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. 2022 May 13;10(5):E703-E706.
doi: 10.1055/a-1788-9888. eCollection 2022 May.

Factors contributing to changes in viscosity and flow rate of a dedicated gel for gel immersion endoscopy

Yuji Hiraki  1 , Atsushi Ohata  1 , Tomonori Yano  2 , Yoshimasa Miura  2 , Alan Kawarai Lefor  3 , Hironori Yamamoto  2
Affiliations

Factors contributing to changes in viscosity and flow rate of a dedicated gel for gel immersion endoscopy

Yuji Hiraki et al. Endosc Int Open. .

Abstract

Background and study aims Gel immersion endoscopy is a novel technique for securing the visual field during endoscopy. Clinical application of a dedicated gel for this technique with an appropriate viscosity to prevent mixing with blood and its efficacy was reported. The aim of this study was to evaluate changes in gel viscosity and flow rate under different conditions. Methods The viscosity of the gel after injection and flow rate were measured under various conditions changing the injection route and method. Gel viscosity was measured at 25, 10, and 4 °C. Results A decrease in gel viscosity was found when the gel was injected via the water jet channel compared to the accessory channel. The flow rate and decrease in viscosity of the gel injected via the water jet channel were 220 mL/min and 63.2 %, while when injected via the accessory channel with a clip device inserted were 560 mL/min and 35.8 %. When the gel was kept at a low temperature, the viscosity increased. Conclusions Gel injection via the accessory channel should be the first choice for efficient use considering the viscosity and flow rate.

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Conflict of interest statement

Competing interests This study was funded by Otsuka Pharmaceutical Factory, Inc. Drs. Yano and Ohata hold patents for and are the inventors of the dedicated gel for the gel immersion method. Drs. Hiraki and Ohata are employed by the Otsuka Pharmaceutical Factory, Inc.

Figures

Fig. 1
Fig. 1
Schematic diagram of gel injection. a The gel was injected via the accessory channel using a syringe, b syringe and BioShield irrigator c with the clip device, and d the OFP-2 pump and BioShield irrigator e with the clip device. f Gel was injected via the water jet channel using the OFP-2 pump.
Fig. 2
Fig. 2
Flow rate and gel viscosity using a water pump with different settings. AC, accessory channel; BSI, BioShield irrigator; CD, clip device; WJC, water jet channel.
See this image and copyright information in PMC

Comment in

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