Measurements of Cardiac Output During Constant Exercises: Comparison of Two Non-Invasive Techniques

Abstract

We compared cardiac output (CO) determined simultaneously by electrical impedance cardiography method (CO_ICG) and by the CO₂ rebreathing technique (CO_2REB) during three different steady-state exercises (target heart rate of 120, 140, and 160 min^-1) in 8 healthy fit young men. The mean difference correlation coefficient obtained between the values of CO_ICG and CO_2REB was 0.85 and the mean difference (CO_ICG-CO_2REB) was 0.06 l/min (0.12 %). At 120 min^-1, CO_ICG was lower than CO_2REB but the tendency was reversed at 140 and 160 min^-1 where CO_ICG was higher than CO_2REB. This evolution may be explained by the difficultly of using CO₂ rebreathing technique at the highest steady-state exercises and by the progressive acidemia due to exercise. The present results suggest that electrical impedance cardiography method provides acceptable evaluation of CO and may favourably replace the CO₂ rebreathing technique during mild (or moderate) to high steady-state exercises.

Impedance cardiography - CO₂ rebreathing technique - indirect Fick principle - steady state exercise

References

• 1 Bland J M, Altman D G. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet 1986: 307-310
• 2 Bloch K E, Russi E W. Comparison of impedance cardiography to invasive techniques for measurement of cardiac output.  Am J Cardiol. 1997;  79 846
• 3 Charloux A, Lonsdorfer-Wolf E, Richard R, Lampert E, Oswald-Mammosser M, Mettauer B, Geny B, Lonsdorfer J. A new impedance cardiograph device for the non-invasive evaluation of cardiac output at rest and during exercise; comparison with the ”direct“ Fick method.  Eur J Appl Physiol. 2000;  82 313-320
• 4 Christensen T B, Jensen B V, Hjerpe J, Kanstrup I L. Cardiac output measured by electric bioimpedance compared with the CO₂ rebreathing technique at different exercise levels.  Clin Physiol. 2000;  20 101-105
• 5 Defares J G. Determination of PV·CO₂ from the exponential CO₂ rise during rebreathing.  J Appl Physiol. 1958;  13 159-164
• 6 Denniston J C, Maher J T, Reeves J T, Cruz J C, Cymerman A, Grover R F. Measurement of cardiac output by electrical impedance at rest and during exercise.  J Appl Physiol. 1976;  40 91-95
• 7 Freund P R. Transesophageal Doppler scanning versus thermodilution during general anesthesia. An initial comparison of cardiac output techniques.  Am J Surg. 1987;  153 490-494
• 8 Jones N L, Robertson D G, Kane J W. Difference between end-tidal and arterial PCO₂ in exercise.  J Appl Physiol. 1979;  47 954-960
• 9 Gluer C C, Blake G, Lu Y, Blunt A, Jergas M, Genant H K. Accurate assessment of precision errors: How to measure the reproducibility of bone densitometry techniques.  Osteoporosis Int. 1995;  5 262-270
• 10 Kubicek W G, Karnegis J N, Patterson R P, Witsoe D A, Mattson R H. Development and evaluation of an impedance cardiac output system.  Aerosp Med. 1966;  37 1208-1212
• 11 Lefrant J Y, Benbabaali M, Ripart J, Aya A G, Sassi G, Dauzat M, de la Coussaye J E, Eledjam J J. CO assessment by suprasternal Doppler in critically ill patients: comparison with thermodilution.  Intensive Care Med. 2000;  26 693-697
• 12 Marik P E, Pendelton J E, Smith R. A comparison of hemodynamic parameters derived from transthoracic electrical bioimpedance with those parameters obtained by thermodilution and ventricular angiography.  Crit Care Med. 1997;  25 1545-1550
• 13 Moore R, Sansores R, Guimond V, Abboud R. Evaluation of cardiac output by thoracic electrical bioimpedance during exercise in normal subjects.  Chest. 1992;  102 448-455
• 14 Newman D G, Callister R. The non-invasive assessment of stroke volume and cardiac output by impedance cardiography: a review.  Aviat Space Environ Med. 1999;  70 780-789
• 15 Nugent A M, McParland J, McEneaney D J, Steele I, Campbell N P, Stanford C F, Nicholls D P. Non-invasive measurement of cardiac output by a carbon dioxide rebreathing method at rest and during exercise.  Eur Heart J. 1994;  15 361-368
• 16 Pianosi P, Garros D. Comparison of impedance cardiography with indirect Fick (CO₂) method of measuring cardiac output in healthy children during exercise.  Am J Cardiol. 1996;  77 745-749
• 17 Pickett B R, Buell J C. Validity of cardiac output measurement by computer-averaged impedance cardiography, and comparison with simultaneous thermodilution determinations.  Am J Cardiol. 1992;  69 1354-1358
• 18 Richard R, Lonsdorfer-Wolf E, Charloux A, Doutreleau S, Buchheit M, Oswald-Mammosser M, Lampert E, Mettauer B, Geny B, Lonsdorfer J. Non-invasive cardiac output evaluation during a maximal progressive exercise test, using a new impedance cardiograph device.  Eur J Appl Physiol. 2001;  85 202-207
• 19 Rose J S, Nanna M, Rahimtoola S H, Elkayam U, McKay C, Chandraratna P A. Accuracy of determination of changes in cardiac output by transcutaneous continuous-wave Doppler computer.  Am J Cardiol. 1984;  54 1099-1101
• 20 Royse C F, Royse A G, Blake D W, Grigg L E. Measurement of cardiac output by transoesophageal echocardiography: a comparison of two Doppler methods with thermodilution.  Anaesth Intens Care. 1999;  27 586-590
• 21 Sun X G, Hansen J E, Stringer W W, Ting H, Wasserman K. Carbon dioxide pressure-concentration relationship in arterial and mixed venous blood during exercise.  J Appl Physiol. 2001;  90 1798-1810
• 22 Warburton D E, Haykowsky M J, Quinney H A, Humen D P, Teo K K. Reliability and validity of measures of cardiac output during incremental to maximal aerobic exercise. Part I: Conventional techniques.  Sports Med. 1999;  27 23-41
• 23 Wasserman K, van Kessel A L, Burton G G. Interaction of physiological mechanisms during exercise.  J Appl Physiol. 1967;  22 71-85
• 24 Wong D H, Onishi R, Tremper K K, Reeves C, Zaccari J, Wong A B, Miller J B, Cordero V, Davidson J. Thoracic bioimpedance and Doppler cardiac output measurement: learning curve and interobserver reproducibility.  Crit Care Med. 1989;  17 1194-1198
• 25 Wong K L, Hou P C. The accuracy of bioimpedance cardiography in the measurement of cardiac output in comparison with thermodilution method.  Acta Anaesthesiol Sin. 1996;  34 55-59