Aims Colonoscopy is the standard procedure to assess the mucosa of the colon. Colon must
be prepared free feces or any residues capable of obstructing the mucosa of the colon
for an adequate safety and security during the study. A poor bowel preparation diminishes
the detection rate of preneoplastic lesions, increases the cost, time and the risk
of complications associated to the procedure itself. Water exchange technique is well
known to increase mucus production in left colon interfering with the complete mucosal
visualization.The aim is to find an association between clinical variables and mucus
amount in a colonoscopy with water exchange technique measured with Left Colon Mucus
Scale (LCMS).
Methods Single-center prospective study was conducted in patients>18 years of age with indication
for colonoscopy between January and July 2024. Bowel preparation was carried out using
PEG complete or split dose. Colonoscopy was performed using water exchange technique
with sterile water or 0.45% sodium chloride solution. Adequate bowel preparation was
considered with a Boston Bowel Preparation Scale≥6, and a LMCS≤1. Demographic variables,
endoscopic findings, factors associated with colonoscopy as the adenoma detection
rate (ADR), the presence of sessile serrated adenomas and colonoscopy time were evaluated.
Univariate and multivariate analyzes were performed, as well as logistic regression
analysis for independent analysis.
Results A total of 92 patients were included, 63 female (68%),age 58±13, split dose PEG (77%).A
good bowel preparation was in 51%. An LCMS≤1was achieved in 16 patients (17.4%); the
ADR was of 53.3% and sessile serrated lesions were detected in 22 patients (23.9%);
in the logistic regression analysis the only variable associated to an increased mucus
production of left colon was the cecal insertion time>9 min (OR 1.24; 95% CI 1.11-1.39,
p=0.043); any other variable don’t showed a statistically significant association,
including the use sodium chloride solution.
Conclusions In colonoscopies with water exchange technique the presence of mucus in left colon
becomes a usual condition, it seems that a protracted cecal insertion is the most
important variable associated to this finding, this could imply the inflammatory effect
of excessive manipulation of the sigmoid, it draws attention that the use of saline
apparently didn’t exert a protective effect as previously reported, we need further
studies to reinforce this conclusion.
