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Determination
of instantaneous arterial blood pressure from bio-impedance
signal
Sofiene Mansouri*, Halima Mahjoubi and Ridha Ben Salah
Biophysics Research Unit, Faculty of Medicine, Sousse,
Tunisia
*Corresponding author.
E-mail:
mansouri_sofienne@yahoo.fr.
Fax: 216 71 928 910. Tel: 216 21 876 532
Accepted
4 December, 2009 |
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The
objective of this study was to determine the instantaneous
arterial blood pressure by the peripheral bio-impedance. To
achieve this goal, the equation of Ben Salah and Flaud,
initially meant to determine the instantaneous aortic
pressure according to the signal of thoracic bioimpedance,
was successfully applied for the determination of the
instantaneous arterial pressure according to the signal of
peripheral bio-impedance. The problem was that this equation
depends directly on systolic and diastolic pressures which
were manually obtained by an electronic sphygmomanometer.
Yet the objective was to determine the instantaneous
arterial blood pressure without having to measure beforehand
diastolic and systolic pressures by the electronic
sphygmomanometer. To solve this problem, interpolation
function linking respectively the pulse pressure to the
impedance variation (with 2,97% error for the determination
of the systolic pressure) and the diastolic pressure to the
basic impedance were determined (with an error close to zero
for the determination of the diastolic pressure). With the
proposed method, for each new measurement on a subject we
acquire its bioimpedance signal, and then use the
interpolation functions to deduce its diastolic and systolic
pressures and then, using the Ben Salah equation, in real
time, to determine its instantaneous arterial blood
pressure. The bio-impedance signal processing, the user
interface and the display were managed by LabVIEW.
Key
words:
Instantaneous arterial pressure, cubic spline interpolation,
bioimpedance, electric plethysmography, LabVIEW. |
