Aspiration occurs when liquid or solid material enters the windpipe (trachea).


The body has important protective mechanisms (reflexes) that usually allow only air to enter the windpipe. If these reflexes are temporarily or permanently disturbed, then foreign materials, such as food, saliva or stomach contents can enter the windpipe. The protective reflexes are most commonly disturbed when a patient is unconscious for any reason (e.g., head injury, drug overdose, or general anesthesia). Some forms of brain injury, such as strokes, are also associated with aspiration.


Treatment depends on what was aspirated. For example, if stomach contents are aspirated, inflammation may occur on the inner lining of the lungs (mucosa) because of stomach acid exposure. The stomach acid causes an injury to the inner lining of the lungs similar to a burn. In more severe cases, it may bleed (hemorrhage). Oxygen may not be able to get through to the blood stream as a result of the inflammation and swelling. Treatment involves immediate removal of the aspirated material by airway suctioning. Often, the patient requires a breathing (endotracheal) tube (inserted via a procedure called intubation) and the support of a breathing machine (ventilator) to improve blood oxygenation. The blood oxygenation is determined by pulse oximetry and/or testing blood samples for arterial blood gases (ABG).


Many people become seriously ill after aspirating a substance that damages the lung mucosa. Aspiration is very very serious because the potential damage to the inner lining of the lung. Aspiration is an important cause of acute respiratory distress syndrome (ARDS) and in the most severe forms may lead to death.

Related Links

National Library of Medicine
The National Library of Medicine presents information and pictures about aspiration.