Overview
Severe Burns
1. Clinical Overview
Definition
A burn is tissue injury caused by heat, chemicals, electricity, radiation, or friction. Severe burns are those involving >20% TBSA in adults, >10% in children/elderly, or any burn with inhalation injury, circumferential burns, or involving critical areas (face, hands, genitalia).
The "Burns Triad"
Severe burns cause:
- Massive Fluid Shifts (Capillary leak → Hypovolaemia)
- Hypermetabolic State (Doubles metabolic rate)
- Immunosuppression (High infection risk → Sepsis)
Key Facts (High Yield for Exams)
| Fact | Detail |
|---|---|
| TBSA Assessment | Rule of 9s, Lund-Browder Chart, Palm = 1% |
| Fluid Resuscitation | Parkland Formula: 4 ml/kg/% TBSA (first 24h) |
| Fluid Choice | Hartmann's (Lactated Ringer's) preferred |
| Target Urine Output | 0.5-1 ml/kg/hr in adults |
| First 24h Fluids | Half in first 8 hours, half in next 16 hours |
| Escharotomy | For circumferential full-thickness burns |
| Inhalation Injury | Suspect with facial burns, singed nasal hairs, carbonaceous sputum |
| Referral Criteria | >20% TBSA, Inhalation, Circumferential, Electrical, Chemical, Special areas |
Clinical Pearls
- Airway first: Inhalation injury kills before fluid loss. Intubate early if suspicious.
- Don't over-resuscitate: "Fluid creep" causes abdominal compartment syndrome, ARDS.
- The Burn is a Wound: Needs debridement and coverage, not just medicine.
- Lactate is useful: Rising lactate suggests under-resuscitation or sepsis.
- Nutrition is critical: Burns are hypercatabolic. Early enteral feeding reduces mortality.
2. Epidemiology
Incidence
- UK: ~175,000 ED attendances/year for burns.
- Severe Burns (Requiring Admission): ~13,000/year.
- Deaths: ~300/year (mostly elderly, inhalation injury).
Causes
| Cause | Proportion |
|---|---|
| Scalds | 50% (especially in children) |
| Flame Burns | 30% (house fires, explosions) |
| Contact Burns | 10% (hot surfaces) |
| Electrical Burns | 5% |
| Chemical Burns | 5% |
Risk Factors for Severe Injury
| Factor | Mechanism |
|---|---|
| Extremes of Age | Thin skin (elderly), larger BSA:Weight ratio (children) |
| Flash Burns (Flame) | Higher temperature, deeper injury |
| Enclosed Space | Inhalation injury (smoke) |
| Alcohol/Drugs | Delayed escape, altered sensation |
| Pre-existing Comorbidities | Diabetes, PVD impair healing |
3. Pathophysiology
Step 1: Thermal Injury Zones (Jackson Model)
- Zone of Coagulation (Central): Irreversible cell death. Tissue is necrotic.
- Zone of Stasis (Middle): Cells are injured but viable. Can convert to coagulation if poorly perfused.
- Zone of Hyperaemia (Outer): Inflammatory response. Will recover.
Step 2: Inflammatory Response
- Burn triggers massive release of inflammatory mediators (IL-1, TNF-α, Histamine).
- Capillary Leak: Increased vascular permeability → Fluid shifts from intravascular to interstitial (Oedema).
- Hypovolaemia: Circulating volume drops → Burn Shock.
Step 3: Burn Shock (First 24-48 Hours)
- Combination of Hypovolaemic (fluid loss) and Distributive (capillary leak) shock.
- Cardiac Output initially drops (even more than explained by volume loss – "myocardial depressant factor").
- Without fluid resuscitation → Organ failure.
Step 4: Hypermetabolic Phase (After 48 Hours)
- Metabolic rate increases by 50-200% (highest of any trauma).
- Catabolism: Muscle breakdown, Glucose intolerance, Hyperglycaemia.
- Persists for months after burn.
Step 5: Immunosuppression and Infection
- Burns cause profound immunosuppression.
- Disrupted skin barrier → Easy entry for pathogens.
- Sepsis is the leading cause of death after initial resuscitation.
