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October 15, 2011
1:00:00 PM - 4:00:00 PM
Room Hall B2 Area K
Reliability of Percutaneous Carbon Dioxide Tension Measurement System, SenTec Digital Monitor ®
Sayaka Masuda, M.D., Yoichi kondo, M.D.,Ph.D., Toshiya Koitabashi, M.D.,Ph.D.
Keio University, Tokyo, Japan

Expiratory gas sampling is commonly used as a method of continuous carbon dioxide monitoring. This is however not always easily achieved in non-intubated patients particularly those using a nasal mask. Recently, a number of studies on the usefulness of percutaneous CO2 monitoring in adult patients (non-intubated, under sedation) have been published. This is also a method which has been traditionally used in intubated neonates whose expiratory gas sampling is difficult. However, few studies have been performed on this method applied in paediatric patients. We compared percutaneous CO2 values (PtcCO2) with both arterial and end-tidal CO2 (PaCO2, EtCO2) values in paediatric patients undergoing surgical procedures to verify its reliability.


The subjects included 34 intubated paediatric patients who underwent surgery with parental written consent. The sensor of PtcCO2 was placed on one of the specific points such as chest, back and extrimities according to the surgical field. PtcCO2 was measured by SenTec Digital Monitor with v-Sign sensor (SenTec, Inc, Switzerland). Invasive blood sampling was conducted through an arterial pressure line to measure PaCO2, which was obtained using ABG analysis (ABL800FLEX, Radiometer, Copenhagen, Denmark). EtCO2 was continuously measured by respiratory gas analyzer (M1019A, IntelliVue G5, Philips Medizin Systeme GmbH, Germany).

Measurements were performed in each patient at specific points such as before incision, after incision and an hour after incision and PtcCO2 was compared with simultaneously obtained PtcCO2 and ETCO2. The absolute differences between the noninvasive methods (PtcCO2 and EtCO2) and PaCO2 were analysed using a two-tailed Wilcoxon's sined rank test for pairs. Liner regression analysis was performed using Excel Statistical Program File Ystat 2008. Corresponding data were compared using Bland-Altman analysis. Statistical significance was taken as a p-value less than 0.05.


Regression analysis of PaCO2 and PtcCO2 values revealed the correlation coefficient of 0.70. Bland-Altman analysis revealed a bias of -2.1 with a precision of +/-4.4 when comparing PtcCO2 and PaCO2. Regression analysis of PaCO2 and EtCO2 values revealed the correlation coefficient of 0.67. Bland-Altman analysis revealed a bias of -6.5 with a precision of +/-4.8 when comparing EtCO2 and PaCO2. Correlation coefficient between PtcCO2 and PaCO2 was higher than that between EtCO2 and PaCO2. PtcCO2 measurement corresponded better to PaCO2.

Discussion and Conclusion

PtcCO2 measured by SenTec Digital Monitor ® corresponds well to PaCO2. We conclude that present study indicate PtcCO2 measured by SenTec Digital Monitor ® reflects PaCO2 more reliably than EtCO2 in non-intubated paediatric patients.

Copyright © 2011 American Society of Anesthesiologists