Plastics: burns

Question 1

How is tissue thermal injury graded/classified starting from the point of contact

Answer 1

Central area = zone of coagulation (dead tissue), next layer is zone of stasis (salvable for 24 hrs, determines the depth of burn), then zone of hyperemia peripherally (will heal).

Question 2

Factors that contribute to depth of burn injury

Answer 2

Temperature and duration of exposure, pt age (affects skin thickness), anatomical location (thick/thin dermis), infection, dryness, use of inotropes (increases burn depth).

Question 3

When can you officially determine full depth of burn?

Answer 3

In 2-3 days post-initial burn. Assess initially, tx accordingly then reassess depth in 2-3d.

Question 4

Describe appearance/approach to 1st, 2nd, 3rd degree burns.

Answer 4

1st degree: epidermal burn. Red with no open wound. Not included in BSA of burns, no tx required, no scarring.

2nd degree: dermal burn.
Superficial dermal burn: heals in 2 wks, no scarring. Appears red, shiny/wet, is painful, blanches under pressure, associated with delayed blistering.

Mid-dermal burn: heals but takes longer. Does not immediately need a skin graft (only if not healed after 3 wks). Increased risk of scarring if not healed in 3 weeks.

Deep dermal burn: treated as deep burn. Poor healing potential (takes >6 wks), treated with excision and skin grafting.

3rd degree burn: full thickness through all layers of skin. May be any color, non-blanching, no pain, leathery/dry, petechial like dots, blisters, thrombosis. Needs excision and grafting.

Question 5

Rule of 9’s and palms to estimate BSA in adults

Answer 5

Palm method: pt palm including fingers represents 1% of BSA. Use when burns are scattered.

Rule of 9’s:
Entire head + neck: 9%, anterior torso 9%, posterior torso 9%, anterior single leg 9%, posterior single leg 9%, entire arm 9%. Crotch = 1%.

Do not include 1st degree burns when calculating involved amt of BSA.

Question 6

Rule of 9’s for kids

Answer 6

Differences from adult: head is 18%, anterior single leg = 7%.

Question 7

How to determine fluid resuscitation requirements for burn patients w/ >20% BSA partial or full thickness burn.

Answer 7

Generalized inflammatory response if >20% BSA –> generalized swelling.

Parkland Formula:
In adults/older children: give Ringer’s lactate 2-4mLx weight (kg) x %TBSA burned.

Infants/young kids: RL 3-4 mL x weight (kg) x % TBSA burned PLUS D5LR at maintanence rate.

Give the first 1/2 of calculated fluid dose over first 8 hrs post-burn (e.g. if they get to the hospital 2 hrs after burn, give 1/2 dose over next 6 hrs). Give the rest over the next 16 hrs.
Maintain urine output at 0.5cc/kg/hr for adults, 1cc/kg/hr for kids. Adjust fluid rate to satisfy this.

Question 8

Mxn’s of inhalational injury, potential sites & respiratory problems caused by inhalational injury

Answer 8

Mechanism of inhalational injury may be thermal, chemical, systemic exposure.
Consider potential sites of injury: supraglottic, tracheobronchial, lung parenchyma.

Respiratory problems:
Burn eschar encircling chest -> need escharotomy to relieve constriction.
CO poisoning.
Direct heat –> supraglottic airway injury.
Smoke inhalation –> pulmonary injury. Causes chemical injury to alveolar BM and pulm edema. Risk of pulmonary insufficiency and edema at 48-72 hrs. Secondary bronchopneumonia resulting in progressive pulmonary insufficiency.

Question 9

Situations in which to suspect inhalational injury

Answer 9

1. Closed-space smoke exposure, 2. concurrent cutaneous burns, 3. unconscious pt, 4. EtOH or drug use immediately before injury or known inhaled toxin.

Question 10

Symptoms of inhalational injury

Answer 10

Lacrimation, severe, brassy cough, hoarsness, SOB, wheezing, anxiety, obtunded/coma.

Question 11

Signs of inhalational injury on PEx

Answer 11

Tachypnea, stridor, conjunctivitis, carbon particles in sputum, facial burns, singed nasal hair/eyebrows, soot around nares/oral cavity.

Question 12

Diagnosis of inhalational injury

Answer 12

Can do: CXR, bronchoscopy (shows edema, ulceration), VQ scan (look for carbon particle deposition on endobronchial mucosa), ABGs (to look for carboxyhgb)

Question 13

Mgmt of inhalational injury

Answer 13

Immediate intubation!!! There is likely impending airway edema (failure to dx/intubate -> airway swelling/obstruction -> death).

Give 100% O2, NG aspiration, pulmonary toilet, bronchodilators.

