TY - JOUR
T1 - N-point moving average
T2 - a special generalized transfer function method for estimation of central aortic blood pressure
AU - Xiao, Hanguang
AU - Butlin, Mark
AU - Qasem, Ahmad
AU - Tan, Isabella
AU - Li, Decai
AU - Avolio, Alberto P.
PY - 2018/6/1
Y1 - 2018/6/1
N2 - Objective: N-point moving average (NPMA) is a simplified method of central aortic systolic pressure (CASP) estimation in comparison with the generalized transfer function (GTF). The fundamental difference or similarity between the methods is not established. This study investigates theoretical properties of NPMA relative to GTF and explores the integer and fractional denominator for the averaging process in the NPMA. Methods: Convolution of a specified square wave and the radial (or brachial) blood pressure waveform constituted the NPMA. A single uniform tube model-based TF (MTF) was employed to investigate potential physiological meaning of NPMA. In experimental analysis, invasive, simultaneously recorded aortic and radial pressure waveforms were obtained in 62 subjects under control conditions and following nitroglycerin administration. CASP was estimated by NPMA (CASP N P M A ), GTF (CASP G T F ), and MTF (CASP M T F ) from radial waveforms by tenfold cross validation. Results: Theoretical analysis showed that NPMA was an inversed constant TF. Its spectrum matched that of MTF in low frequency (<4 Hz for radial and <5 Hz for brachial) by optimizing reflection coefficient and propagation time. Experiment results showed the NPMA optimized fractional denominator of K = 4.4 significantly decreased the mean difference between CASP N P M A and measured CASP to 0.0 ± 4.7 mmHg from -1.8 ± 4.6 mmHg for integer denominator of K = 4. CASP N P M A correlated with CASP M T F and CASP G T F (r 2 = 0.99 and 0.97, mean difference: -0.3 ± 1.8 and 0.5 ± 2.7 mmHg). Conclusion: This study demonstrated that NPMA is similar in nature to the GTF.
AB - Objective: N-point moving average (NPMA) is a simplified method of central aortic systolic pressure (CASP) estimation in comparison with the generalized transfer function (GTF). The fundamental difference or similarity between the methods is not established. This study investigates theoretical properties of NPMA relative to GTF and explores the integer and fractional denominator for the averaging process in the NPMA. Methods: Convolution of a specified square wave and the radial (or brachial) blood pressure waveform constituted the NPMA. A single uniform tube model-based TF (MTF) was employed to investigate potential physiological meaning of NPMA. In experimental analysis, invasive, simultaneously recorded aortic and radial pressure waveforms were obtained in 62 subjects under control conditions and following nitroglycerin administration. CASP was estimated by NPMA (CASP N P M A ), GTF (CASP G T F ), and MTF (CASP M T F ) from radial waveforms by tenfold cross validation. Results: Theoretical analysis showed that NPMA was an inversed constant TF. Its spectrum matched that of MTF in low frequency (<4 Hz for radial and <5 Hz for brachial) by optimizing reflection coefficient and propagation time. Experiment results showed the NPMA optimized fractional denominator of K = 4.4 significantly decreased the mean difference between CASP N P M A and measured CASP to 0.0 ± 4.7 mmHg from -1.8 ± 4.6 mmHg for integer denominator of K = 4. CASP N P M A correlated with CASP M T F and CASP G T F (r 2 = 0.99 and 0.97, mean difference: -0.3 ± 1.8 and 0.5 ± 2.7 mmHg). Conclusion: This study demonstrated that NPMA is similar in nature to the GTF.
KW - Arterial pressure
KW - Blood pressure monitoring
KW - Generalized transfer function
KW - N-point moving average
UR - http://www.scopus.com/inward/record.url?scp=85057593811&partnerID=8YFLogxK
U2 - 10.1109/TBME.2017.2710622
DO - 10.1109/TBME.2017.2710622
M3 - Article
C2 - 29787995
AN - SCOPUS:85057593811
VL - 65
SP - 1226
EP - 1234
JO - IEEE Transactions on Biomedical Engineering
JF - IEEE Transactions on Biomedical Engineering
SN - 0018-9294
IS - 6
M1 - 2710622
ER -