A Simple Adaptive Transfer Function for Deriving the Central Blood Pressure Waveform from a Radial Blood Pressure Waveform.
Generalized transfer functions (GTFs) are available to compute the more relevant central blood pressure (BP) waveform from a more easily measured radial BP waveform. However, GTFs are population averages and therefore may not adapt to variations in pulse pressure (PP) amplification (ratio of radial to central PP). A simple adaptive transfer function (ATF) was developed. First, the transfer function is defined in terms of the wave travel time and reflection coefficient parameters of an arterial model. Then, the parameters are estimated from the radial BP waveform by exploiting the observation that central BP waveforms exhibit exponential diastolic decays. The ATF was assessed using the original data that helped popularize the GTF. These data included radial BP waveforms and invasive reference central BP waveforms from cardiac catheterization patients. The data were divided into low, middle, and high PP amplification groups. The ATF estimated central BP with greater accuracy than GTFs in the low PP amplification group (e.g., central systolic BP and PP root-mean-square-errors of 3.3 and 4.2 mm Hg versus 6.2 and 7.1 mm Hg; p ≤ 0.05) while showing similar accuracy in the higher PP amplification groups. The ATF may permit more accurate, non-invasive central BP monitoring in elderly and hypertensive patients.
Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI, USA.
Mingwu
M
Gao
Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA.
William C
WC
Rose
Division of Cardiology, Department of Medicine, Johns Hopkins Medical Institutions, Baltimore, MD, USA.
Barry
B
Fetics
Division of Cardiology, Department of Medicine, Johns Hopkins Medical Institutions, Baltimore, MD, USA.
David A
DA
Kass
Department of Medicine, National Yang-Ming University, Taipei City, Taiwan (R.O.C.).
Chen-Huan
CH
Chen
Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI, USA.
Ramakrishna
R
Mukkamala
D001794:Blood Pressure; D006801:Humans; D008955:Models, Cardiovascular