Capnography Not Needed For Every Colonoscopy

In the first study of its kind, researchers from Cleveland Clinic’s Digestive Disease Institute (DDI) have challenged proposed regulatory changes that would universally require capnographic monitoring during endoscopy with moderate sedation. The proposed requirements are intended to reduce the incidence of hypoxemia.

“The regulatory changes that are being proposed are based on expert opinion, not on evidence, says DDI Gastroenterology and Hepatology Department Chairman John Vargo, MD, MPH. “Before we conducted this study, there was no data as to whether the use of capnography in healthy adults undergoing ambulatory colonoscopy with moderate sedation would reduce the incidence of hypoxemia.” The findings from this study were presented as part of the Presidential Plenary at the 2014 American College of Gastroenterology’s annual meeting.

Study findings

The DDI researchers conducted a prospective randomized study of 232 healthy patients who were scheduled for routine outpatient colonoscopy. Patients were randomly assigned to an open capnography alarm or blinded capnography alarm group. In both study arms, standard cardiopulmonary monitoring devices were utilized. The primary end point was the incidence of hypoxemia, which was defined as a fall in oxygen saturation to < 90 percent for ≥ 10 seconds. There was no significant difference in rates of hypoxemia between the open and blinded capnography arms. However, there was a significantly lower rate of severe hypoxemia in the group receiving capnography monitoring.

“At this point, the initial evidence seems to suggest that additional capnographic monitoring may not be as beneficial with moderate sedation, as opposed to its known benefit with deeper sedative medications,” says gastroenterologist and lead study author Paresh Mehta, MD. “However, we did find that it was able to lower rates in a small number of patients who had more significant changes to oxygen percentages, and we need to fully evaluate these findings with other studies prior to making any formal changes in our management of patients.

“Overall, universally applying any monitoring device is difficult, as there is significant variation in procedures, sedation strategies, regional sedation patterns and patient populations,” Dr. Mehta says. “All of those things can affect the ability of the device to make procedures safer through early detection of changes in breathing patterns.”

Study impact

“Based on results of this study, at this point, I do not believe capnographic monitoring is indicated for healthy adult patients undergoing ambulatory colonoscopy with moderate sedation,” Dr. Vargo says. “However, further study is needed for patients who may be at risk for severe hypoxemia.”

“In the era of managing healthcare costs and looking for products that continue to improve the safety of our patients, I believe this study provides a first step in evaluating if all advanced monitoring devices in common sedation procedures significantly help improve patient safety,” Dr. Mehta says. “This is important, as these devices come at an increased cost and require specialized training in order for the people who are using them to effectively interpret their findings.”

The researchers

Researchers at the DDI are widely considered to be on the forefront of endoscopy sedation research. They have done multiple studies on gastrointestinal procedures and sedatives and have had a significant number of articles on the use of sedation in complex endoscopic procedures published in major scientific journals.

Next steps

As a follow-up to this study, DDI researchers are in the process of conducting a similar study to evaluate whether or not capnographic monitoring will reduce the risk of hypoxemia in healthy adult patients undergoing upper endoscopy with moderate sedation. The results should be available within the next few months.