![Endobronchial valves placed in airways](https://upload.wikimedia.org/wikipedia/commons/2/22/Endobronchial_valves_placed_in_airways.png)
An endobronchial valve (EBV), is a small, one-way valve, which may be
implanted in an
airway
The respiratory tract is the subdivision of the respiratory system involved with the process of respiration in mammals. The respiratory tract is lined with respiratory epithelium as respiratory mucosa.
Air is breathed in through the nose to th ...
feeding the
lung
The lungs are the primary organs of the respiratory system in humans and most other animals, including some snails and a small number of fish. In mammals and most other vertebrates, two lungs are located near the backbone on either side of t ...
or part of lung. The valve allows air to be breathed out of the section of lung supplied, and prevents air from being breathed in. This leaves the rest of the lung to expand more normally and avoid air-trapping. Endobronchial valves are typically implanted using a flexible delivery
catheter advanced through a
bronchoscope
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 trac ...
in minimally invasive
bronchoscopic lung volume reduction Bronchoscopic lung volume reduction (BLVR) is a procedure to reduce the volume of air within the lungs. BLVR was initially developed in the early 2000s as a minimally invasive treatment for severe COPD that is primarily caused by emphysema. BLVR e ...
procedures in the treatment of severe
emphysema
Emphysema, or pulmonary emphysema, is a lower respiratory tract disease, characterised by air-filled spaces ( pneumatoses) in the lungs, that can vary in size and may be very large. The spaces are caused by the breakdown of the walls of the alve ...
. The valves are also removable if they are not working properly.
Mechanism
The one-way endobronchial valve is typically implanted such that on
exhalation air is able to flow through the valve and out of the lung compartment that is fed by that airway, but on
inhalation
Inhalation (or Inspiration) happens when air or other gases enter the lungs.
Inhalation of air
Inhalation of air, as part of the cycle of breathing, is a vital process for all human life. The process is autonomic (though there are exceptions ...
, the valve closes and blocks air from entering that lung compartment. Thus, an implanted endobronchial valve typically helps a lung compartment to empty itself of air. This has been shown to be beneficial in the treatment of
emphysema
Emphysema, or pulmonary emphysema, is a lower respiratory tract disease, characterised by air-filled spaces ( pneumatoses) in the lungs, that can vary in size and may be very large. The spaces are caused by the breakdown of the walls of the alve ...
, where lungs lose their elasticity and thus cannot contract sufficiently to exhale air, leading to air trapping and hyperinflation. When one or more diseased portions of an emphysematous lung are made to deflate and collapse, other healthier portions of the lung have more room in the chest cavity to inhale and exhale, pressure is removed from the
diaphragm
Diaphragm may refer to:
Anatomy
* Thoracic diaphragm, a thin sheet of muscle between the thorax and the abdomen
* Pelvic diaphragm or pelvic floor, a pelvic structure
* Urogenital diaphragm or triangular ligament, a pelvic structure
Other
* Diap ...
, and even the heart may function better as the hyperinflated lung becomes smaller. The amount of residual volume reduction achieved, correlates with the effects on
FEV1
Spirometry (meaning ''the measuring of breath'') is the most common of the pulmonary function tests (PFTs). It measures lung function, specifically the amount (volume) and/or speed (flow) of air that can be inhaled and exhaled. Spirometry is h ...
, quality of life and exercise capacity. Endobronchial valves have also been shown to be beneficial in treatment of persistent air leaks in the lungs. Their use in the treatment of
tuberculosis
Tuberculosis (TB) is an infectious disease usually caused by '' Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, in ...
and its complications has been studied resulting in promising outcomes but further studies are needed.
Endobronchial valves may be the first successful medical device treatment of emphysema, a disease that affects millions of people worldwide and has no known cure, being managed traditionally by
lung transplantation
Lung transplantation, or pulmonary transplantation, is a surgical procedure in which one or both lungs are replaced by lungs from a donor. Donor lungs can be retrieved from a living or deceased donor. A living donor can only donate one lung lobe. ...
and/or
lung volume reduction surgery (though some people do not meet the eligibility requirements for one or both of these invasive procedures).
History
Although endobronchial isolation techniques for emphysema were developed in the early 2000s, specific valves were developed primarily by the start-up medical device company Emphasys Medical (now Pulmonx - Redwood City, California) as a
minimally invasive
Minimally invasive procedures (also known as minimally invasive surgeries) encompass surgical techniques that limit the size of incisions needed, thereby reducing wound healing time, associated pain, and risk of infection. Surgery by definition ...
alternative to lung volume reduction surgery for emphysema. In lung volume reduction surgery, one or more diseased portion(s) of a lung are
excised. Endobronchial valves were designed to replicate the effects of that procedure without requiring incisions, by simply allowing the most diseased portions of the lung to collapse. Emphasys was purchased by Pulmonx in 2009, and Pulmonx currently markets the Zephyr® endobronchial valve (developed by Emphasys) in Europe, Australia, China and many other locations outside the U.S. Pulmonx also sells the Chartis® Pulmonary Assessment System, which is an assessment tool used with endobronchial valves to help physicians target appropriate lung compartments for treatment.
Another company, Spiration (Seattle, Washington), developed a different type of endobronchial valve and was acquired by Olympus in 2010.
References
Further reading
*
External links
Pulmonx
Spiration
{{DEFAULTSORT:Endobronchial Valve
Implants (medicine)
Medical devices
Valves