(p. 486) Aspiration and inhalation 

This chapter focuses on the pathophysiology, clinical features, management and prevention of aspiration pneumonitis, aspiration pneumonia, and airway obstruction. Aspiration is defined as the inhalation of oropharyngeal or gastric contents into the larynx and lower respiratory tract. Pulmonary syndromes caused by aspiration are different, depending on the amount and nature of the aspirated material, the frequency of aspiration and the host’s response. This results in a chemical burn of tracheobronchial tree and pulmonary parenchyma. The caustic effects of the low pH of the aspirate cause an intense inflammatory reaction. As a consequence, severe hypoxaemia and infiltrates on chest radiograph occur. If colonized oropharyngeal material enters the lungs, aspiration pneumonia develops and antibiotics are needed. Even if not toxic per se, large volumes of fluids may cause suffocation by mechanical obstruction. Prevention of aspiration is of vital importance and the patient at risk must be identified. The major therapeutic approach is to correct hypoxia, support pulmonary function, and prevent pneumonia development.