Chen SW, et al. - This prospective randomized study was performed to examine the optimal sequence for same-day bidirectional endoscopy (BDE) under moderate conscious sedation and carbon dioxide insufflation in terms of sedation doses, patient discomfort, and colonoscopy performance. Followed by colonoscopy, esophagogastroduodenoscopy (EGD) was the optimal sequence for same-day BDE under moderate conscious sedation and carbon dioxide insufflation. Following this order allowed for a reduction of sedation doses and for shorter recovery times.