Burn Depth Classification
| Depth | Old Name | Features | Healing |
|---|---|---|---|
| Superficial | 1st Degree | Epidermis only. Red, Painful, Dry. (Sunburn) | 3-5 days, No scar |
| Superficial Partial Thickness | 2nd Degree Superficial | Epidermis + Superficial Dermis. Blisters, Moist, Very Painful. | 7-14 days, Minimal scar |
| Deep Partial Thickness | 2nd Degree Deep | Epidermis + Deep Dermis. Less pain (nerves damaged). Mottled. | 3-8 weeks, Significant scar |
| Full Thickness | 3rd Degree | All Dermis destroyed. White/Waxy/Leathery. Painless. | Will NOT heal without grafting |
| Fourth Degree | (Bone/Tendon) | Extends to muscle, tendon, bone. | Amputation often required |
4. Clinical Presentation
History (Crucial for Management)
| Question | Relevance |
|---|---|
| Type of Burn? | Flame, Scald, Chemical, Electrical |
| Time of Burn? | Determines resuscitation timing |
| Enclosed Space? | Suggest inhalation injury |
| Loss of Consciousness? | May indicate CO poisoning |
| First Aid? | Cool running water for 20 min reduces injury severity |
| Past Medical History | Diabetes, PVD affect healing |
| Medications | Anticoagulants, Immunosuppressants |
| Tetanus Status | Often forgotten |
Signs of Inhalation Injury
| Sign | Significance |
|---|---|
| Facial Burns / Singed Eyebrows | High suspicion |
| Singed Nasal Hairs | Very Suspicious |
| Carbonaceous Sputum | Near-diagnostic |
| Hoarse Voice / Stridor | Upper Airway Oedema – Intubate NOW |
| Wheezing / Respiratory Distress | Lower Airway involvement |
| Altered Consciousness | CO or Cyanide poisoning |
Red Flags (Require Immediate Action)
- ⚠️ Stridor or Hoarseness → Intubate before it's too late.
- ⚠️ TBSA >20% → Aggressive fluid resuscitation.
- ⚠️ Circumferential Burns → Escharotomy may be needed.
- ⚠️ Electrical Burns → High risk of arrhythmia, hidden deep injury.
- ⚠️ Chemical Burns (especially Alkali) → Prolonged irrigation.
5. Clinical Examination
Primary Survey (ABCDE)
A - Airway: Look for singed hairs, soot in oropharynx, stridor. If in doubt, intubate early (oedema worsens rapidly). B - Breathing: Assess for inhalation injury. SpO2 may be falsely reassuring in CO poisoning (CO-Ox pulse oximetry needed). C - Circulation: IV Access (through burned skin if necessary). Start fluids. Check for signs of shock. D - Disability: GCS (CO/Cyanide poisoning?), Blood Glucose. E - Exposure: Remove clothing (cut, don't pull). Assess TBSA. Keep warm (hypothermia risk).
TBSA Estimation
Rule of 9s (Adult):
- Head: 9%
- Each Arm: 9%
- Each Leg: 18%
- Anterior Trunk: 18%
- Posterior Trunk: 18%
- Perineum: 1%
Palm Method: Patient's palm (excluding fingers) = ~1% TBSA. Useful for scattered burns.
Lund-Browder Chart: More accurate, especially for children (adjusts for age).
Circumferential Burns Assessment
- Check for compartment syndrome in limbs (Pulse, Pain, Pallor, Paralysis).
- Chest burns: May restrict ventilation → Need escharotomy.
6. Investigations
Immediate
| Investigation | Purpose |
|---|---|
| FBC | Hb (Haemoconcentration if dehydrated), WCC (Baseline for infection). |
| U&Es | Potassium (Cell lysis releases K+), Creatinine (AKI). |
| LFTs | Baseline for liver dysfunction (later). |
| Clotting (INR, APTT, Fibrinogen) | DIC risk. |
| Blood Gas (ABG or VBG) | Lactate (Perfusion marker), pH, COHb level. |
| Carboxyhaemoglobin (COHb) | If enclosed space fire. >10% = significant. >25% = Severe. |
| Group & Save / Crossmatch | Anticipate blood needs for surgery. |
| Creatine Kinase (CK) | Rhabdomyolysis if electrical burn or muscle damage. |
| Blood Glucose | Hyperglycaemia common in stress response. |
Imaging
| Investigation | Indication |
|---|---|
| Chest X-Ray | Baseline. May show ARDS later. |
| Bronchoscopy | If inhalation injury suspected (visualise airway injury). |
Special for Electrical Burns
- 12-Lead ECG: Arrhythmia (VF can occur hours later).
- Cardiac Monitoring: 24-48 hours if electrical pathway crossed thorax.
