Capnographic Monitoring Does Not Improve Detection of Hypoxemia in Colonoscopy With Moderate Sedation: A Randomized, Controlled Trial

Abstract

ACG Fellow Award Introduction: Suggested regulatory changes requiring the universal use of capnographic monitoring during endoscopy with moderate sedation has placed financial challenges on ambulatory and hospital endoscopy centers across the United States due to the increased cost of training endoscopy personnel and purchasing capnography-monitoring devices and specialized capnographic sampling ports. To date, there has been no published data proving universal capnographic monitoring in adult patients undergoing routine endoscopic procedures with moderate sedation improves safety. The aim of this randomized study was to determine if capnographic monitoring reduces the incidence of hypoxemia in patients undergoing outpatient colonoscopy targeting moderate sedation. Methods: ASA Physical Classification (ASAPS) I and II patients scheduled for routine outpatient colonoscopy targeting moderate sedation utilizing an opioid and benzodiazepine combination were randomly assigned to an open capnography alarm or blinded capnography alarm group. In both study arms, standard cardiopulmonary monitoring devices were utilized with additional capnographic monitoring. The primary end point was the incidence of hypoxemia defined as a fall in oxygen saturation (SaO2) to <90% for ≥10 seconds. Secondary outcomes included severe hypoxemia (SaO2 <85%), apnea, disordered respiration, hypotension, bradycardia and early procedure termination for any cause. A multivariate analysis was performed to determine the risk factors for developing hypoxemia. Results: A total of 232 patients were randomized. One hundred fifteen patients (49.6%) were male and average body mass index (BMI) was 29.1 (kg/m2). The groups were similar in regards to prior use of opioids (P=0.28), benzodiazpenies (P=0.41), and ASAPS classification (P=0.38). There was no significant difference in rates of hypoxemia between the open and blinded capnography arms (52.1% vs. 54.8%, P=0.69). However, there was a significantly lower rate of severe hypoxemia between the two groups (5.1% open vs. 18.3% blinded, P=0.002). There were no significant differences between the groups in other secondary outcomes. Table 1 shows risk factors for hypoxemia.Table 1: Multivariable Risk Factors for Development of HypoxemiaConclusion: Capnographic monitoring in routine colonoscopy for ASAPS 1 and 2 patients does not reduce the incidence of hypoxemia. However, it may reduce the incidence of more severe hypoxemic events. Further study in this subset of patients exhibiting severe hypoxemia is warranted.