Journal of Clinical Monitoring and Computing

, Volume 31, Issue 1, pp 53–57 | Cite as

Ventilation monitoring during moderate sedation in GI patients

  • Thomas J. EbertEmail author
  • Austin H. Middleton
  • Nikhil Makhija
Original Research


Sedation in locations outside the operating room (OR) is common. Guidelines for safe patient monitoring have been updated by the American Society of Anesthesiology to include monitoring of ventilation and/or carbon dioxide (CO2). Although technologies exist to monitor these variables, the quality and/or availability of these measurements in non-OR settings is not optimal. This quality improvement project assessed the value of impedance technology for monitoring minute ventilation (MV) compared to standard end-tidal monitoring of CO2 (ETCO2). Patients undergoing GI exams with moderate sedation provided by anesthesia providers were monitored for MV with a respiratory volume monitor (ExSpiron 1Xi, Respiratory Motion, Waltham, MA) and ETCO2 via nasal cannula (NC). Calibration and baseline data were collected prior to sedation. Continuous MV and ETCO2 data were collected and averaged, providing minute values after sedation medications throughout the procedure. Stable periods of reduced MV were averaged and used in comparison to ETCO2. Data from 20 patients were evaluated. After sedation, the expected decrease in MV after sedation was observed in 18 of 20 patients (average −47.82 %), while an increase in ETCO2 was observed in just 10 of 20 patients (average −5.17 mm Hg). The correlation coefficient between changes in MV and ETCO2 in response to sedation administration was positive and not significant, r = 0.223. Ventilation monitoring may provide an element of safety for earlier and more reliable detection of reduced ventilation compared to a surrogate for hypoventilation, ETCO2, in patients undergoing sedation for GI procedures outside of the OR.


End-tidal CO2 Minute ventilation Conscious sedation Monitored anesthesia care 


Financial disclosure

The authors received no financial assistance for this study. As a quality assurance study, the Clement J. Zablocki VA Medical Center provided the electrodes for the ExSpiron monitor.

Compliance with ethical standards

Conflict of interest

The authors have no conflicts of interest to report.

Ethical approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Informed consent

These data were gathered as part of a QI Project, and for this type of study, formal consent is not required.


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Copyright information

© Springer Science+Business Media Dordrecht (outside the USA) 2015

Authors and Affiliations

  1. 1.Department of AnesthesiologyZablocki VA Medical Center and Medical College of WisconsinMilwaukeeUSA
  2. 2.Washington University in St. LouisSt. LouisUSA
  3. 3.Nova Southeastern University College of Osteopathic MedicineDavieUSA

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