Burn Injuries: Types, Treatment & Pathophysiology

• A burn injury is tissue damage from heat, electricity, radiation, chemicals, or friction
• Burn injuries vary in severity based on depth, size, and location
• Burns cause pain, swelling, blistering, scarring, infection, and organ dysfunction
• Treatments depend on the burn's degree and cause; some can be treated at home, others need specialized care

Multidisciplinary Burn Care Team

• Surgeons
• Nurses
• Specialists
• Dedicated to fluid resuscitation
• Early wound management
• Critical care

Burn Unit Personnel

• Experienced burn surgeons
• Dedicated nursing personnel
• Physical and occupational therapists
• Social workers
• Dietitians
• Pharmacists
• Respiratory therapists
• Psychiatrists and clinical psychologists provide advice for patients and their parents
• Prosthetists

Physiological Skin Functions Disrupted by Burns

• Barrier against microorganisms
• Temperature regulation
• Fluid retention
• Sensory
• Cosmesis

Pathophysiology of Burns

• Thermal burns damage skin and sometimes the underlying tissues through temperature change
• Changes cause membrane disruption, protein denaturation, and necrosis

Inflammatory Reactions and Fluid Loss

• Burns may cause inflammatory reactions that lead to capillary leak due to exposed dermis
• Intravascular fluid loss can occur
• High fevers are a concern in admitted patients
• Organ malperfusion leads to reduced or blocked blood flow
• Multiple system organ failure (MSOF) is life-threatening when two or more organs fail
• Thermal burn injury results in cell damage and cell death, with cellular injury starting above 44°C
• Damaged capillaries leak water, electrolytes, and plasma proteins
• Metabolic response to burns includes hypermetabolism, increasing glucose metabolism, lipolysis, and proteolysis
• Neuroendocrine response increases catecholamines and cortisol while decreasing thyroid hormone
• Low thyroid hormone may be due to sepsis
• Burns are the most catabolic injury that humans can sustain

Major Problems Encountered in Burn Patients

• Fluid loss leads to dehydration and shock
• Fluid loss depends on the percentage of the burnt area; expect about 4 mL of water loss for every 1% of surface area burned
• Fluid and electrolyte management is required to prevent shock
• Tissue loss leads to loss of barrier and infection
• Severe burn patients are prone to infection due to multiple entry points for microorganisms
• Infection
• Inability to maintain body temperature
• Physical and functional deformities (contractures) can occur
• Rule out abuse in children with burns, even small ones
• Consider comorbidities in injured patients with burns
• Burn contractures limit range of motion

Guidelines for Referral to Burn Center

• Partial-thickness burns greater than 10% total body surface area (TBSA)
• Burns involving the face, hands, feet, genitalia, perineum, or major joints
• Third-degree burns in any age group
• Electrical burns, including lightning injury
• Chemical burns
• Inhalation injury
• Burn injury in patients with complicated preexisting medical disorders
• Patients with burns and concomitant trauma where the burn poses the greatest risk
• Burned children in hospitals lacking qualified personnel
• Burn injury patients needing special social, emotional, or rehabilitative intervention

Etiology and Classifications of Burns

• Flame: Damage from superheated oxidized air by convection and radiation
• Scald: Damage from contact with hot liquids
• Contact: Damage from contact with hot or cold solids
• Chemical: Contact with noxious chemicals
• Electrical: Conduction of electrical current through tissues

Depth of Injury Classifications

• Superficial: Confined to the epidermis

• Superficial partial-thickness: Injury to the epidermis and papillary dermis

• Deep partial-thickness: Injury to the epidermis and reticular dermis

• Full-thickness: Extends through the epidermis and dermis into subcutaneous fat

• Flame, scald, and contact burns cause cellular damage by energy transfer inducing coagulative necrosis

• Electrical and chemical injuries cause direct injury to cellular membranes in addition to heat transfer

Tissue Response to Burns

• Local tissue response can cause injury to deeper layers
• Cutaneous injury divided into three zones:
  • Zone of coagulation
  • Zone of stasis
  • Zone of hyperemia

Jackson Levels of Burn Injury

Zone of Coagulation

• Necrotic area where cells are directly disrupted
• Occupies the central area and the most severe burn injury
• No capillary blood flow - "Whitish"
• Contains dead skin and no vasculature

