Flexible Bronchoscopy

Flexible bronchoscopy (FB) describes the invasive, direct visualization of the airways via aexible bronchoscope for diagnostic and therapeutic purposes. It is a safe procedure, usually performed by pulmonologists and thoracic surgeons to inspect the proximal and distal airways and perform diagnostic and therapeutic procedures in the airways and lung parenchyma. Its ease of use, minimal sedation requirement, and great safety profle account for its preference over more invasive alternatives [1, 2].

The uses and applications of FB have evolved over the last 50 years to various diagnostic and therapeutic modalities. This chapter will review the history of FB, its indications, and contraindications, and describe the procedure and its basic and advanced diagnostic and therapeutic techniques.

T. Dammad (*)

Houston Methodist, Houston, TX, USA

V. Singh

Department of Critical Care Medicine At

AdventHealth Orlando, Orlando, Florida, USA

B. A. Jalil

Department of Pulmonary and Critcal Care at West

Virginia University School of Medicine,

Morgantown, West Virginia, USA

The history of exploring human airways dates back to Hippocrates. Hippocrates mentioned, “cannulas should be carried into the throat along the jaws so that air may be drawn into the lungs.” Internet.

However, it was not until 1897 when Gustav Killian in Freiburg, Germany, performed the frst rigid bronchoscopy, examining the larynx and trachea to extract a pork bone from the right mainstem bronchus of a farmer. He then presented his experience in Heidelberg, Germany, branding it “direct bronchoscopy.” Gustav Killian is regarded today as the Father of Bronchoscopy [3].

Rigid bronchoscopy remained the standard practice for the next 70 years until Shigeto Ikeda, a thoracic surgeon from Tokyo, Japan, introduced the frst prototype exible fberoptic bronchoscope in Copenhagen in 1966 [4] (Fig. 2.1).

The frst commercially available exible bronchoscope was manufactured by Machida in 1968 and comprised over 15,000 glass fbers. Further revisions and improvements by Machida and Olympus allowed an enhanced working channel, image quality, and maneuverability.

The invention of the exible bronchoscope represented a paradigm shift in bronchoscopy. It was easier to perform than rigid bronchoscopy and allowed superior visualization of the distal airways. It continued to evolve with extensive technical and clinical applications.

Fig. 2.1  Dr. Shigeto Ikeda, Surgeon at the National Cancer Center, Japan, 1977. (Photography: Burt Glinn Magnum Photos)

With Ikeda’s contribution, Pentax produced the frst video-­ exible bronchoscope in 1987, where a miniature video camera at the tip of the bronchoscope replaced the fber optic bundle, allowing for the bronchoscopy team to watch the procedure on a screen with tremendous defnition and record it for documentation and educational purposes [5].

A second paradigm shift occurred with the introduction of endobronchial ultrasound (EBUS) bronchoscopy, another form of exible bronchoscopy.

The usefulness of radial probe (RP)-EBUS was frst reported by Hurter and Hanrath in 1992. They studied 74 patients with central tumors and 26 patients with peripheral carcinomas [6]. In 1996, Heinrich Becker demonstrated the great

potential of EBUS in assessing tumor infltration of the bronchial wall and parabronchial structures, including lymph nodes [7].

In the early 2000s, Yasufuku and colleagues were the frst to describe the high diagnostic yield of convex probe EBUS, enabling realtime visualization and sampling of the mediastinal, hilar adenopathy, and central lesions, changing how we diagnose and stage lung cancer forever [8, 9].

Signifcant technological innovations over the last few decades such as light amplifcation by stimulated emission of radiation (LASER) therapy, argon plasma coagulation (APC), transbronchial cryobiopsy, and electromagnetic navigational bronchoscopy (ENB) were specifcally developed and designed to use with the exible bronchoscope [10]. Finally, a signifcant innovation in the feld of exible bronchoscopy has emerged called robot-assisted bronchoscopy that we will discuss in a separate chapter of this book [11].

Description

The exible bronchoscope constitutes a exible hollow vinyl tube called the “insertion tube” containing optical fbers and a longitudinal working channel for suction and ancillary instruments.

The proximal handle contains a control lever to maneuver the distal end of the scope and control buttons for the camera and suction (Fig. 2.2).

Fig. 2.2  The bronchoscope handle with the control lever at the proximal end and working channel insertion point at the distal end

There are two light-transmitting bundles and one viewing bundle. Each bundle contains up to 30,000 ultrafne glass fbers (8–15 μm). In the fber optic bronchoscope, the light entering the system is internally re ected and emitted at the opposite end.

However, a charged coupled device (CCD) has replaced the viewing bundle in the video bronchoscope. The CCD converts energy from light photons into digital information, allowing excellent image capture.

The current exible video bronchoscope’s outer diameter ranges from 2.8 mm for the ultrathin scope to 6.9 mm for convex probe EBUS.

The working channel ranges from 1.2 mm for the ultrathin bronchoscope to 3.0 mm for the therapeutic bronchoscope (Fig. 2.3).

The insertion tube length ranges from 400 to 600 mm, and the distal-end exion angulation ranges from 120° to 210° in the latest-genera- tion bronchoscopes [12]. On the other hand, the

distal-­end extension angle ranges from 60° to 130° on the exible bronchoscope (Fig. 2.4a, b). Of note, the exible bronchoscope was designed to hold with the left hand since Dr. Ikeda was left-handed.

Fig. 2.3  Distal ends of different bronchoscopes ranging from the therapeutic bronchoscope with a 3 mm working channel on the left to the thin bronchoscope with a 1.2 mm working channel on the right