Int J Sports Med 2014; 35(11): 925-932
DOI: 10.1055/s-0034-1367046
Training & Testing
© Georg Thieme Verlag KG Stuttgart · New York

Comparison of Thoracic Bioimpedance with Acetylene Uptake for Measuring Cardiac Output

E. Wang
1   Department of Circulation and Medical Imaging, Faculty of Medicine, the Norwegian University of Science and ­Technology, Trondheim, Norway
,
C. Cruz
1   Department of Circulation and Medical Imaging, Faculty of Medicine, the Norwegian University of Science and ­Technology, Trondheim, Norway
,
M. R. Pettersen
1   Department of Circulation and Medical Imaging, Faculty of Medicine, the Norwegian University of Science and ­Technology, Trondheim, Norway
,
J. Hoff
1   Department of Circulation and Medical Imaging, Faculty of Medicine, the Norwegian University of Science and ­Technology, Trondheim, Norway
2   Department of Physical Medicine and Rehabilitation, St. Olavs University Hospital, Trondheim, Norway
,
J. Helgerud
1   Department of Circulation and Medical Imaging, Faculty of Medicine, the Norwegian University of Science and ­Technology, Trondheim, Norway
3   Hokksund Medical Rehabilitation Centre, Hokksund, Norway
4   Telemark University College, Department of Sports and Outdoor Life Studies, Bø, Norway
› Author Affiliations
Further Information

Publication History



accepted after revision 27 December 2013

Publication Date:
02 June 2014 (online)

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Abstract

Cardiac output is shown to be a key determinant for oxygen transport, performance and health. Reliable and accurate non-invasive measurements of cardiac output, especially during exercise, are therefore of importance. The present study compared a new thoracic bioimpedance method with the established single-breath acetylene uptake method. We assessed cardiac output in 20 (24±4 years.) moderately trained males, at rest and during cycling. Both methods showed good test-retest reliabilities with ±2 SD limits of agreement of 3.67 and −4.50 L ∙ min−1 (thoracic bioimpedance) and 4.46 and −5.69 L ∙ min−1 (single breath), respectively. When thoracic bioimpedance was compared with single breath, the ±2 SD limits of agreement were poor (−6.05 and 9.57 L ∙ min−1). Thoracic bioimpedance displayed significantly lower (p<0.05) absolute cardiac output values than single breath, and the cardiac output-oxygen consumption slopes (y=5.7x+5.5 (single breath) and y=5.0x+5.0 (thoracic bioimpedance) tended (p=0.08) to show less increase for thoracic bioimpedance. Conclusions: Results from the single-breath method are in line with previous findings, showing a good reliability. Although thoracic bioimpedance showed a similar reliability as the single-breath method, and is easier to use, the agreement with single breath was poor, and thoracic bioimpedance seems not to be able to replace it.