Argon Plasma Coagulation with or without Saline Immersion: Comparative In Vivo Study on Tissue Effects

Abstract

Background: Isolated reports suggest that argon plasma coagulation (APC) under saline immersion can deliver energy more evenly to a larger area and in a more superficial manner with less risk of perforation. This manner of application has been used in the rectum and bladder. Our aim was to study the effects of APC with saline immersion in vivo compared to conventional APC application in the stomach and at different power settings. Material and Methods: Two 40-45 kg female domestic pigs were used. An ICC 300 machine and end firing probe (ERBE, Marietta, GA) were utilized. APC was endoscopically performed in the gastric antrum at fixed distance from the mucosa with increasing energy levels in regular (R) fashion and under saline immersion (I), in parallel rows. Three to four rows were made for each group in each animal, so that 6-7 samples could be analyzed. The animals were sacrificed immediately after and the treated areas were excised. Diameter was measured with a micrometer and the tissue was then fixed in formalin for histologic study. Depth of thermal injury was established histologically (in relation to wall layer). Depth and diameter were compared between both groups. Results: average diameter (table below; values = mm) was greater in the R group and increased with increasing power settings. Depth was not statistically different between groups at any power setting. A thermal mucosal effect was evident starting at 15 W in both groups. Submucosal injury was identified at 90 W only in the R group. Histologically, the mucosal thermal damage was attenuated along the borders in some samples from the I group. Macroscopically a white uniform coagulum with an erythematous rim was evident along the margins in the I group in contrast to a charred coagulum seen in the R group. Conclusions: These results do not support the theoretical tissue effects from APC performed under saline immersion. APC performed under saline immersion does not appear to have any advantages for clinical use.