Annals of Biomedical Engineering

, Volume 15, Issue 5, pp 427–441 | Cite as

Short-term regulation of arterial pressure and the calculation of open-loop gain in the intact anesthetized dog

  • R. Burattini
  • P. Borgdorff
  • N. Westerhof


Open-loop gain of the short-term systemic pressure regulation was determined under closed-loop conditions in the closed chest anesthetized dog (n=5). For this purpose, cardiac output and mean systemic pressure were varied by ventricular pacing after the production of complete heart block. From the pressure-flow data resistance gain (the ratio of peripheral resistance change to pressure change in the steady state) was obtained by means of a simple model. The value of this gain was automatically estimated by fitting the pressure-flow relation described by the model to the experimental data. The model allows the pressure-flow relation to be straight or curved with or without a zero-flow pressure intercept. The best fit was obtained when the pressure-flow curve was convex to the pressure axis and had no intercept.

When the model was linearized about the control values of pressure and flow (operating point), open-loop gain could be calculated from resistance gain. Its averaged value in the control condition, 1.63±0.45, is in agreement with values found by other investigators in open-loop conditions. During vasoconstriction open-loop gain, at the (new) operating point, increased to 2.51±0.51; during vasodilation it decreased to 1.17±0.27. Open-loop gain about an operating point thus can be determined in the intact animal from measurements of mean pressure and mean flow in the steady state.


Parameter estimation Model linearization Closed-loop gain Cardiac pacing Baroreflex 



