Endoscopy overview

Section: Endoscopy Curriculum: Curriculum, page 38

Resources:

• Cotton and Williams’ Practical Gastrointestinal Endoscopy: The Fundamentals, Seventh Edition

Endoscopic equipment

• Endoscope consists of:
  • Control head with valves (buttons) for air insufflation, wash and suction
  • Flexible shaft carrying light guide and service channels
  • Bending section at tip
  • Umbilical cord connecting endoscope to light source and processor, air supply, wash and suction.
  • Biopsy channel – approx. 3 mm.

Ancillary equipment

• Suction traps: can be used to take samples of secretions
• Biteguards: to protect patient’s teeth and scope
• Overtubes: flexible plastic sleeves that cover the endoscope shaft and act as conduit for repeated intubations or facilitate therapeutic procedures such as extraction of foreign body and haemostasis
• Caps: attached to tip to facilitate banding and mucosal resection, dissection
• Stretchers/trolleys: Need to have side rails and ability to tilt head down
• Image documentation: video sequences are recorded digitally and can be printed
• Sedation and monitoring: require pulse oximetry as minimum. Usually have continuous BP monitoring and ECG. Appropriate resuscitation equipment available, including oral airways, oxygen delivery systems and wall suction. Endoscopic accessories:
• Biopsy forceps: consist of pair of sharpened cups, spiral metal cable, pull wire and control handle.
• Cytology brush: covering plastic sleeve to protect specimen during withdrawal
• Flexible needles: injections and sampling fluids
• Fluid-flushing devices: can do manual or electric pump flush of channel. Small syringe (1 – 5 ml) generates more pressure than a large one (50 ml) which generates more suction.
• Others: snares, clips

Argon plasma coagulation

• Uses electrical conductivity of argon gas- similar phenomenon to neon lights. Argon passed down electrode catheter and energised with an intelligent-circuitry electrosurgical unit and patient plate, ionises to produce a local plasma arc- like miniature lightning strike. Heating effect is superficial (2-3 mm), unless current applied in same place for many seconds, due to coagulation increasing resistance, causing plasma arc to jump elsewhere.

Reprocessing scope

• Scopes cannot tolerate heat > 60’C so cannot be sterilised (e.g. using autoclave), so must be reprocessed using high level disinfection. See Sterilisation and disinfection
• See https://www.youtube.com/watch?v=3B_SC_y2Kew
• See https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4604272/#:~:text=Clean%20the%20external%20surface%20of,cleaned%20with%20an%20ultrasonic%20cleaner
• 7 steps:

1. Precleaning: a. Wipe down with detergent solution b. Air and solution passed through channels repeatedly c. Transport in closed container
2. Cleaning and brushing a. Leak test first b. Clean with low foam enzymatic detergent using brush and soft cloths
3. Rinsing a. Flushing endoscope with sterile water
4. High level disinfection: a. Immersed in disinfection solution - Glutaraldehyde. Can use automated endoscope reprocessor
5. Final rinse with sterile water
6. Dry channels – can use heated pressurised air.
7. Storage in safe sterile environment, hanging in vertical position without touching floor.

Methods to improve detection of pathology

• NBI – optical filters to select wavelengths of light which correspond to the park light absorption of haemoglobin, enhancing visualisation of blood vessels and certain surface structures.
• Chromoendoscopy