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Technical issues related to the long-term monitoring of blood flow at different depths using LDF and PPG


Jimmie Hagblad, Mia Folke, Lars-Göran Lindberg , Maria Lindén

Research group:

Publication Type:

Journal article


Physiological Measurement


IOP Publishing




The aim of the study was to evaluate an integrated probe using LDF and multiple PPG, for the long-term aspects of skin temperature and blood flow variations at different tissue depths, and especially to investigate whether the presence of the probe affects the temperature. Measurements of temperature and blood flow were performed over 60 minutes on the lower back of 10 subjects, lying on a mattress. The surface temperature of the skin was also measured before and after the 60 minute period, and repeated with three probe configurations with the probe switched on, turned off, and in the absence of a probe. A general increase in the blood flow was found to occur during the 60 minute interval at all depths reached by this probe, but with variations over time. No difference was found in temperatures recorded for the different probe configurations. According to our measurements, the presence of the probe does not affect the skin surface temperature at 60 minutes. Our investigation shows that skin temperature can be expected to increase and approach the body core temperature by just lying in supine position on the mattress. The increase in temperature and blood flow that is known to occur, possibly attributable to pressure-induced vasodilatation, must be taken into consideration when performing these kinds of measurements.


author = {Jimmie Hagblad and Mia Folke and Lars-G{\"o}ran Lindberg and Maria Lind{\'e}n},
title = {Technical issues related to the long-term monitoring of blood flow at different depths using LDF and PPG},
volume = {33},
number = {6},
pages = {985--996},
month = {May},
year = {2012},
journal = {Physiological Measurement},
publisher = {IOP Publishing},
url = {}