Novel mainstream capnometer system is safe and feasible even under CO 2 insufflation during ERCP-related procedure: a pilot study

Background and aims There is a need to safely achieve conscious sedation during endoscopic retrograde cholangiopancreatography (ERCP). We evaluated the safety and feasibility of a mainstream capnometer system to monitor apnoea during ERCP under CO 2 insufflation. Methods Non-intubated adult patients undergoing ERCP-related procedures with intravenous sedation were enrolled. End-tidal CO 2 (EtCO 2 ) was continuously monitored during the procedure under CO 2 insufflation using a mainstream capnometer system, comprising a capnometer and a specially designed bite block for upper gastrointestinal endoscopy and ERCP. Oxygen saturation (SpO 2 ) was also monitored continuously during the procedure. In this study, we evaluated the safety and feasibility of the capnometer system. Results Eleven patients were enrolled. Measurement of EtCO 2 concentration was possible from the beginning to the end of the procedure in all 11 cases. There was no measurement failure, dislocation of the bite block, or adverse event related to the bite block. Apnoea linked to hypoxaemia occurred five times (mean duration, 174.4 s). Conclusion This study confirmed that apnoea was detected earlier than when using a percutaneous oxygen monitor. Measurement of EtCO 2 concentration using the newly developed mainstream capnometer system was feasible and safe even under CO 2 insufflation.