Bronchoalveolar lavage | |
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Pronunciation | /ˌbrɒŋkoʊˌælviˈoʊlərləˈvɑːʒ/ BRONG-koh-AL-vee-OH-lər lə-VAHZH |
Other names | Bronchoalveolar washing |
ICD-9-CM | 33.24 |
MeSH | D018893 |
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 lungs, with a measured amount of fluid introduced and then collected for examination. This method is typically performed to diagnose pathogenic infections of the lower respiratory airways [1] [2] [3] (e.g. pneumonia [4] [5] [6] and COVID-19 [7] [8] ), though it also has been shown to have utility in diagnosing interstitial lung disease. [9] Bronchoalveolar lavage 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. [10] [11]
In particular, bronchoalveolar lavage is commonly used to diagnose infections in people with immune system problems, [12] pneumonia in people on ventilators, [5] [6] and acute respiratory distress syndrome (ARDS). [3] [13] It is the most common method used to sample the epithelial lining fluid (ELF) and to determine the protein composition of the pulmonary airways. [3] [13]
BAL has even been used therapeutically to remove mucus (sputum), improve airway ventilation, and reduce airway inflammation in conditions such as chronic obstructive pulmonary disease (COPD) [14] and pediatric Mycoplasma pneumonia. [15] 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). [16] [17] [18] When conditions disallow WLL, an endoscopic BAL can be used as a bridging procedure. [11]
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. [3] 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. [3]
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. [19] [14]
Meconium aspiration syndrome (MAS) also known as neonatal aspiration of meconium is a medical condition affecting newborn infants. It describes the spectrum of disorders and pathophysiology of newborns born in meconium-stained amniotic fluid (MSAF) and have meconium within their lungs. Therefore, MAS has a wide range of severity depending on what conditions and complications develop after parturition. Furthermore, the pathophysiology of MAS is multifactorial and extremely complex which is why it is the leading cause of morbidity and mortality in term infants.
Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing. The severity of the condition is variable.
Pulmonary aspiration is the entry of material such as pharyngeal secretions, food or drink, or stomach contents from the oropharynx or gastrointestinal tract, into the larynx and lower respiratory tract, the portions of the respiratory system from the trachea (windpipe) to the lungs. A person may inhale the material, or it may be delivered into the tracheobronchial tree during positive pressure ventilation. When pulmonary aspiration occurs during eating and drinking, the aspirated material is often colloquially referred to as "going down the wrong pipe".
Pulmonology, pneumology or pneumonology is a medical specialty that deals with diseases involving the respiratory tract. It is also known as respirology, respiratory medicine, or chest medicine in some countries and areas.
Pulmonary alveolar proteinosis (PAP) is a rare lung disorder characterized by an abnormal accumulation of surfactant-derived lipoprotein compounds within the alveoli of the lung. The accumulated substances interfere with the normal gas exchange and expansion of the lungs, ultimately leading to difficulty breathing and a predisposition to developing lung infections. The causes of PAP may be grouped into primary, secondary, and congenital causes, although the most common cause is a primary autoimmune condition in an individual.
Pneumonitis describes general inflammation of lung tissue. Possible causative agents include radiation therapy of the chest, exposure to medications used during chemo-therapy, the inhalation of debris, aspiration, herbicides or fluorocarbons and some systemic diseases. If unresolved, continued inflammation can result in irreparable damage such as pulmonary fibrosis.
Eosinophilic pneumonia is a disease in which an eosinophil, a type of white blood cell, accumulates in the lungs. These cells cause disruption of the normal air spaces (alveoli) where oxygen is extracted from the atmosphere. Several different kinds of eosinophilic pneumonia exist and can occur in any age group. The most common symptoms include cough, fever, difficulty breathing, and sweating at night. Eosinophilic pneumonia is diagnosed by a combination of characteristic symptoms, findings on a physical examination by a health provider, and the results of blood tests and X-rays. Prognosis is excellent once most eosinophilic pneumonia is recognized and treatment with corticosteroids is begun.
Cryptogenic organizing pneumonia (COP), formerly known as bronchiolitis obliterans organizing pneumonia (BOOP), is an inflammation of the bronchioles (bronchiolitis) and surrounding tissue in the lungs. It is a form of idiopathic interstitial pneumonia.
Ventilator-associated pneumonia (VAP) is a type of lung infection that occurs in people who are on mechanical ventilation breathing machines in hospitals. As such, VAP typically affects critically ill persons that are in an intensive care unit (ICU) and have been on a mechanical ventilator for at least 48 hours. VAP is a major source of increased illness and death. Persons with VAP have increased lengths of ICU hospitalization and have up to a 20–30% death rate. The diagnosis of VAP varies among hospitals and providers but usually requires a new infiltrate on chest x-ray plus two or more other factors. These factors include temperatures of >38 °C or <36 °C, a white blood cell count of >12 × 109/ml, purulent secretions from the airways in the lung, and/or reduction in gas exchange.
