Plastic Surgery SC029: I Have A Scald: Burn

Question 1

Function of Skin

Answer 1

1. Protection from infection and injury
2. Prevent loss of body fluid
3. Regulation of body temperature
4. Sensory contact with environment

Question 2

Burn

Answer 2

1. Mechanism of injury
   - **Flame burn (Dry heat)
   - **Scald burn (Moist heat, water, oil etc.)
   - **Chemical burn
   - **Electric burn (Low / High voltage)
   - Radiation burn
   (- Contact burn
   - Smoke and Inhalational burn
   - Cold burn (Frostnip, Frostbite)
   - Friction burn)
2. Extent and distribution
   - 1st / 2nd / 3rd / 4th degree burn
3. Total body surface area (TBSA)

Question 3

Effects of burn

Answer 3

1. ***Local thermal soft tissue injury
2. Systemic inflammatory response
   - cytokines + inflammatory mediators released —> ↑ capillary permeability —> ***third space loss

Question 4

3 zones from Local thermal injury (Jackson’s burn wound model)

Answer 4

1. Zone of coagulation
   - contact point (i.e. area with most burn)
   - ***coagulation necrosis of cells
   - not much recovery potential
   - clotted blood + thrombosed blood vessels
2. Zone of stasis
   - injured cells
   - ***decreased blood flow
   - area of focus —> prevent deterioration / limit size + depth of burn injury —> hope to convert to Zone of hyperaemia
3. Zone of hyperaemia
   - minimal injury
   - peripheral area around burn with ***increased blood flow to heal injury

Fluid resuscitation —> ensure adequate perfusion of soft tissues —> limit zone of coagulation / prevent zone of stasis evolve into coagulation

Question 5

***Management of Burns

Answer 5

1. Initial assessment
   - Primary survey: ABCDE
   - First aid: Fluids, Analgesic, Tests, Tubes
   - Assess burn + associated injuries
2. Management
   - Crucial in first 24-48 hours

Question 6

Airway assessment

Answer 6

• Strong index of suspicion
• Children: more prone due to enlarged tonsils, adenoids, narrow trachea, bronchospasm

History:
1. Mechanism of injury
- enclosed area burns
- hot smoke
- prolonged time before rescue

P/E:
1. Facial burns
- singed facial hair
- soot in mouth
- swollen lips / tongue
2. Dyspnea, Drooling of saliva
3. Stridor (late sign)

Treatment:
1. Maintain patent airway
- airway maneuvers
- adjuncts (Guedel’s airways, NP airways)
- ETT intubation
2. High flow oxygen
3. ETT intubation considered, esp. for interhospital transfer
4. Frequent assessment of airway
5. Cricothyroidotomy + Tracheostomy

Indications for intubation:
1. Need to maintain / protect a patent airway
- reduced level of consciousness
- impending airway obstruction
- to facilitate safe transport
2. Need for ventilation
- deteriorating oxygenation

Question 7

***First aid in Burns

Answer 7

1. ***Stop burning process
2. **Cool burn wound
   - Tap water ~15°C (8°C - 25°C)
   —> flow / spray / sponging / water gels / hydro gels
   —> 20 minutes
   —> effective within first 3 hours post-burn
   —> no ice or iced water (∵ vasoconstriction —> impair blood flow)
   - Watch for **hypothermia
   - Immediately after accident whilst waiting for assistance
   - ***After primary survey if <=3 hours
   - If presentation after 3 hours first aid not effective
3. ***Limb elevation
   - Reduces swelling
   - Reduces circulatory impairment
   - Improves tissue perfusion
   - Improves tissue nutrition

Question 8

Assessing burns

Answer 8

1. Burn factor
   - Mechanism of burn
   - **%TBSA
   - **Depth + Site of the burn
   - Presence of inhalational injury + associated injuries
   - Contaminated wound / presence of infection
2. Patient factor
   - Age
   - Sex
   - Comorbid conditions

