Techniques of Recording Photoplethysmographic Signals (original) (raw)
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Clinical measurements with multi-spectral photoplethysmography sensors
SPIE Proceedings, 2012
A portable multi-spectral photoplethysmography device has been used for studies of 40 subjects. Multi-spectral (MS) monitoring was performed by means of four wavelengths (454 nm, 519 nm, 632 nm and 888 nm) light emitted diodes (LED) and a single photodiode with multi-channel signal output processing. The proposed methodology and potential clinical applications are discussed.
Feasibility of Imaging Photoplethysmography
2008
Contact and spot measurement have limited the application of photoplethysmography (PPG), thus an imaging PPG system comprising a digital CMOS camera and three wavelength light-emitting diodes (LEDs) is developed to detect the blood perfusion in tissue. With the means of the imaging PPG system, the ideally contactless monitoring with larger field of view and the different depth of tissue by applying multiwavelength illumination can be achieved to understand the blood perfusion change. Corresponding to the individual wavelength LED illumination, the PPG signals can be derived in the both transmission and reflection modes, respectively. The outcome explicitly reveals the imaging PPG is able to detect blood perfusion in a illuminated tissue and indicates the vascular distribution and the blood cell response to individual wavelength LED. The functionality investigation leads to the engineering model for 3-D visualized blood perfusion of tissue and the development of imaging PPG tomography. Index Terms -Imaging Photoplethysmography, visualized blood perfusion, multi-wavelength illumination 2008 International Conference on BioMedical Engineering and Informatics 978-0-7695-3118-2/08 $25.00
Analysis Of Reflectance Photoplethysmograph Sensors
2011
Photoplethysmography is a simple measurement of the variation in blood volume in tissue. It detects the pulse signal of heart beat as well as the low frequency signal of vasoconstriction and vasodilation. The transmission type measurement is limited to only a few specific positions for example the index finger that have a short path length for light. The reflectance type measurement can be conveniently applied on most parts of the body surface. This study analyzed the factors that determine the quality of reflectance photoplethysmograph signal including the emitter-detector distance, wavelength, light intensity, and optical properties of skin tissue. Light emitting diodes (LEDs) with four different visible wavelengths were used as the light emitters. A phototransistor was used as the light detector. A micro translation stage adjusts the emitter-detector distance from 2 mm to 15 mm. The reflective photoplethysmograph signals were measured on different sites. The optimal emitter-detec...
The preliminary investigation of imaging photoplethysmographic system
Journal of Physics: Conference Series, 2007
A preliminary CCD camera-based imaging photoplethysmographic (PPG) system is described to detect the blood perfusion in tissue. Attention of imaging photoplethysmography (PPG) is drawn to the potential applications in visualised blood perfusion. The introduction of the fast digital camera inspires the development of imaging PPG which allows the ideally contactless monitoring with larger field of view and different depth of tissue by applying multi-wavelength LEDs. The CCD camerabased spectral imaging PPG system in both transmission mode and reflection mode is constructed to validate the feasibility of this technique. The PPG signal can be derived in both transmission mode and reflection mode, which is obviously different from multiwavelength LEDs or monitoring at various regions of tissue. The investigation for the system functionality leads to the further development of imaging PPG system and the engineering model for 3-D visualised blood perfusion of tissue.
Applications of Finger Photoplethysmography
Optical sensors that use photons as sensing elements are increasingly becoming important and relevant in the field of non-invasive diagnostics. The reason is that they have simple construction, easy to use and relatively inexpensive in comparison with tools such as EEG, MRI and FMRI that can be used for research with much investment. Among the many optical sensors available, the PPG (photoplethysmography) sensors, are capable of measuring blood volumetric changes in the subcutaneous vessels. Objective is to diagnose parameters like heart rate, respiratory rate. Real time PPG signal is obtained from sensor and heart rate is calculated from it. .Reflectance type of PPG sensor has been used to diagnose the parameters. Detailed analysis of frequency spectrum (FFT) of PPG signal shows a cardiac peak around 1Hz corresponding to 60 pulsations a minute and respiratory peak around 0.25 Hz corresponding to 15 inspiration/expiration cycles per minute.
Clinical and Biomedical Spectroscopy and Imaging II, 2011
A photoplethysmography (PPG) signal can provide very useful information about a subject's hemodynamic status in a hospital or home environment. A newly developed portable multi-spectral photoplethysmography device has been used for studies of 11 healthy subjects. Multi-spectral photoplethysmography (MS-PPG) biosensor intended for analysis of peripheral blood volume pulsations at different vascular depths has been designed and experimentally tested. Multispectral monitoring was performed by means of a three-wavelengths (405 nm, 660 nm and 780 nm) laser diode and a single photodiode with multi-channel signal output processing. The proposed methodology and potential clinical applications are discussed.
Measurement of photoplethysmographic signals in human abdominal organs
There is a need for reliable continuous monitoring of abdominal organ oxygen saturation (SpO 2). Splanchnic ischaemia may ultimately lead to cellular hypoxia and necrosis and contribute to the development of multiple organ failure and increased mortality. A reflectance electro-optical photoplethysmographic (PPG) probe and signal processing system were developed. Satisfactory PPG signals from abdominal organs (bowel, liver and kidney) and the finger were obtained from 12 anaesthetised patients. There were no statistically significant differences between the average PPG amplitudes recorded from the abdominal organs and those obtained simultaneously from the finger. These observations suggest that pulse oximetry can be a valid monitoring technique for abdominal organs such as the bowel, liver and kidney.
Background: Non-invasive methods for screening and diagnosis are the field with fast growing interest which leads to various biological signal measurements like Photoplethysmogram (PPG) and pressure pulse. PPG monitoring is widely used in the healthcare as this single pulse study can provide wide physiological information non-invasively such as oxygen saturation, heart rate, blood pressure (continuous and cuff less), blood volume, arterial stiffness and respiration rate. First and second derivatives of PPG provide important information about the arterial stiffness and vascular health of the person. Aim: This paper explains the design and development of prototype with RED LED (660 nm) and IR LED (860 nm) as a source and OPT 101 as a detector. Second derivative related indices of PPG (for RED LED and IR LED) were calculated. Materials and methods: Study was carried out on 15 healthy female subjects without any known history of blood pressure and blood glucose; aged between 19-23 years...