Acid Burns:

• Hydrofluoric acid: causes liquefactive necrosis and pain out of proportion to exam by the combination of fluoride ions to calcium ions resulting in hyperkalemia.
• Treatment: water then calcium gluconate gel 
• Phosphorous: found in fireworks and fertilizers. Associated with hypocalcemia, hyperphostphatemia, and sudden death
• Treatment includes immediate debridement, copious irrigation, saline soaked gauze or copper solutions, cardiac monitoring 
• Phenol burns:
• Treat with polyethylene glycol.

Electrical Burns:

• Typically treat with fasciotomy, carpal tunnel release, and guyon’s canal release as risk of compartment syndrome is high. Escharotomy is not effective in these cases – need fasciotomy.
• Severity of injury is proportional to the cross-sectional area of tissue able to carry current (most severe injuries are seen in smallest areas like the wrist and ankle). Highest level of resistance is in cortical bone; lowest in muscle. (cortical > cancellous > fat > tendon > skin > muscle > vessel > nerve)
• “high voltage” is anything >1000V and can cause arcing, wide tissue destruction, and fractures

Frost Bite:

• Occurs by formation of ice crystals in the intracellular and extracellular spaces
• Mechanism: Extracellular crystals form and osmotic pressure increases. Water leaves cells leading to intracellular dehydration and eventual cell death.
• Treatment of frost bite includes rapid rewarming in water at temperature of 104F or 40C (do not use radiant heat!) followed by consideration of intra-arterial thrombolytic therapy (after angiography). This can significantly decrease rate of amputation if administered within 24 hours of onset of frostbite.
• May additionally treat with NSAIDS for anti-prostaglandin activity as this inhibits thromboxane and decreases secondary tissue damage.
• Technetium-99 triple phase bone scanning can accurately estimate level of amputation (not therapeutic) and is completed within first few days of injury.

Burn Physiology:

• Hemodynamic changes after a burn (from hypovolemia) include decreased cardiac output, decreased peripheral blood flow, decreased urine output, and increased systemic vascular resistance.
• Burns impair both humoral and cellular immunity by depressing levels of circulating immunoglobulins, upregulation of integrins and cytokines TNF-a and IL1, IL 8, decreased B lymphocytes, NK cells, T helper cells, and increased number of T suppressor lymphocytes. 

Total Body Surface Area (TBSA): Rule of nines, and only second and third degree burns count (blistering and above)

• Head and neck 9%
• Anterior torso 18%
• Posterior torso 18%
• Each upper extremity 9% 
• Each lower extremity 18%
• Perineum 1%

Criteria for transfer to a burn center includes partial thickness burns over 10%, burns that involve sensitive areas (hands, feet, genitalia, joints), third degree burns, electrical or chemical burns, inhalation injury, pediatric patients

• Burns >20% TBSA can get heterotrophic ossification (often at elbow). Prevention is XRT + NSAIDS, treatment is excision

Fluid Resuscitation for Burns

• Parkland formula (4xTBSAx weight in kilograms) within the first 24 hours (half in the first 8 hours and the rest over the 16). This is used for second and third degree burns (do not include first degree) that encompass >20% TBSA.
• Fluid of choice is ringer’s lactate.
• Inadequate resuscitation is associated with hemodynamic collapse, end organ damage
• Over resuscitation can lead to infections, acute respiratory compromise, and abdominal compartment syndrome.
• Best measure of guiding fluid management is urine output (0.5 ml/kg/hr in children) or 30-50ml/hr in adults.

Topical Medications for Burns

• Silver nitrate: has poor tissue penetration. Used in toxic epidermal necrolysis & staph/pseudomonas coverage; can cause hyponatremia.
• Silver sulfadiazine: limited capacity to penetrate wound bed (surface epithelium only).
• Can cause transient neutropenia
• Mafenide acetate/sulfamylon: effectively penetrates burn eschar as well as cartilage. Decreases risk of suppurative chondritis (use on burns of the ear!)
• Carbonic anhydrase inhibitor – associated with metabolic acidosis, can be fatal if used over large surface areas in patients with inhalation injury and related respiratory acidosis

Airway Management in Burn Injuries

• Look for signs of lung injury (singed eyebrows, charred face, difficulty breathing). Diagnosis is made with fiberoptic bronchoscopy.
• Inhalation injuries carry risk of carbon monoxide poisoning although O2 sat is often falsely normal, and patients should be intubated with 100% oxygen delivery (leads to dissociation of CO molecule from hemoglobin).
• Operative airway burns (OR fires) –> if there is a concern for airway injury (smoke and burning odor) immediately remove the endotracheal tube and pour saline in the airway. Immediately re-establish ventilation.

