Limitations
pain
There are several limitations in this clinical trial. First, the authors’ findings should be carefully generalized because of the limited number of patients enrolled and given the heterogeneous nature of the Japanese patients taking part in this study. Although the administration of midazolam or pethidine hydrochloride was based on the arbitrary evaluation by endoscopists in a single research center, it is not possible to indicate standardized results in this study.Second, the average BMI (kg/mThird, it should be noted that this trial was performed during moderate sedation. Deep sedation using another sedative agent, such as dexmedetomidine or anesthetics propofol, is now well accepted in managing ERCP. Vijitpavan et al. [Forth, masking was not possible due to the nature of the study.Finally, in this study pethidine hydrochloride was administered when patients were suspected of experiencing excessive pain or discomfort without evaluating analgesia quantitatively using a VAS score as had been used in a previous study [