| 摘要 |
A method and apparatus for determining a user's Respiratory Quotient (RQ) using just measured O<SUB>2 </SUB>and CO<SUB>2 </SUB>concentrations without use of a flow meter. The RQ is determined by measuring the user's real-time inspired O<SUB>2 </SUB>concentration (INS O2) and end tidal O<SUB>2 </SUB>concentration (ETO2) and measuring the user's real-time inspired CO<SUB>2 </SUB>concentration (INS CO2) and end tidal CO<SUB>2 </SUB>concentration (ETCO2), and then determining the user's RQ from the measured INS O2, ETO2, INS CO2, and ETCO2 values in accordance with the following equation: RQ=(ETCO2-INS CO2)/(INS O2-ETO2). In order to avoid error introduced by the flow rate, the measurement steps are preferably performed while the user is in a resting condition. Also, ETCO2 is preferably measured as the maximum CO<SUB>2 </SUB>value in a breath cycle of the user, while INS CO2 is preferably measured as the minimum CO<SUB>2 </SUB>value in a breath cycle of the user. Similarly, ETO2 is preferably measured as the minimum O<SUB>2 </SUB>value within a breath cycle of the user, while INS O2 is measured as the maximum O<SUB>2 </SUB>value within a breath cycle of the user. On the other hand, the values of INS CO2 and ETCO2 also may be determined in accordance with the invention by analysis of a CO<SUB>2 </SUB>waveform of a breath cycle of the user and the values of INS O2 and ETO2 determined by synchronizing timing of the O<SUB>2 </SUB>waveform of a breath cycle of the user with the CO<SUB>2 </SUB>waveform and sampling INS O2 and ETO2 values simultaneously with sampling of complementary CO<SUB>2 </SUB>values determined by analysis of the CO<SUB>2 </SUB>wavefomm. The RQ measuring device may include the oxygen and CO<SUB>2 </SUB>sensors in a mainstream or sidestream configuration.
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