Comparison of electrical velocimetry and thermodilution techniques for the measurement of cardiac output

Acta Anaesthesiol Scand. 2007 Nov;51(10):1314-9. doi: 10.1111/j.1399-6576.2007.01445.x.


Aim: To compare a new method of non-invasive determination of cardiac output based on electrical velocimetry (EV-CO) with invasive thermodilution methods.

Methods: Fifty critically ill patients were enrolled into the study. EV-CO was compared with cardiac output measured by a pulmonary artery catheter (PA-CO) in one group (n= 25) and by a femoral artery catheter (PiCCO-CO) in a second group (n= 25), by simultaneous measurements. Standard electrocardiography electrodes were used for non-invasive measurements, and EV-CO was calculated using the Bernstein-Osypka equation. The invasive measurements of PA-CO and PiCCO-CO were made by the injection of iced 0.9% saline and the recording of thermodilution curves.

Results: The precision values of EV-CO, PA-CO and PiCCO-CO measurements were +/- 0.46 [95% confidence interval (95% CI), +/- 0.06], +/- 0.57 (95% CI, +/- 0.09) and +/- 0.48 l/min (95% CI, +/- 0.08 l/min), respectively. The mean differences between EV-CO and PA-CO or PiCCO-CO were -0.05 +/- 0.71 and 0.22 +/- 0.78 l/min, respectively. The lower and upper limits of agreement for the comparison of EV-CO with PA-CO were -1.47 and 1.37 l/min (95% CI, +/- 0.25 l/min), respectively. In the comparison of EV-CO and PiCCO-CO, lower and upper limits of -1.34 and 1.78 l/min (95% CI, +/- 0.27 l/min) were found. The percentage errors between EV-CO and PA-CO or PiCCO-CO were 26.5% and 26.4%, respectively.

Conclusions: The values of cardiac output were statistically comparable between the groups. Therefore, electrical velocimetry is a suitable method to evaluate haemodynamic variables with clinically acceptable accuracy.

Publication types

  • Clinical Trial
  • Comparative Study

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Blood Flow Velocity
  • Carbon Monoxide / blood
  • Cardiac Output / physiology*
  • Electricity*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Thermodilution / methods*


  • Carbon Monoxide