mean systemic pressure


mean systemic pressure in control condition


change in systemic pressure from control to a new steady state


initial change of systemic pressure


zero-flow pressure intercept


cardiac output


cardiac output in control condition


change of flow from control to a new steady state


total peripheral resistance


total peripheral resistance in control condition


change of peripheral resistance from control to a new steady state


resistance gain


open-loop gain


closed-loop gain


heart rate


heart rate in control condition


standard deviation


standard error


root mean square error


body weight




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  1. 1.
    Allison, J.L., K. Sagawa and M. Kumada An open-loop analysis of the aortic arch barostatic reflex.Am. J. Physiol. 217:1576–1584, 1969.PubMedGoogle Scholar
  2. 2.
    Angell James, J.E., and M. de Burgh Daly. Comparison of the reflex vasomotor responses to separate and combined stimulation of the carotid sinus and aortic arch baroreceptors by pulsatile and non-pulsatile pressures in the dog.J. Physiol. 209:257–293, 1970.Google Scholar
  3. 3.
    Borgdorff, P. Peripheral resistance after cardiac output reduction in the barodenervated cat.Circ. Res. 52:7–15, 1983.PubMedGoogle Scholar
  4. 4.
    Brunner, M.J., A.S. Greene, K. Sagawa and A.A. Shoukas. Determinants of systemic zero flow arterial pressure.Am. J. Physiol. 245:H453-H460, 1983.PubMedGoogle Scholar
  5. 5.
    Burattini, R. and P. Borgdorff. Closed-loop baroreflex control of total peripheral resistance in the cat: identification of gains by aid of a model.Cardiovasc Res. 18:715–723, 1984.PubMedGoogle Scholar
  6. 6.
    Burattini, R. Comments on “Carotid sinus baroreceptor reflex control and the role of autoregulation in the systemic and pulmonary arterial pressure-flow relationships of the dog.”Circ. Res. 57:198–199, 1985.PubMedGoogle Scholar
  7. 7.
    Chen, H.I. and V.S. Bishop. Baroreflex open-loop gain and arterial pressure compensation in hemorrhagic hypotension.Am. J. Physiol. 245:H54-H59, 1983.PubMedGoogle Scholar
  8. 8.
    Constantine, J.W., W.K. McShane and S.C. Wang. Comparison of carotid artery occlusion and tilt responses in dogs.Am. J. Physiol. 221:1681–1685, 1971.PubMedGoogle Scholar
  9. 9.
    Cox, R.H. and R.J. Bagshaw. Baroreceptor reflex control of arterial hemodynamics in the dog.Circ. Res. 37:772–786, 1975.PubMedGoogle Scholar
  10. 10.
    Dampney, R.A.L., M.G. Taylor and E.M. McLachlan. Reflex effects of stimulation of carotid sinus and aortic baroreceptors on hindlimb vascular resistance in dogs.Circ. Res. 29:119–127, 1971.PubMedGoogle Scholar
  11. 11.
    Donald, D.E. and A.J. Edis. Comparison of aortic and carotid baroreflexes in the dog.J. Physiol. 215:521–538, 1971.PubMedGoogle Scholar
  12. 12.
    Greenway, C.V. and I.R. Innes. Effect of carotid sinus baroreceptor reflex on response to phenylephrine and nitroprusside in anesthetized cats.J. Cardiov. Pharmacol. 3:169–177, 1981.Google Scholar
  13. 13.
    Hosomi, H. Overall characteristics of arterial pressure control system studied by mild hemorrhage.Am. J. Physiol. 234:R104-R109, 1978.PubMedGoogle Scholar
  14. 14.
    Hosomi, H. Unstable state of the arterial pressure control system after a mild hemorrhage.Am. J. Physiol. 235:R279-R285, 1978.PubMedGoogle Scholar
  15. 15.
    Hosomi, H. and K. Sagawa. Sinovagal interaction in arterial pressure restoration after 10% hemorrhage.Am. J. Physiol. 237:R203-R209, 1979.PubMedGoogle Scholar
  16. 16.
    Hosomi, H. and K. Yokoyama. Estimation of open-loop gain of canine arterial pressure control system by a new method.Am. J. Physiol. 240:H832-H836, 1981.PubMedGoogle Scholar
  17. 17.
    Hosomi, H., H. Chatani, T. Kaizuka, S. Katsuda, and Y. Hayashida. Overall open-loop gain of rapidly acting arterial pressure control system in rabbits.Pflügers Arch. 399:134–138, 1983.CrossRefPubMedGoogle Scholar
  18. 18.
    Kirchheim, H.R. Systemic arterial baroreceptor reflexes.Physiol. Rev. 56:100–176, 1976.PubMedGoogle Scholar
  19. 19.
    Levison, W.H., C.O. Barnett and W.D. Jackson. Nonlinear analysis of the baroreceptor reflex system.Circ. Res. 18:673–682, 1966.PubMedGoogle Scholar
  20. 20.
    Milhorn, H.T. Jr.The application of control theory to physiological systems. London, Saunders, 1966, 156–166.Google Scholar
  21. 21.
    Noble, M.I.M., D. Trenchard and A. Guz. Effect of changing heart rate on cardiovascular function in the conscious dog.Circ. Res. 19:206–213, 1966.Google Scholar
  22. 22.
    Powell, M.J.D. An efficient method for finding the minimum of a function of several variables without calculating derivatives.Comput. J. 7:155–162, 1964.CrossRefGoogle Scholar
  23. 23.
    Randall, O.S., N. Westerhof, G.C. van den Bos and P. Sipkema. Production of chronic atrioventricular block in closed chest dogs: an improved technique.Am. J. Physiol. 241:H279-H282, 1980.Google Scholar
  24. 24.
    Rumberger, E., K. Bauman and M. Schottler. Dependence of peripheral resistance on heart rate. Bauer, R.D. and Busse, R., eds.The Arterial System. Berlin, Springer-Verlag, 1978, 250–254.Google Scholar
  25. 25.
    Sagawa, K. Relative roles of the rate sensitive and proportional control elements of the carotid sinus during mild hemorrhage. Kezdi, P., ed.Baroreceptors and Hypertension. Oxford, Pergamon Press, 1967, 97–105.Google Scholar
  26. 26.
    Sagawa, K., M. Kumada and L.P. Schramm. Nervous control of the circulation. Guyton, A.C. and Jones, C.E., eds.Cardiovascular Physiology, Vol. 1. London, Butterworths, 1974, 197–232.Google Scholar
  27. 27.
    Sagawa, K. and A. Eisner. Static pressure-flow relation in the total systemic vascular bed of the dog and its modification by the baroreceptor reflex.Circ. Res. 36:406–413, 1975.PubMedGoogle Scholar
  28. 28.
    Sagawa, K. Concerning “gain”.Am. J. Physiol. 235:H17, 1978.Google Scholar
  29. 29.
    Scher, A.M. and A.C. Young. Servoanalysis of carotid sinus reflex effects on peripheral resistance.Circ. Res. 12:152–162, 1963.PubMedGoogle Scholar
  30. 30.
    Schmidt, R.M., M. Kumada and K. Sagawa. Cardiac output and total peripheral resistance in carotid sinus reflex.Am. J. Physiol. 221:480–487, 1971.PubMedGoogle Scholar
  31. 31.
    Schmidt, R.M., M. Kumada and K. Sagawa. Cardiovascular response to various pulsatile pressures in the carotid sinus.Am. J. Physiol. 223:1–7, 1972.PubMedGoogle Scholar
  32. 32.
    Shoukas, A.A. and M. Connolly Brunner. Epinephrine and the carotid sinus baroreceptor reflex. Influence on capacitive and resistive properties of the total systemic vascular bed of the dog.Circ. Res. 47:249–257, 1980.PubMedGoogle Scholar
  33. 33.
    Shoukas, A.A., M.J. Brunner, A.E. Frankle, A.S. Greene and C.H. Kallman. Carotid sinus baroreceptor reflex control and the role of autoregulation in the systemic and pulmonary arterial pressure-flow relationships of the dog.Circ. Res. 54:674–682, 1984.PubMedGoogle Scholar
  34. 34.
    Stegemann, J. and U. Tibes. Sinusoidal stimulation of carotid sinus baroreceptors and peripheral blood pressure in dogs.Annals N.Y. Acad. of Sci. 1969, 156.Google Scholar
  35. 35.
    Sylvester, J.T., R.D. Gilbert, R.J. Traystman and S. Permutt. Effects of hypoxia on the closing pressure of the canine systemic arterial circulation.Circ. Res. 49:980–987, 1981.PubMedGoogle Scholar
  36. 36.
    Valentinuzzi, M.E., T. Powell, H.E. Hoff, L.A. Geddes and J.A. Posey Jr. Control parameters of the blood-pressure regulatory system. Part 2—Open-loop gain, reference pressure and basal heart rate.Med. and Biol. Eng. 10:596–598, 1972.Google Scholar

Copyright information

© Pergamon Journals Ltd 1987

Authors and Affiliations

  • R. Burattini
    • 1
  • P. Borgdorff
    • 2
  • N. Westerhof
    • 2
  1. 1.Department of Electronics and AutomaticaUniversity of AnconaAnconaItaly
  2. 2.Laboratory for PhysiologyFree University of AmsterdamAmsterdamThe Netherlands

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