Zone of Stasis

• Area surrounding the necrotic zone
• Moderate insult with decreased tissue perfusion (blood flow)
• Can either survive or go on to coagulative necrosis depending on the wound environment
• Associated with vascular damage and vessel leakage
• Salvageable with resuscitation
• Gray area of the burn where some cells live and some die
• Can turn to 3rd-degree burn if lacks O2 and nutrients

Zone of Hyperemia

• Outermost area surrounding the zone of stasis

• Characterized by vasodilatation from inflammation

• Contains viable tissue where healing begins

• Generally not at risk for further necrosis - "Reddish"

• Most cells survive

• Heat (and other injury mechanisms) can denature proteins, causing loss of membrane integrity and cell necrosis

• Burned skin appears dry and leathery, not painful, feels firm or waxy

• Dead tissue and dried secretions form eschar, providing temporary coverage

• Eschar persists less than a month before sloughing off

Stages of Burns:

• Stage of shock
• Stage of eschar
• Stage of healing and reconstruction

Phases of Burn:

• Emergent phase: 24-48 hours
• Acute phase: 48 hours to wound closure
• Chronic phase: wound closure to functional ADL regainement

Thermal Burns

• Flame burns are the most common cause of hospital admission, accompanied by inhalation injury and the highest mortality rate
• Contact burns occur when a hot object touches the skin
• Vapors from steam are considered a scald burn

Chemical Burns

• Occur due to high acid and alkali concentrations
• 3% of admitted burn patients
• Can result in severe burns

Key Differences Between Acid and Alkali Burns:

• Acid causes coagulation necrosis

• Alkali causes liquefactive necrosis

• Initial chemical burn therapy is irrigation with water for at least 30 minutes

• Hydrofluoric acid acts like an alkali, potentially causing hypocalcemia

• If poured on skin or eyes, flush for 30 minutes and apply calcium gluconate gel

Electrical Burns

• 3% of US hospital admissions
• Has direct effects on the body, especially the heart (an electrical organ)
• Has nerves and areas offering the least resistance (blood vessels)

Special Concerns with Electrical Burns:

• Cardiac arrhythmia: Baseline ECG is recommended
• Compartment syndrome and rhabdomyolysis
• Common in high-voltage injuries; muscles are destroyed, causing edema and compartment syndrome
• Vigilance for neurologic or vascular compromise is needed, with fasciotomies even in cases of clinical suspicion
• Fasciotomies should be done even in cases of clinical suspicion Long-term neurologic symptoms and cataract development
• Neurologic and Ophthalmologic consultations are crucial to defining baseline function

Inhalation Burns

• Inhalation injury is a severe injury
• Occurs when breathing smoke in an enclosed area
• Smoke can cause:
  • Carbon monoxide poisoning
  • Irritation/inflammation of the respiratory tract and respiratory depression
  • Asphyxia

Smoke Inhalation Injury Treatments

• Bronchodilators (e.g., albuterol)
• Nebulized heparin
• Nebulized acetylcysteine

Classification of Inhalation Injury

Upper Airway Injury

• Mechanism: Thermal burns from heat transfer
• Clinical Consequences: Airway edema obstruction

Lower Airway/Lung Parenchyma

• Mechanism: Chemical and particulate irritants
• Clinical Consequences:
  • Fibrin casts obstructing airways
  • Inflammation
  • Ventilation/perfusion mismatch
  • Atelectasis
  • Bronchospasm

Systemic Cellular Dysfunction

• Mechanism: Asphyxia/hypoxia due to carbon monoxide and cyanide exposure'
• Clinical Consequences:
  • Lactic acidosis
  • Central nervous system insults
  • Cardiovascular insults

Physical Examination (P.E.)

