Synchronized Measurements of Maximum Blood Flow Velocities in Carotid, Brachial and Femoral Arteries, and ECG in Human Posture Changes.

摘要

A system was developed to measure maximum blood flow velocity in three arteries simultaneously during exercise (i.e., sitting to standing and standing to sitting) using an ultrasonic Doppler technique. The ultrasonic Doppler technique can measure the dynamics of blood flow in arteries that exist deep within the human body. Since the position of the arteries in relation to the probes would change rapidly during the posture changes, conventional ultrasonic systems using narrow directional transducers (7.0 millimeters in diameter) were exchanged for semicircular transducers 15.0 millimeters in diameter that would extend the ultrasonic irradiation range. That allowed the system to work despite a large amount of blood vessel position shift. The system consisted of six parts: an ultrasonic probe, a Doppler signal discriminator, an electrocardiogram (ECG) circuit, a hemodynamometer, an A/D converter, and a personal computer. Noise that could occur if the probes shifted on the skin was eliminated by fitting them into the body using an elastic belt. The blood flow velocity, blood pressure, and ECG of five normal subjects were measured for the carotid, brachial, and femoral arteries. The subjects changed posture from the erect position to the sitting position every 30 seconds. Dynamics of blood flow and ECG were measured for 100 seconds total, and blood pressure was measured once with each posture. The results show that the position of the arteries moved significantly with posture change, and the maximum blood flow velocity in all arteries increased with posture change. Blood flow velocity increased significantly in the femoral artery because of intense contraction of the muscle around the artery. (1 table, 6 figures).