Institute of Neurosciences and Newcastle University Institute for Ageing, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
Institute of Cellular Medicine, MoveLab, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
Br J Anaesth. 2015 Sep;115(3):386-91. doi: 10.1093/bja/aeu560. Epub 2015 Feb 6.
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.
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.
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).
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.
生物电阻抗是一种新颖的非侵入性心输出量测量方法，涉及分析电流通过胸部时相位变化与血流变化之间的关系。本研究评估了生物电阻抗在评估静息和运动期间血流动力学变量的重测可靠性。
22 名健康受试者（26（4）岁）在两次单独的试验（试验 1 和试验 2）中，根据最大耗氧量（Wmax）下的个体功率输出进行递增式功率自行车运动试验方案。参与者以 20%、40%、60%、80%和 90% Wmax 的五个体能进行 3 分钟的阶段运动。在静息和运动方案的整个过程中，评估血流动力学和心肺变量。
在静息时（P=0.948）或在运动方案的任何阶段（所有 P>0.30），两次试验之间的心脏输出量没有显著差异。两次试验之间的心脏输出量估计值之间存在很强的相关性（ICC=0.95，P<0.001）和耗氧量（ICC=0.99，P<0.001）。在静息时（P=0.989）或运动时（所有 P>0.15），两次试验之间的每搏量没有显著差异，并且在两次试验之间发现了很强的相关性（ICC=0.83，P<0.001）。
生物电阻抗方法在评估静息和不同分级运动试验阶段（包括最大用力）的心脏输出量方面具有良好的重测可靠性。
