Abstract:
This work describes the design, development and
testing of an instrument for continuous, noninvasive
measurement of blood pressure in humans. While there is a
great need in medical fields for such an instrument, it is
not available at present.
Tonometry principle is used in this work. This method
has the difficulty in locating the tonometer over the
artery. However, this difficulty was overcome by locating
the tonometer where major arteries are absent, such as
fingertips or ear lobes. Linear relationship between the
blood pressure variations in the arterioles, capillaries and
the main arteries, is shown by mathematical analysis and
simulation tests.
While it is shown that it is possible to obtain the
measurements in various locations, the present work
concentrates to develop a device suitable for the finger.
Such device is built and tested successfully on a number of
individuals as well as in a hospital. Also , a calibration
procedure using a standard cuff method has been worked for
this device. However, one difficulty has been still remains
to be solved, namely, long-term zero shift of the measuring
system. This is due t o the convection currents and the
deterioration of the adhesive presently in use .
