Capnographic Monitoring of Moderate Sedation During Low-Risk Screening Colonoscopy Does Not Improve Safety or Patient Satisfaction: A Prospective Cohort Study

OBJECTIVES: Appropriate monitoring during sedation has been recognized as vital to patient safety in procedures outside of the operating room. Capnography can identify hypoventilation prior to hypoxemia; however, it is not clear whether the addition of capnography improves safety or is cost effective during routine colonoscopy, a high volume, low-risk procedure. Our aim was to evaluate the value of EtCO2 monitoring during colonoscopy with moderate sedation. METHODS: We conducted a prospective study of sedation safety and patient satisfaction before and after the introduction of EtCO2 monitoring during outpatient colonoscopy with midazolam and fentanyl using the validated PROcedural Sedation Assessment Survey (PROSAS). Complications of sedation and PROSAS scores were compared among colonoscopies with and without capnography. RESULTS: A total of 966 patients participated in our study, 465 in the pre-EtCO2 group and 501 in the EtCO2 group. On multivariate analysis, patients and nurses reported higher levels of procedural discomfort after adoption of capnography (1.71 vs. 1.00, P<0.001). No serious adverse events were seen, and minor sedation-related adverse events occurred with similar frequency in both groups (8.2% pre-EtCO2 vs. 11.2% EtCO2, P=0.115). The cost of implementing EtCO2 in our unit was $40,169.95 and added $11.68 per case. CONCLUSIONS: Colonoscopy with moderate sedation is a low-risk procedure, and the addition of EtCO2 did not improve safety or patient satisfaction but did increase cost. These data suggest that routine capnography in this setting may not be cost effective and that EtCO2 might be reserved for patients at higher risk of adverse events.