It is difficult to secure the visual field during endoscopy for GI bleeding or colonoscopy without preparation because the injected water is rapidly mixed with fresh blood or stool. We developed a novel method to secure the visual field in these situations.

Clear gel with the appropriate viscosity to prevent rapid mixing is injected through the accessory channel, instead of water. A vinyl tube was used as an in vitro GI bleeding model. After filling the lumen with indigo carmine dye, air insufflation and water injection are not effective for securing the visual field. However, after gel injection, the bleeding source is observed clearly in the space occupied by the gel. The efficacy of this method was evaluated subjectively in clinical use. From February 2014 until June 2015, gel immersion was used in 17 consecutive patients when the visual field could not be secured with routine insufflation.

Of these 17 patients, gel injection was very effective in 10, effective in 5, slightly effective in 1, and not effective in 1. There were no adverse events associated with this method.

Gel immersion endoscopy is safe and effective for securing the visual field, creating a space for endoscopic visualization and treatment in otherwise difficult situations.