Wearable laser Doppler based on VCSEL and its application in human blood flow

A wearable microcirculation detection device based on VCSEL with high optical speed vertical cavity surface emission laser chip and three-axis acceleration sensor were used in the continuous detection experiment of human microcirculation .20 people of different ages were tested reactive hyperemia of fingers under different pressures on the upper arm(The experiment was divided into two groups. In the first group we continuously changed the pressure, increased the pressure from 0mmHg to 180mmHg. When the pressure reached 0, 100, 150, 180mmHg, the constant pressures was maintained for 1 minute respectively to observe blood flow waveform. In the second group we directly increased the pressure to 180mmHg, and then released the pressure after 3 minutes.). Test results indicate that; Blood flow changed more slowly when the pressure was 0mmHg to 100mmHg. From 100mmHg to 150mmHg, the blood flow had a pulsating waveform with the heart beating, and the blood flow decreased gradually. From 150mmHg to 180mmHg, blood flow varied greatly and decreased to a minimum after the pressure reached 180mmHg and did not change significantly as the pressure increased. When the pressure was released, the Blood flow rose rapidly from the lowest to a peak and then gradually returned to normal state. Compared with young people under 30 years old, the blood flow of the elderly recovered more slowly, and the peak of the blood flow was lower than that of the young. The two groups of experiments can distinguish the difference of age.