Secure care device and system for arteriovenous fistula

The invention discloses a secure care device and system for an arteriovenous fistula. The secure care device comprises a bracelet shell, a first fixing band, a second fixing band, a PCB and a rubber cover; the rubber cover is arc-shaped, and the bracelet shell is a hollow cylinder; the two ends of the bracelet shell are connected with the first fixing band and the second fixing band respectively, the PCB is arranged in the bracelet shell, the lower portion of the bracelet shell is fixedly connected with the rubber cover, the PCB is provided with an ultrasonic speed monitor, an information processor, a wireless communicator, a digital-to-analog converter, a battery and an alarm, and the upper end of the bracelet shell is provided with a display screen; and the ultrasonic speed monitor is electrically connected with the information processor, the information processor is electrically connected with the digital-to-analog converter, the alarm and the wireless communicator, and the digital-to-analog converter is e