Is blood the ideal submucosal cushioning agent? A comparative study in a porcine model

Background and study aims: Creation of a submucosal cushion before endoscopic mucosal resection (EMR) significantly reduces perforation risk. We evaluated six solutions as cushioning agents in live pigs. Material and methods: 5 ml of normal saline, normal saline plus epinephrine, albumin 12.5%, albumin 25%, hydroxypropyl methylcellulose, and the pig's own whole blood were endoscopically injected into the porcine esophageal submucosa. Blood was obtained from a peripheral vein immediately before injection. Injections were made every 4 cm from the gastroesophageal junction. The time from completion of the injection to disappearance of the cushion was recorded. Endoscopy was repeated at 48 hours post injection. Two EMRs were performed after blood injection. Statistical analysis employed one-way analysis of variance followed by pairwise t test comparisons using the Bonferroni correction. Results: Five animal experiments were completed. The mean time to dissipation of the submucosal cushion was shortest for saline plus epinephrine sites (2.87 minutes, SD 2.21) followed by the saline (4.8 minutes, SD 1.56), albumin 12.5% (5.68 minutes, SD 3.48), albumin 25% (7.83 minutes, SD 2.02), hydroxypropyl methylcellulose (9.77 minutes, SD 1.55), and blood sites (38.6 minutes, SD 6.07). Injection of blood resulted in significantly longer mucosal elevation than any other solution (P < 0.0007). Blood from the cushion did not hamper visualization and facilitated EMR. Conclusion: Blood produces the most durable cushion compared with standard agents, also having the advantages of being readily available and without cost. Albumin 25% provides as durable a cushion as hydroxypropyl methylcellulose.