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Br J Anaesth. 2015 Sep;115(3):386-91. doi: 10.1093/bja/aeu560. Epub 2015 Feb 6.

Bioreactance is a reliable method for estimating cardiac output at rest and during exercise.

Author information

1
Institute of Neurosciences and Newcastle University Institute for Ageing, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
2
Institute of Cellular Medicine, MoveLab, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
3
Department of Cardiology, Freeman Hospital, Newcastle upon Tyne, NE7 7DN, UK Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.
4
Institute of Cellular Medicine, MoveLab, Newcastle University, Newcastle upon Tyne NE2 4HH, UK RCUK Centre for Ageing and Vitality, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
5
Institute of Cellular Medicine, MoveLab, Newcastle University, Newcastle upon Tyne NE2 4HH, UK RCUK Centre for Ageing and Vitality, Newcastle University, Newcastle upon Tyne NE2 4HH, UK djordje.jakovljevic@newcastle.ac.uk.

Abstract

BACKGROUND:

Bioreactance is a novel noninvasive method for cardiac output measurement that involves analysis of blood flow-dependent changes in phase shifts of electrical currents applied across the thorax. The present study evaluated the test-retest reliability of bioreactance for assessing haemodynamic variables at rest and during exercise.

METHODS:

22 healthy subjects (26 (4) yrs) performed an incremental cycle ergometer exercise protocol relative to their individual power output at maximal O2 consumption (Wmax) on two separate occasions (trials 1 and 2). Participants cycled for five 3 min stages at 20, 40, 60, 80 and 90% Wmax. Haemodynamic and cardiorespiratory variables were assessed at rest and continuously during the exercise protocol.

RESULTS:

Cardiac output was not significantly different between trials at rest (P=0.948), or between trials at any stage of the exercise protocol (all P>0.30). There was a strong relationship between cardiac output estimates between the trials (ICC=0.95, P<0.001) and oxygen consumption (ICC=0.99, P<0.001). Stroke volume was also not significantly different between trials at rest (P=0.989) or during exercise (all P>0.15), and strong relationships between trials were found (ICC=0.83, P<0.001).

CONCLUSIONS:

The bioreactance method demonstrates good test-retest reliability for estimating cardiac output at rest and during different stages of graded exercise testing including maximal exertion.

KEYWORDS:

cardiac output; exercise test; haemodynamics; monitoring, physiological

PMID:
25659999
DOI:
10.1093/bja/aeu560
[Indexed for MEDLINE]
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