urine
– Alkalinization of the urine with HCO3
Thermal Injury
• Electrical injury- management
– Fasciotomy to relieve elevated muscle
pressure.
QuickTi me™ and a
TIFF (Uncompressed) decompressor
are needed to see thi s pi cture.
Thermal Injury
• New topics on the horizon
– Enhancement of dermal and epidermal
regeneration using gene transfer technology
– Use of monoclonal antibody to decrease the zone
of stasis
– Use of laser Doppler imaging to assess depth of
injury
– Recognition of relative hypoadrenalism is a small
population of severely burned individuals
– Recognition of the DVT risk in immobilized burn
patients
Thermal Injury
• New topics on the horizon
– Currently, problems with less than good
answers include
• Burns in the elderly
• Patients with inhalation injury
• Patients with high percentage TBSA
injured
• Long term cosmetic and quality of life
issues
Thermal Injury
• Conclusions
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