Does Capnography Prevent Hypoxemia During Endoscopic Retrograde Cholangiopancreatography and Endoscopic Ultrasound?

Does Capnography Prevent Hypoxemia During Endoscopic Retrograde Cholangiopancreatography and Endoscopic Ultrasound?

Subjects undergoing elective ERCP and EUS will receive standard monitoring and sedation. In addition, capnography which measures carbon dioxide levels and can graphically assess respiratory activity will be used. Subjects will be randomized to either a capnography blinded or titration arm. In the capnography titration arm, the endoscopy team would be made aware of capnographic abnormalities as they arise throughout the procedure. In the capnography blinded arm, this information will not be available to the endoscopy team and represents standard of care. It is our hypothesis that using capnography can prevent low oxygen levels known as hypoxemia, during these procedures.

Subjects undergoing elective ERCP and EUS will receive standard monitoring and sedation. In addition, capnography which measures carbon dioxide levels and can graphically assess respiratory activity will be used. Subjects will be randomized to either a capnography blinded or titration arm. In the capnography titration arm, the endoscopy team would be made aware of capnographic abnormalities as they arise throughout the procedure. In the capnography blinded arm, this information will not be available to the endoscopy team and represents standard of care. It is our hypothesis that using capnography can prevent low oxygen levels known as hypoxemia, during these procedures. The primary outcome of our study is the proportion of patients with hypoxemia in the two arms. Review of the literature indicates that the incidence of hypoxemia without supplemental oxygen varies from 30-70%. Our sample size calculation is based on a reduction of the hypoxemia incidence from 40% to 20%. Secondary outcomes will be the proportions of patients with oxygen requirements, major hypoxemia and apnea (lack of respiratory activity via capnography for at least 15 seconds) in the two arms. We will perform a univariable and multivariable analysis to determine the risk factors for apnea.

Capnography: Subjects randomized to capnography-titration arm: The endoscopy team would be made aware of the capnographic abnormalities as they arise. In this arm, the endoscopy team will have the graphic representation of respiratory activity (capnography) as well as end-epxiratory levels of carbon dioxide in addition to the normal physiologic monitoring portfolio of pulse oximetry, blood pressure and electrocradiography. This observation phase would take place for a baseline prior to sedation, during the administration of sedation as well as throughout the procedure. Monitoring for the study would stop upon completion of the endoscopic procedure.

Subjects randomized to capnography-blinded arm: In this arm, the endoscopy team will not have the graphic representation of respiratory activity (capnography) as well as end-expiratory levels of carbon dioxide available. Only a standard of care physiologic monitoring portfolio of pulse oximetry, blood pressure and electrocradiography at the disposal of the endoscopy team to titrate the sedative medications.

Capnography: Passive measurement of carbon dioxide via a special bite block which allows graphic assessment of the subject's respiratory activity

Inclusion Criteria: Adults age 18 or greater Subjects undergoing elective ERCP and EUS ASA class 1-3 Inpatient and outpatient Able to give informed consent Exclusion Criteria: ASA Class 4 and 5 Emergent procedures Procedures requiring MAC sedation Subjects unable to give informed consent Subjects on oxygen before procedure Subjects on CPAP/BiPAP Allergies to fentanyl/demerol/midazolam

Qadeer MA, Vargo JJ, Dumot JA, Lopez R, Trolli PA, Stevens T, Parsi MA, Sanaka MR, Zuccaro G. Capnographic monitoring of respiratory activity improves safety of sedation for endoscopic cholangiopancreatography and ultrasonography. Gastroenterology. 2009 May;136(5):1568-76; quiz 1819-20. doi: 10.1053/j.gastro.2009.02.004.