Editing Gastroscopy procedures (section)

== '''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.