2.2. Participant recruitment
Participants are recruited from the Nagasaki University Hospital, where the subsequent study also took place. The treating clinical research coordinator provided an explanation of the study to all participants, and these participants signed an informed consent form. This is a randomized control study, comprised of 2 groups of participants. While both groups received intravenous anesthesia during ERCP, 1 group concomitantly used an NHF device. After giving consent, subjects who meet the registration requirements are randomly assignment to 1 of the 2 groups.