Hemodynamic response to exercise as measured by the solar IKG impedance cardiography module and correlation with
Stephan Ziegeler1, Ulrich Grundmann, Oliver Fuerst
1Department of Anesthesiology and Intensive Care Medicine, University of Saarland, 66421, Homburg/Saar, Germany. stephan.ziegeler@uniklinik-saarland.de
Objective:
Impedance Cardiography (ICG) has been shown to be a feasible and accurate method for non-invasive measurement of cardiac index (CI). Aim of this investigation was the correlation of hemodynamic variables under exercise as measured by a specific ICG-monitor (Solar IKG-Modul, Version 3.0, GE-Healthcare, Freiburg, Germany) with metabolic variables.
Methods:
Ten healthy volunteers were included in the investigation doing ergometer exercise (5 min equilibration followed by 5 min each at 50, 75, 100 and 125 W). Hemodynamic parameters were obtained by ICG. Metabolic variables were assessed by indirect calorimetry with the Deltatrac II Metabolic monitor using a helmet system for spontaneous respiration.
Results:
CI increased throughout exercise (baseline: 3.0 +/- 0.4 l/min/m(2); 125 W: 4.8 +/- 0.5 l/min/m(2)). Heart rate (baseline: 87.2 +/- 13.4 bpm; 125 W: 152.7 +/- 22.4 bpm) and contractility (velocity index) (baseline: 48.9 +/- 9.3/1000 s; 125 W: 70.5 +/- 10.0/1000 s) showed a continuous rise while the stroke index decreased after an initial rise (baseline: 35.0 +/- 4.6 ml/m(2); 50 W: 37.6 +/- 4.9 ml/m(2); 75 W: 41.2 +/- 5.9 ml/m(2); 125 W: 32.3 +/- 6.1 ml/m(2)). VO(2) (baseline: 335.2 +/- 84.1 ml/min; 125 W: 1298.9 +/- 282.3 ml/min) and VCO(2)(baseline: 255.4 +/- 74.5 ml/min; 125 W: 1342.5 +/- 282.5 ml/min) increased throughout exercise. There was a good correlation in the individual fits between hemodynamic and metabolic variables.
Conclusion:
CI in healthy volunteers, as measured by the Solar IKG-Modul, correlates well with O(2)-consumption and CO(2)-production in individual subjects, thus indicating the metabolic needs under exercise conditions in healthy individuals.
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