【Aspiration Pneumonia 吸入性肺炎】
【原文】 Aspiration pneumonia is best considered not as a distinct entity but as part of a continuum that also includes community- and hospital-acquired pneumonias. It is estimated that aspiration pneumonia accounts for 5 to 15% of cases of community-acquired pneumonia. Large-volume aspiration (macro-aspiration) of colonized oropharyngeal or upper gastrointestinal contents is the sine qua non of aspiration pneumonia. This review focuses on aspiration involving the lung parenchyma, primarily aspiration pneumonia and chemical pneumonitis. Challenges remain indistinguishing aspiration pneumonia from chemical pneumonias. Aspiration pneumonia is an infection caused by specific micro-organisms, whereas chemical pneumonitis is an inflammatory reaction to irritative gastric contents. The diagnosis of aspiration pneumonia depends on a characteristic clinical history (witnessed macroaspiration), risk factors, and compatible findings on chest radiography. These radiographic findings include infiltrates in gravity-dependent lung segments (superior lower-lobe or posterior upper-lobe segments, if the patient is in a supine position during the event, or basal segments of the lower lobe, if the patient is upright during the event). The caustive agents of aspiration pneumonia have shifted from anaerobic to aerobic bacteria. Treatment and prevention strategy are discussed.