EGD examination included the following steps: introduction of the endoscope and passage through the throat; slow progression of the scope to the Z-line; advancement of the scope to the pylorus along the lesser curvature; CHIR-99021 supplier passage through the pyloric ring; inspection of the duodenal bulb and superior duodenal angle; further advancement and exploration of the second duodenal portion; withdrawal into the stomach and inspection of the antrum and angular fold; retroflexion maneuver with visualization of the fundus and body; returning the endoscope to the antrum; and withdrawal from the antrum to the upper esophagus with exploration of the whole

stomach and esophagus (Table 2).14 Colonoscopy was considered successful only if the base of the cecum could be reached with the scope.15–17 The cecum was recognized by identifying endoscopic landmarks of the ileocecal valve and appendiceal orifice. A detailed examination of the entire luminal mucosa and interventions such as biopsy and polypectomy were performed during the endoscopic withdrawal process to the

anus. check details All videotaped EGDs were randomly reviewed by three experienced endoscopists (S.K. Lee, J.H. Cho, and J.H. Kim) who were blinded to the experimental design of the study as well as patient data. All reviewers had previously performed at least 5000 EGD examinations and were qualified for ‘The Board of Gastrointestinal Endoscopy Specialist’ from ‘The Korean Society of Gastrointestinal Endoscopy’. Reviewers were asked to score 18 however EGD

items used to assess the overall quality of the examination and the feasibility of each EGD step. These assessment items were graded using the following numeric scale: 1, excellent; 2, good; 3, moderate; 4, just sufficient; 5, poor; and 6, very poor.14,18 During colonoscopy, the intubation time to the cecum, total duration of the procedure, and the adequacy of bowel cleansing were assessed. In addition, insertion times were categorized into two groups according to duration (prolonged insertion, > 10 min; rapid insertion, ≤ 10 min).15,17 Finally, patient questionnaires were used to assess patient discomfort. The primary objective of this study was to compare the quality of EGD steps achieved by two bidirectional endoscopic sequences, EGD-colonoscopy (Group I) or colonoscopy-EGD (Group II). We assumed that a score on the general assessment of EGD steps (P15) more than ‘good’ would signify a complete EGD examination and anticipated that the expected rates of complete examination in EGD steps would be 80% in Group I.14 Further, based on previous experience, we predicted that the rate of EGD completion would be 60% in Group II. The sample size required for our study was estimated based on this predicted 20% difference and designed to detect significant differences at P < 0.05 with a power of 80%.