Discussion
respiratory abnormality, obstructive disorders, respiratory abnormalities, allergies
OXYGEN DEFICIENCY, ADVERSE EVENTS, EVENT, HYPOXIC, ALLERGIES, EVENTS
In this phase II study, no major safety issues were observed with the nasal pressure monitor as a novel approach to monitoring during invasive endoscopic procedures under sedation with propofol and fentanyl. SpOOf the 45 patients, two cases dropped out: one due to the cancellation of the endoscopic procedure itself and the other due to the non-display of the monitor due to the occlusion of the cannula by the patient’s body, causing inhibition of pressure transmission. No similar event had occurred since then by taking care not to press the cannula. Two adverse events clearly related to endoscopic procedures were observed, but they had no effect on the primary goal of this phase II study, that is, confirming the safety of nasal pressure monitoring. Furthermore, waveform analysis revealed that the nasal pressure monitoring system could detect respiratory abnormalities when oxygen desaturation episodes occurred. Therefore, nasal pressure monitoring can be used as a respiratory monitor during the endoscopic procedure under sedation to detect respiratory abnormalities before SpOAccording to waveform analysis, there were more patients with high detectability of respiratory abnormalities at oxygen desaturation by the nasal pressure monitor than by capnography. However, no significant differences were observed. As previously reported, even if capnography did not display respiratory abnormalities, hypoxic events occurred in this study. The nasal pressure monitor also could not detect respiratory abnormalities before all hypoxic eventsThis study also thoroughly examined respiratory abnormalities during oxygen deficiency, demonstrating that only the nasal pressure monitor could detect obstructive disorders, which capnography did not (Table In this study, ASA class I and allergies were risk factors associated with a decrease in SpOThis study has several limitations. First, this was a single-center study conducted at Chiba University. Second, waveform analysis may be biased due to physician subjectivity, even though waveform analysis was performed by three physicians, one of whom was an expert in waveform analysis, and each respiratory abnormality was defined in detail. Third, a waveform analyst examined respiratory abnormalities at the point of oxygen desaturation a few weeks after the procedure to compare the two monitoring systems, even though it is critical that the physician in charge of sedation be able to make a decision regarding respiratory abnormalities during the procedure. This point should be investigated further in future research. Fourth, since the trial was planned as a phase II pilot trial to evaluate the safety and feasibility of nasal pressure monitoring compared to capnography, sample size and event size were low even though the statistically demanded size was reached. Therefore, the study was underpowered to find differences in hypoxic event rates and false alarms for nasal pressure monitoring and capnography. Fifth, since the Japanese guidelines for sedation in gastroenterological endoscopy describe the effectiveness of the combined use of propofol and fentanyl for ERCPIn conclusion, this study confirmed the safety of the nasal pressure monitor to proceed to a phase III trial. This monitoring method during an endoscopic procedure that requires sedation may be useful in detecting respiratory abnormalities before SpO