Bronchoscopy

Bronchoscopy is a procedure in which a thin tube is threaded through the nose or mouth into the windpipe and lungs. This allows the clinician to look inside a patient's airway for abnormalities like blockages, bleeding, tumors, or inflammation. The clinician often takes samples from inside the lungs: biopsies, fluid (bronchoalveolar lavage), or endobronchial brushing. The clinician may use either a rigid or a flexible bronchoscope.

Bronchoscopy was developed in the late nineteenth century as a way for physicians to access the airways through the mouth. Since then, it has developed into an important way to diagnose and treat diseases and conditions of the lungs and trachea.

In a bronchoscopy, a bronchoscope is inserted through the nose or mouth and into the trachea, bronchus, and lung. The illustration shows lymph nodes along the trachea and bronchi and cancer in one lung. Inset shows patient lying on a table having a bronchoscopy. Source: Wikimedia Commons

Why Bronchoscopy Is Done

Diagnosis

Bronchoscopy is used to diagnose diseases or conditions that affect the lungs or throat. The damage may first be detected by chest x-ray or computed tomography (CT) scan. Some conditions a bronchoscopy can evaluate include the following:

• Excessive mucus
• Possible lung infection
• Bleeding
• Blockage, usually in children (e.g., by food or tumors)
• Swelling of vocal cords or upper airways (e.g., in patients burned by fire or who inhaled the smoke)
• Tumors
• Lung abnormalities
• Persistent or unexplained cough;
• Blood in the sputum (coughed-up mucus from the lungs)
• Abnormal chest x-ray such as a mass, nodule, or inflammation in the lung

Treatment

Bronchoscopy is not just a diagnostic tool; it also allows treatments. The doctor can:

• Remove foreign bodies in the airway
• Place a stent (a tiny tube) to open a collapsed airway due to pressure by a mass or tumor
• Remove a tumor or growth that is blocking the airway
• Deliver medication to the lungs

Removal or insertion of tissue or devices

Often samples of mucus, tumor, or other tissue are taken from the lungs during a bronchosocopy. These samples are taken in a variety of ways:

• A bronchoalveolar lavage uses small amounts of salt water squirted into the lungs through the bronchoscope and sucked out with samples of cells and bacteria.
• A transbronchial lung biopsy involves insertion of forceps into the bronchoscope in order to pick out samples from the airways.
• In transbronchial needle aspiration, the bronchoscope is outfitted with a needle designed to remove cells from the lymph nodes in the lungs. These nodes trap bacteria and cancer cells and help fight infection. This latter technique can now use ultrasound tipped catheters to correctly localise the lymph nodes.
• With new radation therapy techniques such as 3-D gamma radiation from cyberknife or gamma knife machines, bronchoscopy can also be used to place gold tracking particles, or fiducials, which allow the tumor to be imaged and irradiated.

Types

There are two ways to perform a bronchoscopy, depending on which bronchoscope is used—a rigid bronchoscope or a flexible fiberoptic bronchoscope.

Rigid bronchoscopy

Rigid bronchoscopy was invented in the 19th century, and uses a large, hollow, rigid tube to allow viewing of the airway. It requires general anesthesia and the services of an anesthesiologist, and is therefore used less frequently than its easier counterpart, flexible bronchoscopy. Rigid bronchoscopy still has its place in certain situations. For example, if a patient is coughing up large amounts of blood, a rigid bronchoscope is used since it has a large suction channel and allows for the use of instruments that can better control bleeding.

Flexible fiberoptic bronchoscopy

Flexible fiberoptic bronchoscopy uses a fiberoptic camera on a flexible mounting to look inside the airway. This techique is more comfortable for the patient and does not require general anesthesia, although, in most cases, conscious sedation ("twilight sleep") is utilized. It was introduced in the early 1970s and has since become more common than rigid bronchoscopy. Today, the majority of bronchoscopies are performed using the flexible fiberoptic scope because of the improved patient comfort and reduced use of anesthesia.

Preparation

Preparation for a bronchoscopy generally requires a patient to fast for six hours beforehand, and to receive a chest x-ray. Some patients need blood tests to determine if they have an abnormally high risk of bleeding, which would make the procedure riskier.

How Bronchoscopy Is Done

Physicians using a bronchoscope to view inside a patient's body. Source: National Cancer Institute

The bronchoscope is inserted through the nose (or mouth), down the throat, and into the airways. The bronchoscope can also be inserted into the airway through a breathing tube. A flexible bronchoscope is a long, thin tube of optical fibers that transmit light. Before the procedure, the nose and throat are numbed by a spray of medicine squirted into those areas. This helps prevent coughing and gagging when the bronchoscope is inserted. The vocal cords, windpipe and airways are visualized by a light and mini-camera situated on the tip of the bronchoscope. Pre-medication is given before the procedure to relax the patient but not cause loss of consciousness.

