Thermal Injury Mohan K. Rao MD FACS. Thermal Injury Objectives –To identify types of burns and...

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

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• 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

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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

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• 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

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• 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

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• Pathophysiology– Histological assessment of the burn wound

• Zone of coagulation (necrosis) • Zone of stasis (injury) • Zone of hyperemia

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• Pathophysiology– Evaluation

• Depth• Size

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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

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• 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.

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• Don't be so intimidated by the burn wound that you don't treat the associated trauma.

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Thermal Injury

• Management– Primary survey

• Airway• Breathing• Circulation• Disability• Exposure/Enviornment

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• 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

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• 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

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• 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 aTIFF (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.

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• 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

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• 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





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• 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

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• Airway injury- tests– ABG’s, CXR are often normal acutely– Bronchoscopy– Xenon I131 lung scan

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• 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

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• 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

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• Fluid replacement



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

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• Fluid replacement



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• 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

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• Fluid replacement– Why Lactated Ringers solution?



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• Complications of edema formation

– Airway edema

– Extremity edema limiting circulation

• 6 p’s of circulatory insufficiency

– Torso edema limiting ventilation• High peak ventilatory pressures

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• 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

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• Wound care

– Goals

• Cosmesis

• Comfort

• Decrease wound flora to less than 105 organisms/gram of tissue

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• Wound care– Topical antibiotics

Agent Advantages Disadvantages

0.5% AgNO3 Broad spectrum Electrolyte abn’s,

inconvenient

Silvadene Broader spectrum Leukopenia

(silver sulfadiazine)

Sulfamylon Broadest spectrum Painful,metabolic (mafenide) acidosis

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• 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

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• 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

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• 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.

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• 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

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• Complications– Pneumonia– Infection of thermally injured cartilage– Invasive catheter infection– Invasive burn wound infections

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• Complications– Pneumonia

• More likely in intubated patients, especially those with inhalation injury

• Need to distinguish between pneumonia and colonization

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• Complications– Infection of thermally injured cartilage

• Often requires cartilage removal• Very disfiguring

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• Complications– Invasive catheter infections

• Frequent line changes necessary• Gram + or Gram - possible

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• 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 InjuryElectrical 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 aTIFF (Uncompressed) decompressor


Thermal Injury

• Electrical injury– Early complications

• Cardiac dysrhythmia• Spine fractures• Bowel necrosis• Seizures• Renal failure

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• Electrical injury

– Late complications

• Cataracts

• Gallstones

• Neuropsychiatric changes

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• Electrical injury

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• 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

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• 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.

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• 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

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• 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

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• Electrical injury- management– Fasciotomy to relieve elevated muscle

pressure.

QuickTime™ and aTIFF (Uncompressed) decompressor


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

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• 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

Thermal Injury Mohan K. Rao MD FACS. Thermal Injury Objectives –To identify types of burns and...

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