Nutrition in Burns

• Enteral feeding is the preferred modality of access in burn patients.
• Poor intestinal perfusion is a risk in burn patients and thus gastric feeding should be reduced to trophic feeds.
• Signs of threatened intestinal perfusion include firm abdominal distention, gastric output >200mL a day, and hypotension requiring vasopressor support.
• Curreri formula used to calculate nutritional needs: 25kCal/Kg/Day + 40kCal/%TSBA/day (so 25x weight in kg + 40x TBSA)

Initial Operative Treatment

• Initial excisions include escharotomies if circumferential
• Excision for suspected infection in critically ill patients include excision down to fascia.

Burn Reconstruction

• Split thickness autografts
• Use NPWT (negative pressure wound therapy) for graft dressing as this has improved survival.
• Integra: bilaminar skin substitute composed of silicone outer layer and biologic scaffold. Application of integra to removal and STSG is 21 days or 3 weeks
• decrease in hypertrophic scarring; requires second surgery for STSG and thus can increase in length of stay
• CEA: cultured epidermal autografts: option to resurface large wounds in massively burned patient with limited donor sites. Works by engineering a small skin biopsy and expanding the keratinocytes by 10,000 fold.
• Lack a dermal layer, fragile, expensive
• Post operative splinting: Optimal position should include the neck in slight extension, shoulder fully abducted at 90 degrees, elbow fully extended at 180 degrees, wrist in neutral or slightly extended, and hands in intrinsic plus position.
• Facial burns in the periorbital area should be intervened upon early. In the case of eyelid contracture: release followed by skin grafting with FTSG rather than STSG should be done to reduce contracture recurrence. Contracture release: superficial to orbicularis oculi and superior to tarsal plate
• Oxandrolone (testosterone derivative) –> better bone, heart, and muscle strength

Paediatric Burns

• Intravenous fluid resuscitation should include ringer’s lactate with 5% dextrose in pediatric patients.
• Oxandrolone (synthetic steroid) administration in pediatric patients with >30% TBSA burns has shown to improve height, bone mineral content, cardiac work, muscle strength.
• Suspected child abuse includes significant burns to hands and feet and are indications to transfer to a burn center.

Scar Treatment after Burns

• Pressure garment therapy: this works by exerting pressure perpendicular and parallel to the surface of the scar, working opposite of the contracture.
• Mechanism includes inhibition of transformation of fibroblasts to myofibroblasts 
• Scar strength improved, with smaller more densely packed collagen observed.

Scar Contractures

• Severe burn contractures should indicate perforator based local flaps if available or free tissue transfer particularly when no local options or extensive burns preclude Z plasties.
• Z plasty: lengthens contracted scar, breaks of straight line, shifts soft tissue contour (great for neck contractures. Z Plasties are transposition flaps. 
• Other options include tissue expansion, skin grafting
• Skin grafting and ectropion release appropriate treatment for burn ectropion (particularly full thickness skin grafting).
• Neck contracture release most commonly performed contracture release.

Complications

• Worse prognosis/inc mortality: age >60, >40% TBSA, inhalational injury, significant 3^rd degree burn, pre existing illness, hx tobacco or etoh abuse
• Electrical burns and circumferential burns carry risk for compartment syndrome. This can lead to a volkmann’s ischemic contracture of the upper extremity if left untreated. Remember deep compartment fibrosis first, FDP, FPL.
• Remember the 5 P’s of compartment syndrome: pain, pallor, paresthesia, pulselessness, and paralysis
• Treatment for compartment syndrome is fasciotomies
• Compartment syndrome sequela include rhabdomyolysis and consequent renal and metabolic disorders (hyperkalemia, hypocalcemia)
• Can treat with insulin/glucose, mannitol
• Hypovolemic shock: can be seen after tangential excisions of large TBSA burns and include decreased urine output, tachycardia, hypotension.
• Sepsis after burns: most common bacteria includes MRSA, pseudomonas, and klebsiella
• Treat with vancomycin and zoysn (antifungal treatment not necessary)
• Heterotopic Ossification: complication of massive burn injury (>20%). The elbow is the most common site of occurrence. Prevent with radiation therapy/NSAIDs, surgical excision is tx for restoration of ROM
• X-ray shows soft tissue lamellar calcification 
• Marjolin’s ulcer: malignant degeneration of previous scar to SCC, typically 10 years out at earliest

Miscellaneous

• TENS or Steven’s Johnson syndrome: present with several days of indolent and nonspecific symptoms (after medication administration such as bactrim, allopurinol, phenytoin etc) and include fever, malaise, dysphagia. This progresses to hemodynamic collapse, skin exfoliation, and mucosal sloughing.