The bronchoscopy itself usually lasts about 30 minutes. But the entire procedure, including preparation and recovery time, takes about four hours.

Benefits

Bronchoscopy offers a relatively safe way to diagnose a treat a wide spectrum of diseases—infectious, malignant, and inflammatory—of the airways and lungs. It may prevent the need for surgery.

Risks

Though most patients tolerate bronchoscopy well, like any medical procedure it carries some risks. A hoarse voice, sore throat, or minor bleeding sometimes occur. A rare but serious complication is a pneumothorax, or collapsed lung. In this condition, air collects in the space around the lungs, which causes them to collapse. While serious, a collapsed lung is treatable. Some other serious complications include the following:

• Fever
• Pneumonia
• Chest pain
• Difficulty breathing
• Coughing up more than a few tablespoons of blood

Effectiveness

An analysis of studies performed before 2001 compared the accuracy of different techniques used to diagnose lung cancer.^[1] The study found that successful diagnoses were made in 88% of patients with samples taken from the airways. The success rate for difficult-to-access lesions, those deeper into the lung, was 69% and that for small lesions (less than 2 cm in diameter) was only 33%. A successful diagnosis was made in 90% of patients treated by transthoracic needle aspiration. This latter procedure removes cells by inserting a needle into the lungs through the chest.

The diagnostic ability of bronchoscopy, especially for small cancers, continues to improve. Successful diagnosis rates of 35%, 61% and 95% for lesions 10 mm (millimeters) or less, between 10 mm and 20 mm, and greater than 20 mm in diameter, respectively, have been reported for a technique using CT-assisted navigation.^[2] See New and emerging technologies for more on virtual bronchoscopy and other advances.

History

How bronchoscopy was developed

Gustav Killian and his bronchoscope. Source: Wikimedia Commons.

The German physician Gustav Killian is considered the founder of bronchoscopy. In 1897, he was the first to explore the bronchi (airways) of the lungs with a rigid tube when he removed a pork bone that was stuck in the trachea of a farmer using a makeshift bronchoscope and a pair of forceps.^[3] He was proposed as a candidate for a Nobel Prize in Physiology or Medicine for the development of bronchoscopy, but he died before the nomination was made.

Since Killian's pioneering work, the bronchoscopy technique and the bronchoscope have undergone several modifications. A significant advance occurred in 1967 when a flexible form of the bronchoscope was introduced. In the 1980s, bronchoscopes were equipped with cameras to record videos of the interior of the airways.

New and emerging technologies

New methods of bronchoscopy are being developed. One method is virtual bronchoscopy, which is a form of computed tomography (CT). This procedure uses special x-ray equipment to take clear, detailed pictures of the inside of the lungs. It has improved the ability of bronchoscopy to detect small, cancerous lung lesions that are inaccessible by conventional methods. Virtual bronchoscopy is still not used often, mainly because although it can image problems it cannot actually be used to do anything about them. Another advance is electromagnetic navigation. Like virtual bronchoscopy, this method helps navigate the bronchoscope and improves diagnostic ability. Electromagnetic navigation bronchoscopy detects lung tumors by using low-frequency electromagnetic waves to guide the bronchoscope.

Combining electromagnetic navigation bronchoscopy with a technique called endobronchial ultrasound is another significant advance in lung tumor detection. This combination is superior to using either technique alone for the diagnosis of lung lesions. One study found that the combination of the two techniques was able to successfully diagnose lesions in 88% of patients, whereas electromagnetic navigation bronchoscopy alone successfully diagnosed lesions in 59% of patients.^[4]

References

1. ↑ Schreiber G, McCrory DC. Performance characteristics of different modalities for diagnosis of suspected lung cancer: summary of published evidence. Chest 2003;123(1 Suppl):115S-128S. Abstract | PDF
2. ↑ Tachihara M, Ishida T, Kanazawa K, et al. A virtual bronchoscopic navigation system under X-ray fluoroscopy for transbronchial diagnosis of small peripheral pulmonary lesions. Lung Cancer 2007;57:322-7. Abstract
3. ↑ UpToDate Online—Rigid bronchoscopy: History and current instrumentation.
4. ↑ Eberhardt R, Anantham D, Ernst A, et al. Multimodality bronchoscopic diagnosis of peripheral lung lesions: a randomized controlled trial. Am J Respir Crit Care Med 2007;176:36-41. Abstract

External Links

University of Iowa Department of Physiologic Imaging

Bronchoscopy International