ABSTRACT
Pulmonary inflammation resulting from aspiration of exogenous material into the respiratory system is known as aspiration pneumonitis. The most characteristic feature of aspiration pneumonitis is the hypoxemia seen with an arterial blood gas sample. The causes of hypoxemia include diffusion impairment, ventilation-perfusion mismatch, intrapulmonary shunting, and venous admixture. The pulmonary defense mechanisms often neutralize acid within several minutes of the aspiration event, making exogenous buffering unnecessary. Instilling large volumes of fluid into the compromised airway can spread debris further into smaller airways and contribute to pulmonary edema fluid. The prophylactic use of antibiotics in patients with documented aspiration pneumonitis is controversial. Empirical antibiotic coverage following an aspiration event favors the development of resistant bacteria. The prognosis in patients with aspiration pneumonitis largely depends on the type and amount of substance aspirated, the degree of pulmonary infiltration and damage, whether any underlying illness is present, and the patient’s response to therapy.
