Burn Injuries

transcript

Burn Injuries Dr. Eranda Epaarachchi

The layers of the skin

Anatomy of the skin

Classification of burns – By depth

What is shown here?

What is the diagnosis?

First degree burns

Characteristics

Epidermis is involved Appearance : Redness (Erythema) Dry & painful Heals within 1 week Complications : Risk of developing skin cancer in

later life

What are these lesions?

Superficial – partial thickness burn (20)

Second degree – Partial thickness

Characteristics

Extends into superficial dermis Red with clear blister & Blanches with pressure Moist & painful Heals within 2-3 weeks Complications : Local infection, Cellulitis

Deep partial thickness burn

Characteristics

Extends into deep dermis Red-and-white with bloody blisters & Less blanching Moist & painful May heal in weeks or progress into a third degree burn Complications : Scarring, contractures (May need skin grafts)

Third degree burns (Full thickness)

Characteristics

Extends through entire dermis Stiff and white/brown Dry, leathery to touch Painless Requires excision Complications : Scarring, contractures, amputation

It’s a fourth degree burn

Characteristics

Extends through skin, subcutaneous tissue and into underlying muscle and bone

Black (charred) Dry Painless Requires excision Complications : Amputation, significant functional impairment, possible

gangrene, and in some cases death

Classification of burns by causes

Chemical

Most chemicals that cause burns are strong acids & bases Acids : H2SO4, HNO3, HCl Bases : NaOH Acid burns : Most of the injury occurs at the point of impact Alkali burns : Capable of deep penetration and can cause severe

NaOH burn after 44 hours from exposure

Electrical burns – Causes

1. Workplace injuries2. Taser wounds3. Being defibrillated

without a conductive gel

4. Lightning

Electrical burns

Human body is very vulnerable to application of supra-physiologic electric fields

Some electrocutions produce no external burns at all, as very little current is required to cause fibrillation of the heart muscle

The internal injuries sustained may be disproportionate to the size of the burns seen (if any), and the extent of the damage is not always obvious

Such injuries may lead to Cardiac arrhythmias Cardiac arrest Unexpected falls with resultant fractures or dislocations

Electrical burns – Low voltage injuries Low-voltage (<500 AC volts) injuries usually doesn’t

have skin burns This is sufficient to cause cardiac arrest and

ventricular fibrillation

VF (Can lead to aystole in minutes) – Defibrillation to save the life

Electrical burns – High voltage (> 1000V) injuries Common cause of third and fourth degree burns Explosions caused by electrical faults produce high

intensity Ultraviolet radiation which can also cause radiation burns

Radiation burn – causes

Radiation burns are caused by prolonged exposure to UV light (Sun exposure – the commonest) : Severity UVB > UVA Tanning booths Radiation therapy Radioactive fallout X-rays

More severe cases of sun burn result in what is known as "heatstroke“

Microwave burns are caused by the thermal effects of microwave radiation

Heatstroke

Microwave burn

Scalding

Caused by hot liquids (water or oil) or gases (steam) Immersion scald is created when an extremity is held under the surface

of hot water (Common form of burn seen in child abuse) Scald burns are more common in children Generally scald burns are first or second degree burns, but third degree

burns can result, especially with prolonged contact (Diabetic neuropathy)

Immersion scald

Child abuse?

Inhalation injury

Steam, smoke and high temperatures can cause inhalational injury to the airway and lungs

Inhalation injury

Pathophysiology of burns injuries

Burn injury results in a local or systemic inflammatory response (Depends on the size of the burn)

The lungs may be doubly compromised by smoke inhalation Following a major burn injury, heart rate and peripheral vascular

resistance increase This is due to the release of catecholamines from injured tissues and the

relative hypovolemia that occurs from fluid volume shifts

Initially cardiac output decreases

At approximately 24 hours after burn injuries, cardiac output returns to normal if adequate fluid resuscitation has been given

Following this, cardiac output increases to meet the hyper-metabolic needs of the body

The effects of high temperature on tissue include speeding chemical reactions & denaturing proteins

