title: Evaluation of changes in cardiac output from the electrical impedance waveform in the forearm.
abstract: We tested the validity of regional impedance cardiography (RIC) for measuring changes in both cardiac output and stroke volume by comparing the values with a 2D ultrasound technique in response to the breath-hold manipulation. Among 13 subjects, changes in the maximum amplitude of the regional impedance waveform from the forearm conformed to those in stroke volume (r = 0.86, p < 0.001) and cardiac output (r = 0.76, p < 0.003) measured with the ultrasound technique in baseline and immediately after a 30 s breath-hold maneuver. We also found that the per cent change in cardiac output (r = 0.73, p < 0.005) and the per cent change in stroke volume (r = 0.84, p < 0.0003) by the echocardiography were both positively correlated with the per cent change in the peak impedance amplitude. In addition, both the change and the per cent change in the mean area under the impedance curve were consistent with those in the stroke volume, respectively. Accordingly, the regional electrical impedance waveform from lower limbs may be helpful in providing a non-invasive and continuous assessment of left ventricular output, especially during cardiac procedures.
authors.affiliation: Department of Biomedical Engineering, I-Shou University, Taiwan, Republic of China. wangjj@isu.edu.tw
authors.forename: Jia-Jung
authors.initials: JJ
authors.lastname: Wang
authors.forename: Ping-Wei
authors.initials: PW
authors.lastname: Wang
authors.forename: Chun-Peng
authors.initials: CP
authors.lastname: Liu
authors.forename: Shih-Kai
authors.initials: SK
authors.lastname: Lin
authors.forename: Wei-Chih
authors.initials: WC
authors.lastname: Hu
authors.forename: Tsiar
authors.initials: T
authors.lastname: Kao
mesh_terms: D000328:Adult; D002302:Cardiac Output / Q000502:physiology*; D003936:Diagnosis, Computer-Assisted / Q000379:methods; D017097:Electric Impedance; D005542:Forearm / Q000098:blood supply* / Q000502:physiology*; D006334:Heart Function Tests / Q000379:methods*; D006801:Humans; D008297:Male; D010992:Plethysmography, Impedance / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D013318:Stroke Volume / Q000502:physiology*