The midazolam and fentanyl versus additional use of propofol in difficult-to-sedate cases during bronchoscopy by transcutaneous gas monitoring: a case control study

Background: bronchoscopy is a relatively invasive procedure, and standard anesthesia is often inadequate. The recently introduced transcutaneous carbon dioxide ( tcp CO 2 ) monitoring has become a convenient surrogate method for continuous monitoring of the partial pressure of arterial carbon dioxide (PaCO 2 ). The objective of this study was to evaluate the safety of additional use of propofol during bronchoscopy by transcutaneous blood gas monitoring. Methods: patients in whom transcutaneous gas monitoring was performed during bronchoscopy were included in this study. The study subjects were divided into two groups: 1) the midazolam + fentanyl group (MF group), and 2) the group in which midazolam was switched to propofol because of inadequate sedation with midazolam + fentanyl (MFP group). We conducted a retrospective analysis of the transcutaneous gas measurement data obtained during bronchoscopy. Results: data of a total of 61 patients (MF group, n=41; MFP group, n=20) were analyzed. The duration over which the tcp CO 2 remained over 50 mm Hg was longer in the MFP group (MF 0.0 min vs. MFP 7.8 min, p =0.042). The percentage of patients in whom the tcp CO 2 rose to over 50 mm Hg was also higher in the MFP group (MF group, 14.6% vs. MFP group, 65.0%). None of the patients required discontinuation of the bronchoscopic procedure due to inadequate sedation. Conclusions: while the addition of propofol improved the tolerability of the procedure in difficult-to-sedate patients, it was also associated with a higher risk of ventilatory failure and hypoxemia. Thus, in order to ensure safety, additional propofol should be used with caution under continuous p CO 2 monitoring, such as by transcutaneous measurement. Trial registration: this study was conducted with the approval of the Clinical Research Management Division of Dokkyo Medical University (Approval No.: R-15-5J) under the supervision of a well-trained bronchoscopist. The contents of the study were disclosed in an opt-out format.