13.6 Burns and Soft-Tissue Injury: Thermal, Chemical, Electrical & Inhalation

13.6 Burns and Soft-Tissue Injury: Thermal, Chemical, Electrical & Inhalation

Burns sit within CPCF Appendix A foundational knowledge #2 and #4 (integumentary structure, function, and pathology) and #12 (environmental emergencies), and their management draws on skills #27A (fluid resuscitation), #28 (tissue and minor wound care), and #21 to #25 (airway and ventilation). The examinable principle is that the burn is rarely what kills the patient in the first hour — the airway, the hypovolaemia, and the missed associated trauma are.

Skin Structure and Why Depth Matters

The skin has three functional layers: the epidermis (barrier), the dermis (nerve endings, hair follicles, sweat glands, capillary plexus, collagen), and the subcutaneous tissue. Burn depth is defined by how far destruction extends, and depth determines pain, healing, and disposition.

[!IMPORTANT] A painless, white, leathery burn is the worst burn, not the mildest. Full-thickness injury has destroyed the dermal nerve endings. Patients with large full-thickness burns still complain bitterly of pain — from the partial-thickness areas at the margins.

Estimating Burn Size: Total Body Surface Area

Only partial-thickness and full-thickness burns are counted toward total body surface area (TBSA). Superficial (erythema-only) burns are excluded — counting them is the single most common overestimation error.

Rule of Nines (adult): head and neck 9%, each arm 9%, each leg 18%, anterior trunk 18%, posterior trunk 18%, perineum 1%.

Rule of Nines (paediatric modification): the head is proportionally much larger and the legs smaller. In an infant the head is approximately 18% and each leg approximately 14%, shifting gradually toward adult proportions through childhood.

Palmar surface rule: the patient's own palm including the fingers is approximately 1% of their TBSA — the most practical tool for scattered or irregular burns.

Immediate Management

1. Stop the burning process.

• Thermal: remove from the heat source, remove smouldering and non-adherent clothing and all jewellery before oedema develops. Do not peel away adherent material.
• Cool running water at roughly 15 to 25 °C for about 20 minutes is effective for up to about three hours after a thermal burn. Never use ice, ice water, or frozen gel packs — they cause vasoconstriction, deepen the injury, and accelerate hypothermia.
• Then stop cooling and start warming. Burn patients lose thermoregulation with their skin barrier. For burns over roughly 10% TBSA, cool only briefly or in segments, and prioritize preventing hypothermia, which worsens coagulopathy and mortality.

2. Airway — the decision that cannot wait. Look for evidence of inhalation injury and act before the airway closes:

• Burns to the face, singed nasal hairs, soot in the mouth, nose, or sputum
• Hoarseness, stridor, or a change in voice — the most reliable warning
• Cough, carbonaceous sputum, dyspnoea
• Enclosed-space fire, loss of consciousness at the scene, or prolonged extrication
• Circumferential neck or chest burns

Upper-airway oedema progresses over minutes to hours and is worsened by fluid resuscitation. A patient with a hoarse voice and facial burns needs a definitive airway resource early, not a reassessment in 20 minutes.

3. Consider carbon monoxide and cyanide in any enclosed-space fire. Pulse oximetry cannot distinguish carboxyhaemoglobin from oxyhaemoglobin and will read falsely normal or high. Give high-concentration oxygen regardless of the SpO2 reading. Cyanide toxicity from combusting synthetic materials produces profound lactic acidosis with a normal SpO2 and warrants specific antidote therapy at hospital.

4. Cover and protect. Clean, dry, non-adherent dressings, or clean dry sheets for large burns. Avoid wet dressings over large areas (hypothermia). Separate burned digits. Keep the patient warm.

5. Fluids. For large burns, isotonic crystalloid through an intravenous or intraosseous route where authorized, per local directive. Formula-based resuscitation such as the Parkland formula calculates the first 24 hours from the time of the burn, not from the time of paramedic contact, and prehospital practice is generally to begin a measured infusion rather than attempt the full calculation on scene.

