Comparison of pediatric end-tidal CO2 measured with nasal/oral cannula circuit and capillary Pco2

Thomas J. Abramo, Michael R. Cowan, Susan M. Scott, Patricia A. Primm, Robert A. Wiebe, Marla Signs

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


This study was designed to determine whether end-tidal carbon dioxide (ETCO2) values obtained by noninvasive oral/nasal cannula circuit with side-stream capnometry correlate reliably with capillary Pco2 (CapCO2) in a pediatric population without cardiopulmonary problems. Each patient was monitored until a reliable 5-minute ETCO2 waveform was obtained. A capillary blood gas sample was drawn while, simultaneously, ETCO2 was recorded. The difference between CapCO2 and ETCO2 levels was tested with a paired t-test at P < .001. The limits of agreement were established with a 95% confidence level. The stability of the measured difference across the range of mean scores (CapCO2 + ETCO2 2), age, and respiratory rate was tested using simple linear regression. Fifty-eight children (23 girls and 35 boys) had mean ETCO2 readings of 33.96 mm Hg (SD 4.26), and mean CapCO2 readings of 35.93 (SD 4.04). A relative average bias of 1.96 with ETCO2 lower than CapCO2 was established with 95% limits of agreement of ±5.2 mm Hg (t = 5.71). Variability of difference scores was not related to range of mean scores (r = .08), age (r = .09), or respiratory rate (r = .25). End-tidal CO2 measured by an oral/nasal cannula capnometry circuit is a noninvasive method of assessing indirect measurements of Pco2 in a normal pediatric population.

Original languageEnglish (US)
Pages (from-to)30-33
Number of pages4
JournalAmerican Journal of Emergency Medicine
Issue number1
StatePublished - Jan 1995


  • End-tidal carbon dioxide
  • capillary Pco
  • capnometry
  • oral/nasal cannula

ASJC Scopus subject areas

  • Emergency Medicine


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