title: Noninvasive cardiac output monitoring during exercise testing: Nexfin pulse contour analysis compared to an inert gas rebreathing method and respired gas analysis.
abstract: OBJECTIVE
  Exercise testing is often used to assess cardiac function during physical exertion to obtain diagnostic information. However, this procedure is limited to measuring the electrical activity of the heart using electrocardiography and intermittent blood pressure (BP) measurements and does not involve the continuous assessment of heart functioning. In this study, we compared continuous beat-to-beat pulse contour analysis to monitor noninvasive cardiac output (CO) during exercise with inert gas rebreathing and respired gas analysis.
  
  
  METHODS
  Nineteen healthy male volunteers were subjected to bicycle ergometry testing with increasing workloads. Cardiac output was deter- mined noninvasively by continuous beat-to-beat pulse contour analysis (Nexfin) and by inert gas rebreathing, and estimated using the respired gas analysis method. The effects of the rebreathing maneuver on heart rate (HR), stroke volume (SV), and CO were evaluated.
  
  
  RESULTS
  The CO values derived from the Nexfin- and inert gas rebreathing methods were well correlated (r = 0.88, P < 0.01) and the limits of agreement were 30.3% with a measurement bias of 0.4 ± 1.8 L/min. Nexfin- and respired gas analysis-derived CO values correlated even better (r = 0.94, P < 0.01) and the limits of agreement were 21.5% with a measurement bias of -0.70 ± 1.6 L/min. At rest, the rebreathing maneuver increased HR by 13 beats/min (P < 0.01), SV remained unaffected (P = 0.7), while CO increased by 1.0 L/min (P < 0.01). Rebreathing did not affect these parameters during exercise.
  
  
  CONCLUSIONS
  Nexfin continuous beat-to-beat pulse contour analysis is an appropriate method for noninvasive assessment of CO during exercise.
authors: Department of Intensive Care, Erasmus MC, University Medical Center Rotterdam, The Netherlands. s.bartels@erasmusmc.nl
authors: Sebastiaan A
authors: SA
authors: Bartels
authors: Wim J
authors: WJ
authors: Stok
authors: Rick
authors: R
authors: Bezemer
authors: Remco J
authors: RJ
authors: Boksem
authors: Jeroen
authors: J
authors: van Goudoever
authors: Thomas G V
authors: TG
authors: Cherpanath
authors: Johannes J
authors: JJ
authors: van Lieshout
authors: Berend E
authors: BE
authors: Westerhof
authors: John M
authors: JM
authors: Karemaker
authors: Can
authors: C
authors: Ince
mesh_terms: D000328:Adult; D015924:Blood Pressure Monitors; D002302:Cardiac Output / Q000502:physiology*; D002320:Cardiovascular Physiological Phenomena; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods*; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods*; D010101:Oxygen Consumption / Q000502:physiology; D011674:Pulse; D015656:Respiratory Mechanics / Q000502:physiology*; D012143:Respiratory Physiological Phenomena