Water Exchange Colonoscopy in Elderly Patients

September 15, 2026 updated by: Yongjian Liao, First People's Hospital Of Lin'an District, Hangzhou

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

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.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

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.

Study Type

Interventional

Enrollment (Actual)

200

Phase

Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

China
- Zhejiang
  - Hangzhou, Zhejiang, China, 311300
    - Department of Colorectal Surgery, The First People's Hospital of Lin'an District, Hangzhou

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

55 years to 80 years (Adult, Older Adult)

Accepts Healthy Volunteers

Genders Eligible for Study

All

Description

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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Primary Purpose: Screening
Allocation: Randomized
Interventional Model: Parallel Assignment
Masking: None (Open Label)

Number of Arms

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Non-anesthesia water injection (NW) Participants receive water exchange colonoscopy without anesthesia. Warm water at 37°C is injected through the biopsy channel during insertion; gas and fluid are aspirated as needed. No anesthesia or analgesia is administered.	Procedure: Water exchange colonoscopy 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
Experimental: Non-anesthesia gas insufflation (NA) Participants receive conventional gas insufflation colonoscopy without anesthesia. Air is used to expand the intestinal lumen. No anesthesia or analgesia is administered.	Procedure: Gas insufflation colonoscopy Conventional air insufflation is employed to expand the intestinal lumen, thereby aiding in endoscope insertion. Other Names: Air insufflation colonoscopy
Experimental: Anesthesia water injection (AW) Participants receive water exchange colonoscopy under intravenous general anesthesia with propofol and a small quantity of opioid drugs, administered by an anesthesiologist with continuous vital sign monitoring.	Procedure: Water exchange colonoscopy 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 Drug: Propofol and opioid anesthesia 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
Experimental: Anesthesia gas insufflation (AA) Participants receive conventional gas insufflation colonoscopy under intravenous general anesthesia with propofol and a small quantity of opioid drugs, administered by an anesthesiologist with continuous vital sign monitoring.	Procedure: Gas insufflation colonoscopy Conventional air insufflation is employed to expand the intestinal lumen, thereby aiding in endoscope insertion. Other Names: Air insufflation colonoscopy Drug: Propofol and opioid anesthesia 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

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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).	Baseline and periprocedural
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).	Periprocedural

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	Periprocedural
Adverse events Time Frame: Periprocedural	Incidence of procedure-related adverse events, including abdominal distension, pain, intestinal perforation, respiratory depression, cardiovascular events, and allergic reactions.	Periprocedural

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

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

Investigators

Principal Investigator: Yongjian Liao, MD, First People's Hospital of Hangzhou

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

November 1, 2024

Primary Completion (Actual)

December 1, 2025

Study Completion (Actual)

January 1, 2026

Study Registration Dates

First Submitted

September 10, 2026

First Submitted That Met QC Criteria

September 15, 2026

First Posted (Actual)

September 21, 2026

Study Record Updates

Last Update Posted (Actual)

September 21, 2026

Last Update Submitted That Met QC Criteria

September 15, 2026

Last Verified

September 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

LY2024013K

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Studies a U.S. FDA-regulated device product

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Water Exchange Colonoscopy in Elderly Patients