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Original article

Vol. 146 No. 4344 (2016)

Transcutaneous versus blood carbon dioxide monitoring during acute noninvasive ventilation in the emergency department – a retrospective analysis

  • Christian Michael Horvath
  • Martin Hugo Brutsche
  • Florent Baty
  • Jochen Julius Rüdiger
Cite this as:
Swiss Med Wkly. 2016;146:w14373


QUESTIONS UNDER STUDY: Transcutaneous measurement of carbon dioxide (PtCO2) has been suggested as an alternative to invasively obtained PaCO2 for the monitoring of patients with hypercapnic respiratory failure during noninvasive ventilation (NIV). Current data on monitoring in hypoxaemic respiratory failure are scarce and show conflicting results in hypercapnic patients in the emergency department.

METHODS AND SETTING: We performed a retrospective comparison of real-time PtCO2 (SenTec Digital Monitor) and arterial/venous carbon dioxide tension (PaCO2/PvCO2) measurements in patients with severe hypoxaemic and/or hypercapnic respiratory failure during NIV. Agreement between PtCO2 and PaCO2/PvCO2 was the primary endpoint. Bland-Altman analysis and linear regression were used.

RESULTS: 102 patients had at least one matched measurement of PtCO2 and PaCO2/PvCO2. For patients with arterial blood gas analysis, the mean difference was 0.46 kPa at baseline (95% confidence interval [CI] 0.23 to 0.60, limits of agreement 95% CI –0.54 to 1.45) and 0.12 kPa after NIV (95% CI –0.04 to 0.29, limits of agreement 95% CI: –0.61 to 0.86). The linear regression analysis found a correlation R 2 of 0.88 (p <0.001) at baseline and an R 2 of 0.99 (p <0.001) after initiating NIV. For patients with venous blood gas analysis, the mean difference was 0.64 kPa at baseline (95% CI 0.04 to 1.24, limits of agreement 95% CI –0.72 to 2) and 0.80 kPa after NIV (95% CI 0.51 to 1.10, limits of agreement 95% CI 0.29 to 1.32), R 2 0.78 (p <0.001) at baseline and R 2 0.91 (p <0.001) after initiating NIV.

A PaCO2/PvCO2 >8 kPa was associated with a lesser degree of agreement between the levels of PtCO2 and PaCO2/PvCO2 (p <0.001).

CONCLUSION: Transcutaneous PCO2 monitoring shows a good concordance with PaCO2 and is a reliable, feasible, patient-friendly and safe alternative to repeated blood gas analysis for patients with severe hypoxaemic and/or hypercapnic respiratory failure receiving emergency NIV in the emergency department. An initial blood gas analysis to evaluate the respiratory and metabolic state and to rule out a significant discrepancy compared with the transcutaneous measurement is recommended.