Pitfalls:
1. Burn wounds are dynamic
- Depth may change according to circumstance of circulation, wound infection etc.
2. Burn wounds are heterogeneous
- Not all areas are burnt to the same degree

Question 9

***Burn wound assessment

Answer 9

1. ***Depth / Degree
   - Superficial (1st degree) (epidermis only)
   - Superficial-partial thickness / Superficial dermal (2nd degree, dermis also affected)
   - Deep-partial thickness / Deep dermal (2nd degree, dermis also affected)
   - Full thickness (3rd degree, epidermis + whole dermis) —> need surgery (∵ wound will not heal by itself)
   - Beyond skin (4th degree, involve muscle / bone) —> need amputation
2. **Extent
   - **TBSA (%)
   - Rule of 9
   —> Head: anterior (4.5%) + posterior (4.5%) = 9%
   —> Upper limb: anterior (4.5%) + posterior (4.5%) x 2 limbs = 18%
   —> Trunk: anterior (18%) + posterior (18%) = 36%
   —> Lower limb: anterior (9%) + posterior (9%) x 2 limbs = 36%
   —> Perineum: 1%

(Children: Head take up larger proportion)

Question 10

***Depth / Degree of burn

Answer 10

1. Superficial (1st degree)
   - Causes: UV light, very short flash of flame exposure
   - Appearance: ***Dry, Red, Blanches with pressure
   - Sensation: Painful
   - Healing time: 3-6 days
   - Scarring: None
2. Superficial-partial thickness / Superficial dermal (2nd degree)
   - Causes: Scald (spill / splash), short flash
   - Appearance: **Blisters, **Moist, Red, Weeping, Blanches with pressure —> ***Indicate presence of capillary refill
   - Sensation: Painful to air / temperature
   - Healing time: 7-20 days (by Secondary intention)
   - Scarring: Unusual, potential pigmentary changes
3. Deep-partial thickness / Deep dermal (2nd degree)
   - Causes: Scald (spill), flame, oil, grease
   - Appearance: Blisters (easily unroofed), Wet / **Waxy dry, Variable colour (patchy to **cheesy white to red), ***Not blanch with pressure
   - Sensation: Perceptive of pressure only
   - Healing time: >=21 days
   - Scarring: Severe (hypertrophic), Risk of contracture
4. Full thickness (3rd degree)
   - Causes: Scald (immersion), flame, steam, oil, grease, chemical, high-voltage electricity
   - Appearance: Waxy white to **Leathery gray to **Charred / Black, Dry and inelastic, Not blanch with pressure —> Dead skin: **Eschar
   - Sensation: Deep pressure only
   - Healing time: Never (if the burn affects >=2% of TBSA)
   - Scarring: Very severe, **Risk of contracture

(Epidermal burn:
- Re-epithelialisation to heal
Full thickness burn:
- Re-epithelialisation cannot happen from layers below —> only from peripheral areas growing inwards —> Contraction of wound)

Question 11

***Fluid resuscitation

Answer 11

• In large burns over 20-30% —> significant vascular permeability + 3rd space loss —> hypovolemic shock

Children more prone and may decompensate more rapidly:
- Blood volume 80mL/kg vs 60-70mL/kg in adults
- Poorer renal tubular concentrating capacity
- Higher SA:BW radio
- Signs of decompensation occur late but rapidly

Start IV fluid resuscitation:
- Children >10% burns
- Adults >20% burns

Goal:
- Least amount of fluid necessary to maintain adequate tissue / organ perfusion (∵ third space loss)
- Best guide is **hourly **urine output: **0.5 ml/kg/hr —> put in **Foley

**Parkland formula:
- Crystalloid: **Lactated Ringer’s solution (LR) (try to keep fluid within intravascular space)
- Determine total amount of fluid given in first **24 hours **after injury
- **2-4 ml (arbitrary, depend on surgeon / urine output) x **BW (kg) x ***TBSA

