Bowel Preparation Efficacy and Safety of 1 L vs 2 L Polyethylene Glycol With Ascorbic Acid for Colonoscopy: A Randomized Controlled Trial.

INTRODUCTION: Polyethylene glycol with ascorbic acid (PEG/Asc) is a well-established bowel preparation solution with guaranteed effectiveness and safety. A new low-volume agent, 1 L-PEG/Asc, has recently been released. This study aimed to compare the bowel cleansing efficacy and safety of 1 L-PEG/Asc and 2 L-PEG/Asc administered to adult outpatients in a split-dose manner. METHODS: Outpatients undergoing colonoscopy enrolled in a single-blinded, single-center, noninferiority study conducted between July and October 2021 were randomized in a 1:1 manner to a 1 L-PEG/Asc or 2 L-PEG/Asc group. Bowel cleansing was assessed using the Boston Bowel Preparation Scale (BBPS) and the Harefield Cleansing Scale in intention-to-treat and per-protocol populations. RESULTS: Two hundred forty participants were randomized and allocated, with 120 patients in the 1 L and 2 L-PEG/Asc groups, respectively. Noninferiority was demonstrated for overall successful bowel cleansing (BBPS: 92.5% vs 90.8%; 95% confidence interval [CI], -0.054 to 0.087) and the high-quality cleansing rate of the right-sided colon (BBPS = 3, 40.0% vs 35.8%; 95% CI, -0.082 to 0.165; Harefield Cleansing Scale ≥3, 50.0% vs 43.3%; 95% CI, -0.060 to 0.194) in the intention-to-treat population. The overall incidence of adverse events was similar in both groups ([82/120] 68.3% vs [72/120] 60.0%; P = 0.178). The tolerability, acceptability, and compliance rates of both regimens were similar, with no significant differences. DISCUSSION: Compared with 2 L-PEG/Asc, 1 L-PEG/Asc achieved successful overall bowel cleansing efficacy with high-quality cleansing in the proximal colon and proved its noninferiority. Therefore, 1 L-PEG/Asc is an acceptable alternative bowel cleansing solution.

Efficacy and safety of a thermosensitive hydrogel for endoscopic submucosal dissection: An in vivo swine study.

Injectable thermo-sensitive chitosan hydrogels have recently been developed for the use of submucosal fluids in endoscopic submucosal dissections (ESD). This study aimed to investigate the efficacy and safety of chitosan hydrogels during ESD. Submucosal fluids were administered as follows: 0.9% normal saline (NS), 0.4% hyaluronic acid (HA) and chitosan/ß-glycerophosphate (CS/GP) hydrogel. Each solution was administered twice into the stomach and colon of a pig, with a total of 72 ESD procedures performed on 12 pigs. The injected volume and procedure-related parameters were recorded and analyzed. ESDs that created ulcers after 7 days were histologically compared. All ESD specimens were resected en bloc. The total injected volumes during ESD of the stomach (NS, 16.09±3.27 vs. HA, 11.17±2.32 vs. CS/GP, 9.44±2.33; p<0.001) and colon (NS, 9.17±1.80 vs. HA, 6.67±1.50 vs. CS/GP, 6.75±1.57; p = 0.001) were significantly different. Hydrogel showed significant differences from normal saline in terms of fluid power (mm2/vol; NS, 35.70±9.00 vs. CS/GP 57.48±20.77; p = 0.001) and consumption rate (vol/min; NS, 2.59±0.86 vs. CS/GP, 1.62±0.65; p = 0.013) in the stomach. Histological examination revealed preserved muscularis propria, although the chitosan hydrogel resulted in a partial inflammatory response, with a hypertrophied submucosal layer. Chitosan hydrogel was found to be superior to normal saline, with an efficacy similar to that of hyaluronic acid. Nonetheless, long-term histological changes should be evaluated before clinical implementation.