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.
