Photoplethysmography in noninvasive cardiovascular assessment
Ping Shi
2134/5399
https://repository.lboro.ac.uk/articles/thesis/Photoplethysmography_in_noninvasive_cardiovascular_assessment/9533834
The electro-optic technique of measuring the cardiovascular pulse wave known as
photoplethysmography (PPG) is clinically utilised for noninvasive characterisation of
physiological components by dynamic monitoring of tissue optical absorption. There
has been a resurgence of interest in this technique in recent years, driven by the
demand for a low cost, compact, simple and portable technology for primary care and
community-based clinical settings, and the advancement of computer-based pulse
wave analysis techniques. PPG signal provides a means of determining cardiovascular
properties during the cardiac cycle and changes with ageing and disease. This thesis
focuses on the photoplethysmographic signal for cardiovascular assessment.
The contour of the PPG pulse wave is influenced by vascular ageing. Contour analysis
of the PPG pulse wave provides a rapid means of assessing vascular tone and arterial
stiffness. In this thesis, the parameters extracted from the PPG pulse wave are
examined in young adults. The results indicate that the contour parameters of the PPG
pulse wave could provide a simple and noninvasive means to study the characteristic
change relating to arterial stiffness.
The pulsatile component of the PPG signal is due to the pumping action of the heart,
and thus could reveal the circulation changes of a specific vascular bed. Heart rate
variability (HRV) represents one of the most promising quantitative markers of
cardiovascular control. Calculation of HRV from the peripheral pulse wave using
PPG, called pulse rate variability (PRV), is investigated. The current work has
confirmed that the PPG signal could provide basic information about heart rate (HR)
and its variability, and highly suggests a good alternative to understanding dynamics
pertaining to the autonomic nervous system (ANS) without the use of an electrocardiogram (ECG) device. Hence, PPG measurement has the potential to be
readily accepted in ambulatory cardiac monitoring due to its simplicity and comfort.
Noncontact PPG (NPPG) is introduced to overcome the current limitations of contact
PPG. As a contactless device, NPPG is especially attractive for physiological
monitoring in ambulatory units, NICUs, or trauma centres, where attaching electrodes
is either inconvenient or unfeasible. In this research, a prototype for noncontact
reflection PPG (NRPPG) with a vertical cavity surface emitting laser (VCSEL) as a
light source and a high-speed PiN photodiode as a photodetector is developed. The
results from physiological experiments suggest that NRPPG is reliable to extract
clinically useful information about cardiac condition and function.
In summary, recent evidence demonstrates that PPG as a simple noninvasive
measurement offers a fruitful avenue for noninvasive cardiovascular monitoring.
Key words: Photoplethysmography (PPG), Cardiovascular assessment, Pulse wave
contour analysis, Arterial stiffness, Heart rate (HR), Heart rate variability (HRV),
Pulse rate variability (PRV), Autonomic nervous system (ANS), Electrocardiogram
(ECG).
2009-10-14 13:57:48
Photoplethysmography
Cardiovascular assessment
Pulse wave contour analysis
Arterial stiffness
Heart rate (HR)
Heart rate variability (HRV)
Pulse rate variability (PRV)
Autonomic nervous system (ANS)
Electrocardiogram (ECG)
Mechanical Engineering not elsewhere classified