Aspiration

Aspiration occurs when liquids or solids enter the respiratory tract via the trachea. Swallowed food, stomach contents, and even saliva can be aspirated when the body's normal protective mechanisms, or reflexes, have been disabled or otherwise disturbed. These protective mechanisms normally only permit air to enter the trachea and can be adversely affected, for example, when a person is unconscious. Head injuries, drug overdoses, being under a general anesthetic, and strokes are associated with aspiration events.

There are several pulmonary syndromes that can be ascribed to aspiration. The primary factors that determine the development of a syndrome depend on the nature and amount of aspirated material, the frequency of aspiration, and the individual's particular response to the event (1). Examples of these syndromes include: airway obstruction, lung abscess, chronic fibrosis, and varying forms of pneumonia. Two syndromes in particular, aspiration pneumonitis and aspiration pneumonia, can be especially serious. Aspiration pneumonitis describes the inhalation of sterile gastric contents, such as occurs during vomiting. This is also known as Mendelson's syndrome. Aspiration pneumonia occurs when material that has undergone microbial colonization is inhaled. This colonization typically happens in the throat region before aspiration and results in community-acquired pneumonia. Moreover, it has been suggested that between 5-15% of 4.5 million cases of community-acquired pneumonia stem from aspiration pneumonia (2). In any event, there is usually a latent period between an aspiration episode and the development of pulmonary symptoms (3). The appearance of telltale symptoms such as: wheezing, cyanosis, hoarseness, sore throat, night fevers/sweats, bloody sputum, and chronic cough follow a latent period of 1-2 hours.

Treatment options for aspiration depend on the material aspirated. Inhaled stomach acid can injure the lungs much the same way as a burn would. Inflammation, swelling, and bleeding may occur which can complicate oxygen delivery to the blood stream. The patient often requires suctioning and the support of a breathing machine via a tube inserted in the throat.

'Aspiration' Sources:
  1. Marik, P.E., "Aspiration pneumonitis and aspiration pneumonia". N. Eng. J. Med.;344:665-71, 2001.
  2. Swaminathan, A. et al., "Aspiration pneumonia". Emedicine. June 21, 2006.
  3. Mikita, C.P. et al., "Aspiration syndromes". Emedicine. June 12, 2006.

 

 

 

 

 
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