Respiratory diseases, or lung diseases, are pathological conditions affecting the organs and tissues that make gas exchange difficult in air-breathing animals. They include conditions of the respiratory tract including the trachea, bronchi, bronchioles, alveoli, pleurae, pleural cavity, the nerves and muscles of respiration. Respiratory diseases range from mild and self-limiting, such as the common cold, influenza, and pharyngitis to life-threatening diseases such as bacterial pneumonia, pulmonary embolism, tuberculosis, acute asthma, lung cancer, and severe acute respiratory syndromes, such as COVID-19. Respiratory diseases can be classified in many different ways, including by the organ or tissue involved, by the type and pattern of associated signs and symptoms, or by the cause of the disease.
A sputum culture is a test to detect and identify bacteria or fungi that infect the lungs or breathing passages. Sputum is a thick fluid produced in the lungs and in the adjacent airways. Normally, fresh morning sample is preferred for the bacteriological examination of sputum. A sample of sputum is collected in a sterile, wide-mouthed, dry, leak-proof and break-resistant plastic-container and sent to the laboratory for testing. Sampling may be performed by sputum being expectorated, induced, or taken via an endotracheal tube with a protected specimen brush in an intensive care setting. For selected organisms such as Cytomegalovirus or "Pneumocystis jiroveci" in specific clinical settings a bronchoalveolar lavage might be taken by an experienced pneumologist. If no bacteria or fungi grow, the culture is negative. If organisms that can cause the infection grow, the culture is positive. The type of bacterium or fungus is identified by microscopy, colony morphology and biochemical tests of bacterial growth.
Alveolar lung diseases, are a group of diseases that mainly affect the alveoli of the lungs.
Exercise-induced pulmonary hemorrhage (EIPH), also known as "bleeding" or a "bleeding attack", refers to the presence of blood in the airways of the lung in association with exercise. EIPH is common in horses undertaking intense exercise, but it has also been reported in human athletes, racing camels and racing greyhounds. Horses that experience EIPH may also be referred to as "bleeders" or as having "broken a blood vessel". In the majority of cases, EIPH is not apparent unless an endoscopic examination of the airways is performed following exercise. This is distinguished from other forms of bleeding from the nostrils, called epistaxis.
Bronchoscopy is an endoscopic technique of visualizing the inside of the airways for diagnostic and therapeutic purposes. An instrument (bronchoscope) 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 abnormalities such as foreign bodies, bleeding, tumors, or inflammation. Specimens may be taken from inside the lungs. The construction of bronchoscopes ranges from rigid metal tubes with attached lighting devices to flexible optical fiber instruments with realtime video equipment.
Pulmonary hygiene, also referred to as pulmonary toilet, is a set of methods used to clear mucus and secretions from the airways. The word pulmonary refers to the lungs. The word toilet, related to the French toilette, refers to body care and hygiene; this root is used in words such as toiletry that also relate to cleansing.
Ground-glass opacity (GGO) is a finding seen on chest x-ray (radiograph) or computed tomography (CT) imaging of the lungs. It is typically defined as an area of hazy opacification (x-ray) or increased attenuation (CT) due to air displacement by fluid, airway collapse, fibrosis, or a neoplastic process. When a substance other than air fills an area of the lung it increases that area's density. On both x-ray and CT, this appears more grey or hazy as opposed to the normally dark-appearing lungs. Although it can sometimes be seen in normal lungs, common pathologic causes include infections, interstitial lung disease, and pulmonary edema.
Indium lung is a rare occupational lung disease caused by exposure to respirable indium in the form of indium tin oxide. It is classified as an interstitial lung disease.
Lipid-laden alveolar macrophages, also known as pulmonary foam cells, are cells found in bronchoalveolar lavage (BAL) specimens that consist of macrophages containing deposits of lipids (fats). The lipid content of the macrophages can be demonstrated using a lipid targeting stain like Oil Red O or Nile red. Increased levels of lipid-laden alveolar macrophages are associated with various respiratory conditions, including chronic smoking, gastroesophageal reflux, lipoid pneumonia, fat embolism, pulmonary alveolar proteinosis and pulmonary aspiration. Lipid-laden alveolar macrophages have been reported in cases of vaping-associated pulmonary injury.
Vaping-associated pulmonary injury (VAPI), also known as vaping-associated lung injury (VALI) or e-cigarette, or vaping, product use associated lung injury (E/VALI), is an umbrella term, used to describe lung diseases associated with the use of vaping products that can be severe and life-threatening. Symptoms can initially mimic common pulmonary diagnoses, such as pneumonia, but sufferers typically do not respond to antibiotic therapy. Differential diagnoses have overlapping features with VAPI, including COVID-19. According to a systematic review article, "Initial case reports of vaping-related lung injury date back to 2012, but the ongoing outbreak of EVALI began in the summer of 2019." According to an article in the Radiological Society of North America news published in March 2022, EVALI cases continue to be diagnosed. “EVALI has by no means disappeared,” Dr. Kligerman said. “We continue to see numerous cases, even during the pandemic, many of which are initially misdiagnosed as COVID-19.”
Whole lung lavage (WLL), also called lung washing, is a medical procedure in which the patient's lungs are washed with saline by filling and draining repeatedly. It is used to treat pulmonary alveolar proteinosis, in which excess lung surfactant proteins prevent the patient from breathing. Some sources consider it a variation of bronchoalveolar lavage.