bronchoscopy

bronchoscopy, medical examination of the bronchial tissues using a lighted instrument known as a bronchoscope. The procedure is commonly used to aid the diagnosis of respiratory disease in persons with persistent cough or who are coughing up blood, as well as in persons who have abnormal chest findings following computerized axial tomography scanning or X-ray examination. Bronchoscopy is also employed to remove foreign objects from the airways, to deliver certain therapeutic agents directly into the lungs, and to assist in the placement of stents (tubes, typically made of expandable wire mesh) or in the resection (removal) of tissue in cases in which cancerous growths block the airways.

There are two types of bronchoscopes. The most frequently used scope consists of a flexible tube containing a bundle of thin fibre-optic rods that project light onto the tissues being examined. A flexible bronchoscope may be passed through the nose to examine the upper airways or through the mouth to examine the trachea (windpipe) and lungs. Flexible scopes, because of their ability to bend and twist, can be used to examine bronchial passageways down to the level of the tertiary bronchi—the smallest passages preceding the bronchioles. The second type of scope, known as a rigid bronchoscope, consists of a metal tube that has a wide suction channel, which enables large volumes of fluid (e.g., blood) to be removed during an examination. Although rigid bronchoscopes have been replaced by flexible scopes for the majority of procedures, they remain superior for specific applications. They are used most often to examine the central airways when blockage by a foreign body is suspected and to resect diseased tissue in a procedure known as laser bronchoscopy. All bronchoscopes can be fitted with a small video camera that enables real-time visualization of the procedure. In addition, both flexible and rigid scopes have a channel through which instruments can be passed. The latter feature is commonly employed for biopsy—the collection of tissues for histological study.

Flexible bronchoscopy of the upper airways generally requires the use of a local anesthetic to numb the tissues. In contrast, rigid bronchoscopy, because of the discomfort caused by the device, necessitates the use of general anesthesia, which can cause side effects in some people, including nausea and vomiting, upon waking. In addition, there are several important risks associated with the bronchoscopy procedure itself. For example, the movement of a bronchoscope through the airways often scratches superficial tissues, causing them to bleed. Bleeding is especially common following biopsy. In most cases, however, bleeding subsides without the need for medical intervention. The bronchoscope or the removal of tissue for biopsy may lead to the perforation of lung tissue, causing a condition known as pneumothorax, in which air enters the space between the pleural membranes lining the lungs and thoracic cavity. Another risk factor associated with bronchoscopy is the introduction of infectious agents into the lungs, which occurs when the instrument is not sanitized properly.

For more information about the use of scopes for the medical examination of internal tissues of the human body, see endoscopy.