Journal of Applied Physiology, Vol 73, Issue 5 1946-1957, Copyright © 1992 by American Physiological Society
Estimation of blood pressure-related parameters by electrical impedance measurement
J. H. Muntinga and K. R. Visser
Department of Medical Physiology, University of Groningen, The Netherlands.
In 13 healthy volunteers a computerized experimental set-up was used to
measure the electrical impedance of the upper arm at changing cuff
pressure, together with the finger arterial blood pressure in the
contralateral arm. On the basis of a model for the admittance response, the
arterial blood volume per centimeter length (1.4 +/- 0.3 ml/cm), the venous
blood volume as a percentage of the total blood compartment (49.2 +/-
12.6%), and the total arterial compliance as a function of mean arterial
transmural pressure were estimated. The effective physiological arterial
compliance amounted to 2.0 +/- 1.3 microliters.mmHg-1.cm-1 and the maximum
compliance to 33.4 +/- 12.0 microliters.mmHg-1.cm-1. Additionally, the
extravascular fluid volume expelled by the occluding cuff (0.3 +/- 0.3
ml/cm) was estimated. These quantities are closely related to
patient-dependent sources of an unreliable blood pressure measurement and
vary with changes in cardiovascular function, such as those found in
hypertension. Traditionally, a combination of several methods is needed to
estimate them. Such methods, however, usually neglect the contribution of
extravascular factors.
