In our March 2014 What's New in the Patient Safety World column “New ASGE Endoscopy Safety Guidelines” we noted that the ASGE (American Society for Gastrointestinal Endoscopy) position (Calderwood 2014) on use of capnography was that there was inadequate data to support the routine use of capnography when moderate sedation is the target. Our own warning was that the “target” of moderate sedation is often overshot and some patients inadvertently receive deep sedation. While the evidence base for use of capnography in this setting may be limited, it only takes one case of a disaster related to oversedation to destroy whatever other good work you’ve done. Capnography is rapidly becoming a standard of care whenever patients are being given intravenous sedation or opioids.
Several studies suggest that capnography monitoring during gastrointestinal endoscopic procedures reduces the incidence of hypoxemia, but the impact on other adverse outcomes has been less clear. Now new study (Jopling 2017) retrospectively looked at a large database of patients undergoing gastrointestinal endoscopic procedures with sedation. Patients were put in one of 4 categories: (1) pulse oximetry (SpO2) only, (2) capnography only, (3) SpO2 with capnography, and (4) neither SpO2 nor capnography. Propensity-score matching was done to make groups comparable. For inpatients, capnography monitoring was associated with a 47% estimated reduction in the odds of death at discharge (OR: 0.53) and a non-significant 10% estimated reduction in the odds of pharmacological rescue event at discharge (OR: 0.91). For outpatients, capnography monitoring was associated with a 61% estimated reduction in the odds of pharmacological rescue event at discharge (OR: 0.39) and a non-significant 82% estimated reduction in the odds of death at discharge (OR: 0.18). The authors conclude that, despite the retrospective nature of the study, use of capnography during these procedures is recommended.
The ASGE guidelines for sedation and anesthesia in GI endoscopy have also recently been updated (Early 2018). They have been reviewed and endorsed by the American Association for the Study of Liver Diseases, the American College of Gastroenterology, and the American Gastroenterological Association, in addition to the Governing Board of the American Society for Gastrointestinal Endoscopy.
Those guidelines state “capnography has been demonstrated to detect depressed respiratory activity before transient hypoxemia, but a clear link between transient hypoxemia and serious cardiopulmonary unplanned events during sedated endoscopy has not been established. Integrating capnography into patient monitoring protocols for endoscopic procedures with moderate sedation has not been shown to improve patient safety; however, there is evidence supporting itsuse in procedures targeting deep sedation.”
However, under its recommendations for propofol use during endoscopy, it does state “Capnography should be considered because it may decrease the risks during deep sedation.” And under their summary recommendations they “suggest that capnography monitoring be considered for patients undergoing endoscopy targeting deep sedation.”
We’re glad to see these recommendations for increased use of capnography during procedures using sedation n the GI lab. Capnography monitoring is rapidly becoming the standard of care for patients undergoing procedures under sedation in a wide variety of settings.
Calderwood AH, Chapman FJ, Cohen J, et al for the ASGE Ensuring Safety in the Gastrointestinal Endoscopy Unit Task Force. Guidelines for safety in the gastrointestinal endoscopy unit. Gastrointestinal Endoscopy 2014; article in press published 30 Jan 2014
Jopling MW, Qiu J. Capnography Sensor Use Is Associated With Reduction of Adverse Outcomes During Gastrointestinal Endoscopic Procedures With Sedation Administration. BMC Anesthesiol 2017; 17: 157 Published: 28 November 2017
Early DS, Lightdale JR, Vargo JJ, et al. Guidelines for sedation and anesthesia in GI endoscopy. Gastrointest Endosc 2018; 87(2): 327-337