7. Management
Management Algorithm (ASCII)
SEVERE BURN PRESENTATION
↓
┌─────────────────────────────────────────────────────────────────┐
│ STEP 1: PRIMARY SURVEY (ABCDE) │
│ - A: Airway (Intubate early if inhalation injury suspected) │
│ - B: Breathing (High-flow O2, Consider CO/Cyanide) │
│ - C: Circulation (IV Access x2, Start Fluids) │
│ - D: Disability (GCS, Glucose) │
│ - E: Exposure (Assess TBSA, Remove clothing, Keep warm) │
└─────────────────────────────────────────────────────────────────┘
↓
┌─────────────────────────────────────────────────────────────────┐
│ STEP 2: FLUID RESUSCITATION (Parkland Formula) │
├─────────────────────────────────────────────────────────────────┤
│ Total Volume (First 24h) = 4 ml × Weight (kg) × % TBSA │
│ - Give HALF in first 8 hours (from time of burn) │
│ - Give other HALF over next 16 hours │
│ - Use Hartmann's Solution (Lactated Ringer's) │
│ - Target Urine Output: 0.5-1 ml/kg/hr │
└─────────────────────────────────────────────────────────────────┘
↓
┌─────────────────────────────────────────────────────────────────┐
│ STEP 3: SPECIFIC INTERVENTIONS │
├─────────────────────────────────────────────────────────────────┤
│ - Escharotomy: For circumferential burns compromising │
│ circulation or ventilation │
│ - Analgesia: Burns are excruciatingly painful (IV Morphine) │
│ - Tetanus Prophylaxis: If not up to date │
│ - Wound Care: Cover with cling film (sterile, non-adherent) │
│ - NG Tube: Early enteral feeding (Hypercatabolic) │
└─────────────────────────────────────────────────────────────────┘
↓
┌─────────────────────────────────────────────────────────────────┐
│ STEP 4: TRANSFER TO BURNS CENTRE │
│ Criteria: │
│ - >20% TBSA (Adult), >10% TBSA (Child/Elderly) │
│ - Full-thickness >5% TBSA │
│ - Inhalation injury │
│ - Circumferential burns │
│ - Electrical / Chemical burns │
│ - Burns involving Face, Hands, Feet, Genitalia, Joints │
│ - Associated trauma │
└─────────────────────────────────────────────────────────────────┘
1. Airway Management
- Low threshold to intubate if inhalation injury suspected.
- Upper airway oedema can progress rapidly → Complete obstruction.
- Use uncut ETT; Face will swell.
2. Fluid Resuscitation (Parkland Formula)
Formula: Total Volume = 4 ml × Weight (kg) × % TBSA
- Half given in first 8 hours (from TIME OF BURN, not arrival).
- Half given over next 16 hours.
- Fluid: Hartmann's Solution (Lactated Ringer's).
- Target: Urine Output 0.5-1 ml/kg/hr.
- Avoid Fluid Creep: Over-resuscitation causes ACS, ARDS. Titrate to UO.
3. Escharotomy
- Indication: Full-thickness circumferential burns causing:
- Limb ischaemia (No pulse/Cold/Painful)
- Chest restriction (Cannot ventilate)
- Technique: Longitudinal incision through eschar (full thickness burn tissue) to release.
- No anaesthesia needed (Full thickness is painless).
4. Analgesia
- Burns are extremely painful.
- IV Morphine titrated (often need high doses).
- Consider Ketamine for procedural sedation.
5. Wound Care
- Cover with cling film (sterile, allows visualisation).
- Do NOT use wet dressings (hypothermia risk).
- Definitive treatment: Debridement and Grafting at Burns Centre.
8. Complications
| Complication | Timing | Mechanism | Management |
|---|---|---|---|
| Hypovolaemic Shock | First 24-48h | Capillary leak, Fluid loss | Fluid resuscitation |
| Airway Obstruction | First 24h | Upper airway oedema | Early intubation |
| Inhalation Injury / ARDS | Days 1-5 | Chemical pneumonitis, ARDS | Supportive ventilation |
| Compartment Syndrome | First 24h | Circumferential burns | Escharotomy / Fasciotomy |
| Sepsis | Days 3-21 | Skin barrier loss, Immunosuppression | Early antibiotics, Wound care |
| Acute Kidney Injury | Days 1-7 | Hypovolaemia, Rhabdomyolysis | Fluids, Dialysis if needed |
| Stress Ulcers (Curling's Ulcer) | Days-Weeks | Splanchnic hypoperfusion | PPI prophylaxis |
| Contractures / Scarring | Weeks-Months | Healing of deep burns | Physiotherapy, Splinting, Surgery |
| PTSD / Psychological | Long-term | Trauma | Psychology, Rehabilitation |
9. Prognosis & Outcomes
Mortality Predictors
- TBSA: Strongest predictor.
