Polarized light spectroscopy for measurement of the microvascular response to local heating at multiple skin sites.
OBJECTIVE
To evaluate whether TiVi, a technique based on polarized light, could measure the change in RBC concentration during local heating in healthy volunteers.


METHODS
Using a custom-made transparent heater, forearm skin was heated to 42 °C for 40 minutes while the change in RBC concentration was measured with TiVi. The perfusion response during local heating was measured at the same time with Laser Doppler flowmetry.


RESULTS
Mean RBC concentration increased (91 ± 34 vs. 51 ± 34 A.U. at baseline, p < 0.001). The spatial heterogeneity of the RBC concentration in the measured skin areas was 26 ± 6.4% at baseline, and 23 ± 4.6% after 40 minutes of heating. The mean RBC concentrations in two skin sites were highly correlated (0.98 at baseline and 0.96 after 40 minutes of heating). The change in RBC concentration was less than the change in perfusion, measured with LDF. Unlike with LDF, a neurally mediated peak was not observed with TiVi in most of the test subjects.


CONCLUSIONS
TiVi is a valuable technique for measuring the microvascular response to local heating in the skin, and offers a high reproducibility for simultaneous measurements at different skin sites, provided carefully controlled experiments are ensured.
Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden. erik.tesselaar@liu.se
Erik
E
Tesselaar
Max
M
Bergkvist
Folke
F
Sjöberg
Simon
S
Farnebo
D000328:Adult; D004912:Erythrocytes / Q000378:metabolism*; D005260:Female; D006358:Hot Temperature; D006801:Humans; D008027:Light; D008297:Male; D008833:Microcirculation / Q000528:radiation effects*; D012867:Skin / Q000098:blood supply*