Thermal Infrared Imaging for Investigating Changes of Vasomotion in Peripheral Circulation

Background & aim: In 2017, WHO estimated 48.9 million incident cases of sepsis worldwide, with 11 million sepsis related deaths. In early stages of sepsis microcirculatory function is impaired. An expression for general microcirculatory function is vasomotion, which is possible to measure on the dorsal side of the hand using an infrared camera. Thus, the objective of this study is to assess if sympathetic stimulation changes vasomotion in the peripheral circulation. Method: To investigate changes in vasomotion, infrared recordings of the hand were obtained. A cold pressor test was conducted on 10 healthy subjects. From the infrared recordings, four areas of interest were selected on the thumb muscle, index, middle and ring finger, which were converted to signals, and decomposed using discrete wavelet transform. Specific details from the discrete wavelet transform were reconstructed to assess changes in vasomotion. Results: During the cold pressor test changes in vasomotion were observed. However, there were no significant changes in vasomotion (thumb $P=.237$, index $P=.219$, middle $P=.253$ and ring $P=.066$). Conclusion: The sympathetic stimulation resulted in change in microcirculatory activity in the hand, however it did not result in significant change in temperature oscillations in vasomotion frequency bands.