Flexible endoscopy: basic technique

image of Flexible endoscopy: basic technique
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This chapter details the basic principles for using flexible endoscopes, including safe use, preparing the patient, endoscope handling and biopsy techniques. The chapter also includes three video clips.

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3.1 Advances in imaging quality. (a) HD-quality image of human fingerprints, showing the level of magnification now available. (b) HDTV-quality image of normal canine duodenal mucosa. Note that the individual villi are visible. (c) Narrowband endoscopic image of the stomach of a dog. Removal of red light from the illumination makes red objects (blood and blood vessels) appear black. The distortion of normal blood vessel patterns in the mucosa is suggestive of dysplasia or neoplasia.
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3.2 (a) Carbon dioxide insufflator to allow safe insufflation of small patients and during endoscopic electrosurgery. (b) Peristaltic flushing pump, operated by foot pedal, allows food and faecal material to be cleared from the field of view. (c) Suction pump with collecting reservoir. (d) Disposable liners for suction pump reservoirs contain a gel that solidifies liquid waste, allowing safe disposal in a clinical waste bin.
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3.3 Damage to a flexible endoscope can make it unusable. Compression damage to the bending section of this gastroscope was caused by a trolley being wheeled over the tip as it trailed on the floor.
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3.4 Endoscopes should be carried securely in (a) one or (b) both hands to avoid accidental damage.
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3.5 (a) Holding a fibreoptic gastroscope correctly in the left hand while guiding the insertion tube with the right. Fibreoptic endoscopes must be held to the eye to view unless a charge-coupled device (CCD) camera attachment is available. (b) Holding a video-gastroscope. Without the need to hold a eyepiece to the eye, the endoscopist can stand in a more relaxed position and view the monitor in front of them. In this image, the monitor behind the endoscopist is for teaching purposes and the monitor viewed by the endoscopist is connected by Wi-Fi.
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3.6 Holding the handpiece. The handpiece is held in the palm of the left hand with the umbilical cord running down the back of the hand between the thumb and index finger, allowing the fingers to reach the buttons and control wheels.
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3.7 Gripping the endoscope handpiece. (a) Using the fourth and fifth fingers to stabilize the endoscope handpiece, the left index and middle fingers are free to operate the air/water and suction buttons, respectively. (b) Using a three-finger grip to stabilize the handpiece, the left index finger is used to operate the buttons, while the thumb controls the up/down steering wheel. (c) Rotation of the handpiece of a video-endoscope once almost full insertion has been achieved allows the left thumb to operate the suction and air/water buttons, and the right thumb and fingers to manipulate the steering wheels.
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3.8 The suction valve/button (red) and air/water valve/button (blue). Covering the hole in the air/water button deflects air and insufflates the viscus. Depression of the red and blue buttons causes suction and water flushing, respectively. (a) Suction (red) and air/water (blue) valves before insertion in the handpiece. (b) Position of the suction (red) and air/water (blue) buttons on the handpiece.
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3.9 Two types of disposable rubber valve for the instrument/accessory/biopsy channel. These valves provide a seal around biopsy forceps, preventing the escape of air after insufflation.
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3.10 The red dot in the mucosa (arrowed) is a suction artefact caused by tissue being sucked up accidentally, and must not be mistaken for a lesion.
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3.11 (a) Upward deflection of the endoscope tip and (b) longitudinal rotation effectively allow the endoscopist to look to the left or right without having to manipulate the left/right steering wheel.
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3.12 Application of the friction brakes (labelled ‘F’) permits the endoscope tip to be held in a deflected position without the need to control the steering wheels. (a) Friction brakes ‘off’. (b) Friction brakes ‘on’. With the brakes ‘off’, the small arrows indicate the direction of turn of the lever and knob to put the brakes ‘on’ for the up/down and left/right wheels, respectively.
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3.13 Holding the handpiece of a fibreoptic bronchoscope, with a lever for two-way tip deflection being operated by the left thumb, and the suction button by a finger. There is no air/water channel in bronchoscopes.
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3.14 (a) Red-out is the loss of a clear image that occurs when the endoscope lens is too close to the mucosa. (b) Red-out is corrected by withdrawing the endoscope, deflecting the tip slightly and insufflating. In general, the lumen is towards the darker region of the image; in this image, the direction of the lumen is denoted by the arrow.
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3.15 (a) Flushing using a large-bore syringe attached to the biopsy channel valve. (b) Adapter for the biopsy channel to allow flushing by syringe or flushing pump while still permitting biopsy.
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3.16 Slide-by technique for advancing the endoscope around a flexure. Red-out occurs as the endoscope tip passes along the wall until the next straight length of intestine is reached. Drawn by S. J. Elmhurst BA Hons (www.livingart.org.uk) and reproduced with her permission.
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3.17 Artefactual linear haemorrhages at a small intestinal flexure caused by the tip of the endoscope scraping the mucosa of the outer curvature of the flexure.
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3.18 Pre-deflection of the endoscope tip before reaching a flexure allows visualization along the next length of intestine, and avoids slide-by induced artefacts. Drawn by S. J. Elmhurst BA Hons (www.livingart.org.uk) and reproduced with her permission.
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3.19 Correct (a) opening and (b) closing of biopsy forceps. The thumb is inserted in the handle and the fingers clasp the slider. As the palm of the hand is clenched, the cups close. Insert: Breakage of reusable biopsy forceps due to over-vigorous closure of the cups. Excessive pressure on the handles does not improve the quality of the biopsy specimen, but stretches and ultimately breaks the internal operating wire or the hinge mechanism.
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3.20 (a) As swing-jaw biopsy forceps are opened, (b) the cups tilt towards the tissue. This aids taking biopsy samples when the forceps are not perpendicular to the tissue surface. (c) Illustration showing swing-jaw forceps in use. (c, Redrawn after ). Drawn by S. J. Elmhurst BA Hons (www.livingart.org.uk) and reproduced with her permission.
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3.21 Tissue cassette with a foam insert for collecting biopsy specimens before fixation in formalin and processing. (a) Open cassette with foam insert (left) and dehydrated cucumber slice (right) each with six biopsy samples. (b) The cassette is closed before being placed in 10% formalin. (a, courtesy of Guillaume Ruiz)
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3.22 Sections of endoscopic biopsy samples demonstrating common artefacts. (a) Crush artefact with loss of discernible tissue and cellular structure. (b) Cross-sections of isolated villi when tissue is not oriented in a perpendicular fashion. (c) Fragmentation of a small tissue biopsy sample. Haematoxylin and eosin-stained sections. (Reproduced from the B)


Leakage test of an endoscope.

Escape of air bubbles during a leakage test of an endoscope

Single- and two-handed manipulation of steering wheels.

Single- and two-handed manipulation of steering wheels.

Steering by tip deflection and torquing.

Steering by tip deflection and rotation on the long axis (torquing).

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