4.5 Practice Drills and Readiness Markers

4.5 Burns and Environmental Emergencies

Burn and environmental scenarios are calculation- and recognition-heavy, so drill the two formulas until they are automatic. First classify burn depth: superficial (first-degree) = epidermis only, red and painful, no blisters (sunburn); partial-thickness (second-degree) = into the dermis, blisters, very painful, moist; full-thickness (third-degree) = through the dermis, leathery/white/charred, often painless centrally because nerve endings are destroyed.

The critical scoring rule: only partial- and full-thickness burns count toward total body surface area (TBSA) for fluid resuscitation — superficial burns are excluded. A patient with extensive red, painful but unblistered skin may have a high apparent area but a low resuscitation TBSA.

Rule of Nines and Parkland formula

Estimate burned TBSA with the adult Rule of Nines:

The palm (palmar surface incl. fingers) ≈ 1% for scattered burns. In children the head is proportionally larger (~18%) and legs smaller (~14% each) — use a pediatric chart.

Resuscitate significant burns with the Parkland (Baxter) formula:

4 mL × body weight (kg) × %TBSA = total Lactated Ringer's over the first 24 hours, with HALF given in the first 8 hours (from the time of the burn, not from EMS arrival) and the remaining half over the next 16 hours.

Worked example: an 80 kg adult with 30% TBSA: 4 × 80 × 30 = 9600 mL over 24 h → 4800 mL in the first 8 hours (≈ 600 mL/h). The exam tests both the calculation and the 'half in the first 8 hours' timing.

Airway, electrical, and special burns

Inhalation/airway burns are the burn killer EMS must catch early. Red flags: fire in an enclosed space, singed facial or nasal hair, soot around the mouth/nose, carbonaceous (sooty) sputum, hoarseness, or stridor. Edema can close the airway within minutes to hours, so secure the airway early — intubate before swelling makes it impossible. Assume carbon monoxide poisoning in enclosed-space fires: SpO2 reads falsely normal, so give high-flow oxygen and consider cyanide toxicity (hydroxocobalamin) from burning synthetics.

Electrical burns are deceptive: small entrance/exit wounds hide massive deep-tissue and muscle injury, and current can cause cardiac dysrhythmias and arrest (monitor the ECG continuously) plus rhabdomyolysis with hyperkalemia. Chemical burns are managed by removing the agent (brush off dry powders first) and copious irrigation. Stop the burning process, remove jewelry/constrictive items before swelling, cover with dry sterile dressings for large burns, and keep the patient warm — burned patients lose heat rapidly, feeding the lethal triad.

The trauma triage decision runs in parallel: the CDC/ACS National Field Triage guidelines route physiologic instability (GCS <= 13, systolic < 90 mmHg, RR < 10 or > 29) and anatomic injuries (penetrating torso wounds, flail chest, two or more proximal long-bone fractures, crushed/degloved/amputated limbs, pelvic fracture) directly to the highest-level trauma center, bypassing closer non-trauma hospitals. Major burns with inhalation injury or large TBSA likewise meet burn-center transfer criteria.

When physiologic and anatomic criteria are absent, mechanism (high-speed crash, fall > 20 ft) and special considerations (age extremes, anticoagulation, pregnancy) still lower the threshold for trauma-center transport.

Hypothermia and hyperthermia

Hypothermia is staged by core temperature: mild ~32-35 °C (shivering, alert), moderate ~28-32 °C (shivering stops, altered mentation, bradycardia), severe < 28 °C (no shivering, rigid, risk of dysrhythmia, Osborn/J wave on ECG). Management is gentle handling and gradual rewarming — rough movement or aggressive interventions in a severely hypothermic heart can precipitate ventricular fibrillation. Remove wet clothing, insulate, apply warm packs to the trunk (axilla/groin), and warm fluids.

Hyperthermia/heat illness progresses from heat cramps → heat exhaustion (heavy sweating, weakness, normal-ish mentation, normal/slightly elevated temp) → heat stroke, a true emergency with altered mental status and a high core temperature (often > 40 °C), where sweating may be absent in classic heat stroke. Heat stroke management is rapid, aggressive active cooling (cold-water immersion or evaporative cooling with cold packs to the neck/axilla/groin), airway support, and fluids — cooling is the priority intervention, not just fluids.

Worked scenario and exam traps

A 90 kg adult is burned over the anterior trunk (18%), the entire right arm (9%), and the anterior right leg (9%) — partial- and full-thickness — for 36% TBSA. Parkland: 4 × 90 × 36 = 12,960 mL of Lactated Ringer's over 24 hours, 6480 mL in the first 8 hours from the time of the burn (≈ 810 mL/h), the rest over the next 16 hours. He was pulled from a closed garage fire with soot in the mouth and hoarseness — assume inhalation injury and CO poisoning, give high-flow oxygen, and secure the airway early.

High-yield traps:

• Counting superficial (first-degree) burns toward TBSA — only partial- and full-thickness burns count for Parkland.
• Starting the 8-hour clock at EMS arrival — it starts at the time of injury; if an hour has passed, the remaining first-half volume is given over the remaining time.
• Trusting SpO2 in fire victims — carbon monoxide gives a falsely normal reading; treat with high-flow oxygen.
• Rough handling or aggressive interventions in severe hypothermia — can trigger ventricular fibrillation; rewarm gently and remember 'not dead until warm and dead.'
• Treating heat stroke with fluids alone — the priority is rapid active cooling.
• Forgetting that burn patients lose heat fast — cover and keep warm to avoid feeding the lethal triad.