Adults:
- 2-4 ml crystalloids x BW x TBSA
—> Half given in first 8 hours after injury
—> Half given in next 16 hours after injury

Children:
- 2-4 ml crystalloids x BW x TBSA + ***Maintenance fluids
—> Constant rate over 24 hours
—> 100ml/kg (first 10kg of body weight)
—> 50ml/kg for each kg (10kg - 20kg)
—> 20ml/kg for each kg (over 20kg)
—> 5% glucose in 0.45% (1/2 normal) saline

Caution:
- Under-resuscitation —> Progression of wound, Inadequate organ perfusion (may even lead to multi-organ failure)
- Over-resuscitation —> Fluid creep (major third space loss —> edematous), Compartment syndrome, Pulmonary edema

Question 12

Assessment of fluid status

Answer 12

1. Mental state and behaviour (e.g. agitation)
2. Tachycardia
3. Capillary refill
4. ***Urine output (Target 1mL/kg/hr, min 0.5)
   - best indicator of end organ perfusion (put in a urinary catheter for major burns)
5. Hypotension (late sign)

Children:
- Tachycardia and agitation can be due to distress / pain

Question 13

***Management after first 24 hours

Answer 13

1. Change of ***dressings
   - “Standard dressing”
   —> Bathing —> paraffin gauze —> Gauze —> “Velband” —> crepe bandage
   - Special dressings
   —> non-adherent dressings
   —> dressing with antibacterial compounds (e.g. Silver ions, hydrocolloid dressings, hydrogel dressings)
2. Frequent reassessment
   - Burn depth may change
   - May need to plan for surgical debridement
3. ***Surgical debridement
   - Balance between wound healing vs scarring
   - Longer the wound takes to heal, the worse the scar
   - If wound expected not to heal conservatively in 3 weeks —> Debridement + Skin graft advisable
   - Esp. in functionally / cosmetically sensitive areas

Question 14

***Surgery management in burns

Answer 14

1. Debridement (Removal necrotic skin / eschar)
   - ***Escharotomy
   —> Chest —> Allow chest expansion
   —> Limb —> Maintain circulation into limb with overlying rigid eschar
   - Auto-debridement / Mechanical / Chemical / Enzymatic / Surgical debridement
2. Skin graft (epidermis + various thickness of dermis)
   - Partial vs Full thickness
   - will adhere to wound bed in 7 days, stable in 14 days
3. Fluid resuscitation

Question 15

Escharotomy vs Fasciotomy

Answer 15

Escharotomy:
- Divide eschar
- Can be performed bedside

Fasciotomy:
- Usually for limbs / extremities
- Divide deep fascia
- Release compartmental pressure
- Avoids ischemia to muscles and nerves
- Performed under GA in theatre

Question 16

Circumferential burn

Answer 16

360o burn around a limb / trunk / neck, if deep dermal / full thickness —> can have severe constricting effect

Effect:
1. ***Circulation
- numbness and tingling
- Doppler flowmeter
- If give fluid —> constricting effect

2. ***Compromise chest wall + abdominal expansion
   - compromise ventilation —> may need mechanical ventilator
3. ***Compartment syndrome

Management:
1. Escharotomy
- Bedside
- Bloodless (∵ simply cutting away non-perfused skin)
- Diathermy cautery
—> prevent dead inelastic skin from constricting blood supply
—> allow remaining skin to expand while giving fluid
—> maintaining perfusion to distal sites

Question 17

Inhalational injury

Answer 17

Definition:
- Dysfunction within the respiratory tract (larynx to alveolus) during the first 5 days after inhaling smoke and irritating products of incomplete combustion

Larynx:
- Causes: Hot air / steam
- Effects: Laryngeal obstruction, Bronchospasm

Trachea:
- Causes: Smoke, Hot particles, Aspiration
- Effects: Mucosal slough, Infection, Bronchiolar plugging, Atelectasis, Bronchospasm