6. Analgesia. Burn pain is severe and under-treated, particularly in children. Treat it within your scope.

Circumferential Burns

A full-thickness circumferential burn creates an inelastic eschar that acts as a tourniquet as oedema develops beneath it:

• Limb: progressive loss of distal pulses, pallor, paraesthesia, and pain — reassess distal circulation repeatedly and document each check.
• Chest: restriction of chest-wall excursion producing rising airway pressures and ventilatory failure despite a patent airway.

Both are surgical emergencies requiring escharotomy at hospital; the prehospital contribution is recognition, elevation, and urgent transport.

Chemical Burns

• Brush off dry powders first, then irrigate. Adding water to some dry chemicals generates heat.
• Irrigate copiously and for far longer than feels necessary — typically 20 minutes or more, and considerably longer for alkalis.
• Alkalis are worse than acids. Acids cause coagulative necrosis that limits their own penetration; alkalis cause liquefactive necrosis and keep penetrating. Cement, oven cleaner, and drain cleaner burns often present late and deep.
• Do not attempt chemical neutralization — the reaction is exothermic and adds a thermal burn.
• Eyes: irrigate immediately and continuously, including during transport, after removing contact lenses. Irrigation is time-critical; do not delay it to find a specific solution.
• Protect yourself. Consult the safety data sheet and the Emergency Response Guidebook, and do not become contaminated.

Electrical Injury

Electrical injury is fundamentally different: the visible skin wounds are the least of it.

• Current travels through the path of least resistance — nerves, blood vessels, and muscle — causing deep tissue destruction between entry and exit wounds that are frequently tiny.
• Cardiac: ventricular fibrillation, asystole, or later dysrhythmias. Cardiac monitoring is mandatory.
• Muscle: rhabdomyolysis releasing myoglobin, producing tea-coloured urine and acute kidney injury; also hyperkalaemia.
• Associated trauma: violent tetanic contraction and falls cause fractures, posterior shoulder dislocation, and spinal injury.
• Scene safety is absolute. Do not approach until the source is confirmed isolated by the utility. For downed high-voltage lines, stay at least one span of wire away in every direction.
• Lightning differs again: the current is massive but extremely brief, so deep burns are less common; cardiac and respiratory arrest dominate, and reverse triage applies — in a multiple-casualty lightning strike, resuscitate the apparently dead first, because they may have a recoverable respiratory arrest while others have self-sustaining circulation.

Minor Wounds and Soft-Tissue Care

CPCF skill #28 includes tissue and minor wound care and wound closing within the PCP scope where authorized.

• Haemorrhage control first, then assess.
• Irrigate with clean water or saline under moderate pressure; this reduces infection more than any antiseptic choice.
• Assess neurovascular and tendon function distal to the wound before dressing, and document it.
• Do not close wounds that are contaminated, more than roughly 6 to 12 hours old, caused by bites or punctures, or that overlie a suspected fracture or foreign body.
• Retained foreign bodies and deep structures need imaging and exploration, not a dressing.
• Impaled objects are stabilized in place, not removed, unless they obstruct the airway or prevent chest compressions.
• Amputated parts: wrap in saline-moistened gauze, seal in a plastic bag, and place that bag on ice — never directly on ice and never in water.
• Tetanus status and bite risk belong in the handover.

When to Escalate to a Burn Centre

Criteria that commonly trigger burn-centre referral and should raise your index of urgency: partial-thickness burns over a substantial TBSA; any full-thickness burn; burns to the face, hands, feet, genitalia, perineum, or over major joints; circumferential burns; inhalation injury; electrical or significant chemical burns; burns with associated trauma; and burns at the extremes of age or in patients with significant comorbidity. Suspected non-accidental injury — a burn with a pattern inconsistent with the history, sharply demarcated immersion lines, or a delayed presentation — triggers the mandatory reporting duty in your province.