A single‐sided trans‐nasal catheter for smooth and efficient oxygen delivery can improve the safety in patients undergoing pancreato‐biliary endoscopy under intravenous sedation: A... oleh Ken Ishii, Kensuke Kubota, Tomomi Nakao, Yuji Koyama, Yuji Fujita, Kuniaki Akaba, Nobuyuki Matsuhashi, Atsushi Nakajima