Exploring the Hemodynamic Changes in Deeper Dermal Vasculature During Cold-Induced Vasoconstriction and Vasodilation Using a Laser Speckle-Based Optical Flowmetry Method

Abstract

While the Lewis hunting reaction has been studied for decades, little remains known about the hemodynamic changes which occur in the deeper dermal arteries and arterioles during its alternating phases of cold-induced vasoconstriction (CIVC) and cold-induced vasodilation (CIVD). Here, we present an integrated sensor that simultaneously measures blood flow speed and fingertip temperature to study this relatively unknown physiology. Using diffuse speckle pulsatile flowmetry (DSPF), a laser speckle-based optical flowmetry method which measures blood flow speed from relatively deeper vasculature (up to around 15 mm depth), we show that the sensor was able to detect the changes in five morphological features within arterial blood flow speed waveforms—average blood flow speed, amplitude, time to peak, 50% pulse width, and area under the curve. In a pilot study with 14 subjects, a decrease in the value of all five features was observed during CIVC (significant for three features), whereas a subsequent significant increase in all five features was observed during CIVD. This study provides further insight into the Lewis hunting reaction and demonstrates the feasibility of our sensor in monitoring the physiological response to cold environments. It will potentially contribute to the diagnosis and prevention of cold-related pathologies such as hypothermia and Raynaud’s syndrome.