Objective To investigate the safety of argon plasma coagulation (APC) with submucosal injection for colon polyps.Methods A total of 30 sets of fresh sigmoid colon from healthy pigs were assigned to control group to receive direct APC,and to treatment group to receive APC with submucosal injection,respectively.After same time and energy of APC,each specimen was sampled for pathological evaluation and the damage extent was determined as mucosa,submucosa (superior 1/3,middle1/3,inferior 1/3),and muscularis propria.Ten cases of colon sessile polyps with diameter of about 1-2 cm,elevated within 3mm by endoscopic ultrasonography(EUS).Direct APC or APC with submucosal injection were performed,respectively,and the difference was observed by EUS.Results In 30 cases of control group,the injury depth of 5 cases reached to the muscularis propria and of 25 cases to submucosa layer,among which 4 cases showed damage to superior submucosa 12 middle submucosa and 9 inferior submucosa.In 30 cases of treatment group,there was no damage to muscularis propria.The injury depth of 26 cases reached submucosa layer,among which 22 cases showed damage to superior submucosa,4 middle submucosa.The results showed significant difference between two groups (P ＜0.01).In patients who underwent APC with submucosal injection,EUS showed effective isolation of mucosa and muscularis propria.It confined the injury to the mucosal layer.Without treatment of submucosal injection in advance,it seemed easier to damage the submucosa and muscularis propria.Conclusion Submucosal injection can protect the colon injured by APC,and may reduce the risk of colon perforation by APC for colon polyps.

Medical electronic endoscope is one of the indispensable tools in medical diagnosis and treatment. With the development of science and technology, electronic endoscope has higher safety and accuracy than traditional optical endoscope. Due to the sophisticated construction and high price, hospitals spend a lot of money on maintenance every year. In order to prolong the working life of electronic endoscope, reduce the incidence of artificial failure and save hospital costs, this study made a retrospective analysis on the common faults of electronic endoscope, and summarized the maintenance strategies for reference.
Electronics, Medical ; Endoscopes ; Retrospective Studies