Bronchus:
- Causes: Irritant gases
- Effects: Pneumonia, Pulmonary edema, Aveolar capillary defect

History:
- Conscious level
- Noxious chemicals
- Closed space (maybe chance of CO poisoning)

P/E:
- Singed facial hairs / Facial burn / Soot on face
- Carbonaceous sputum (coughing out soot)
- Hoarseness
- Elevated CarboxyHb levels (CO poisoning)

Investigations:
- CXR
- Bronchoscope to check airway

Management:
- ***Early prophylactic intubation (airway protection ∵ may be hard to intubate once respiratory symptoms developed)
- Humidified high flow O2 (for CO poisoning)

Question 18

Electric burn

Answer 18

• Grand masquerader (∵ not much external wound seen —> electricity pass through path of least resistance i.e. in between muscle compartments / along periosteum —> prone to muscle injury / compartment syndrome)

Burn:
- Entry + Exit site

Complications:
- **Compartment syndrome
- **Rhabdomyolysis
- Cardiac complications
- Neurological complications

Classification:
- High vs Low voltage injuries
- Type of current (AC vs DC)
- Pathway of flow (Arcing / Flash)
- Duration of contact
- Local tissue resistance

S/S:
- Loss of consciousness
- **Cardiac / Pulmonary arrest at scene —> Treat cardiac arrhythmia / asystole + Airway protection
- **Paralysis / Mummification of extremities
- Flexor surface burns (e.g. popliteal fossa)
- **Compartment syndrome (pain, sensation loss) —> Fasciotomy
- **Myoglobinuria (∵ muscle injury) —> Forced alkaline diuresis (Fluid resuscitation with NaHCO3 + Mannitol) + Monitor urine output (aim 1 ml/kg/hour)

Compartment syndrome:
- Paresthesia, Pain, Pallor, Pulselessness, Paralysis
- Compartment pressure
- Fasciotomy (?GA)

Question 19

Chemical burn

Answer 19

Types:
1. Alkalis
- Liquefaction necrosis (∴ Extensive damage) + Protein denaturation
- worse than acids

2. Acids
   - Coagulation necrosis (∴ Confined damage) + Protein precipitation
3. Organic compounds
   - Fat solvent action
   - Renal / Hepatotoxicity

History:
1. Agent
2. Strength + Concentration
3. Volume
4. Duration

Management:
1. **Removal of contaminated clothing
2. **Immediate continuous irrigation with water ~10-15 mins (same as Flame burn) (X ice: induce more tissue injury)
- irrigate eyes if in contact
- until pH back to normal
3. Early surgical debridement
4. Skin graft
- full thickness skin graft (epidermis + dermis) —> less chance of scarring / contracture (important in areas e.g. eye lids, mouth) (graft usually from pre-auricular, post-auricular, lower neck, axilla, flexure areas, bottocks, groin)

Question 20

Paediatric burn

Answer 20

1. Scald burn
2. Flame burn
3. Electric burn
4. Child abuse / neglect

Physiology:
- Greater surface area per unit of body weight
- Thinner dermal layer
- Impaired capacity for thermal regulation
- Less metabolic reserve

Calculating TBSA
- ***Lund-Browder chart

Management:
1. Airway protection
2. Prevent hypothermia
3. Prevent hypoglycaemia (∵ lower metabolic reserve)
4. Fluid resuscitation (Resuscitative fluid + Maintenance fluid)
- aim for higher urine output: 1 ml/kg/hour
- Resuscitative fluid: **3-4 ml x BW x TBSA
- Maintenance fluid (Lactated Ringer’s solution + Dextrose —> **D5LR)
—> First 10kg: 100 ml/kg
—> Second 10kg: 50 ml/kg
—> Each kg above 20kg: 20 ml/kg

