Gastroscopy procedures

Removal food bolus

• See separate topic under UGIS

PEG insertion

• See separate topic

NJ feeding tube insertion

• Equipment
  • 10Fr feeding tube (often use Freka 8Fr NJT too, but theoretically a larger tube is less likely to kink)
    • See separate topic under 'Nutrition' for details on Freka tubes including insertion
  • Vicryl stitch - tie a loop at the end of the feeding tube
  • Rat tooth grasper if available
  • 2x adhesive (comfeel or hypafix)
  • Lots of lube
• Diagnostic gastroscopy then come out with scope
• Liberal lube to feeding tube and scope (to about 50cm of both)
• Insert feeding tube and follow it down with the scope
• Sometimes it will go directly through the pylorus - try and get it to take a direct path through the stomach
• Other times need to use the forceps to push it into the pylorus
• Hard to directly push it around into D2 - generally just push it through the pylorus, ensure it's continuing to D2 from afar, then push it through further from stomach. Although ideally take it to DJ flexure with forceps.
• Ensure it holds position as you come out
• Fix any loops by grasping just distal to the loop then straightening from the nose
• Secure in between the two adhesives
• AXR in recovery, with Gastrografin study if it's hard to tell whether it's looped or in stomach

Botox injection

• Pylorus
  • 100IU Botox, reconstituted with 4mL saline
  • Inject 1mL (25IU) into four quadrants around pylorus

Oesophageal dilation

• Can do under propofol
• Withhold anticoagulants if possible
• No difference in outcome between bougie and CRE
• Targets:
  • 18mm (54Fr) allows solid diet
  • 15-17mm (45-51Fr) typically allows solid diet
  • 13-14mm (39-42Fr) allows pureed diet
• Specific aetiologies:
  • High risk of perforating when dilating eosinophilic oesophagitis strictures
  • Anastomotic strictures best treated with CRE
  • Try steroids with recurrent strictures
  • Radiation - bougie is best
  • Webs/rings - bougie, to rupture it
  • Dilating malignant strictures provides only temporary relief
  • Achalasia - balloon, but don't do it in patients who aren't fit for surgery
• CRE (controlled radial expansion) dilator:
  • The simplest type of CRE balloons (Boston Scientific - CRE Pro Wireguided) have three different inflation steps for graded dilation (also comes in 180cm lengths)

Balloon Inflated O.D. (mm)	Balloon Inflated O.D. (Fr)	Balloon Length (cm)	Inflation Pressure (ATM)	Inflation Pressure (kPa)	Minimum Working Channel (mm)	Catheter Size (Fr)	Working Length (cm)
6-7-8	18-21-24	5.5	3-6-10	304-608-1013	2.8/3.2*	7.5	240
8-9-10	24-27-30	5.5	3-5.5-9	304-557-912	2.8/3.2*	7.5	240
10-11-12	30-33-36	5.5	3-5-8	304-507-811	2.8/3.2*	7.5	240
12-13.5-15	36-40.5-45	5.5	3-4.5-8	304-456-811	2.8/3.2*	7.5	240
15-16.5-18	45-49.5-54	5.5	3-4.5-7	304-456-709	2.8/3.7*	7.5	240
18-19-20	54-57-60	5.5	3-4.5-6	304-456-608	2.8/3.7*	7.5	240

• • First dilation size should match the current estimated stricture size (gastroscope is 9mm)
  • Advance wire through stricture, until the entire balloon is just outside the scope
  • Expand slowly to desired pressure, while holding it firmly in position, then leave up for 30-60s
  • Inflate with water rather than air
  • 'Rule of 3' dilations per session does not apply to balloon dilators (Gastrointestinal Endoscopy in Practice)
• Wire-guided bougie
  • Rule of 3 - no more than 3 successive dilations
• Serial dilatations
  • Individualise the length of time between dilations, but need at least 1-2 weeks
  • Start with the largest dilator from the previous session

Pyloric dilation

• 20mm CRE balloon - check pressures
• Push balloon out of scope, across stricture, so purple part is showing
• Inflate to chosen pressure and hold for two minutes
  • Be careful not to allow the balloon to push itself either forward or backward - often tries to go forward