Question 14

CO poisoning: pathophysiology, signs of poisoning, tx

Answer 14

CO = product of combustion, binds Hb and shifts curve left thus impairing O2 unloading. Binds to cytochrome oxidase and impairs mitochondrial functioning and ATP production.

Signs of CO poisoning: HA, confusion, coma, arrhythmias. Look for elevated CO levels in blood.

Treat with 100% O2 by facemask until carboxyhb <10%.

Question 15

Conservative tx for superficial burns.

Answer 15

Conservative tx (superficial burns): Heal through epithelialization. Hair follicles contain epithelial cells that migrate up and lay down epidermal buds that populate the wound bed and epithelialize the burn. If burn is too deep or hair follicles far apart, there will not be epithelialization.

Debride any large blisters and cover the open wound with moist dressing that should be changed as infrequently as possible. Best dressing = acticoat (SR nanosilver, change only every 3-7 days). Avoid flamazine dressing if possible.

No abx required for conservative tx.

Question 16

Indications and rationale for escharotomy

Answer 16

Cut through burn eschar in FULL length and depth to release pressure on underlying tissues.
Indicated for full thickness burns which prevent edema-related expansion of tissues. Pressure can increase in muscle compartments –> block venous circulation/further increase P –> decreased arterial blood flow -> distal and muscle necrosis.

Indicated for circumferential and full thickness burns: e.g. arms, legs, chest, penis.

Check pulses, elevate limbs. May need fasciotomy in addition.

Question 17

Indications for surgery in burns.

Answer 17

OR as soon as Dx of deep burn made. Remove dead tissue, optimize wound healing with graft. Give topical abx to prevent infection and secondary sepsis.
Give NSAIDs for pain control.

Question 18

Phases of soft tissue wound healing.

Answer 18

Inflammatory phase: days 1-6.
Reactive -> limits damage, prevents further injury. Debris and organisms cleared via inflammatory response. Involves neuts, macs, lymphocytes.
Process results in hemostasis, chemotaxis.

Proliferative phase: day 4 - week 3.
Regenerative phase– fibroblasts attracted and activated by mac GFs. Reparative process begins w/ re-epithelialization, matrix synthesis, angiogenesis. Tensile strength increases around day 4-5.
Process results in collagen synthesis, angiogenesis, epithelialization.

Remodeling phase: 3 weeks to 1 yr.
Increasing collagen organization, stronger crosslinks. Type I collagen replaces type III until normal 4:1 ratio achieved. Peak tensile strength at 60 days.
Process results in contraction, scarring, remodeling of scar.

Question 19

Comparison of skin grafts, split thickness grafts and full thickness grafts.

Answer 19

Skin grafts include the following types:
Autograft- pts own skin taken from donor site on their body.
Allograft- skin from bank, wound heals underneath, is a temporary graft.
Xenograft- skin from another species (typically pig).
Artificial skins- e.g. biobrane (temporary, good for wounds that don’t need skin grafting, allows for faster healing), integra (permanent, results in less scarring, top layer has to be removed).

Split thickness grafts: includes 100% epidermis, part of dermis.
High chance of graft survival but less resistant to trauma. Higher rate of contraction/distortion. Poor cosmetic appearance (color/texture match). Use at abdomen, buttock, inner/outer arm, inner forearm, thigh.

Full thickness grafts: 100% epidermis, 100% dermis.
Lower chance graft survival, longer healing time for donor site (more prone to deformation/hypertrophic scar). More resistant to trauma. Prevents contraction/deformation of area. Better-quality cosmetic appearance. Use in areas where you can match skin to graft (color/texture).

Question 20

Compare electrical vs chemical injuries.

Answer 20

Electrical: depth depends on voltage and resistance of the tissue.
Tissue resistance to electricity: bone > fat > tendon > skin > muscle > blood > nerve. (higher resistance = worse injury)
Deeper tissues may be burned more severely b/c cools slower compared to surface.
Associated with small punctate burns on skin but with extensive deep tissue damage.
Requires ongoing monitoring for cardiac arrythmias and latent injury.

Chemical burns: Chemical solutions coagulate tissue protein and can cause necrosis.
Severity related to –> type of chemical (alkali worse than acid), temperature, voluem and concentration. Contact time, site, mxn of chemical action, degree of tissue penetration.
Burns often deeper than they initially appear and may progress with time.

Question 21

Types of scars and methods to reduce scarring/disfigurement with burns.

Answer 21

Hypertrophic scar: red, raised, widened, pruritic scar that remains within boundaries of injury.
Keloid scar: thicker, different color and texture from normal skin. Extend beyond injury boundaries.

Can tx with scar removal and skin closure or dermabrasion. Alternate = skin flap surgery.