Dynamic article: Steady pressure CO₂ colonoscopy: Its feasibility and underlying mechanism

BACKGROUND: Steady pressure automatically controlled endoscopy is a new insufflation concept, achieving a laparoscopy-like steady environment in the upper GI tract, recently reported in the esophagus. OBJECTIVE: The purpose of this work was to validate the feasibility and safety of steady pressure automatically controlled endoscopy in the lower GI tract and to identify major factors that enable it. DESIGN: This was a nonsurvival animal study using canine models. SETTINGS: The study was conducted in an academic center. PATIENTS: Canine models were used in this study. INTERVENTIONS: In experiment 1, steady pressure automatically controlled endoscopy was attempted in the cecum with insufflation pressures of 4, 8, and 12 mm H g. We assessed performance by video review and continuous intracecal pressure monitoring. Next, steady pressure automatically controlled endoscopy was performed for 20 minutes under optimal pressure, 8 mm Hg (n = 10). In experiment 2, steady pressure automatically controlled endoscopy was attempted in the rectum with or without artificial colonic flexure and with either low (8 mm H g) or high (16 mm H g) insufflation pressure to assess the effects of anatomic flexure and insufflation pressure on the establishment of steady pressure automatically controlled endoscopy (n = 6). MAIN OUTCOME MEASURES: We measured multipoint intraluminal pressure monitoring in the upstream bowel, as well as cardiopulmonary parameters. RESULTS: For experiment 1, steady pressure automatically controlled endoscopy in cecum was successful at all of the tested insufflation pressures; 8 mm H g provided the optimal result. Steady pressure automatically controlled endoscopy was safely performed for 20 minutes at 8 mm H g without any cardiopulmonary parameter changes or intraluminal pressure elevation in the upstream bowel. For experiment 2, confinement of the steady pressure environment to the rectum was achieved only with the assistance of colonic flexure and at 8 mm H g insufflation pressure. In other conditions, the insufflated gas extended throughout the entire colon. LIMITATIONS: This study was limited by being an animal study. CONCLUSIONS: Steady pressure automatically controlled endoscopy is feasible and safe in the lower GI tract under the optimized insufflation pressure and in the presence of anatomical flexure (see Video, Supplemental Digital Content 1, http://links.lww.com/DCR/A150).