An Effective Instillation Method for Water-Assisted Colonoscopy as Performed by In-Training Endoscopists in Terms of Volume and Temperature

Abstract

There is general consensus that water instillation helps insert a colonoscope. However, the most effective method for water instillation has not yet been established, especially for endoscopists-in-training. The aim of this study was to determine volume and temperature for effective water instillation colonoscopy. This is a prospective, randomized, controlled trial that was carried out at a single center, and a total of 207 consecutive subjects who underwent colonoscopic examination for health checkup were included in the study. Water instillation of supplied water was conducted under four different conditions: 100 and 300 ml at room temperature, 300 ml at 30 °C and no use of water instillation. The following parameters were recorded and analyzed: intubation success rate, independent predictors of successful intubation and intubation time to reach the cecum. The intubation success rate was not significantly different between individual groups. Independent predictors of successful intubation were younger age (P = 0.004) and later examined subjects (P = 0.016). The 300-ml warm water instillation during colonoscopy significantly reduced intubation time over the conventional method without water instillation (P = 0.034). Instillation of 300-ml warm (30 °C) water during colonoscopy can reduce cecal intubation time for in-training endoscopists without improving the intubation success rate.