N-point moving average: a special generalized transfer function method for estimation of central aortic blood pressure

Hanguang Xiao, Mark Butlin, Ahmad Qasem, Isabella Tan, Decai Li, Alberto P. Avolio

Research output: Contribution to journalArticleResearchpeer-review

Abstract

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 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.

LanguageEnglish
Article number2710622
Pages1226-1234
Number of pages9
JournalIEEE Transactions on Biomedical Engineering
Volume65
Issue number6
DOIs
Publication statusPublished - 1 Jun 2018

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Blood pressure
Transfer functions
Convolution
Experiments

Keywords

  • Arterial pressure
  • Blood pressure monitoring
  • Generalized transfer function
  • N-point moving average

Cite this

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title = "N-point moving average: a special generalized transfer function method for estimation of central aortic blood pressure",
abstract = "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.",
keywords = "Arterial pressure, Blood pressure monitoring, Generalized transfer function, N-point moving average",
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N-point moving average : a special generalized transfer function method for estimation of central aortic blood pressure. / Xiao, Hanguang; Butlin, Mark; Qasem, Ahmad; Tan, Isabella; Li, Decai; Avolio, Alberto P.

In: IEEE Transactions on Biomedical Engineering, Vol. 65, No. 6, 2710622, 01.06.2018, p. 1226-1234.

Research output: Contribution to journalArticleResearchpeer-review

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T1 - N-point moving average

T2 - IEEE Transactions on Biomedical Engineering

AU - Xiao, Hanguang

AU - Butlin, Mark

AU - Qasem, Ahmad

AU - Tan, Isabella

AU - Li, Decai

AU - Avolio, Alberto P.

PY - 2018/6/1

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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.

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