Transcutaneous gas monitoring is a useful tool to detect respiratory depression during bronchoscopy performed under propofol sedation.

BACKGROUND

Bronchoscopy is a relatively invasive procedure where patients are often sedated. However, adequate sedation is not always achieved. Propofol is often used for difficult-to-sedate patients undergoing bronchoscopy despite a potential risk of respiratory depression. Transcutaneous carbon dioxide (tcpCO2) monitoring, introduced recently, is recognized as a convenient surrogate method for continuous monitoring of the partial pressure of arterial carbon dioxide (PaCO2). This study examined the safety of switching to propofol during bronchoscopy by using transcutaneous carbon dioxide monitoring.

METHODS

Patients in whom transcutaneous gas monitoring had been performed during bronchoscopy were included in this study. The participants were divided into two groups: 1) the midazolam + fentanyl group (MF group), and 2) the group in which midazolam was switched to propofol owing to inadequate sedation obtained with midazolam + fentanyl (MFP group). We retrospectively analyzed the transcutaneous gas measurement data collected in patients under propofol sedation for bronchoscopy.

RESULTS

This study included 61 (MF, n = 41; MFP, n = 20) patients. The duration of elevated tcpCO2 (>50 mm Hg) was greater in the MFP group (MF 8.5 min vs. MFP 22.1 min, p = 0.042).

CONCLUSION

Switching midazolam to propofol during bronchoscopy was significantly associated with a higher risk of elevated tcpCO2, which is indicative of respiratory depression. Therefore, continuous tcpCO2 monitoring is required to ensure the safety of patients under propofol sedation for bronchoscopy.