Cardiac output in middle-aged patients determined with CO2 rebreathing method

1970 ◽  
Vol 28 (3) ◽  
pp. 337-342 ◽  
Author(s):  
J. P. Clausen ◽  
O. A. Larsen ◽  
J. Trap-Jensen
Keyword(s):  
Cardiac Output ◽  
Middle Aged ◽  
Aged Patients ◽  
Co2 Rebreathing ◽  
Rebreathing Method

Comparison of cardiac output during exercise by single-breath and CO2-rebreathing methods

1985 ◽  
Vol 58 (4) ◽  
pp. 1372-1377 ◽  
Author(s):  
M. D. Inman ◽  
R. L. Hughson ◽  
N. L. Jones
Keyword(s):  
Cardiac Output ◽  
Partial Pressure ◽  
Co2 Rebreathing ◽  
Single Breath ◽  
Partial Pressure Of Co2 ◽  
The Difference ◽  
End Tidal ◽  
Rebreathing Method ◽  
Single Breath Method

Cardiac output (Q) was estimated in supine rest and in upright cycling at several work rates up to 200 W in five male and one female subjects. At least four repetitions of both the CO2-rebreathing plateau method (Collier, J. Appl. Physiol. 9:25–29, 1956) and the Kim et al. (J. Appl. Physiol. 21: 1338–1344, 1966) single-breath method were performed at each work rate, in a steady state of O2 consumption and heart rate. At supine rest and low work rates, estimates of Q were similar by the two methods. However, at higher work rates, the single-breath method significantly (P less than 0.05) underestimated the value obtained by CO2 rebreathing. The reason for the difference in estimates of Q by the two methods was traced to the determination of arterial partial pressure of CO2 (PaCO2) and mixed venous partial pressure of CO2 (PvCO2). The estimate of PaCO2 from the single-breath method was approximately 88.5% of the estimate from end-tidal PCO2 used with the rebreathing method (P less than 0.001). The oxygenated PvCO2 calculated from the single-breath Q averaged approximately 92.5% of the PvCO2 from CO2 rebreathing (P less than 0.0001). The difference in estimates of Q was not eliminated by using a logarithmic form of the CO2 dissociation curve with the single-breath method.

Comparison of CO2 rebreathing and acetylene methods for cardiac output

1965 ◽  
Vol 20 (4) ◽  
pp. 763-766 ◽  
Author(s):  
K. Klausen
Keyword(s):  
Cardiac Output ◽  
Partial Pressure ◽  
Venous Blood ◽  
Mixed Venous Blood ◽  
Co2 Rebreathing ◽  
Arterial Blood ◽  
Co2 Output ◽  
Partial Pressure Of Co2 ◽  
Douglas Bag ◽  
Rebreathing Method

The cardiac output during rest and work was determined by a CO2 rebreathing method as suggested by Defares. The partial pressure of CO2 in the mixed venous blood (PvCOCO2) was calculated from the rise of the CO2 percent in a Grollman bag during rebreathing. In the rest experiments the partial pressure of CO2 in arterial blood (PaCOCO2) was obtained from analysis of alveolar samples taken by the Haldane-Priestley direct sampling method. In the work experiments the PaCOCO2 was calculated using the Bohr formula and a dead space estimated from Asmussen and Nielsen's data. The metabolic rate including both O2 uptake and CO2 output was determined by the Douglas bag method. In each experiment the acetylene method as described by Christensen was applied after the CO2 rebreathing method. The values obtained by the two methods were almost identical, the standard deviation for all experiments being ±7.3%, and were of the same magnitude as those obtained by others with the dye-dilution or direct Fick method both during rest and work. cardiac output at rest and work; arterial Pco2 and venous Pco2 at rest and work; stroke volume at rest and work Submitted on November 25, 1964

Estimation of cardiac output by the CO2 rebreathing method during tethered swimming

1978 ◽  
Vol 44 (5) ◽  
pp. 821-824 ◽  
Author(s):  
G. J. Heigenhauser ◽  
J. A. Faulkner
Keyword(s):  
Cardiac Output ◽  
Oxygen Uptake ◽  
Treadmill Walking ◽  
Dilution Method ◽  
Published Data ◽  
Free Swimming ◽  
Dye Dilution ◽  
Co2 Rebreathing ◽  
Rebreathing Method

The reproducibility of cardiac output (Q) estimated by the CO2 rebreathing method during tethered swimming was studied in five highly trained college swimmers. The reproducibility of the CO2 rebreathing method for estimations of Q during tethered swimming was similar to the reproducibility reported for the CO2 rebreathing method, direct Fick method, or dye-dilution method during either cycling or treadmill walking. All duplicate estimates of Q by the CO2 rebreathing method were within 15% of one another. A comparison was made between the Q's estimated by the CO2 rebreathing method during tethered swimming and previously published data on Q determined by the dye-dilution method during free swimming in a flune. At any given oxygen uptake, Q obtained by the CO2 rebreathing method during tethered swimming was not significantly different from the Q obtained by the dye-dilution method during flume swimming. Estimates of Q by the CO2 rebreathing method made during high intensities of tethered swimming were reproducible and appear to be valid.

Improved Accuracy Of Cardiac Output Estimation By The Partial CO2 Rebreathing Method

2009 ◽  
Vol 23 (3) ◽  
pp. 149-155 ◽  
Author(s):  
Yoshifumi Kotake ◽  
Takashige Yamada ◽  
Hiromasa Nagata ◽  
Takeshi Suzuki ◽  
Ryohei Serita ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Co2 Rebreathing ◽  
Improved Accuracy ◽  
Rebreathing Method

Cardiac output in exercise by impedance cardiography during breath holding and normal breathing

1987 ◽  
Vol 62 (1) ◽  
pp. 101-107 ◽  
Author(s):  
M. C. Du Quesnay ◽  
G. J. Stoute ◽  
R. L. Hughson
Keyword(s):  
Cardiac Output ◽  
Linear Relationship ◽  
Impedance Cardiography ◽  
Motion Artifact ◽  
Breath Holding ◽  
Breath Hold ◽  
Cycle Exercise ◽  
Co2 Rebreathing ◽  
Normal Breathing ◽  
Rebreathing Method

Estimation of cardiac output by impedance cardiography (QZ) in exercise during normal breathing (NB) has been limited by motion artifact. Our objective was to obtain readable impedance cardiograms on five subjects during upright cycle exercise at 0, 50, 100, 150, and 200 W to permit comparisons of QZ during NB, expiratory breath hold (EXP) and inspiratory breath hold (INSP). Q was also determined using an equilibration CO2 rebreathing method [Q(RB)]. QZ during NB exceeded EXP QZ at 100, 150, and 200 W, and exceeded INSP QZ at 100 W (P less than 0.05). The low EXP QZ values were due to a significantly lower stroke volume at 100, 150, and 200 W (P less than 0.05). For the INSP QZ at 100 W, heart rate was lower than during EXP (P less than 0.05). Regression of QZ (NB) against Q(RB) resulted in a linear relationship (r = 0.93) over the range of Q = 7–26 1/min. The slope of the regression differed significantly from 1.0 (P less than 0.05). We conclude that QZ values obtained during EXP or INSP should not be assumed to represent QZ during NB, at least at work rates greater than 50 W. A consequence of the linear relationship between QZ(NB) and Q(RB) over the range of 0–200 W is that estimates of CO2 rebreathing cardiac output can be obtained by impedance cardiography if QZ is adjusted using an appropriate empirical factor.

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