Thermal and Inhalation Injury Chapter 39 Written by : Melissa Dearing – LSC-Kingwood

Epidemiology In the U.S. In the U.S. Results in 60,000 hospitalizations annually Results in 60,000 hospitalizations annually 6000 deaths annually 6000 deaths annually Mortality the highest in Mortality the highest in Young children Young children elderly elderly

Epidemiology In pediatric thermal injuries: In pediatric thermal injuries: Less than 5% are the result of chemical or electrical burns Less than 5% are the result of chemical or electrical burns 10-15% result from flame burns 10-15% result from flame burns When associated with smoke inhalation are the most deadly When associated with smoke inhalation are the most deadly Scalding burns account for 75-80% Scalding burns account for 75-80%

Prevention Smoke detectors that work Smoke detectors that work Keep matches out of reach Keep matches out of reach Lower the temp on hot water heaters Lower the temp on hot water heaters Cover electrical outlets Cover electrical outlets Buy flame resistant children’s clothing Buy flame resistant children’s clothing Use fire-safe cigarettes Use fire-safe cigarettes

Mortality Rate Highest when: Highest when: Burn exceeds 30% body surface area. Burn exceeds 30% body surface area. See figure 39-1 See figure 39-1 Associated with smoke inhalation Associated with smoke inhalation Child younger than 4 years old Child younger than 4 years old

Pathophysiology Disruption of the protection provided by skin: Disruption of the protection provided by skin: Protects body from infection and injury Protects body from infection and injury Prevents fluid loss Prevents fluid loss Regulates body temp Regulates body temp Provides sensory input from environment Provides sensory input from environment

Pathophysiology Composed of 2 layers Composed of 2 layers Epidermis – thin outer layer Epidermis – thin outer layer Dermis – deeper, thick inner layer Dermis – deeper, thick inner layer Dermis contains: Dermis contains: Hair follicles Hair follicles Sweat glands Sweat glands Sebaceous glands Sebaceous glands Sensory fibers for touch, pain, pressure and temp Sensory fibers for touch, pain, pressure and temp Beneath the dermis Beneath the dermis Subcutaneous tissue composed of connective tissue and fat Subcutaneous tissue composed of connective tissue and fat

Classification of Burn 1 st Degree 1 st Degree Superficial Superficial Involves only the dermis Involves only the dermis Skin is red Skin is red No blisters No blisters Painful and sensitive to touch Painful and sensitive to touch

Classification of Burn 2 nd Degree 2 nd Degree Involve the epidermis and part of the dermis Involve the epidermis and part of the dermis Very painful due to nerve endings that survive the insult Very painful due to nerve endings that survive the insult Blistering is common Blistering is common Healing occurs quickly Healing occurs quickly

Classification of Burn 3 rd Degree 3 rd Degree “Full thickness” burns “Full thickness” burns Involve injury and necrosis below the hair follicles thru the entire thickness of skin and into subcutaneous tissue Involve injury and necrosis below the hair follicles thru the entire thickness of skin and into subcutaneous tissue Area swells slowly and appears blanched Area swells slowly and appears blanched Sensory nerves are destroyed causing local anesthesia Sensory nerves are destroyed causing local anesthesia

Management 1 st degree usually heals by itself 1 st degree usually heals by itself 2 nd and 3 rd degree may require grafting, excision and antimicrobial therapy such as Silva dine 2 nd and 3 rd degree may require grafting, excision and antimicrobial therapy such as Silva dine

Management Important to initiate accurate fluid resuscitation ASAP Important to initiate accurate fluid resuscitation ASAP Careful: overaggressive fluid resuscitation may result in high extravascular hydrostatic pressure, pulmonary edema and soft tissue swelling Careful: overaggressive fluid resuscitation may result in high extravascular hydrostatic pressure, pulmonary edema and soft tissue swelling Urine output is a good indicator of hydration Urine output is a good indicator of hydration

Inhalation Injury Mortality from smoke injury alone is 0-11% Mortality from smoke injury alone is 0-11% Mortality from smoke injury and burns is 30-90% Mortality from smoke injury and burns is 30-90% Smoke inhalation that results in pneumonia has a mortality rate of 60% Smoke inhalation that results in pneumonia has a mortality rate of 60%

Physiologic Consequences of Inhalation Injury Box 39-1 Box 39-1

Upper Airway Injury Results in obstruction from: Results in obstruction from: Edema Edema Hemorrhage Hemorrhage Ulceration of mucosa Ulceration of mucosa Mild pharyngeal edema can lead to complete upper airway obstruction and asphyxia in only a few hours Mild pharyngeal edema can lead to complete upper airway obstruction and asphyxia in only a few hours Inflammation can be the result of ammonia, hydrogen chloride and chemical irritants found in smoke Inflammation can be the result of ammonia, hydrogen chloride and chemical irritants found in smoke

Lung Parenchyma Injury Only steam is capable of overwhelming the upper airway defenses and transmitting heat to the subglottic airways Only steam is capable of overwhelming the upper airway defenses and transmitting heat to the subglottic airways Direct cellular injury results in inflammatory response Direct cellular injury results in inflammatory response Leads to bronchoconstriction Leads to bronchoconstriction Increase in tracheobronchial blood flow with edema Increase in tracheobronchial blood flow with edema Leukocyte infiltration Leukocyte infiltration

Lung Parenchyma Injury Sloughing of necrotic tissue plugs up the airways Sloughing of necrotic tissue plugs up the airways Can cause partial or complete airway obstruction Can cause partial or complete airway obstruction Can be fatal Can be fatal

