title: Hemodynamic response to exercise as measured by the solar IKG impedance cardiography module and correlation with metabolic variables.
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, University of Saarland, 66421, Homburg/Saar, Germany. stephan.ziegeler@uniklinik-saarland.de
authors.forename: Stephan
authors.initials: S
authors.lastname: Ziegeler
authors.forename: Ulrich
authors.initials: U
authors.lastname: Grundmann
authors.forename: Oliver
authors.initials: O
authors.lastname: Fuerst
authors.forename: Alexander
authors.initials: A
authors.lastname: Raddatz
authors.forename: Sascha
authors.initials: S
authors.lastname: Kreuer
mesh_terms: D000293:Adolescent; D000328:Adult; D002245:Carbon Dioxide / Q000737:chemistry; D002302:Cardiac Output; D002307:Cardiography, Impedance; D004566:Electrodes; D015444:Exercise; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D018670:Monitoring, Ambulatory / Q000379:methods*; D010100:Oxygen / Q000737:chemistry; D010101:Oxygen Consumption; D012044:Regression Analysis; D013318:Stroke Volume
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen