End-tidal capnographic monitoring to detect apnea episodes during flexible bronchoscopy under sedation

Abstract

BackgroundApnea developing as a result of oversedation is a potential clinical problem in patients undergoing flexible bronchoscopy (FB) under sedation. However, there are no reports of evaluation using a standardized method of the frequency of occurrence of apnea episodes during FB under sedation. The aim of this study was to investigate the frequency of apnea episodes during FB under sedation in the clinical setting by end-tidal capnography.MethodsThis study was a single-institution retrospective review of a prospectively maintained database and medical records, including capnographic data, from April 2015 to March 2016. We enrolled patients who were sedated with midazolam and underwent diagnostic FB under end-tidal capnographic monitoring. Apnea was defined as cessation of airflow for more than 10 s.ResultsData from a total of 121 eligible patients were analyzed. A total of 131 apnea episodes (median duration 33 s) were recorded in 59 patients (48.8%). Prolonged apnea episodes lasting for more than 30 s occurred in 24 patients (19.8%). Furthermore, 55 apnea episodes (42.0%) were followed by a decline of the SpO2 by ≥4% from the baseline.ConclusionsIn this study, end-tidal capnography revealed the occurrence of apnea episodes at a high frequency in patients undergoing FB under sedation in the clinical setting.

Safety of Monitored Anesthesia Care Using Propofol-Based Sedation for Pleuroscopy

“…MAC involves personnel who are trained specifically in the use of propofol and routinely use additional monitoring to optimize sedation delivery. Specifically, end-tidal capnography has been shown to be useful in titrating the depth of sedation in a variety of procedures that require sedation [6,[14][15][16][17]. The results of this study are similar to other studies evaluating end-tidal capnography during sedation in endoscopy [6,18].…”

Efficacy of End-Tidal Capnography Monitoring during Flexible Bronchoscopy in Nonintubated Patients under Sedation: A Randomized Controlled Study

“…The decline in SpO 2 might be delayed especially in sedated patients receiving supplemental oxygen [11,12]. In a previous study, we found that the median delay between the onset of an apnea episode and a significant SpO 2 decline was 31 s [7]. End-tidal capnography alerts of apnea episodes in real time in the form of a visual line and by setting off an alarm, which allows for the recognition of the apnea episodes earlier than pulse oximetry and prompts performance of appropriate corrective measures such as increasing supplemental oxygen flow or chin-lift/jaw-thrust maneuver.…”

“…In a retrospective study, we reported that end-tidal capnography was a graphic approach that could easily detect frequent apnea episodes during flexible bronchoscopy (FB) under moderate sedation and that it could detect apnea earlier than standard pulse oximetry monitoring [7]. However, the utility of end-tidal capnography monitoring in reducing hypoxemia during FB under sedation has not been fully evaluated.…”

“…Sample size calculation was based on the results of our retrospective study [7] which determined hypoxemic incidence rate as 47.6% in patients under sedation. We assumed a reduction of hypoxemia from 50 to 30% as clinically relevant.…”

“…A Smart CapnoLine Guardian TM (Medtronic, Ireland) was used as a capnography mouth device [7] that was connected via a sampling tube to an automated capnographic monitoring device (Capnostream 20P TM , Medtronic, Ireland). This monitoring device performs continuous measurement of carbon dioxide concentrations in the expired air of patients and shows capnographic data as a curved line on a front display.…”