Post written by Sahaj Rathi, MD, DM, MRCP, from the Department of Hepatology, Post Graduate Institute of Medical Education and Research, Chandigarh, India.

Noncontact thermoablation is often used for mucosal bleeding during endoscopy, as it has the advantage of thermal injury limited to superficial layers. Practically, argon plasma coagulation (APC) is the only modality most centers use.

In this technical report, we describe spray coagulation as an alternative noncontact thermoablative technique to APC.

The principles of physics governing both modes are very similar. Both involve ionization of intervening gas between mucosa and electrode, leading to formation of hot plasma. The key difference lies in the intervening gas: argon in APC versus air (78% N₂, 21% O₂) in spray coagulation. Argon is known for easy ionization. However, when argon is unavailable, spray coagulation can produce a similar effect by ionizing air.

It is always a good idea to be familiar with various settings in our equipment and how these may be used to their full potential. APC units are expensive, and they sometimes may be unavailable at smaller endoscopy units.

Alternatively, unavailability of argon gas or APC probes may become an issue in certain situations (as was our case during the COVID-19 pandemic). Spray coagulation is a mode available with many electrocautery setups and can be used with any cautery-enhanced accessory such as a snare, biopsy forceps, and needle-knife.

In our study, we observed that using spray coagulation yielded similar results as APC on the mucosal surface in terms of hemostasis. We used a snare to act as the electrode and felt that the control over burn was a little erratic compared with a smoother burn with APC. However, this may be a matter of becoming familiar with this modality.

In conclusion, although APC remains our workhorse for noncontact thermoablation, spray coagulation can be an alternative for lower-volume centers that do not wish to invest in an APC unit, or in case argon or probe availability becomes an issue.

Schematic representation and comparison of technical aspects for both modalities.

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