Gel submarine technique: a novel gel immersion endoscopy for securing the view in emergency upper gastrointestinal endoscopy

Emergency upper gastrointestinal (GI) endoscopy for hemostasis of upper GI bleeding becomes challenging if the stomach contains retained gastric contents, including debris and blood clots. Endoscopic aspiration may be insufficient for their removal as they can block the channel, complicating the identification of the bleeding source and the execution of effective hemostasis [1]. Patient repositioning, the preferred technique for displacing gastric contents, has limited efficacy. Despite the introduction of specialized suction tubes for gastric content removal [2], their use risks associated complications such as accidental esophageal perforation [3]. Recently, gel immersion endoscopy, which uses a transparent gel for endoscopic observation and procedures, has gained popularity [4]. Here, we present a case in which a novel gel immersion technique – the gel submarine technique – proved to be highly effective in identifying the source of bleeding, despite the presence of blood clots in the stomach ([Video 1]).

The gel submarine technique allowed us to “dive” beneath the clots, which were difficult to remove, and ensure an appropriate field of view.Video 1

An 85-year-old woman experienced hematemesis; emergency upper GI endoscopy was performed due to suspicion of upper GI bleeding. As many blood clots were present in the stomach, aspiration was unsuccessful due to channel obstruction ([Fig. 1]). By injecting gel (Viscoclear; Otsuka Pharmaceutical Factory, Tokushima, Japan) through the channel, we created a submerged layer of gel beneath the clots, akin to “diving” beneath them ([Fig. 2]). The endoscope was carefully maneuvered along the gastric wall to maintain an appropriate field of view utilizing the gel. An exposed vessel with exudative hemorrhage was identified along the greater curvature of the upper gastric body. Hemostasis was achieved while preserving an optimal field of view.

Fig. 1 Many blood clots were present in the stomach, and aspiration was unsuccessful due to obstruction of the channel.

Fig. 2 By injecting gel, an appropriate field of view was achieved beneath the clots and the source of bleeding was identified.

The gel submarine technique demonstrates significant utility in maintaining visualization during emergency upper GI endoscopy in the presence of difficult-to-remove gastric contents. The key to this technique is to ensure complete aspiration of air beforehand, as the gel may be vomited if the stomach is distended excessively.

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Publication History

Article published online:
09 April 2025

• References

• 1 Targownik LE, Murthy S, Keyvani L. et al. The role of rapid endoscopy for high-risk patients with acute nonvariceal upper gastrointestinal bleeding. Can J Gastroenterol 2007; 21: 425-429
• 2 Xiao X, Yan H, Liu J. et al. Novel approach for efficient removal of massive blood clots during emergency endoscopic hemostasis. Endoscopy 2023; 55: E248-E250
• 3 el-Newihi HM, Mihas AA. Esophageal perforation as a complication of endoscopic overtube insertion. Am J Gastroenterol 1994; 89: 953-954
• 4 Yano T, Nemoto D, Ono K. et al. Gel immersion endoscopy: a novel method to secure the visual field during endoscopy in bleeding patients (with videos). Gastrointest Endosc 2016; 83: 809-811