Esophagogastroduodenoscopy

The goal of this clinical trial is to evaluate whether intravenous ondansetron can improve patient tolerance and reduce discomfort during unsedated emergency esophagogastroduodenoscopy (EGD). The main questions it aims to answer are: * Does pre-procedural administration of ondansetron improve patient cooperation during emergency EGD? * Does it improve endoscopic field visibility and improve the success rate of initial endoscopic hemostasis？ * Does it reduce the operator's perceived workload or stress? Researchers will compare patients who received intravenous ondansetron with patients who received placebo to see if ondansetron can reduce patient discomfort and improve patient cooperation, therefore improve the quality of the procedure. Participants will receive either intravenous ondansetron and dyclonine hydrochloride mucilage or intravenous saline and dyclonine hydrochloride mucilage prior to the endoscopic procedure.

The goal of this randomized, double-blind, placebo-controlled clinical trial is to assess whether the combination of N-acetylcysteine and simethicone improves mucosal visibility during upper gastrointestinal endoscopy in adults aged 18 to 99 years of both sexes, including both healthy individuals and those with non-bleeding gastrointestinal symptoms. The main questions this study aims to answer are: Does pre-endoscopy administration of N-acetylcysteine/simethicone improve mucosal visualization based on the Toronto Upper Gastrointestinal Cleanliness Score (TUGS)? Is this combination safe and well tolerated in this patient population? Researchers will compare patients receiving N-acetylcysteine (600 mg) and simethicone (100 mg) orally 20-60 minutes before the procedure with those receiving placebo (water) to determine if there is a significant improvement in TUGS scores. Participants will: Receive a single oral dose of either N-acetylcysteine/simethicone or placebo prior to endoscopy Undergo a routine upper GI endoscopy Have mucosal cleanliness evaluated using the TUGS scoring system Be monitored for any adverse events or intolerance