Bronchoalveolar lavage (BAL), also known as bronchoalveolar washing, is a diagnostic method of the lower respiratory system in which a
bronchoscope is passed through the mouth or nose into an appropriate airway in the
lung
The lungs are the primary Organ (biology), organs of the respiratory system in many animals, including humans. In mammals and most other tetrapods, two lungs are located near the Vertebral column, backbone on either side of the heart. Their ...
s, with a measured amount of fluid introduced and then collected for examination. This method is typically performed to
diagnose pathogenic
infection
An infection is the invasion of tissue (biology), tissues by pathogens, their multiplication, and the reaction of host (biology), host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmis ...
s of the lower respiratory airways
(e.g.
pneumonia
Pneumonia is an Inflammation, inflammatory condition of the lung primarily affecting the small air sacs known as Pulmonary alveolus, alveoli. Symptoms typically include some combination of Cough#Classification, productive or dry cough, ches ...
and
COVID-19
Coronavirus disease 2019 (COVID-19) is a contagious disease caused by the coronavirus SARS-CoV-2. In January 2020, the disease spread worldwide, resulting in the COVID-19 pandemic.
The symptoms of COVID‑19 can vary but often include fever ...
), though it also has been shown to have utility in diagnosing
interstitial lung disease
Interstitial lung disease (ILD), or diffuse parenchymal lung disease (DPLD), is a group of respiratory diseases affecting the interstitium (the tissue) and space around the alveoli (air sacs) of the lungs. It concerns alveolar epithelium, pulm ...
.
Bronchoalveolar
lavage
In medicine, therapeutic irrigation or lavage ( or ) is cleaning or rinsing. Types
Specific types include:
* Antral lavage
* Antiseptic lavage
* Bronchoalveolar lavage
* Whole lung lavage
* Gastric lavage
* Peritoneal lavage
* Arthroscopic ...
can be a more sensitive method of detection than nasal swabs in respiratory molecular diagnostics, as has been the case with SARS-CoV-2 where bronchoalveolar lavage samples detect copies of viral RNA after negative nasal swab testing.
In particular, bronchoalveolar lavage is commonly used to diagnose infections in people with
immune system problems,
pneumonia
Pneumonia is an Inflammation, inflammatory condition of the lung primarily affecting the small air sacs known as Pulmonary alveolus, alveoli. Symptoms typically include some combination of Cough#Classification, productive or dry cough, ches ...
in people on
ventilators,
and
acute respiratory distress syndrome
Acute respiratory distress syndrome (ARDS) is a type of respiratory failure characterized by rapid onset of widespread inflammation in the lungs. Symptoms include shortness of breath (dyspnea), rapid breathing (tachypnea), and bluish skin co ...
(ARDS).
It is the most common method used to sample the
epithelial lining fluid (ELF) and to determine the protein composition of the pulmonary airways.
BAL has even been used therapeutically to remove mucus (
sputum
Sputum is mucus that is coughed up from the lower airways (the trachea and bronchi). In medicine, sputum samples are usually used for a naked-eye examination, microbiological investigation of respiratory infections, and Cytopathology, cytological ...
), improve airway ventilation, and reduce airway inflammation in conditions such as
chronic obstructive pulmonary disease
Chronic obstructive pulmonary disease (COPD) is a type of progressive lung disease characterized by chronic respiratory symptoms and airflow limitation. GOLD defines COPD as a heterogeneous lung condition characterized by chronic respiratory s ...
(COPD)
and pediatric
Mycoplasma pneumonia.
A much more intense version involving up to 50 liters of fluid is called
whole lung lavage (WLL) and is used to treat
pulmonary alveolar proteinosis (PAP).
When conditions disallow WLL, an endoscopic BAL can be used as a bridging procedure.
Equipment and procedure
The primary equipment used in BAL includes a fiber-optic bronchoscope, sterile collection traps for collecting test
specimens, a sterile
saline source, a
suction device, and suction tubing.
Essentially, the saline source is connected to sterile bronchoscope, as is the specimen collection trap, and then suction tubing is connected to the trap and the suction source. If the bronchoscope is not sterile, saline should initially be used to flush it clean. With the patient under some sort of anesthesia (depending on the rigidity of the scope), the fiber-optic cable is lowered into the correct area of the lower lungs (
tracheobronchial tree), wedged into place, and saline applied. Once the saline is fully applied, then either suction is applied to collect the fluids, or the fluids are collected with a sterile syringe through the irrigation channel. The collection trap is then appropriately labeled and sent off for testing.
Recent literature for the use of endoscopic BAL in therapy uses essentially the same process. A flexible bronchoscope is most commonly used. The physician seeks out areas with excess mucus or other abnormalities, then uses saline and suction to clean it.
See also
*
Asbestosis
Asbestosis is long-term inflammation and pulmonary fibrosis, scarring of the human lung, lungs due to asbestos fibers. Symptoms may include shortness of breath, cough, wheezing, and chest pain, chest tightness. Complications may include lung canc ...
*
Asthma
Asthma is a common long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wh ...
*
Chronic obstructive pulmonary disease
Chronic obstructive pulmonary disease (COPD) is a type of progressive lung disease characterized by chronic respiratory symptoms and airflow limitation. GOLD defines COPD as a heterogeneous lung condition characterized by chronic respiratory s ...
*
COVID-19
Coronavirus disease 2019 (COVID-19) is a contagious disease caused by the coronavirus SARS-CoV-2. In January 2020, the disease spread worldwide, resulting in the COVID-19 pandemic.
The symptoms of COVID‑19 can vary but often include fever ...
*
Lung cancer
Lung cancer, also known as lung carcinoma, is a malignant tumor that begins in the lung. Lung cancer is caused by genetic damage to the DNA of cells in the airways, often caused by cigarette smoking or inhaling damaging chemicals. Damaged ...
*
Mesothelioma
Mesothelioma is a type of cancer that develops from the thin layer of tissue that covers many of the internal organs (known as the mesothelium). The area most commonly affected is the lining of the lungs and chest wall. Less commonly the lini ...
*
Pneumoconiosis
Pneumoconiosis is the general term for a class of interstitial lung disease where inhalation of dust (for example, ash dust, lead particles, pollen grains etc) has caused interstitial fibrosis. The three most common types are asbestosis, silico ...
*
Silicosis
Silicosis is a form of occupational lung disease caused by inhalation of crystalline silica dust. It is marked by inflammation and scarring in the form of Nodule (medicine), nodular lesions in the upper lobes of the lungs. It is a type of pneum ...
References
{{DEFAULTSORT:Bronchoalveolar Lavage
Diagnostic pulmonology
Respiratory system procedures