Propofol Safety in Bronchoscopy: Prospective Randomized Trial Using Transcutaneous Carbon Dioxide Tension Monitoring

BACKGROUND: Midazolam is commonly used for sedation during flexible bronchoscopy because of its relatively wide therapeutic window. Recently, sedation with propofol for bronchoscopy has gained popularity, although concern has been raised regarding its potential ability to induce severe respiratory depression. OBJECTIVES: The aim of this study was to evaluate the safety of sedation under midazolam + alfentanil compared to propofol. METHODS: We conducted a prospective randomized trial using continuous transcutaneous carbon dioxide tension monitoring. The study group included 115 patients undergoing bronchoscopy, prospectively randomized to receive sedation with either midazolam + alfentanil (n = 59) or propofol (n = 56). RESULTS: Intra-procedural carbon dioxide tension values were higher in the midazolam + alfentanil group than in the propofol group (maximum 53.72 vs. 49.49 mm Hg, mean 46.78 vs. 43.78 mm Hg), but the differences did not reach statistical significance (p = 0.149 and 0.193, respectively). Carbon dioxide tension values were significantly higher in the midazolam + alfentanil group than in the propofol group at 5 and 10 min following procedure (51.7 vs. 49.3 mm Hg, p = 0.026, and 50.8 vs. 42.7 mm Hg, p < 0.01, respectively), and significantly more patients in the midazolam + alfentanil group needed oxygen supplementation or airway support (24 vs. 8 patients, respectively). CONCLUSION: Midazolam + alfentanil and propofol are equally safe for sedation during bronchoscopy. Sedation with propofol, using small boluses at short intervals, does not cause excessive respiratory drive depression and represents an excellent alternative to traditional sedation agents.