Smoke Inhalation and Thermal Injuries

Comprehensive vocabulary and key concepts regarding thermal injuries, the stages of smoke inhalation, clinical manifestations, and emergency management.

Thermal injury

Injury caused by the inhalation of hot gases, usually confined to the upper airway including the nasal cavity, oral cavity, nasopharynx, oropharynx, and laryngopharynx.

Smoke inhalation injury

Pathologic changes in the distal airways and alveoli caused by irritating and toxic gases, suspended soot particles, and vapors associated with incomplete combustion.

Early Stage (Smoke Inhalation)

The period from $0$ to $24$ hours after inhalation characterized by tracheobronchial inflammation, bronchospasm, mucous retention, and potential noncardiogenic high-permeability pulmonary edema (ARDS).

Intermediate Stage (Smoke Inhalation)

The period from $2$ to $5$ days after inhalation where pathologic changes peak, mucosal sloughing occurs (at $3$ to $4$ days), and mucus plugging leads to atelectasis and bacterial colonization.

Late Stage (Smoke Inhalation)

The period starting $5$ or more days after inhalation where the major concern is sepsis-induced multi-organ failure, pneumonia, and potential pulmonary embolism.

Pyrolysis

The process of smoldering in a low-oxygen environment.

Combustion

The process of burning with a visible flame in an environment with adequate oxygen.

First degree burn

A superficial burn with damage limited to the outer layer of the epidermis, characterized by reddened skin and pain without blisters; heals in $6$ to $10$ days.

Second degree burn

A burn extending through the epidermis into the dermis, usually featuring blisters; heals in $7$ to $21$ days with results ranging from normal to depigmented skin.

Third degree burn

A full-thickness burn destroying both epidermis and dermis, extending into underlying tissues; heals with hypertrophic scars (keloids) and may require skin grafting.

Rule of Nines

A system used to estimate the percentage of body surface area ($BSA$) injury by assigning values of $9\%$ or $18\%$ to specific anatomic regions.

Parkland Formula

A fluid resuscitation protocol initiating $4\,mL/kg$ of body weight for each percent of body surface area burned over a $24$-hour period.

Carboxyhemoglobin ($COHb$)

A measure of carbon monoxide bound to hemoglobin; levels of $20-30\%$ typically cause throbbing headache, nausea, vomiting, and impaired judgment.

Leaky alveoli

A term used in smoke inhalation cases to describe noncardiogenic high-permeability pulmonary edema or ARDS.

Cryptogenic organizing pneumonia (BOOP)

Also known as bronchiolitis obliterans organizing pneumonia, a pathologic condition that involves the tracheobronchial tree and alveoli following smoke inhalation.

Inspiratory stridor

A clinical sign of acute upper airway obstruction resulting from thermal injury and pharyngeal edema.

Cyanide poisoning treatment

A medical intervention involving amyl nitrite inhalation and intravenous sodium thiosulfate.

Hyperbaric oxygen therapy

A treatment modality useful for the rapid elimination of carbon monoxide ($CO$) and enhancing the viability of skin grafts.

Pulmonary embolism (Late Stage)

A complication that may develop within $2$ weeks after serious body surface burns due to deep venous thrombosis secondary to hypercoagulability and immobility.