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Evaluation of transcutaneous CO 2 responses following acute changes in PaCO 2 in healthy subjects
Author(s) -
FUKE Satoshi,
MIYAMOTO Kenji,
OHIRA Hiroshi,
OHIRA Megumi,
ODAJIMA Nao,
NISHIMURA Masaharu
Publication year - 2009
Publication title -
respirology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 85
eISSN - 1440-1843
pISSN - 1323-7799
DOI - 10.1111/j.1440-1843.2008.01442.x
Subject(s) - medicine , anesthesia , mouthpiece , arterial blood , oxygen saturation , oxygen , chemistry , dentistry , organic chemistry
Background and objective: Transcutaneous blood gas‐monitoring systems with miniaturized SpO 2 (peripheral blood oxygen saturation)/PCO 2 combined sensors (TOSCATM) have been widely used. There are no reports of the inter‐ and intra‐individual variability in transcutaneous measurements of PaCO 2 (PtcCO 2 ) in response to acute progressive changes in PaCO 2 . This study examined inter‐ and intra‐individual variability of PtcCO 2 measurements under semi‐steady‐state conditions, and characterized the behaviour of PtcCO 2 in response to acute progressive changes in PaCO 2 . Methods: Subjects breathed mixed gases through a mouthpiece connected to an automatic arterial blood gas controller. Using end‐tidal PCO 2 and PO 2 as guides, PaCO 2 was controlled to increase and/or decrease between baseline and ≥ 60 mm Hg, in a stepwise ( n = 9) or progressive fashion ( n = 6). Arterial blood was sampled when needed. Results: Intra‐individual correlation coefficients between PtcCO 2 and PaCO 2 were excellent in all subjects (0.971–0.989); however, the slope of the regression line varied among subjects (1.040–1.335). Bias and limits of agreement (± 2 SD from bias) between PtcCO 2 and PaCO 2 were −1.8 mm Hg and −7.7 to 4.1 mm Hg. Changes in PtcCO 2 in response to acute progressive changes in PaCO 2 also varied among subjects. Conclusion: The PtcCO 2 measurement system allows reliable estimation of PaCO 2 in a given subject. However, caution is needed when comparing absolute values between subjects or when acute changes in PaCO 2 occur.