Estimation of beat-to-beat changes in stroke volume from arterial pressure: A comparison of two pressure wave analysis techniques during head-up tilt testing in young, healthy men
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The aim of this study was to compare beat-to-beat changes in stroke volume (SV) estimated by two different pressure wave analysis techniques during orthostatic stress testing: pulse contour analysis and Modelflow,ie, simulation of a three-element model of aortic input impedance.
A reduction in SV was introduced in eight healthy young men (mean age, 25; range, 19–32 y) by a 30-minute head-up tilt maneuver. Intrabrachial and noninvasive finger pressure were monitored simultaneously. Beat-to-beat changes in SV were estimated from intrabrachial pressure by pulse contour analysis and Modelflow. In addition, the relative differences in Modelflow SV obtained from intrabrachial pressure and noninvasive finger pressure were assessed.
Beat-to-beat changes in Modelflow SV from intrabrachial pressure were comparable with pluse contour measures. The relative difference between the two methods amounted to 0.1±1% (mean±SEM) and was not dependent on the duration of tilt. The diference between Modelflow apoplied to intrabrachial pressure and finger pressure amounted to −2.7±1.3% (p=0.04). This difference was not dependent on the duration of tilt or level of arterial pressure.
Based on different mathematical models of the human arterial system, pulse contour and Modelflow compute similar changes in SV from intrabrachial pressure during orthostatic stress testing in young healthy men. The magnitude of the differnece in SV derived from intrabrachial and finger pressure may vary among subjects; Modelflow SV from noninvasive finger pressure tracks fast and brisk changes in SV derived from intrabrachial pressure.
Keywordsaortic impedance blood pressure Finapres head-up tilt pulse contour simulation stroke volume
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- 1.Benditt DG, Ferguson DW, Grubb BP, et al. Tilt table testing for assessing syncope. American College of Cardiology.J Am Coll Cardiol 1996; 28:263–275.Google Scholar
- 2.Smit AAJ, Wieling W, Karemaker JM. Clinical approach to cardiovascular reflex testing.Clin Sci 1996; 91(Suppl):108–112.Google Scholar
- 3.Stevens PM. Cardiovascular dynamics during orthostasis and the influence of intravascular instrumentation.Am J Cardiol 1996; 17:211–218.Google Scholar
- 4.Smith JJ, Ebert J. General response to orthostatic stress. In: Smith JJ, Ed.Circulatory Response to the Upright Posture. Boca Raton, FL: CRC Press; 1990:1–46.Google Scholar
- 6.Jellema WT, Imholz BPM, Van Goudoever J, et al. Finger arterial versus intrabrachial pressure and continuous cardiac output during head-up tilt testing in healthy subjects.Clin Sci 1996; 91:193–200.Google Scholar
- 9.McDonald DA.Blood flow in arteries. London: Arnold; 1974:420–445.Google Scholar
- 13.Peñáz J. Photoelectric measurement of blood pressure, volume and flow in the finger. Dresden: Digest of the International Conference on Medicine and Biological Engineering (abstract) 1973;104.Google Scholar
- 14.Wesseling KH, De Wit B, Van der Hoeven GMA, et al. Physiocal, calibrating finger vascular physiology for Finapres.Homeostasis 1995; 36:67–82.Google Scholar
- 15.Wesseling KH, De Wit B, Weber JAP, et al. A simple device for the continuous measurement of cardiac output.Adv Cardiovasc Physics 1983; 5–11:16–52.Google Scholar
- 22.Harms MPM, Wesseling KH, Pott F,et al. Continuous stroke volume by modelling flow from non-invasive arterial pressure in humans under orthostatic stress.Clin Sci 1999, in press.Google Scholar
- 23.Bos WJW, Van Goudoever J, Van Montfrans GA, et al. Reconstruction of brachial artery pressure from non-invasive finger pressure measurements.Circulation 1996; 94:1870–1875.Google Scholar
- 25.Ward A.Sequential Analysis. New York: John Wiley and Sons; 1947.Google Scholar
- 27.O'Rourke MF, Blazek JV, Moreels CL, et al. Pressure wave transmission along the human aorta; changes with age and in arterial degenerative disease.Circ Res 1955; 3:623–631.Google Scholar
- 33.Schondorf R, Cameli L, Benoit J, et al. Comparison of pulse contour and impedance cardiograph measurements of stroke volume and cardiac output during head-up tilt (abstract).Clin Autonom Res 1997; 7:265.Google Scholar
- 34.Van Lieshout EJ, Toska K, Eriksen M, et al. Non-invasive continuous cardiac stroke volume monitoring: evaluation of a novel technique.Neth J Med 1998; 52:A44 (Abstract).Google Scholar