Oesophageal stenting

• Stents
  • SEMS
  • Can be covered or uncovered
  • Covered - resist tumour ingrowth. May be removable. Higher incidence of migration. Offer better long-term palliation than uncovered stents for malignant disease.
  • Uncovered - embed into surrounding tissue. Tumour ingrowth occurs frequently.
  • Can be effective with extrinsic compression, but not as effective as for primary oesophageal lesions.
• Outcomes
  • Provides rapid relief of dysphagia
• Contraindications
  • Haemodynamically unstable, clotting disorder, or cannot tolerate moderate sedation
  • Plan for future radiotherapy (high risk trache-oesophageal fistula)
• Technique principles
  • Can be performed under either endoscopic or fluoroscopic guidance
  • Stricture needs to be dilated to between 9 and 14mm
  • Aim for 2cm margin proximally and distally
  • Avoid traversing the stent after deployment due to risk of migration before it is fully expanded (takes about 48 hours)
  • If two stents are required to traverse a long stricture, overlap them by 1-2cm
  • Avoid leaving excessive stent length in stomach due to risk of ulceration
  • Can be done in cervical oesophagus, although with lower efficacy. At least 1-2mm between upper oesophageal sphincter and proximal margin of stent (reported feeling of choking if stent is within 5cm of upper oesophageal sphincter - try to avoid).
• Wallstent (I think WallFlex is same - perhaps the old version - made of nitinol instead of steel)
  • Information
    • Partially coated with bare proximal and distal ends (2cm each end)
    • 18.5Fr delivery system
    • 18 or 23mm diameter (some surgeons use 18 for women, 23 for men)
    • 18mm stent comes in 103mm, 123mm or 153mm lengths; 23mm stent comes in 105mm, 125mm or 155mm lengths
    • Can be partially covered or fully covered - all same sizes available
    • Can be recaptured and repositioned as long as <50% of the stent has been deployed
    • Can foreshorten after deployment
    • High radial force compared to other stents - good dysphagia relief, but increased post-procedural pain
    • Ideal for patients with advanced lesions
  • Technique
    • Need - 2x straightened paperclips with tape, II from start, 260cm straight tip jagwire for guidewire (none in package), and appropriate stent sizes in room
    • Dilate the stricture adequately
    • Pass scope to stomach/duodenum and get a nice screening II that has all the relevant points of interest in field, so the II doesn't have to be moved again
    • Use markers/paperclips taped to skin to measure distance from top to bottom, with 2cm overlap at top and bottom edge of tumour. Open appropriate stent.
    • Insert the guidewire across the stricture, into the stomach/duodenum
    • Remove the scope, keeping wire in place
    • After flushing inner channel with saline, insert the stent delivery mechanism over the guidewire - three markers on the delivery system

• • • 1. Distal extent (be aware it's a little bit back from tip)
      2. Point of no return
      3. Proximal extent

• • • Open the stent by pulling the distal handle towards the proximal handle (open slowly under fluoro)
    • Remove stent delivery mechanism and guidewire
• Post-stenting advice
  • Liquids for first 24 hours
  • Eat slowly, small bites, chew food well
  • Sit upright while eating
  • Take sips of coca-cola if food feels stuck

Removal of AXIOS stent

• Can stay on anticoagulation
• Clarify size of stent beforehand
• Large snare, wrap around, tighten, pull
• Once in the stomach, get the snare around the middle section and tighten it there to compress the shape more, then just pull straight out

Argon Plasma Coagulation (APC)

• Principles and equipment
  • Non-contact monopolar electrocoagulation technique, primarily used for superficial haemostasis and tissue ablation
  • Probe contains a tungsten electrode that delivers a high frequency electric current using ionised argon gas (plasma)
  • Depth of coagulation dependent on the power of the electrosurgical generator, the distance between the probe and the target tissue, and duration of application
  • Power between 0-150W and gas flow 0.5-7L/min.
  • Catheters available in 1.5mm, 2.3mm (most common), and 3.2mm. Wider diameter is good for treating a wider tissue area.
  • Creates three zones in tissue - desiccation, coagulation, devitalisation
  • Patients should have a full bowel prep prior to using anywhere in the large bowel, due to risk of explosion
• Technique
  • Flush probes
  • The probe should protrude from the scope to at least the first black mark to prevent damage to the endoscope
  • Place the tip 1-2mm from the target tissue. The best way to do it is to touch the tissue then withdraw and fire. Don't fire when it is in contact with tissue.
  • Don't repeatedly fire in the same place.
  • Increasing power allows firing from further away
  • Don't touch anything metal - it might melt or conduct current
  • Aspirate the gas as you go, to prevent over-distension
• Complications
  • Perforation 0.2% (increased power setting, longer application, short probe to tissue distance, right colon)
  • Colonic explosion (no bowel prep, lactulose)
  • Ulcers typically occur afterwards, although they are rarely symptomatic. UTD suggests routine PPI and sucralfate after stomach use.

Gold probe

• Bipolar probe where the current passes between the electrodes located at the tip of the probe
• Deeper injury is uncommon, because after local desiccation, resistance to further tissue coagulation increases exponentially
• Can be used tangentially and en face
• Usually place in the base of an ulcer with firm pressure
• The most common type comes with a built in injection needle

Heater probe

• Different to gold probe - generates heat in the ceramic tip, and can cause deeper tissue injury