A new study finds that colonoscopy trainees had a better experience with and performed better when using water exchange (WE) than when using air insufflation. The new study was published in the Journal of Clinical Gastroenterology.
According to study author Felix W. Leung, MD, from the Veterans Affairs Greater Los Angeles Healthcare System in North Hills, Calif., and the University of California, Los Angeles, WE is less painful than air insufflation and increases cecal intubation rate because it reduces loop formation. He added that it also increases polyp and adenoma detection rates.
Although WE has compared favorably with air insufflation for ADR and pain, there is little evidence regarding how trainees view WE versus air insufflation. Dr. Leung pointed out that the issue could be particularly important among millennial trainees, who may have a different learning style than previous generations. He also noted that previous studies of WE versus air insufflation among trainees measured the perspective of trainers, and did not include the trainees’ opinions of the learning process or trainee outcomes like polyp detection rate.
Seeking to fill this knowledge gap, Dr. Leung conducted a prospective observational study at a Veterans Administration Hospital. Trainees conducted unsedated colonoscopies using WE, as well as WE and air insufflation colonoscopies in alternating order in sedated patients. A total of 83 air insufflation and 119 WE colonoscopies were performed. Trainees rated their experiences on a 1- to 5-point scale, with 1 being “strongly agree” and 5 “strongly disagree” to two statements: “My colonoscopy experience was better than expected” then “I was confident with my technical skills using this method.”
On average, trainees using WE reported a better than expected experience when using WE, compared with air insufflation (2.02 vs. 2.43; P = .0087), but no significant difference in the ensuing confidence in their technical skills (2.76 vs. 2.85; P = .48). There was a longer insertion time for WE (40 minutes vs. 30 minutes; P = .0008). WE was associated with a significantly higher adjusted cecal intubation rate (99% vs. 89%; P = .0031) and a significantly higher polyp detection rate (54% vs. 32%; P = .0447). Overall insertion time was longer with WE than air insufflation (40 minutes vs. 30 minutes; P = .0008), but withdrawal times were similar (22 minutes vs. 20 minutes; P = .3369).
The reduction in pain associated with WE can potentially improve training, in which cases procedures are typically performed on patients under moderate sedation, according to John Allen, MD, who was asked to comment on the study.
He also said that WE can sometimes do a better job than air of opening the lumen. It can help clean the colon surface, and even improve visibility. “Viewing the mucosa under water is like having a lens that helps view the surface and enhance polyp detection,” said Dr. Allen, who is a retired clinical professor of medicine at the University of Michigan, Ann Arbor.
Dr. Allen noted that either air sufflation or WE can be used to overcome the inexperience of the trainee, and that there shouldn’t be much difference between the two methods for sedated colonoscopies. The time of exam is similar, and WE does not require use of carbon dioxide or other gases, which avoids extra costs. “A highly skilled colonoscopist can perform exams using any of the available media. That said, WE is proving to be helpful no matter what your skill level. The only disadvantage I can see is that many trainers do not know how WE works and are unused to this process, although it is easy to learn,” said Dr. Allen.
The study is limited by the fact that it was conducted at a single institution in a nonblinded, nonrandomized population.
Dr. Leung declared there are no conflicts of interest to disclose. Dr. Allen has no relevant financial disclosures.