Question 21

Transferral

Answer 21

Burn service in HK:
Level 1 burn (Minor burn) —> General surgical / Orthopaedic department / AED
Level 2 burn (Moderate burn: >=5-20% BSA, full thickness, electrical, chemical, circumferential burn) —> Burn facility (KWH, QEH, TMH)
Level 3 burm (Major burn: >20% in adults, >10% in children) —> Burn unit (QMH, PWH: have Multidisciplinary support (ICU, Orthopaedic, Plastic surgery)

QMH:
- catchment area: HKWC, HKEC, KWC

Burn unit:
- Isolation ward with special ventilation system to reduce bacterial load
- Dedicated dressing + bathroom

Skin bank:
- Cryo-preserved cadaveric skin
—> important in major burn (>60-80%) BSA
—> as a mean of dressing
- alternatives: Biological dressing, Porcine skin

Question 22

Multidisciplinary care in burn

Answer 22

1. Physiotherapist —> prevent contracture
2. Occupational therapist —> scar management
3. Psychologist
4. Psychiatrist
5. Social worker
6. Nurses specialised in burn care

Question 23

Advances in burn management

Answer 23

1. Biological dressing
   - Amniotic membrane: apply across joint, used in paediatric patients
2. Assessment of degree of burn: Indocyanine green angiography
   - esp. in 2nd degree burn: Superficial dermal / Deep dermal
   - assess which burn wound more likely to respond to conservative management (dressing) / warrant surgery

Question 24

SpC Interactive tutorial: Burns
Definition of Burn

Answer 24

• Burns are a wound resulting from an exogenous agent on the skin and other tissues
• Human skin can tolerate temperatures up to 42-44oC —> Above these temperatures, the higher the temperature the more severe the tissue destruction
• Below 45 0C, resulting changes are mostly reversible
• > 45 0C, protein damage becomes permanent

Question 25

Physiologic Response to Burn

Answer 25

Emergent Phase (Stage 1):
- Pain response
- **Catecholamine release
- **Tachycardia, Tachypnea, Mild hypertension, Mild anxiety

Fluid Shift Phase (Stage 2):
- Duration 18-24 hours
- Begins after Emergent Phase
- Reaches peak in 6-8 hours
- Damaged cells initiate inflammatory response
- **Increased blood flow to cells
- **Shift of fluid from intravascular to extravascular space leading to massive edema

Hypermetabolic Phase (Stage 3):
- Last for days to weeks
- ***Large increase in the body’s need for nutrients as it repairs itself

Resolution Phase (Stage 4):
- Scar formation
- General rehabilitation and progression to normal function

Question 26

Admission criteria to Burn facilities and Burn centres (HK Guidelines)

Answer 26

Burn facilities (TMH, QEH, KWH):
- Burn greater than 5% BSA
- Burn that involves and threatens functional or cosmetic impairment of the face, hands, feet, genitalia, perineum and major joints
- Full-thickness burn
- Electrical burn (∵ entry point can be small but deep burn)
- Chemical burn
- Circumferential burn of limbs and chest (∵ need escharotomy)
- Burn at the extremes of age (children and elderly)
- Burn in patients with pre-existing medical disorders which could complicate management, prolong recovery, or affect mortality

Burn centres (QMH, PWH):
Additional criteria:
- Burn greater than 20% BSA for adult patients and 10% BSA for children≦12
- Burn which have major functional and/or cosmetic implications
- Burn in patients with significant pre-existing medical disorders which could complicate management, prolong recovery or affect mortality

Remarks: Pure inhalation injury without skin involvement excluded (handled by respiratory physician)

Question 27

CO poisoning

Answer 27

CarboxyHb:
- Check **ABG + send in AED
- **SaO2 NOT helpful as guide (SC chem path: mistake COHb as OxyHb)
- Diffuse rapidly in blood
- Affinity for Hb 240x greater than O2
- Reduces O2 carrying capacity
- Check COHb level
- Give 100% O2