4. Discussion
TB, poor bowel preparation
This prospective, single-center, single-blind, randomized controlled study aimed to determine the optimal timing for simethicone administration along with 2 L of PEG plus ascorbic acid solution to reduce the number of bubbles formed during colonoscopy. Administering simethicone was found to reduce bubbles significantly when compared to not taking it, and taking it on the day of colonoscopy reduced more bubbles than taking it the day before the examination. The number of bubbles did not change taking simethicone before or after bowel cleansing as long as it was taken on the day of colonoscopy.There have been many previous studies on the effects of oral administration of simethicone before colonoscopy. A study showed that taking simethicone significantly reduced bubbles,The digestive endoscopy center of the authors empirically prescribed 200 mg of simethicone on the day of examination and after the completion of bowel cleansing, and we had a decent BS in the usual colonoscopy tests unlike previous studies’ results. Therefore, we attempted to determine the best timing and found that taking simethicone on the day of colonoscopy is more effective than taking it the day before the examination. When the simethicone was taken the day before, 1 L of bowel cleansing solution was added on the day of the test, and this led to the formation of bubbles again.Before the study, we hypothesized that taking simethicone before preparation on the day of the test would be the most effective approach. The reason is that colonoscopy is performed 3 to 5 hours after taking the last bowel cleansing solution, and we thought that a small amount of simethicone (10 mL) would not pass through the alimentary tract during that time. So, we anticipated the “TB” group would have better BS than “TA” group. However, on the day of endoscopy, there was no significant difference depending on the administration time in this present study. This is probably because the number of bubbles was influenced not only by the timing of simethicone administration but also by the level of bowel cleansing itself. In other words, patients with poor bowel preparation scores also had poor BS. Although it had null data, the effect of the time between the completion of bowel preparation and the colonoscopy did not seem to be negligible.Although simethicone is not expensive, many endoscopy centers still do not pay much attention to taking simethicone as much as bowel cleansing medicine (price, patient education, checking patient compliance, etc). However, taking simethicone before colonoscopy clearly reduced BS and increased endoscopist satisfaction in this study. In addition, simethicone irrigation was forced to remove remaining bubbles, but when taken simethicone in advance, the total amount of use including irrigation was also reduced. In this study, if endoscopists used 20 mL of simethicone per once for irrigation to reduce bubbles, then approximately 52 mL of simethicone was used in the control group, 35 mL in the BB and BA groups, and 6.75 mL in the TB and TA groups. It is also recommended to take simethicone on the day of the test in a cost-effective manner. As expected, and as reported in previous studies and in this study, there were no serious side effects of simethicone.The strength of this study is that, based on the results of a previous study, the administration time was divided in more detail and clearly. Second, because all participants prepared for colonoscopy during hospitalization, compliance with bowel cleansing and simethicone medication was guaranteed. Third, unlike other studies, the frequency of simethicone irrigation was analyzed to determine the difference in the amount of simethicone used between patients treated with simethicone and those who did not.However, this study has several limitations. First, the subjects were randomized into 5 groups with administration timing, but randomization of 5 colonoscopy operators was not performed. Therefore, the same evaluation criteria may not have been applied in each group. Each endoscopist may have different scoring criteria; therefore, we tried to reduce this difference by attaching a guideline paper to each endoscopy room. However, the endoscopist tendency to decide on simethicone irrigation based on the number of bubbles could vary. Second, in this study, BS and ABPS improved together, but the causal relationship could not be clearly defined. Endoscopists were asked to consider BS and ABPS separately, but both had the same tendencies. It seemed that the BS and the ABPS themselves would have an effect on each other and would also affect the satisfaction score. Third, because of the small number of samples, it was not possible to analyze which time period would be the best on the day of colonoscopy. A follow-up study is required in this regard.