One of the major problems for the endoscopist during esophagogastroduodenoscopy (EGDS) is the presence of foam, bubbles, mucus and saliva, whether small or large, which can compromise correct endoscopic visibility. Endoscopy of the upper gastrointestinal tract, like that of the lower gastrointestinal tract, requires optimal visualization of the mucosa. It is clear that endoscopic vision is often hindered by the presence of bubbles and foam: multiple aspirations alternating with intraprocedural washes are therefore necessary, which lengthen the time necessary for the endoscopic examination. Nowadays there's no universal raccomandation about a specific preparation before EGDS.

The aim of our study is to compare fasting versus the use of simethicone premedication in combination with N-acetyl- cysteine and acetic acid (LumevisTM).

The study is observational, randomized 1:1, and double blind. Primary outcomes are: grade of mucosa visualization defined by visual analogue scale (0-10) for each analyzed segment (esophagus, stomach and duodenum).

Secondary aims: general patient satisfaction defined by visual analogue scale, eventual adverse events, duration of the exam.

Inclusion Criteria:

• adult patients that underwent EGDS

Exclusion Criteria:

• previous upper GI surgery
• previous endoscopic bariatric procedures
• known upper GI stenosis (benign and malign)
• previous diagnosis of achalasia or motility disorders
• diabetes
• allergy to one of lumevis components
• cystinuria
• fasting not correctly respected
• pregnant or brest-feeding women
• urgent-emercengy setting
• inpatients
• patients who don't give their consent to partecipate to the trial

adult patients who had to perform EGDS