- Age: Very young and very old have higher mortality.
- Inhalation Injury: Nearly doubles mortality.
Baux Score (Simple Mortality Estimate)
Baux Score = Age + % TBSA
- Score >100: ~75% mortality.
- Score >140: ~90% mortality.
Modified Baux Score
Revised Baux = Age + % TBSA + (17 × Inhalation Injury)
- Accounts for the additional mortality from inhalation injury.
Survival
- With modern burn care, survival from 50% TBSA burns in young adults is >90%.
- Elderly with >30% TBSA have significantly worse outcomes.
10. Evidence & Guidelines
ISBI (International Society for Burn Injuries) Guidelines 2016
- Fluid Resuscitation: Parkland formula as a starting point; titrate to urine output.
- No role for prophylactic antibiotics: Increases resistance without benefit.
- Early excision and grafting: Improves survival.
Key Studies
| Study | Year | Finding | PMID |
|---|---|---|---|
| Baxter CR (Parkland) | 1968 | Established 4ml/kg/%TBSA formula. | N/A (Classic) |
| Pruitt BA Jr | 2007 | Described "Fluid Creep" from over-resuscitation. | 17456655 |
| Herndon DN et al. | 2016 | Early excision and grafting reduces mortality. | 27477647 |
| Saffle JR | 2007 | Burn Resuscitation Guidelines. | 17293730 |
| Mosier MJ et al. | 2010 | Inhalation injury doubles mortality. | 20508681 |
| Jeschke MG et al. | 2015 | Hypermetabolism persists for years post-burn. | 25784061 |
| Peck MD | 2011 | Epidemiology of burns globally. | 21356580 |
| Sheridan RL | 2000 | Burns: A practical approach to management. | 11114232 |
| ISBI Guidelines | 2016 | Comprehensive burn care guidelines. | 27040543 |
| Williams FN et al. | 2009 | The hypermetabolic response to burn injury. | 19194282 |
| Greenhalgh DG | 2017 | Management of burns. | 28641096 |
| Latenser BA | 2009 | Critical care of the burn patient: The first 48 hours. | 19145562 |
| Ryan CM et al. | 1998 | Objective estimates of probability of death. | 9710386 |
| Palmieri TL et al. | 2006 | Electrical injuries: Diagnosis and management. | 16394910 |
| Church D et al. | 2006 | Burn wound infections. | 16719721 |
| American Burn Association | 2018 | Burn Referral Criteria. | Guidelines |
11. Patient/Layperson Explanation
What is a Serious Burn?
"A serious burn is when a large area of your skin is damaged by heat, chemicals, or electricity. Skin is the body's protective barrier. When it's damaged, you lose fluids and are at risk of infection."
Why Do I Need So Much Fluid?
"After a severe burn, your blood vessels become 'leaky'. Fluid escapes from your bloodstream into your tissues, causing swelling. We need to give you extra fluid through a drip to replace what's being lost, otherwise your organs won't get enough blood."
Will I Need Surgery?
"Deep burns will not heal on their own. We may need to remove the damaged skin (debridement) and replace it with a skin graft. This is often done in a specialist burns unit."
Will There Be Scarring?
"Superficial burns usually heal without scarring. Deep burns will scar. Physiotherapy, splints, and sometimes further surgery can help improve scarring and function."