Trials registration number: EKSG13/118


  1. Giner J, Casan P, Belda J, González M, Miralda RM, Sanchis J. Pain during arterial puncture. Chest. 1996;110(6):1443–5. doi: PubMed
  2. Gillies ID, Morgan M, Sykes MK, Brown AE, Jones NO. The nature and incidence of complications of peripheral arterial puncture. Anaesthesia. 1979;34(5):506–9. doi: PubMed
  3. Storre JH, Magnet FS, Dreher M, Windisch W. Transcutaneous monitoring as a replacement for arterial PCO(2) monitoring during nocturnal non-invasive ventilation. Respir Med. 2011;105(1):143–50. doi: PubMed
  4. Storre JH, Steurer B, Kabitz H-J, Dreher M, Windisch W. Transcutaneous PCO2 monitoring during initiation of noninvasive ventilation. Chest. 2007;132(6):1810–6. doi: PubMed
  5. Maniscalco M, Zedda A, Faraone S, Carratù P, Sofia M. Evaluation of a transcutaneous carbon dioxide monitor in severe obesity. Intensive Care Med. 2008;34(7):1340–4. doi: PubMed
  6. McVicar J, Eager R. Validation study of a transcutaneous carbon dioxide monitor in patients in the emergency department. Emerg Med J. 2009;26(5):344–6. doi: PubMed
  7. Delerme S, Montout V, Goulet H, Arhan A, Le Saché F, Devilliers C, et al. Concordance between transcutaneous and arterial measurements of carbon dioxide in an ED. Am J Emerg Med. 2012;30(9):1872–6. doi: PubMed
  8. Nicolini A, Ferrari MB. Evaluation of a transcutaneous carbon dioxide monitor in patients with acute respiratory failure. Ann Thorac Med. 2011;6(4):217–20. doi: PubMed
  9. Heuss LT, Chhajed PN, Schnieper P, Hirt T, Beglinger C. Combined pulse oximetry/cutaneous carbon dioxide tension monitoring during colonoscopies: pilot study with a smart ear clip. Digestion. 2004;70(3):152–8. doi: PubMed
  10. Chhajed PN, Kaegi B, Rajasekaran R, Tamm M. Detection of hypoventilation during thoracoscopy: combined cutaneous carbon dioxide tension and oximetry monitoring with a new digital sensor. Chest. 2005;127(2):585–8. doi: PubMed
  11. Chhajed PN, Rajasekaran R, Kaegi B, Chhajed TP, Pflimlin E, Leuppi J, et al. Measurement of combined oximetry and cutaneous capnography during flexible bronchoscopy. Eur Respir J. 2006;28(2):386–90. doi: PubMed
  12. Schafroth Török S, Leuppi JD, Baty F, Tamm M, Chhajed PN. Combined oximetry-cutaneous capnography in patients assessed for long-term oxygen therapy. Chest. 2008;133(6):1421–5. doi: PubMed
  13. Bobbia X, Claret P-G, Palmier L, Robert M, Grandpierre RG, Roger C, et al. Concordance and limits between transcutaneous and arterial carbon dioxide pressure in emergency department patients with acute respiratory failure: a single-center prospective observational study. Scand J Trauma Resusc Emerg Med. 2015;23(1):40. doi: PubMed. Erratum in: Scand J Trauma Resusc Emerg Med. 2015 Oct 6;23:77. doi:10.1186/s13049-015-0154-7. PMID 26572985
  14. Kim J-Y, Yoon Y-H, Lee S-W, Choi S-H, Cho Y-D, Park S-M. Accuracy of transcutaneous carbon dioxide monitoring in hypotensive patients. Emerg Med J. 2014;31(4):323–6. doi: PubMed
  15. Kelly A-M, Klim S. Agreement between arterial and transcutaneous PCO2 in patients undergoing non-invasive ventilation. Respir Med. 2011;105(2):226–9. doi: PubMed
  16. Janssens JP, Howarth-Frey C, Chevrolet JC, Abajo B, Rochat T. Transcutaneous PCO2 to monitor noninvasive mechanical ventilation in adults: assessment of a new transcutaneous PCO2 device. Chest. 1998;113(3):768–73. doi: PubMed
  17. van Oppen JD, Daniel PS, Sovani MP. What is the potential role of transcutaneous carbon dioxide in guiding acute noninvasive ventilation? Respir Care. 2015;60(4):484–91. doi: PubMed
  18. Kelly A-M, McAlpine R, Kyle E. Venous pH can safely replace arterial pH in the initial evaluation of patients in the emergency department. Emerg Med J. 2001;18(5):340–2. doi: PubMed
  19. Kelly A-M, Kerr D, Middleton P. Validation of venous pCO2 to screen for arterial hypercarbia in patients with chronic obstructive airways disease. J Emerg Med. 2005;28(4):377–9. doi: PubMed
  20. Lemoël F, Govciyan S, El Omri M, Marquette C-H, Levraut J. Improving the validity of peripheral venous blood gas analysis as an estimate of arterial blood gas by correcting the venous values with SvO2. J Emerg Med. 2013;44(3):709–16. doi: [A]. PubMed
  21. Schönhofer B, Kuhlen R, Neumann P, Westhoff M, Berndt C, Sitter H. Nichtinvasive Beatmung als Therapie der akuten respiratorischen Insuffizienz1 [Non-invasive mechanical ventilation in acute respiratory failure]. Pneumologie. 2008;62(8):449–79. German. PubMed
  22. Bland JM, Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet. 1986;1(8476):307–10. doi: PubMed
  23. [homepage on the internet]. Vienna: R Foundation for Statistical Computing R Core Team (2015). [updated 2015 December 12; cited 2015 December 14]. Available from:
  24. Hinkelbein J, Floss F, Denz C, Krieter H. Accuracy and precision of three different methods to determine Pco2 (Paco2 vs. Petco2 vs. Ptcco2) during interhospital ground transport of critically ill and ventilated adults. J Trauma. 2008;65(1):10–8. doi: PubMed
  25. Wimberley PD, Grønlund Pedersen K, Olsson J, Siggaard-Andersen O. Transcutaneous carbon dioxide and oxygen tension measured at different temperatures in healthy adults. Clin Chem. 1985;31(10):1611–5. PubMed

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