Due to the inflammatory response, permeability of blood vessels is increased in the burn area This causes exudation of proteins and fluid into the adjacent

interstitial tissue Red cells are not extravasated

This results in increase in the oncotic pressure in the interstitium

The volume of fluid loss is directly proportional to the burn area If burn area is 10% to 15% of the total body surface area (TBSA),

then the consequent fluid loss may cause circulatory shock If it is more than 25% of TBSA, then inflammation occurs even in

the blood vessels remote to the burn, causing greater fluid loss

Diagnosis – By severity

By American Burn Association

Major burns – Treat in specialized burn units 1. Age 10-50yrs : Partial thickness burns >25% of total body surface area2. Age <10 or >50 : Partial thickness burns >20% of total body surface area3. Full thickness burns >10%4. Burns involving the hands, face, feet or perineum5. Burns that cross major joints6. Circumferential burns to any extremity7. Any burn associated with inhalational injury8. Electrical burns9. Burns associated with fractures or other trauma10.Burns in infants and the elderly11.Burns in persons at high-risk of developing complications

Moderate burns – Treat in hospitals

1. Age 10-50yrs : Partial thickness burns involving 15-25% of total body surface area

2. Age <10 or >50 : Partial thickness burns involving 10-20% of total body surface area

3. Full thickness burns involving 2-10% of total body surface area

Minor burns – Doesn’t require hospitalization 1. Age 10-50yrs : Partial thickness burns <15% of total body

surface area2. Age <10 or >50 : Partial thickness burns involving <10% of

total body surface area3. Full thickness burns <2% of total body surface area, without

associated injuries

Estimating surface area burnt – Rule of 9

Lund & Browder charts (More accurate) The size of a person's hand print (palm and fingers) is approximately

0.8% of their TBSA, but for quick estimates, medical personnel round this to 1%, slightly overestimating the size of the affected area

Burns of >/= 10% in children or >/=15% in adults are potentially life threatening injuries (because of the risk of hypovolemic shock) and should have formal fluid resuscitation and monitoring in a burns unit

Lund & Browder charts

Management

Once the injured person is stabilized, attention is turned to the care of the burn wound itself

Until then, it is advisable to cover the burn wound with a clean and dry sheet or dressing

Early cooling reduces burn depth and pain, but care must be taken as uncontrolled cooling can result in hypothermia

IV fluids

Children with >10% TBSA burns, and adults with >15% TBSA burns need formal fluid resuscitation and monitoring (blood pressure, pulse rate, temperature and urine output)

Once the burning process has been stopped, the injured person should be volume resuscitated according to the Parkland formula

This formula calculates the amount of Ringer's lactate required to be administered over the first 24 hours post-burn.

Parkaland formula

Composition of Ringer’s lactate Hartman’s solution (Very similar, but ionic concentrations are different)

Na+ = 131K+ = 5Ca2+ = 4Cl– = 111Lactate = 29

IV fluids

Parkland formula = 4ml x (percentage of total body-surface-area sustaining non-superficial burns) x (person's weight in kg)

Half of this total volume should be administered over the first 8 hours, with the remainder given over the following 16 hours

This time frame is calculated from the time at which the burn is sustained, and not the time at which fluid resuscitation is begun

IV fluids

Children also require the addition of maintenance fluid volume

The formula is a guide only and infusions must be tailored to the urine output and central venous pressure

Inadequate fluid resuscitation may cause renal failure and death, but over-resuscitation also causes morbidity

Crystalloid fluids appear just as good as colloid fluids and as colloids are more expensive they are not recommended

Other aspects of the management

Wound care : Biosynthetic dressings may speed healing Antibiotics Analgesics Surgery : Skin grafts (As early as possible for better

results) Alternative therapy : Bee honey

Biosynthetic dressing

Complications – Infections Risk factors for infections 1. Burn > 30% TBSA2. Full-thickness burn3. Extremes in age (very young, very old)4. Preexisting disease e.g. diabetes5. Virulence and antibiotic resistance of colonizing organism6. Failed skin graft7. Improper initial burn wound care8. Prolonged open burn wound

Complications

Burn wounds are prone to tetanus (A tetanus booster shot is required if individual has not been immunized within the last 5 years)

Circumferential burns of extremities may compromise circulation. Elevation of limb may help to prevent dependent edema

Acute Tubular Necrosis of the kidneys can be caused by myoglobin and hemoglobin released from damaged muscles and red blood cells

Prognosis

The modified Baux score determines the futility point for major burn injury The Baux score is determined by adding the size of the burn (% TBSA) to

the age of the patient In most burn units a score of 140 or greater is a non-survivable injury, and

comfort care should be offered In children all burn injuries less than 100% TBSA should be considered a

survivable injury. A major concern of a survivor of any traumatic injury is post-traumatic

stress disorder (PTSD) Another significant concern for children is coping with a disturbance in

body image

Thank you!

Burn Injuries

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