Lung Parenchyma Injury Pulmonary parenchyma shows: Pulmonary parenchyma shows: Varying degrees of congestion Varying degrees of congestion Interstitial and alveolar edema Interstitial and alveolar edema Hyaline membranes Hyaline membranes Dense atelectasis Dense atelectasis

Lung Parenchyma Injury Systemic effects: Systemic effects: Increase in RAW Increase in RAW V/Q mismatch V/Q mismatch Increase in oxygen consumption Increase in oxygen consumption Decrease in compliance Decrease in compliance Decrease in oxygenation Decrease in oxygenation Decreased surfactant production Decreased surfactant production

Carbon Monoxide Poisoning Smoke inhalation from all types of fires result in significant CO exposure. Smoke inhalation from all types of fires result in significant CO exposure. Pulse oximeter do not reflect the true oxygen saturation in the presence of COHB. Pulse oximeter do not reflect the true oxygen saturation in the presence of COHB. Symptoms- Table 39-1 Symptoms- Table 39-1

Clinical Manifestations Smoke inhalation injury more likely in individuals with: Smoke inhalation injury more likely in individuals with: History of burn injury in an enclosed space History of burn injury in an enclosed space Appearance of facial burns Appearance of facial burns Singed nose and facial hair Singed nose and facial hair Erythema of the oropharynx Erythema of the oropharynx Carbonaceous sputum Carbonaceous sputum Debris around the nose, mouth and pharynx Debris around the nose, mouth and pharynx

Bronchoscopy Gold standard for diagnosis of inhalation injury Gold standard for diagnosis of inhalation injury Provides direct visualization of airway Provides direct visualization of airway Soot Soot Charring Charring Mucosal erythema Mucosal erythema Ulceration Ulceration Hemorrhage Hemorrhage Edema Edema inflammation inflammation

Management Oxygen Therapy Oxygen Therapy Airway Maintenance Airway Maintenance Bronchial Hygiene Therapy Bronchial Hygiene Therapy Pharmacologic Management Pharmacologic Management Mechanical Ventilation Mechanical Ventilation Conventional Conventional High frequency High frequency

Management Oxygen Therapy Oxygen Therapy Initially give 100% Initially give 100% Wean by blood gas values Wean by blood gas values Analyze COHB with co-ox Analyze COHB with co-ox

Management Airway maintenance Airway maintenance Intubation by most skilled clinician Intubation by most skilled clinician Nasal intubation is easier for securing a tube to a burned face Nasal intubation is easier for securing a tube to a burned face Burns to the neck can cause tightening of the tissue causing restriction to the airway Burns to the neck can cause tightening of the tissue causing restriction to the airway Escharotomies to reduce the pressure exerted to the area Escharotomies to reduce the pressure exerted to the area

Management Bronchial Hygiene Therapy Bronchial Hygiene Therapy Retained secretions can be life threatening Retained secretions can be life threatening Early ambulation Early ambulation Therapeutic coughing Therapeutic coughing Chest PT Chest PT Airway suctioning Airway suctioning Therapeutic bronchoscopy Therapeutic bronchoscopy Pharmacologic agents for retained secretions Pharmacologic agents for retained secretions

Management Pharmacological Management Pharmacological Management Inhalation injury creates intense bronchospasm and wheezing Inhalation injury creates intense bronchospasm and wheezing Manage with B2 – agonists Manage with B2 – agonists Racemic epinephrine to promote vasoconstriction (trx edema), bronchodilation, and breaking up of secretions Racemic epinephrine to promote vasoconstriction (trx edema), bronchodilation, and breaking up of secretions Mucomyst to break down mucus in the airway Mucomyst to break down mucus in the airway Heparin/mucomyst nebulizer may reduce pts mortality Heparin/mucomyst nebulizer may reduce pts mortality

Management Mechanical Ventilation Mechanical Ventilation For resp failure associated with inhalation injury For resp failure associated with inhalation injury Pts with this type of injury are at increased risk of ventilator associated injury Pts with this type of injury are at increased risk of ventilator associated injury

Management Conventional Mechanical Ventilation Conventional Mechanical Ventilation Start with Vt of ml/kg Start with Vt of ml/kg Better outcomes with non conventional modes of ventilation such as: Better outcomes with non conventional modes of ventilation such as: Pressure limited ventilation Pressure limited ventilation Reduced rate of death with this type of injury Reduced rate of death with this type of injury

High Frequency Ventilation Provides o2 at lower concentrations and adequate ventilation at reduced airway pressures. Provides o2 at lower concentrations and adequate ventilation at reduced airway pressures. Reduces barotrauma Reduces barotrauma Less incidence of pneumonia Less incidence of pneumonia Improved PaO2/FiO2 ratio Improved PaO2/FiO2 ratio

Complications Most common complications are infection and resp failure Most common complications are infection and resp failure Barotrauma due to MV Barotrauma due to MV Late complications due to inflammatory responses of the body Late complications due to inflammatory responses of the body Bronchiectasis Bronchiectasis Bronchial stenosis Bronchial stenosis ETT cuffs erosion ETT cuffs erosion

Long Term Outcomes Most patients have normal lung parenchyma return within 5 months Most patients have normal lung parenchyma return within 5 months Children heal slowly Children heal slowly PFT changes for up to 8 years PFT changes for up to 8 years Altered lung mechanics Altered lung mechanics Impaired gas exchange Impaired gas exchange Chest wall scarring Chest wall scarring Weak resp muscles Weak resp muscles Some children never regain normal lung function Some children never regain normal lung function