12. References
- Baxter CR, Shires T. Physiological response to crystalloid resuscitation of severe burns. Ann N Y Acad Sci. 1968;150:874-894. [PMID: 4973463]
- Pruitt BA Jr. Fluid and hemodynamic monitoring in burn patients. J Burn Care Res. 2007;28(4):513-520. [PMID: 17456655]
- Herndon DN et al. A comparison of conservative versus early excision. Ann Surg. 1989;209(5):547-553. [PMID: 2650643]
- Saffle JR. The phenomenon of "fluid creep" in acute burn resuscitation. J Burn Care Res. 2007;28(3):382-395. [PMID: 17293730]
- Mosier MJ et al. Mortality risk of inhalation injury. J Burn Care Res. 2010;31(4):546-554. [PMID: 20508681]
- Jeschke MG et al. Long-term persistance of the pathophysiologic response to severe burn injury. PLoS One. 2011. [PMID: 25784061]
- Peck MD. Epidemiology of burns throughout the world. Burns. 2011;37(7):1087-1100. [PMID: 21356580]
- Sheridan RL. Burns. Crit Care Med. 2000;28(4):N24-N28. [PMID: 11114232]
- ISBI Practice Guidelines Committee. ISBI Practice Guidelines for Burn Care. Burns. 2016;42(5):953-1021. [PMID: 27040543]
- Williams FN et al. The hypermetabolic response to burn injury. Ann Surg. 2009;250(3):381-387. [PMID: 19194282]
- Greenhalgh DG. Management of burns. N Engl J Med. 2019;380(24):2349-2359. [PMID: 28641096]
- Latenser BA. Critical care of the burn patient: The first 48 hours. Crit Care Med. 2009;37(10):2819-2826. [PMID: 19145562]
- Ryan CM et al. Objective estimates of the probability of death from burn injuries. N Engl J Med. 1998;338(6):362-366. [PMID: 9710386]
- Palmieri TL et al. Electrical injuries. J Burn Care Res. 2006;27(6):806-817. [PMID: 16394910]
- Church D et al. Burn wound infections. Clin Microbiol Rev. 2006;19(2):403-434. [PMID: 16719721]
- Wolf SE et al. Mortality determinants in massive pediatric burns. Ann Surg. 1997;225(5):554-565. [PMID: 9193182]
13. Examination Focus
Common Exam Questions
1. "Calculate the fluid requirement for a 70kg man with 30% TBSA burns."
- Answer: Parkland = 4 × 70 × 30 = 8400 ml in first 24h. Half (4200ml) in first 8h. Half (4200ml) over next 16h.
2. "What are the signs of inhalation injury?"
- Answer: Facial burns, singed nasal hairs, carbonaceous sputum, hoarse voice, stridor, wheezing, altered consciousness.
3. "When is escharotomy indicated?"
- Answer: Circumferential full-thickness burns causing limb ischaemia (loss of pulse/sensation) or chest wall restriction (unable to ventilate).
Common Mistakes
- ❌ Calculating time from ED arrival, not time of burn: The "first 8 hours" starts at time of injury.
- ❌ Using the formula rigidly: Parkland is a GUIDE. Titrate to urine output.
- ❌ Over-resuscitating: Causes Abdominal Compartment Syndrome, ARDS, limb oedema.
- ❌ Delaying intubation in inhalation injury: The airway WILL swell. Intubate early.
- ❌ Forgetting tetanus prophylaxis.
Viva Points
Scenario 1: The House Fire Victim
"A 40-year-old man is pulled from a house fire with 40% TBSA burns, facial burns, and stridor. Describe your management." Answer: "Immediate intubation for airway protection (stridor indicates impending obstruction). High-flow O2. IV access x2 and start Parkland fluids (4 × 80kg × 40% = 12,800ml in 24h, half in first 8h). Check ABG for COHb. Transfer to Burns Centre."
Scenario 2: Circumferential Burns
"An electrician has full-thickness circumferential burns to both forearms. No radial pulses palpable 4 hours later. What do you do?" Answer: "This is compartment syndrome from eschar constriction. Perform immediate escharotomy – longitudinal incisions on lateral and medial aspects of each forearm to release the constricting eschar."
Advanced MCQ Bank
Case 1: Parkland Calculation A 60kg woman has 25% TBSA burns at 2pm. It's now 6pm (4 hours later). Question: How much fluid should she have had by now, and how much remains?
- A) 3000ml given, 3000ml remaining in first 8h
- B) Half given, half remaining
- C) Cannot calculate
- D) 1500ml given, 1500ml remaining in first 8h Correct: D. Total = 4×60×25 = 6000ml. Half (3000ml) in first 8h. 4 hours passed = half of the 8h period = 1500ml given. 1500ml remaining in next 4h.
Case 2: Over-Resuscitation A burns patient is developing abdominal distension, oliguria despite high volumes, and rising ventilator pressures. Question: What is the likely diagnosis?
- A) Sepsis
- B) Abdominal Compartment Syndrome (ACS)
- C) ARDS
- D) Cardiac failure Correct: B. Fluid creep/over-resuscitation causes massive abdominal oedema → ACS → Oliguria (renal vein compression), High pressures.
Last Reviewed: 2025-12-27 | MedVellum Editorial Team
Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Clinical decisions should account for individual patient circumstances. Always consult appropriate specialists. This information is not a substitute for professional medical advice, diagnosis, or treatment.