Evaluation of Sympathetic Vasomotor Activity of the Brachial Arteries Using Doppler Ultrasound

BACKGROUND The sympathetic nervous system is principally accountable for peripheral artery regulation, and its effect is that vasospasm occurs in the medium and large arteries of the extremities, resulting in decreased flow of blood. Because of this information of how the body works, our goal is to create a noninvasive and repeatable self-test model that uses Doppler ultrasound examination. MATERIAL AND METHODS The study was conducted on 31 healthy and active participants who volunteered for the study. Written informed consent was obtained from all participants. The baseline diameter and flow rates of the brachial artery from 2 cm superior to the antecubital fossa were determined using a Doppler probe, which remained stationary throughout the experiment, allowing for continuous measurements. Then, to activate the sympathetic fibers, an electrical stimulus was applied for 5 s with an intensity of 10 mA and frequency of 1 Hz at the level of the median nerve at the wrist via the bipolar stimulation electrode. Immediately following the sixth stimulation, the artery diameter and flow rates were assessed again. RESULTS Following the stimulation, a statistically significant decrease in flow rate was observed (P<0.001). Moreover, stimulation resulted in a statistically significant reduction in the diameter of the brachial artery (P<0.001). CONCLUSIONS Our research suggests that Doppler ultrasonography can be routinely used to detect the normal and abnormal functioning of the peripheral sympathetic nervous system.