07/13/2019
FIRE IN , Pa
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Inhalation injury is a nonspecific term that refers to damage to the respiratory tract or lung tissue from heat, smoke, or chemical irritants carried into the airway during inspiration. The term is often used synonymously with smoke inhalation injury. Inhalation injury resulting from fire remains one of the leading causes of death.
Inhalation injury can affect the airways as well as result in systemic toxicity. The location and severity of injury depends on several factors, including the ignition source, the size and diameter of the particles in the smoke, the duration of the exposure, and the solubility of the gases. Direct toxin damage is caused by the lower-molecular-weight constituents of smoke because of their pH, ability to form free radicals, and ability to reach the distal airways and alveoli. Based upon the primary localization of the insult, inhalation injury is classified into injuries of the upper airway, the tracheobronchial system, or the lung parenchyma.
The leading injury in the upper airway (above the vocal cords) is thermal injury due to the efficient heat exchange in the oro- and nasopharynx. The immediate injury results in erythema, ulcerations, and edema. In combined burn and inhalation injury, aggressive fluid administration required to treat burn shock promotes early edema formation.
Toxic inhalation of noxious gases (eg, chlorine), liquids (eg, acid), and direct airway fire (eg, intraoperative) can also be associated with a similar process. Clinical symptoms include persistent coughing and wheezing, soot-containing airway secretions (ie, melanoptysis), increased work of breathing resulting in hypoventilation, erythema, hyperemia, and increased pulmonary shunting from lobar collapse or atelectasis.
Damage to the lung parenchyma is delayed. The time difference from the initial injury to the occurrence of a decrease in arterial oxygen tension to inspiratory oxygen fraction ratio (PaO2:FiO2 ratio) is correlated with the severity of the lung injury .
The diagnosis of inhalation injury may be suspected based upon clinical findings in the setting of smoke exposure, but a definitive diagnosis relies upon direct examination of the airways.
Treatment of inhalation injury is supportive and aimed at relieving bronchospasm, reducing pulmonary secretions, and clearing the airways of fibrin casts and sloughed, necrotic bronchial epithelium, which can cause airway obstruction and atelectasis leading to pneumonia.
The clinical manifestations (eg, cough, dyspnea, wheeze, chest tightness) of reactive airways dysfunction syndrome (RADS) and irritant-induced asthma (IIA) differ mainly in the rapidity of onset of symptoms. In RADS, the onset of symptoms is usually so abrupt that subjects are able to date their occurrence precisely, although a few patients report respiratory symptoms developing up to seven days after the exposure. Patients with multiple exposures to high concentrations of products such as chlorine may be able to identify the timing, nature, and frequency of events. However, patients with the not-so-sudden onset variant of IIA may not be aware of multiple low level irritant exposures and may report episodic symptoms that are not precisely linked to known exposures.
After an acute exposure to gas, smoke, fumes, or vapors with irritant properties, some subjects with no history of respiratory complaints report a burning sensation in the throat and nose referred to as respiratory upper airways distress syndrome (RUDS), in addition to cough, dyspnea, wheeze, and chest pain. These symptoms typically develop within 24 hours of the exposure and are severe enough that approximately 78 percent seek emergency room treatment. In most series, cough is the predominant symptom in RADS and IIA
We are equipped to perform a full range of pulmonary function tests and evaluations as part of a set of comprehensive screening and diagnostic services. These services are designed to successfully diagnose the patient’s condition, treat their symptoms, and help them breathe and sleep better.
Dr. Benjamin Laracuente is a Monaca, PA specializing in the treatment of respiratory/breathing conditions such as COPD, chronic , , , , pulmonary , pulmonary hypertension, lung cancer, and pleural effusions.