Aspiration refers to the inhalation of foreign material into the lungs and lower airways. This can include blood, vomit, and oropharyngeal secretions, as well as exogenous substances. Aspiration pneumonia can develop as a resulting complication.
The phrase “aspiration pneumonia” is often used as a blanket term to cover three separate pulmonary issues. However, it is important to differentiate between them since treatment protocols will change depending on which type it is.
Chemical Pneumonitis
Most people can aspirate a small amount of gastric contents with little sequellae. Yet when large quantities of gastric contents are aspirated into the lower airways and lungs, chemical pneumonitis can develop. The gastric acid causes damage to the lungs and inflammation results. Affected individuals may present with difficulty breathing, cough and fever.
Treatment for uncomplicated chemical pneumonitis should be supportive in nature. This can range from airway suctioning to oxygen therapy or positive pressure ventilation.
Generally, it is believed that antibiotics are not warranted to treat chemical pneumonitis. Studies have suggested that there is no change in clinical outcome and that it promotes the development of more resistant bacteria. Instead, patients should be closely monitored for the development of a secondary bacterial infection via chest x-ray and respiratory status assessment.
When it is unclear whether a patient has chemical pneumonitis or primary bacterial aspiration pneumonia, it is suggested to start antibiotics pending respiratory cultures and clinical status. If after 48 to 72 hours cultures remain negative and the patient shows signs of clinical improvement, antibiotics can then be discontinued.
Primary Bacterial Aspiration Pneumonia
This is the most common form of aspiration pneumonia and results from bacteria from oral and nasal airways entering the lower airways. Presentation can range from mild to critical, and it is often seen in patients with a decreased ability to protect their airway. Patients will often have a cough with sputum and fever, and a chest x-ray will reveal infiltrates.
Supportive treatment such as oxygen and mechanical ventilation can be initiated as needed, but this type of aspiration pneumonia should also be treated with antibiotics. Antibiotic selection will depend on the causative bacteria. Community-acquired cases of aspiration pneumonia will often be treated with Clindamycin, beta-lactam penicillins and new quinolones. Nosocomial aspiration pneumonia generally requires broad-spectrum antibiotics such as beta-lactam penicillins, carbapenems, or monobactams with an anti-staphylococcol drug. Antibiotic coverage can then be adjusted once results from respiratory cultures are received.
Secondary Bacterial Pneumonia Resulting From Chemical Pneumonitis
About 25 percent of patients with chemical pneumonitis will experience an initial improvement after a few days, but then will have a significant decline due to the development of a secondary bacterial pneumonia. The choice of antibiotics will be similar to cases of primary bacterial pneumonia depending on the type of bacteria that is present.
Prevention should always be priority
It is important that the focus remains on preventing the development of aspiration pneumonia in the first place. Several common strategies include elevating the head of the bed, performing oral hygiene and suctioning the oropharynx/trachea to remove aspirate.
Editor's Note: This blog was originally published in June, 2016. It has been re-published with additional up to date content.