• ABC's (Airway, Breathing, Circulation) are the same as for any other trauma assessment
• Do not debride or dress burns before complete examination
• Get the patient's weight
• Look at the following
  • Airway: Establish definitive airway if not intact
  • Breathing: address impaired respiration/oxygenation
  • Circulation: address decreased perfusion
  • Disability: address altered mental status
  • Exposure: Manage other injuries and calculate burn area

Initial Management of Major and Critical Burns:

• Intubate if:
  • Burns 50% BSA
  • Suspected Inhalation injury
  • Smoke inhalation
• Insert IV line for fluid resuscitation
• Insert Foley catheter (to monitor UO)
• Insert NGT (to decompress stomach) and IV PPI (to avoid Curling's ulcer)

Immediate Concerns in Burn Care

• Airway: Ensure patency and consider airway protection
  • Visual inspection
  • Administration of oxygen
  • Application of hard cervical collar or sandbags
• Consider Indications for Emergency Endotracheal Intubation
  • Acute airway obstruction
  • Hypoventilation
  • Hypoxemia
  • Altered mental status
  • Cardiac arrest
  • Hemorrhagic shock
• Breathing: Adequate oxygenation and ventilation are a must
  • Assess
  • Inspect
  • Palpate
  • Auscultate
• Circulation: Hemorrhagic shock should be assumed
  • Look for bleeding
  • Assess the pulse, skin color, and capillary refill
  • Initiate IV catheterization with two large-bore catheters and consider venous cutdown or central line insertion
• Disability: Glasgow Coma Scale (GCS)
  • Calculated by adding the scores of the best motor response, best verbal response, and the best eye response
  • Consider spinal injury in appropriate cases
• Fluid Resuscitation: Initiate the appropriate IV fluid

Inhalation Burns

• Common in high-voltage injuries; muscles are literally destroyed; vigilance for neurologic or vascular compromise
• Long-term neurologic symptoms and cataract development
• Inhalation injury - admissible agad ang pasyente
• TABLE 20.3 Inhalation treatments of smoke inhalation injury

ATLS way of trauma management

• Preparation
• Triage
• Primary survey (ABCDEs)
• Resuscitation
• Adjuncts to primary survey and resuscitation
• Secondary survey
• Adjuncts to secondary survey
• Continuous post resuscitation monitoring and re evaluation
• Definitive care

Airway Management with Cervical Spine Protection

• Must ensure patency of airway and consider airway protection
• Visual inspection: airway cleared of any debris, blood and foreign bodies
• Administration of oxygen is needed
• Application of hard cervical collar or sandbags on both sides of the neck to immobilize neck (except with penetrating trauma)
• Manual airway maneuvers: serve to elevate the tongue out of the hypopharynx
• Jaw thrust (Esmarch maneuver)
  • Chin lift

Estimating Burn Size (TBSA)

• Burn size is expressed as percent total body surface area burned (%TBSA)
• Count only those areas with partial (second degree) or full thickness (third degree) burns
• Tools available include: the Rule of Nines, the Lund-Browder chart, and the Berkow Diagram

Methods for size estimation

• Palmar Method: an estimate of 1% of TBSA (hand plus fingers)
• Lund-Browder Chart: considers three zones on the body that vary depending on age and takes into consideration changes in body proportions
• 6-year-old female with burns in her right buttocks and entire right thigh. The right thigh burn covers 10.5% BSA involvement (8% for the entire right thigh, and 2.5% for the right buttock). Berkow Diagram

Parkland or Baxter Formula for Fluid Resuscitation (initial 24 hours):

• IVF Requirement is TBSA burned (%) x Weight(Kg) x 4mL/Kg
• Half the requirement should be given during the first 8 hours after the burn
• The remaining half is administered over 16 hours

Initial Emergency Room Management

• Primary Survey (ABCDE) & Resuscitation
• Secondary Survey (burn-specific): History, time of injury, tetanus immune status, and height/weight
• Fluid Resuscitation is the method of stabilizing the fluids within the patient with the main mortality cause being inadequate fluid

Initial Wound Management

• Performed in the sterile areas, give patient a full body bath, debride and wash the burn areas, dress wounds

Escharotomies

• These surgical procedures release the burn eschar that constricts the circulation/movement of the affected body parts
• Indicated for deep partial/ full-thickness burns that encompass the circumference of an extremity or the trunk

Nutrition

• Severe burn causes hypermetabolism, resulting in very high energy utilization and depletion of essential body nutrients
• Lack of essential nutrients leads to poor organ function, inefficient wound healing, and poor response to treatment
• Adequate nutrition can be based on the Harris-Benedict formula, other methods include the Curreri formula