scholarly journals Wearable Laser Doppler Flowmetry Sensor: A Feasibility Study with Smoker and Non-Smoker Volunteers

Biosensors ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 201
Author(s):  
Mou Saha ◽  
Viktor Dremin ◽  
Ilya Rafailov ◽  
Andrey Dunaev ◽  
Sergei Sokolovski ◽  
...  
Keyword(s):  
Laser Doppler Flowmetry ◽  
Blood Circulation ◽  
Blood Perfusion ◽  
Pulse Frequency ◽  
Laser Doppler ◽  
Doppler Flowmetry ◽  
Left Hand ◽  
Non Invasive ◽  
Blood Microcirculation ◽  
Left Middle

Novel, non-invasive wearable laser Doppler flowmetry (LDF) devices measure real-time blood circulation of the left middle fingertip and the topside of the wrist of the left hand. The LDF signals are simultaneously recorded for fingertip and wrist. The amplitude of blood flow signals and wavelet analysis of the signal are used for the analysis of blood perfusion parameters. The aim of this pilot study is to validate the accuracy of blood circulation measurements recorded by one such non-invasive wearable LDF device for healthy young non-smokers and smokers. This study reveals a higher level of blood perfusion in the non-smoker group compared to the smoker group and vice-versa for the variation of pulse frequency. This result can be useful to assess the sensitivity of the wearable LDF sensor in determining the effect of nicotine for smokers as compared to non-smokers and also the blood microcirculation in smokers with different pathologies.

scholarly journals Laser Doppler Flowmetry versatile acquisition system with low quantization error

2018 ◽  
Vol 4 (1) ◽  
pp. 25
Author(s):  
Francesco Marrazzi ◽  
Frederic Truffer ◽  
Martial Geiser
Keyword(s):  
Laser Doppler Flowmetry ◽  
Analog Circuit ◽  
Scattered Light ◽  
Blood Perfusion ◽  
Electrical Signal ◽  
Laser Doppler ◽  
Physical Models ◽  
Acquisition System ◽  
Invasive Technique ◽  
Doppler Flowmetry

The Laser Doppler Flowmetry (LDF) is a non-invasive technique used to evaluate blood perfusion of various human tissues like the skin or the fundus of the eye. It is based on the scattering of light on moving red blood cells in tissue. Frequency shifted scattered light is detected and provide an electrical signal. Physical models for LDF use the DC and AC components of this signal. If AC is small relative to the DC, digitalization becomes an issue, and if more than two LDF signal acquisitions and analysis have to be done simultaneously, the device becomes expensive and bulky. We propose here a versatile and inexpensive acquisition system, which overcomes quantization errors issue by first separating DC from AC, then amplifying AC and finally recombining both signals before digitalization. We designed an analog circuit combined with a 12 bit analog-to-digital converter, a microcontroller unit and a Raspberry Pi2 (Rpi2) for the signal processing. Results are accessed remotely from the Rpi2 through HTTP protocol. Multiple systems can easily be used simultaneously for multichannel acquisitions.

scholarly journals Laser doppler flowmetry assessment of microcirculation in children of 6–7 years old

2021 ◽  
Vol 20 (3) ◽  
pp. 46-53
Author(s):  
V. I. Kozlov ◽  
V. N. Sakharov ◽  
O. A. Gurova ◽  
V. V. Sidorov
Keyword(s):  
Blood Flow ◽  
Laser Doppler Flowmetry ◽  
Laser Doppler ◽  
Lower Limbs ◽  
Doppler Flowmetry ◽  
Flow Modulation ◽  
Left Hand ◽  
Flow Fluctuations ◽  
Ongoing Development

Introduction. The state of the blood flow within the capillaries and close blood vessels is highly important in practice for the revealing of pathogenetic mechanisms of both systemic and local circulatory disorders. Aim of the study was to define the parameters of microcirculation and the level of blood flow fluctuations (flux) in the distal segments of upper and lower limbs (in fingers of hands and toes of feet) in children of 6–7 years old; and to describe the possible differences in the mechanisms of blood flow modulation in boys and girls. Materials and methods. Skin microcirculation was assessed in middle fingers of hands and great toes of feet in children of 6-7 years old (14 girls and 7 boys in prone position) by means of laser doppler flowmetry. Results. The ranges for parameters of microcirculation (PM) for distal segments of upper and lower limbs in children of mentioned age group were defined, also it was shown that the PM are significantly lower in the lower limbs comparing to those of the upper limbs (both in groups of girls and boys). Asymmetry of PM in the feet was not found; the features of right hand-left hand asymmetry for PM in girls and boys are described. The analysis of modulation of blood flow fluctuations (fluxmotions) of different frequencies showed the profound role of vasomotor (myogenic) rhythm for regulation of microcirculation. Conclusion. Increased neurogenic influences on the modulation of fluxmotions in girls of 6-7 years old may be an evidence of the ongoing development of the mechanisms of blood flow regulation, particularly the association with the growth rate of girls is possible.

scholarly journals Laser doppler flowmetry for human blood microcirculation assessment

2014 ◽  
Vol 95 (1) ◽  
pp. 63-69 ◽  
Author(s):  
I V Barhatov
Keyword(s):  
Blood Flow ◽  
Frequency Analysis ◽  
Laser Doppler Flowmetry ◽  
Maximum Amplitude ◽  
Blood Perfusion ◽  
Laser Doppler ◽  
Doppler Flowmetry ◽  
Functional Changes ◽  
Microcirculatory Disorders ◽  
The Impact

The prevention and treatment of various microcirculation disorders are one of the most important problems of medical practice. The difficulties of studying the microcirculation are related to the blood vessels small size and extensive branching within organ tissues. At present, various methods of microcirculation assessment using the laser Doppler flowmetry are applied in active clinical practice in our country. The review covers the main methods of laser Doppler flowmetry used for the diagnosis of various microcirculation disorders. The method is based on the determination of tissue blood perfusion by measuring the Doppler frequency shift while tissue is illuminated by a laser beam, followed by the registration of the reflected radiation from moving and stationary tissue components. Microcirculatory oscillation rhythm plays an important role, especially in early diagnosis of many diseases. The loss of certain types of oscillations at laser Doppler flowmetry is interpreted as «spectral narrowing» and serves as a diagnostic criterion for microcirculation deregulation, which is directly related to decreased blood perfusion and tissue hypotrophy. The use of amplitude-frequency analysis of blood flow oscillations can non-invasively evaluate the impact of the various components of microvascular tone, allowing to calculate an index of neurogenic and myogenic tone and bypass index. The amplitude-frequency analysis of the laser Doppler flowmetry spectrum uses normalized parameters determining the maximum amplitude of the blood flow oscillation in different bands, as well as their ratio - microcirculation effectiveness index. Hyperemic, spastic, spastic-atonic, structural and degenerative, congestive and stasic forms of various microcirculation disorders are marked out. Each of these microcirculatory disorders is characterized by a certain ratio of structural and functional changes and changes in blood velocity, as well as impaired barrier function. The main principles of the microcirculatory disorders are described.

Sign in / Sign up

Export Citation Format

Share Document