title: Beat-to-beat stroke volume estimation from aortic pressure waveform in conscious rats: comparison of models.
abstract: Several methods for estimating stroke volume (SV) were tested in conscious, freely moving rats in which ascending aortic pressure and cardiac flow were simultaneously (beat-to-beat) recorded. We compared two pulse-contour models to two new statistical models including eight parameters extracted from the pressure waveform in a multiple linear regression. Global as well as individual statistical models gave higher correlation coefficients between estimated and measured SV (model 1, r = 0.97; model 2, r = 0.96) than pulse-contour models (model 1, r = 0.83; model 2, r = 0.91). The latter models as well as statistical model 1 used the pulsatile systolic area and thus could be applied to only 47 +/- 17% of the cardiac beats. In contrast, statistical model 2 used the pressure-increase characteristics and was therefore established for all of the cardiac beats. The global statistical model 2 applied to data sets independent of those used to establish the model gave reliable SV estimates: r = 0.54 +/- 0.07, a small bias between -8% to +10%, and a mean precision of 7%. This work demonstrated the limits of pulse-contour models to estimate SV in conscious, unrestrained rats. A multivariate statistical model using eight parameters easily extracted from the aortic waveform could be applied to all cardiac beats with good precision.
authors.affiliation: Faculty of Pharmacy, Department of Physiology and Clinical Pharmacology, Centre National de la Recherche Scientifique UMR 5014, 69373 Lyon Cedex 08, France. cerruti@univ-lyon1.fr
authors.forename: C
authors.initials: C
authors.lastname: Cerutti
authors.forename: M P
authors.initials: MP
authors.lastname: Gustin
authors.forename: P
authors.initials: P
authors.lastname: Molino
authors.forename: C Z
authors.initials: CZ
authors.lastname: Paultre
mesh_terms: D000818:Animals; D001011:Aorta / Q000502:physiology*; D015982:Bias; D001794:Blood Pressure / Q000502:physiology; D005240:Feasibility Studies; D006439:Hemodynamics / Q000502:physiology; D008297:Male; D008955:Models, Cardiovascular; D015233:Models, Statistical; D011674:Pulse; D051381:Rats; D017207:Rats, Sprague-Dawley; D012044:Regression Analysis; D015203:Reproducibility of Results; D013318:Stroke Volume / Q000502:physiology*; D014851:Wakefulness / Q000502:physiology*