Smoke inhalation is the breathing in of harmful fumes (produced as by-products of combusting substances) through the respiratory tract. This can cause smoke inhalation injury (subtype of acute inhalation injury) which is damage to the respiratory tract caused by chemical and/or heat exposure as well as possible systemic toxicity after smoke inhalation. Smoke inhalation can occur from fires of various sources such as residential, vehicle, and wildfires. Morbidity and mortality rates in fire victims with burns are increased in those with smoke inhalation injury. Victims of smoke inhalation injury can present with cough, difficulty breathing, low oxygen saturation, smoke debris and/or burns on the face. Smoke inhalation injury can affect the upper respiratory tract (above the larynx), usually due to heat exposure, or the lower respiratory tract (below the larynx), usually due to exposure to toxic fumes. Initial treatment includes taking the victim away from the fire and smoke, give 100% oxygen at high flow through face mask (non-rebreather if available), and check the victim for injuries to the body. Treatment for smoke inhalation injury is largely supportive with varying degrees of consensus on benefits of specific treatments. Epidemiology
The U.S. Fire Administration reported almost 1.3 million fires in 2019 causing 3,704 deaths and almost 17,000 injuries. Residential fires were found to be most often cooking related and resulted in the highest amount of deaths when compared to other fire types such as vehicle and outdoor fires.
Acute Respiratory Distress Syndrome (ARDS) is a relatively delayed complication of smoke inhalation injury caused by chemical fumes inducing an inflammatory response in the lung tissue especially the small air sacs known as alveoli where critical gas exchange occurs. Another potential complication is swelling of the upper airway from both heat and chemical damage and can become profound enough to obstruct breathing. The onset of airway swelling can be relatively delayed making it difficult to intubate later on thus endotracheal intubation should be considered early in certain patients. Other possible complications include pneumonia, vocal cord damage and/or dysfunction, and tracheal stenosis (usually delayed). Mechanism
Inhalation of chemical toxins produced by combusting materials can cause damage to tissues of both the upper (above larynx) and lower respiratory tract (below larynx). Damage to lower airways, air sacs, and lung tissue is due to an inflammatory cascade in response to the noxious chemicals which causes a variety of downstream effects such as increased secretions and exudative material thus clogging the airways and/or air sacs, collapse of air sacs (atelectasis), vascular permeability leading to pulmonary edema (fluid in the lungs), bronchoconstriction, activation of the coagulation cascade, and impaired function of the mucociliary escalator.Inhalation of hot fumes can cause thermal damage to tissues usually limited to the upper respiratory tract (above larynx).