- Hydrofluoric burns: behaves as a strong acid at higher concentrations. This causes liquefactive necrosis and pain out of proportion to exam by the combination of fluoride ions to calcium ions resulting in hyperkalemia.
- Treatment: surface irrigation with copious amounts of water at low pressure followed by topical calcium gluconate to bind fluoride ions before they penetrate into the soft tissues.
- Phosphorous is extremely volatile and found in fireworks and fertilizers.
- Treatment includes immediate debridement of visible debris, copious irrigation, most gauze dressings, cardiac monitoring
- Phenol burns:
- Treat with polyethylene glycol.
- Typically treat with fasciotomy, carpal tunnel release, and guyon’s canal release as risk of compartment syndrome is high.
- 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.
- 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 antiprostaglandin activity as this inhibits thromboxane and decreases secondary tissue damage.
- Technetium-99 triple phase scanning can accurately estimate level of amputation (not therapeutic) and is completed within first few days of injury.
- 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
- 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
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 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 infections, 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; can cause hyponatremia.
- Silver sulfadiazine: limited capacity to penetrate wound bed (surface epithelium only).
- Can cause reversible neutropenia
- Mafenide acetate: effectively penetrates burn eschar as well as cartilage. Decreases risk of suppurative chondritis (use on burns of the ear!)
- Associated with metabolic 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, and patients should be intubated with 100% oxygen delivery (leads to dissociation of CO molecule from hemoglobin).
- Carbon monoxide injury can falsely show normal appearing oxygen saturation.
- 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
- Excision for suspected infection in critically ill patients include excision down to fascia.
- 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
- 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.
- Intravenous fluid resuscitation should include ringer’s lactate with 5% dextrose in pediatric patients.
- Oxandrolone 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.
- 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.
- 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)
- 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.