Figures & data
Table 1. Patient characteristics
Table 2. Cardiorespiratory responses to cycle exercise
Figure 1. Cardiac output in COPD derived using various non-invasive techniques. Results consistently show significantly lower measured using N2O-RB as compared to the PaCO2-derived CO2-RB or the bioimpedance approach, at rest as well as for all exercise intensities (*p < 0.05).
End-tidal CO2-derived rebreathing values are also significantly lower than those calculated using direct PaCO2 under all conditions (§p < 0.05); End-tidal CO2-derived rebreathing values are however not statistically different from those obtained using N2O-RB; CO2-RB(PaCO2): Cardiac output () derived from non-inert CO2 gas rebreathing with PaCO2 correction; CO2-RB(PETCO2): Cardiac output (
) derived from non-inert CO2-RB gas rebreathing without PaCO2 correction; N2O-RB: Cardiac output (
) derived from inert N2O gas rebreathing; Impedance: Cardiac output (
) determined by impedance cardiography.
![Figure 1. Cardiac output in COPD derived using various non-invasive techniques. Results consistently show significantly lower measured using N2O-RB as compared to the PaCO2-derived CO2-RB or the bioimpedance approach, at rest as well as for all exercise intensities (*p < 0.05).End-tidal CO2-derived rebreathing values are also significantly lower than those calculated using direct PaCO2 under all conditions (§p < 0.05); End-tidal CO2-derived rebreathing values are however not statistically different from those obtained using N2O-RB; CO2-RB(PaCO2): Cardiac output () derived from non-inert CO2 gas rebreathing with PaCO2 correction; CO2-RB(PETCO2): Cardiac output () derived from non-inert CO2-RB gas rebreathing without PaCO2 correction; N2O-RB: Cardiac output () derived from inert N2O gas rebreathing; Impedance: Cardiac output () determined by impedance cardiography.](/cms/asset/3bf98362-f3c7-448f-b464-11338378dd6b/icop_a_1043985_f0001_b.gif)
Figure 2. Cardiac output derived using various non-invasive techniques in healthy subjects measured in our laboratory. Comparison of techniques at rest or at each exercise intensities reveals no statistically significant differences.
CO2-RB(PETCO2): Cardiac output () derived from non-inert CO2-RB gas rebreathing without PaCO2 correction; N2O-RB: Cardiac output (
) derived from inert N2O gas rebreathing. Impedance: Cardiac output (
) determined by impedance cardiography.
![Figure 2. Cardiac output derived using various non-invasive techniques in healthy subjects measured in our laboratory. Comparison of techniques at rest or at each exercise intensities reveals no statistically significant differences.CO2-RB(PETCO2): Cardiac output () derived from non-inert CO2-RB gas rebreathing without PaCO2 correction; N2O-RB: Cardiac output () derived from inert N2O gas rebreathing. Impedance: Cardiac output () determined by impedance cardiography.](/cms/asset/aa569560-3449-4922-99b1-a1f66e25155c/icop_a_1043985_f0002_b.gif)