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

Tsukasa Ishiwata,Naoko Kawata,Jiro Terada,Koichiro Tatsumi,Mai Fujie,Kenichi Suzuki,Kosuke Hirota,Kenji Tsushima,Mitsuhiro Abe

doi:10.1186/s12890-016-0361-7

Tsukasa Ishiwata, Naoko Kawata + Show 7 more

Open Access

https://doi.org/10.1186/s12890-016-0361-7

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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.

Highlights

Apnea developing as a result of oversedation is a potential clinical problem in patients undergoing flexible bronchoscopy (FB) under sedation
The median minimum SpO2 during the FB procedure was lower in the group with apnea episodes (89%; interquartile ranges (IQR) 87–93 vs. 96%; IQR 92–97, P < 0.001) and the median maximum flow rate of supplemental O2 required was higher in the group with apnea episodes than in the group without apnea episodes (2 L/min; IQR 2–4 vs. 2 L/min; IQR 2-2, P < 0.001)
Our results revealed that apnea episodes occur at a high frequency during FB under sedation in the clinical setting

Summary

Introduction

Apnea developing as a result of oversedation is a potential clinical problem in patients undergoing flexible bronchoscopy (FB) under sedation. 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. Bronchoscopic procedures require moderate sedation to alleviate the patient’s anxiety and to suppress the cough reflex. This is associated with the risk of respiratory depression developing during prolonged procedures, especially diagnostic bronchoscopies, as administration of high doses of sedatives is often necessitated during such procedures. The aim of this study was to investigate the actual frequency of occurrence of apnea episodes during FB under sedation by end-tidal capnography

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