Aspiration in Medical Terms

Aspiration has two meanings in medicine describing either the drawing in of a fluid with the sucking motion or the drawing out of a fluid with a suction. The first usage commonly describes the accidental ingestion of a fluid or solid into the trachea (windpipe) and lungs. The second describes the extraction of fluid from the body, either for the purpose of treatment or diagnosis.

Airway Aspiration

Airway aspiration refers to the drawing in of a foreign substance into the lungs. This may include liquids, food, stomach acids, and even toxic fumes, gases, and airborne particles. When food or liquids "go down the wrong pipe," you are experiencing aspiration.

Airway aspiration may occur in the following ways:

• People can aspirate food or fluids into their airways while eating. This is a common complication among people with stroke or traumatic head injury who are learning to eat again.
• With drowning accidents, water can be aspirated into the lungs.
• Unconscious people may aspirate some of their stomach contents into the airways when vomiting. This is why people undergoing general anesthesia must be in a fasted state.
• People with chronic reflux can sometimes aspirate gastric acid while sleeping, especially those with Parkinson's disease or a swallowing disorder.
• Newborns who have their first bowel movement (called meconium) before birth run the risk of meconium aspiration.
• People exposed to excessive amounts of smoke, toxic gases, or dust can incur injury, sometimes serious, due to prolonged aspiration.

Complications of Aspiration

In many cases, a foreign substance aspirated into the lungs expelled by coughing. However, in some cases, a person may not even realize that aspiration has occurred, especially if elderly, intoxicated, unconscious, or hospitalized with a feeding tube or mechanical ventilation.

Whenever you aspirate a foreign substance into the lungs, bacteria not commonly found in the lungs can be carried along. This even includes saliva, which contains a plethora of aerobic bacteria (those needing oxygen to survive) and anaerobic bacteria (those that thrive without oxygen).

Symptoms of aspiration pneumonia may include:

• Shortness of breath (dyspnea)
• Wheezing
• Chest pain
• Cough, possibly with blood or greenish sputum
• Difficulty swallowing (dysphagia)
• Fatigue
• Weakness
• Fever
• Profuse sweating
• Bad breath

If toxic fumes, chemicals, or particles are introduced into the lungs, a subset of aspiration pneumonia known as chemical pneumonia may occur. Unlike aspiration pneumonia, chemical pneumonia causes inflammation in the lungs but not an infection.

Aspiration for Medical Suction

Aspiration may also refer to the extraction of fluids using a needle and syringe or other suctioning devices. The medical technique has dual purposes. It may be used to remove excessive or harmful fluids from the body. The aspirated fluid can then be sent to a pathology laboratory for analysis.

Aspiration for Treatment

Fluid can build up inside the body for many reasons. If this happens, small amounts can be drawn off using a needle and syringe. Larger amounts or thicker liquid may need to be drained over a period of time using a thin plastic tube. Among the reasons aspiration may be needed to treat a medical condition:

• Infection: As the body fight an infection, dead white blood cells can combine with body fluids and other dead cells to form pus. Pus can collect in the area of infection and may need to be drained to relieve pain or aid in treatment. The draining of an abscess is one such example.
• Effusion and Hemorrhage: Sometimes other fluids can accumulate inside the body and cause problems. Examples include a pleural effusion in which fluids build up in the space between the lung lining and chest wall and an internal hemorrhage where blood can pool inside the abdomen or other organs.
• Joint Swelling: Joints can sometimes become swollen with excessive synovial fluid. Synovial fluid is a viscous substance that help lubricates the joint space. Following an injury or inflammation condition, the synovial fluid can build to excess and combine with other body fluids released during inflammation. The extraction of fluids from a joint space is called arthrocentesis.
• Arthritis: People with arthritis and other conditions affecting joint mobility may benefit from the injection of lubricating fluids, such as hyaluronic acid, into the joint space. Prior to this, synovial fluid may need to be extracted to leave room for the injected fluids.
• Airway Clearance: A suctioning device may be needed to keep the airways clear in people with a tracheostomy (a breathing tube inserted through the neck into the windpipe).
• Abortion: Vacuum aspiration is a technique sometimes used during an early abortion, usually between weeks 5 and 12 of gestation.

Aspiration for Diagnosis

Whether used on its own or in tandem with treatment, the draining of body fluids can provide doctors with a means to identify the cause of a disease. These may include procedures such as fine needle aspiration (FNA) using a lower gauge needle and core needle biopsy (CNB) using a larger gauge needle to extract fluids, tissues, and cells. Among some of the conditions where aspiration may be used for diagnosis:

• Identifying if a tumor contains cancer cells
• Culturing the fluid to identify bacterial or fungal strains
• Staining the fluid to identify bacterial types under the microscope
• Examining the fluid for evidence of crystals (such as occurs with gout or pseudogout)
• To extract amniotic fluid or placental tissue during pregnancy to screen for congenital diseases.