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FLEXIBLE BRONCHOSCOPY

FLEXIBLE BRONCHOSCOPY
Endoscopic examination of the tracheobronchial tree is an essential procedure in the diagnosis and treatment of patients with diseases of the lungs and airways. Although rigid bronchoscopy has been performed since 1897, the first flexible bronchoscope was introduced in 1968. Major advantages of the flexible bronchoscope are that it allows visualization and sampling of peripheral lesions that cannot be reached using a rigid instrument. Additionally, whereas flexible bronchoscopy can be performed with topical anesthesia and moderate sedation in the endoscopy suite or intensive care unit, rigid bronchoscopy requires general anesthesia and is typically performed in the operating room. Early flexible bronchoscopes used fiberoptic cables to send light in and out of the peripheral airways. With the miniaturization of electronic devices, the first video bronchoscope was introduced in 1987. Video technology offers an incredibly sharp image to be displayed on multiple monitors and allows the operator to capture both still images and video.



EQUIPMENT
The external diameter of the flexible bronchoscope varies from 2.7 mm to 6.3 mm in diameter. The diameter of the working channel ranges from 1.2 mm to
3.2 mm. A working channel 2.8 mm or larger is recommended for more therapeutic flexible bronchoscopy because it allows for better suction and the passage of larger instruments. It is important to note the relative anatomy at the tip of the bronchoscope. By convention, as viewed from the operator’s perspective, the camera is at 9:00, and the instrument and suction channel are at 3:00. These landmarks play a role when navigating the airways, and the bronchoscope may need to be rotated to visualize the intended target.
As with all procedures, a careful history and physical examination are essential. The operator should have a plan as to what needs to be done and should communicate it to his or her support staff. Informed consent is required, and patients should be monitored as per local policy for moderate sedation. Because hypoxemia can be seen during bronchoscopy, all patients should receive supplemental oxygen. Adequate topical anesthesia is essential to reduce patient discomfort, and the total dose of lidocaine should be kept to less than 8 mg/ kg in adults. Premedication with anticholinergic medications is not recommended.
The bronchoscope can be introduced transorally, transnasally, or through an endotracheal or tracheostomy tube. When passing the bronchoscope through the oropharynx, one should use a bite block to prevent damage to the bronchoscope.
The operator typically stands in front of the patient if he or she is seated or semi-recumbent or above the patient’s head if he or she is supine. Knowledge of nasopharyngeal, oropharyngeal, and laryngeal anatomy is essential, as is a thorough understanding of the segmental bronchial anatomy. Familiarity with the controls of the bronchoscope is important to enable its tip to be properly directed without damage to the instrument or the mucosal lining. The bronchoscope should be kept straight because any curves will limit transmission of rotating the head of the bronchoscope to its tip.
Many techniques are available during flexible bronchoscopy to sample both central and peripheral lesions. Endobronchial biopsies, brushings, washings, and needle aspiration can all be performed for visible lesions. Likewise, transbronchial needle aspiration, transbronchial biopsy, brushing, and bronchoalveolar lavage can be used to sample peripheral lesions. Advanced techniques such as endobronchial ultrasonography, virtual bronchoscopic navigation, and electromagnetic navigation may all increase the yield for sampling peripheral lesions.
Complications requiring immediate treatment include laryngospasm and bronchospasm and any bleeding that is more than mild in quantity. A pneumothorax, depending on its size, may call for placement of chest tubes. Severe hypoxemia and ventricular dysrhythmias usually require cessation of the procedure.

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