Thermal and Inhalation Injury Chapter 39 Written by : Melissa Dearing – LSC-Kingwood
Epidemiology n In the U. S. n Results in 60, 000 hospitalizations annually n 6000 deaths annually n Mortality the highest in n Young n elderly children
Epidemiology n In pediatric thermal injuries: n Less than 5% are the result of chemical or electrical burns n 10 -15% result from flame burns n When associated with smoke inhalation are the most deadly n Scalding burns account for 75 -80%
Prevention n Smoke detectors that work n Keep matches out of reach n Lower the temp on hot water heaters n Cover electrical outlets n Buy flame resistant children’s clothing n Use fire-safe cigarettes
Mortality Rate n Highest when: n Burn n See exceeds 30% body surface area. figure 39 -1 n Associated n Child with smoke inhalation younger than 4 years old
Pathophysiology n Disruption of the protection provided by skin: n Protects body from infection and injury n Prevents fluid loss n Regulates body temp n Provides sensory input from environment
Pathophysiology n Composed of 2 layers n Epidermis – thin outer layer n Dermis – deeper, thick inner layer n Dermis contains: Hair follicles n Sweat glands n Sebaceous glands n Sensory fibers for touch, pain, pressure and temp n n Beneath n the dermis Subcutaneous tissue composed of connective tissue and fat
Classification of Burn n 1 st Degree n Superficial n Involves only the dermis n Skin is red n No blisters n Painful and sensitive to touch
Classification of Burn n 2 nd Degree n Involve the epidermis and part of the dermis n Very painful due to nerve endings that survive the insult n Blistering is common n Healing occurs quickly
Classification of Burn n 3 rd Degree n “Full thickness” burns n Involve injury and necrosis below the hair follicles thru the entire thickness of skin and into subcutaneous tissue n Area swells slowly and appears blanched n Sensory nerves are destroyed causing local anesthesia
Management 1 st degree usually heals by itself n 2 nd and 3 rd degree may require grafting, excision and antimicrobial therapy such as Silva dine n
Management n Important to initiate accurate fluid resuscitation ASAP n Careful: overaggressive fluid resuscitation may result in high extravascular hydrostatic pressure, pulmonary edema and soft tissue swelling n Urine output is a good indicator of hydration
Inhalation Injury Mortality from smoke injury alone is 0 -11% n Mortality from smoke injury and burns is 30 -90% n Smoke inhalation that results in pneumonia has a mortality rate of 60% n
Physiologic Consequences of Inhalation Injury n Box 39 -1
Upper Airway Injury n Results in obstruction from: n Edema n Hemorrhage n Ulceration of mucosa Mild pharyngeal edema can lead to complete upper airway obstruction and asphyxia in only a few hours n Inflammation can be the result of ammonia, hydrogen chloride and chemical irritants found in smoke n
Lung Parenchyma Injury Only steam is capable of overwhelming the upper airway defenses and transmitting heat to the subglottic airways n Direct cellular injury results in inflammatory response n n Leads to bronchoconstriction n Increase in tracheobronchial blood flow with edema n Leukocyte infiltration
Lung Parenchyma Injury n Sloughing of necrotic tissue plugs up the airways n Can cause partial or complete airway obstruction n Can be fatal
Lung Parenchyma Injury n Pulmonary parenchyma shows: n Varying degrees of congestion n Interstitial and alveolar edema n Hyaline membranes n Dense atelectasis
Lung Parenchyma Injury n Systemic effects: n Increase in RAW n V/Q mismatch n Increase in oxygen consumption n Decrease in compliance n Decrease in oxygenation n Decreased surfactant production
Carbon Monoxide Poisoning Smoke inhalation from all types of fires result in significant CO exposure. n Pulse oximeter do not reflect the true oxygen saturation in the presence of COHB. n Symptoms- Table 39 -1 n
Clinical Manifestations n Smoke inhalation injury more likely in individuals with: n History of burn injury in an enclosed space n Appearance of facial burns n Singed nose and facial hair n Erythema of the oropharynx n Carbonaceous sputum n Debris around the nose, mouth and pharynx
Bronchoscopy Gold standard for diagnosis of inhalation injury n Provides direct visualization of airway n n Soot n Charring n Mucosal erythema n Ulceration n Hemorrhage n Edema n inflammation
Management Oxygen Therapy n Airway Maintenance n Bronchial Hygiene Therapy n Pharmacologic Management n Mechanical Ventilation n n Conventional n High frequency
Management n Oxygen Therapy n Initially n Wean give 100% by blood gas values n Analyze COHB with co-ox
Management n Airway maintenance n Intubation by most skilled clinician n Nasal intubation is easier for securing a tube to a burned face n Burns to the neck can cause tightening of the tissue causing restriction to the airway n Escharotomies to reduce the pressure exerted to the area
Management n Bronchial Hygiene Therapy n Retained n Early secretions can be life threatening ambulation n Therapeutic n Chest coughing PT n Airway suctioning n Therapeutic bronchoscopy n Pharmacologic agents for retained secretions
Management n Pharmacological Management n Inhalation injury creates intense bronchospasm and wheezing n Manage with B 2 – agonists n Racemic epinephrine to promote vasoconstriction (trx edema), bronchodilation, and breaking up of secretions n Mucomyst to break down mucus in the airway n Heparin/mucomyst nebulizer may reduce pts mortality
Management n Mechanical Ventilation n For resp failure associated with inhalation injury n Pts with this type of injury are at increased risk of ventilator associated injury
Management n Conventional Mechanical Ventilation n Start with Vt of 12 -15 ml/kg n Better outcomes with non conventional modes of ventilation such as: n Pressure limited ventilation n Reduced rate of death with this type of injury
High Frequency Ventilation Provides o 2 at lower concentrations and adequate ventilation at reduced airway pressures. n Reduces barotrauma n Less incidence of pneumonia n Improved Pa. O 2/Fi. O 2 ratio n
Complications Most common complications are infection and resp failure n Barotrauma due to MV n Late complications due to inflammatory responses of the body n n Bronchiectasis n Bronchial stenosis n ETT cuffs erosion
Long Term Outcomes Most patients have normal lung parenchyma return within 5 months n Children heal slowly n n PFT changes for up to 8 years n Altered lung mechanics n Impaired gas exchange n Chest wall scarring n Weak resp muscles n Some children never regain normal lung function
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