Prediction of circulatory equilibrium in response to changes in stressed blood volume

Kazunori Uemura, Toru Kawada, Atsunori Kamiya, Takeshi Aiba, Ichiro Hidaka, Kenji Sunagawa, Masaru Sugimachi

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31 Citations (Scopus)


Accurate prediction of cardiac output (CO), left atrial pressure (PLA), and right atrial pressure (PRA) is a prerequisite for management of patients with compromised hemodynamics. In our previous study (Uemura et al. Am J Physiol Heart Circ Physiol 286: H2376-H2385, 2004), we demonstrated a circulatory equilibrium framework, which permits the prediction of CO, PLA, and PRA once the venous return surface and integrated CO curve are known. Inasmuch as we also showed that the surface can be estimated from single-point CO, PLA, and PRA measurements, we hypothesized that a similar single-point estimation of the CO curve would enable us to predict hemodynamics. In seven dogs, we measured the PLA-CO and P RA-CO relations and derived a standardized CO curve using the logarithmic function CO = SR[ln-(PLA - 2.03) + 0.80] for the left heart and CO = SR[ln(PRA - 2.13) + 1.90] for the right heart, where SL and SR represent the preload sensitivity of CO, i.e., pumping ability, of the left and right heart, respectively. To estimate the integrated CO curve in each animal, we calculated SL and SR from single-point CO, PLA, and P RA measurements. Estimated and measured CO agreed reasonably well. In another eight dogs, we altered stressed blood volume (-8 to +8 ml/kg of reference volume) under normal and heart failure conditions and predicted the hemodynamics by intersecting the surface and the CO curve thus estimated. We could predict CO [y = 0.93x + 6.5, r2 = 0.96, standard error of estimate (SEE) = 7.5 ml · min-1·kg-1], PLA (y = 0.90x + 0.5, r2 = 0.93, SEE = 1.4 mmHg), and PRA (y = 0.87x + 0.4, r2 = 0.91, SEE = 0.4 mmHg) reasonably well. In conclusion, single-point estimation of the integrated CO curve enables accurate prediction of hemodynamics in response to extensive changes in stressed blood volume.

Original languageEnglish
Pages (from-to)H301-H307
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Issue number1 58-1
Publication statusPublished - Jul 2005
Externally publishedYes


  • Heart failure
  • Logarithmic function
  • Venous return surface

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)


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