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NCT Number: NCT07830823

Water Exchange Colonoscopy in Elderly Patients

Colonoscopy is an important test for detecting colorectal polyps and cancer, but it can cause pain and discomfort, especially in older adults. Traditional colonoscopy uses air to expand the colon. Water exchange colonoscopy uses warm water instead of air, which may reduce pain and make the examination easier. This study compared four colonoscopy methods in patients aged 55 years and older: non-anesthesia water injection, non-anesthesia gas insufflation, anesthesia water injection, and anesthesia gas insufflation. Two hundred participants were randomly assigned to one of the four groups. The study measured pain using a visual analog scale, the time needed to reach the cecum, and blood levels of inflammatory markers (IL-1β, IL-6, and PGE2). The results may help doctors choose a safer and more comfortable colonoscopy method for older patients, especially when anesthesia may not be suitable.

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Key information

Conditions

Colonoscopy Colorectal Cancer Screening

Age range

55 year–80 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Department of Colorectal Surgery, The First People's Hospital of Lin'an District, Hangzhou

Hangzhou, Zhejiang, 311300, China

About this study

Background: Colorectal cancer incidence and mortality increase with age, and colonoscopy is essential for screening and managing colorectal polyps. Conventional gas insufflation can cause abdominal distension, pain, and loop formation, particularly in elderly patients who often have relaxed abdominal muscles, elongated colons, and comorbidities that increase anesthesia risk. Water exchange colonoscopy has been reported to reduce pain by using warm water to navigate the colon without full gas distension.

Objective: To evaluate the clinical value of non-anesthesia water exchange colonoscopy in elderly patients and compare it with anesthesia water exchange, non-anesthesia gas insufflation, and anesthesia gas insufflation.

Methods: This was a single-center, prospective, randomized controlled trial that enrolled 200 patients aged 55 years or older undergoing colonoscopy between November 2024 and December 2025. Participants were randomly assigned (1:1:1:1) using a random number table to four groups (n=50 each): non-anesthesia water injection (NW), non-anesthesia gas insufflation (NA), anesthesia water injection (AW), and anesthesia gas insufflation (AA). All procedures were performed by an experienced endoscopist using a high-definition colonoscope (Olympus CF-HQ290I). Bowel preparation used standard polyethylene glycol electrolyte powder. In water injection groups, warm water at 37°C was injected through the biopsy channel during insertion, with suction of gas and fluid as needed. In gas insufflation groups, conventional air insufflation was used. Anesthesia groups received intravenous propofol combined with a small amount of opioid, administered by an anesthesiologist with continuous vital sign monitoring. The non-anesthesia groups received no anesthesia or analgesia.

Outcomes: The primary outcomes included maximum pain score during examination measured by a 10-point visual analog scale (VAS), cecal intubation time (minutes from insertion to identification of the ileocecal landmark), and serum levels of inflammatory and pain mediators (IL-1β, IL-6, and PGE2) measured by ELISA before and during colonoscopy. Non-inferiority of AW versus NW was assessed for inflammatory mediator inhibition using pre-specified margins. Statistical analysis used SPSS 25.0, with one-way ANOVA, Tukey HSD test, chi-square test, and non-inferiority testing; P<0.05 was considered statistically significant.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age ≥ 55 years
  • Indications for colonoscopy
  • Signed informed consent form

Exclusion criteria

  • History of intestinal surgery
  • Severe intestinal stenosis or obstruction
  • Cognitive impairment that precludes cooperation with assessment

Treatment and study plan

Water exchange colonoscopy

Procedure

During endoscope insertion, warm water at 37°C is injected through the biopsy channel to facilitate the procedure. Gas and liquid within the cavity are aspirated as thoroughly as possible. A minimal amount of gas is introduced for observation when necessary.

Other names: Water-aided colonoscopy

Gas insufflation colonoscopy

Procedure

Conventional air insufflation is employed to expand the intestinal lumen, thereby aiding in endoscope insertion.

Other names: Air insufflation colonoscopy

Propofol and opioid anesthesia

Drug

Intravenous general anesthesia consisting of propofol combined with a small quantity of opioid drugs, administered by an anesthesiologist prior to the examination, with continuous monitoring of vital signs.

Other names: Intravenous anesthesia

Primary outcomes

  1. Serum inflammatory factors and pain mediators

    Time frame: Baseline and periprocedural

    Change from baseline in serum levels of interleukin-1β (IL-1β), interleukin-6 (IL-6), and prostaglandin E2 (PGE2) measured by ELISA before and during colonoscopy. Used for non-inferiority comparison between non-anesthesia water injection (NW) and anesthesia water injection (AW).

  2. Pain score (VAS)

    Time frame: Periprocedural

    Maximum pain level during colonoscopy assessed by the patient using a visual analog scale (VAS, 0-10 points, where 0 indicates no pain and 10 signifies severe pain).

Secondary outcomes

  1. Cecal intubation time

    Time frame: Periprocedural

    Duration from colonoscope insertion to reaching the ileocecal area and identifying the cecal landmark (e.g., appendiceal orifice or ileocecal valve), recorded in minutes.

  2. Adverse events

    Time frame: Periprocedural

    Incidence of procedure-related adverse events, including abdominal distension, pain, intestinal perforation, respiratory depression, cardiovascular events, and allergic reactions.

Sponsors and collaborators

Lead sponsor

First People's Hospital Of Lin'an District, Hangzhou

Other

Registry information

Official study title

Water Exchange Colonoscopy in Elderly Patients: A Prospective Randomized Controlled Trial

Important dates

Study start
2024
Primary completion
2025
Study completion
2026
First posted
Sep 21, 2026
Registry last updated
Sep 21, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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