Electrical characteristics of various submucosal injection fluids for endoscopic mucosal resection

Submucosal fluid injection, prerequisite to endoscopic mucosal resection, necessitates detailed evaluation for proper selection. We aimed to compare height of gastric tissues after submucosal injection, and to verify electrical implications of injectants. Porcine stomach pieces were cut out, and eight solutions were used: normal saline, 0.5% sodium hyaluronate (SH), 0.25% SH, hydroxypropyl methylcellulose, 10% glycerin, fibrinogen, 1% sodium alginate (SA), and 2.5% SA. Elevated heights were measured after submucosal injection of the eight fluids, and electrical impedance was measured for fluids plus a reference solution (0.01 N KCl) with a potentiostat electro-impedance spectrometry and an insulation-tipped knife. Resistivity was calculated thereafter. Normal saline and 10% glycerin solution showed greater height diminution. Resistivity were in the range of 80-110 Ω cm, except for 309.7 Ω cm for fibrinogen. Higher resistivity may improve performance of electrosurgery, probably by strengthening impedance and heat dissipation. Further studies are required to back up this basic experiment for clinical application.