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An investigation of underlying biophysical mechanisms in the use of pulse wave velocity for cuffless measurement of blood pressure

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thesis
posted on 13.04.2022, 05:02 by James CoxJames Cox

  

Background: Blood pressure (BP) is a health-based risk factor predictive of cardiovascular complications. Conventional cuff-based techniques measuring BP are limited by being discontinuous and inconvenient. This thesis investigates the underlying components of an alternative cuffless approach, utilising a subject-specific calibration method. This approach aims to minimise the use of a cuff, therefore, addressing these limitations by estimating BP through its relationship with arterial pulse wave velocity (PWV), a measure of arterial stiffness. Methods: Carotid-femoral PWV measurements were taken under baseline conditions and following two interventions; a postural change and a cold pressor test. The postural change generated a calibration factor that was investigated for repeatability. Consecutive PWV measurements assessed reliability and measurement variability. A cross-sectional multivariate statistical analysis was performed to determine possible predictors of the calibration factor. The cold pressor test investigated potential PWV differences in different arterial segments in response to a BP change.Results: The mean calibration factor was 18.78±7.39 mmHg/m/s with good repeatability (difference: 1.40±9.76 mmHg/m/s, p=0.48). This factor correlated with weight (standardised β=0.247, p=0.003) and diastolic BP (β=0.244, p=0.004). The cross-sectional stepwise linear regression model predicted 15% of the calibration factor variability (p<0.05, R2=0.146). Wave-form quality and distance were a source of potential variability. There were significant differences in regional PWV following a change in BP (p<0.05).Conclusions: These findings demonstrate the capacity of the subject-specific calibration factor to estimate BP. Variability present was primarily associated with the PWV measurement. Pulse transit time was significantly affected by changes in BP. As this thesis has only articulated the potential of the calibration approach and factors contributing towards its variability, future research is still required to validate BP estimation incorporating the calibration factor.

History

Table of Contents

1 Introduction -- 2 Literature Review -- 3 The repeatability of a subject-specific calibration factor for cuffless estimation of blood pressure -- 4 Sources of error in the measurement of PWV -- 5 Predictors of a subject-specific calibration factor -- 6 Regional differences of PWV following a change in BP -- 7 Conclusions -- 8 Future research -- A Ethics approval for all research conducted in this thesis -- Bibliography

Notes

A thesis submitted in fulfilment of the requirements for the degree of Master of Research

Awarding Institution

Macquarie Unversity

Degree Type

Thesis MRes

Degree

Thesis (Mres), Macquarie University, Faculty of Medicine and Health Sciences

Department, Centre or School

Department of Biomedical Sciences

Year of Award

2019

Principal Supervisor

Mark Butlin

Additional Supervisor 1

Isabella Tan

Additional Supervisor 2

Alberto Avolio

Rights

Copyright disclaimer: https://www.mq.edu.au/copyright-disclaimer Copyright Macquarie University 2019.

Language

English

Extent

xvi, 138 pages