Characterization of the Microcirculatory Response to Gravity-induced Changes by Noninvasive Thermal Imaging

Background: Peripheral microcirculatory has been found to reflect both local and systemic changes during different conditions of perfusion. The goal of this study was to characterize the changes in the palm’s blood distribution in response to a decrease in blood pressure due to gravity-induced changes, using thermal imaging.

Methods: Thermal hands images were taken from ten healthy volunteers, without any known vascular pathologies, in three different stages: baseline, gravitation and recovery. In the baseline stage the hand was set on a table, at heart height. During the gravitation stage one hand was placed 40 cm above the table for 10 minute while the second hand was stayed on the table. The recovery stage, in which both hands were placed back on the table, was recorded for 10 minutes. Thermal images of both hands were taken every ten seconds throughout the experiment.

Results: Mean skin temperatures were increased during hand elevating in both the palm center and the distal phalanx of the middle finger by 2.57 ˚C and 3.33 ˚C, respectively. This increase was significant and remained high for 10 minutes during the recovery period, until the session ended (p

Conclusions and Applications: The temperature increase of palm during gravity conditions reflects blood perfusion compensation due to high local oxygen consumption during decrease in local blood pressure. Thermal imaging allows characterization of the palm’s blood distribution under gravitational conditions. Since this technique is non-invasive, noncontact and safe, it could be useful for assessment of blood supply during physical effort in clinics, as well as at home. In addition, we believe that the use of thermal image monitoring and processing will promote new aspects of basic research in the field of hemodynamics.