Bronchoalveolar lavage

Lavage

In medicine, therapeutic irrigation or lavage is a general term referring to cleaning or rinsing.Specific types include:* Antiseptic lavage* Bronchoalveolar lavage* Gastric lavage* Peritoneal lavage* Arthroscopic lavage* Ductal lavage...

(BAL) is a medical procedure

Medicine

Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....

 in which a bronchoscope

Bronchoscopy

Bronchoscopy is a technique of visualizing the inside of the airways for diagnostic and therapeutic purposes. An instrument is inserted into the airways, usually through the nose or mouth, or occasionally through a tracheostomy. This allows the practitioner to examine the patient's airways for...

 is passed through the mouth

Mouth

The mouth is the first portion of the alimentary canal that receives food andsaliva. The oral mucosa is the mucous membrane epithelium lining the inside of the mouth....

 or nose into the lung

Lung

The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...

s and fluid is squirted into a small part of the lung and then recollected for examination. BAL is typically performed to diagnose

Medical diagnosis

Medical diagnosis refers both to the process of attempting to determine or identify a possible disease or disorder , and to the opinion reached by this process...

 lung disease

Disease

A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...

. In particular, BAL is commonly used to diagnose infection

Infection

An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...

s in people with immune system problems, pneumonia

Ventilator-associated pneumonia

Ventilator-associated pneumonia is a sub-type of hospital-acquired pneumonia which occurs in people who are receiving mechanical ventilation. VAP is not characterized by the causative agents; rather, as its name implies, definition of VAP is restricted to patients undergoing mechanical...

 in people on ventilators

Mechanical ventilation

In medicine, mechanical ventilation is a method to mechanically assist or replace spontaneous breathing. This may involve a machine called a ventilator or the breathing may be assisted by a physician, respiratory therapist or other suitable person compressing a bag or set of bellows...

, some types of lung cancer, and scarring of the lung (interstitial lung disease). BAL is the most common manner to sample the components of the epithelial lining fluid (ELF) and to determine the protein composition of the pulmonary airways, and it is often used in immunological research as a means of sampling cells or pathogen levels in the lung. Examples of these include T-cell populations and influenza

Influenza

Influenza, commonly referred to as the flu, is an infectious disease caused by RNA viruses of the family Orthomyxoviridae , that affects birds and mammals...

 viral levels. Examples of normal and abnormal BAL cells can be found in this BAL Atlas.

Limitations

A major clinical limitation for the utility of examining bronchoalveolar lavage fluid (BALf) is the large range of normal values for each parameter, which makes BALf insensitive in detecting disease. Furthermore, abnormalities in BALf are rarely specific for any of the interstitial lung diseases. There are some subjects who have normal BALf constituents despite a definite disease and some without any evidence of disease despite abnormal BALf findings. There is large interindividual variation which may not be related to the disease, and the airspace cells and secretions may not reflect interstitial processes. The removal of BALf may preferentially select, activate or injure some cells, and the composition of the epithelial lining

Epithelium

Epithelium is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. Epithelial tissues line the cavities and surfaces of structures throughout the body, and also form many glands. Functions of epithelial cells include secretion, selective...

fluid may change during the bronchoalveolar lavage.