Nasopharyngeal versus transcutaneous CO2 monitoring during ERCP

J. Vargo, G. Zuccaro, D. Conwell, J. Ryckman, S. Shay

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Transcutaneous carbon dioxide monitoring (TCO2) has been shown to have a strong correlation to arterial CO2 levels. It has been suggested that TCO2 may detect hypoventilation better than pulse oximetry and other standard monitoring techniques. However, TCO2 is cumbersome and impractical for routine endoscopic procedures. Recently, a sidestream CO2 monitor became available that allows for continuous CO2 measurement via nasal prongs. Purpose: To assess the correlation between transcutaneous and nasopharyngeal CO2 monitoring during ERCP. Methods: Patients underwent simultaneous TCO2 and nasopharyngeal (NCO2) monitoring during ERCP utilizing a sidestream CO2 detector coupled with nasal cannula sampling device, providing a real time graphic assessment of respiratory rate and pattern. Patients received standard sedation and analgesia with meperidine and midazolam. Results: Ten patients were studied. There is a significant correlation between the simultaneous NCO2 and TCO2 measurement (r = 0.6, p < 0.001) Placement of the nasopharyngeal cannula was well-tolerated and did not require topical anesthesia. There were much weaker albeit significant correlations between the respiratory rate and both NCO2 (r = -0.27, p < 0.01) and TCO2 (r = -0.26, p < 0.01). Conclusions: 1) There is a strong correlation between NCO2 and TCO2. 2) NCO2 is a well-tolerated, easy to use method for monitoring alveolar hypo ventilation 2) NCO2 provides a real time graphic assessment of respiratory rate and pattern which supplants the need for visual assessment of respiratory excursion during ERCP.

Original languageEnglish
Pages (from-to)AB61
JournalGastrointestinal Endoscopy
Issue number4
StatePublished - 1998

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Gastroenterology


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