Chest
Clinical InvestigationsEvaluation of Cardiac Output by Thoracic Electrical Bioimpedance during Exercise in Normal Subjects
Section snippets
METHODS
Eleven healthy male volunteers, ages 21 to 40 years, who were hospital personnel or respiratory therapy students, were recruited for the study. Their physical characteristics are shown in Table 1. Cardiac output was determined simultaneously by both CO2 rebreathing and thoracic impedance techniques at rest and during exercise with the subjects seated on a cycle ergometer (Lode Model Corival 400, Groningen, Netherlands).
Measurements of ventilation, gas exchange, and cardiac output by the CO2
RESULTS
The coefficients of variation for the same day in the three subjects at the different levels of exercise and the intrasubject coefficients of variability for the same subjects on different days are shown in Table 2. The coefficient of variation was highest for the resting determinations done on different days. The intersubject variability was somewhat greater than the intrasubject variability. Table 3 compares the individual data of cardiac output obtained by both methods in all subjects at
DISCUSSION
Of the many methods estimating cardiac output, invasive methods such as the Fick, dye dilution, and thermodilution have become standard in the clinical setting. However, noninvasive methods are more appropriate in the exercise laboratory and in instances where more extensive procedures are unwarranted or contraindicated. The CO2 rebreathing technique (indirect Fick) has been shown to agree well with invasive methods of cardiac output estimation.21, 22, 23, 24, 25 The added advantage of using
ACKNOWLEDGMENTS
We thank Marcia Gofsky of Cardiostat Inc for the loan of the Bomed NCCOM-3 equipment used in the study, Nancy Hanes and Colleen Kennell for their help with the statistical analysis and the preparation of the figures and tables, and Dr. Richard Pardy for his review of the manuscript.
REFERENCES (34)
- et al.
Comparison of bioimpedance and thermodilution methods for determining cardiac output: experimental and clinical studies
Ann Thorac Surg
(1988) - et al.
Analysis of factors affecting the variability of Fick versus indicator dilution measurements of cardiac output
Am J Cardiol
(1985) Clinical exercise testing
(1988)Determination of mixed venous CO2 tensions by rebreathing
J Appl Physiol
(1956)- et al.
Cardiac output in healthy subjects determined with a CO2 rebreathing method
Acta Physiol Scand
(1963) Determination of P co2 from the exponential CO2 rise during rebreathing
J Appl Physiol
(1958)- et al.
Development and evaluation of an impedance cardiac output system
Aerospace Med
(1966) - et al.
Measurement of cardiac output by electrical impedance at rest and during exercise
J Appl Physiol
(1976) - et al.
Estimation of cardiac output by electrical impedance during arm exercise in women
J Appl Physiol
(1981) - et al.
Cardiac output measured by impedance cardiography during maximal exercise tests
Cardiovasc Res
(1985)
Use of transthoracic bioimpedance to determine cardiac output in pediatric patients
Crit Care Med
Comparison of cardiac output estimation by thoracic electrical bioimpedance, thermodilution, and Fick methods
Crit Care Med
Comparison of transthoracic electrical impedance and thermodilution methods for measuring cardiac output
Crit Care Med
A new stroke volume equation for thoracic electrical bioimpedance: theory and rationale
Crit Care Med
Continuous noninvasive real-time monitoring of stroke volume and cardiac output by thoracic electrical bioimpedance
Crit Care Med
Automated noninvasive measurement of cardiac output: comparison of electrical bioimpedance and carbon dioxide rebreathing techniques
Br Heart J
Rebreathing equilibration of CO2 during exercise
J Appl Physiol
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Manuscript received March 11; revision accepted January 21.