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The main difficulty found in vascular surgery is reliable evaluation of intraoperatory performance of vascular prosthesis in patients with vascular diseases. A system is proposed which uses CW Doppler ultrasonic equipment. The ultrasonic transducer is fixed on arteries and/or prosthesis using a special device, developed by the authors for on-site blood flow evaluation. A 16-bit microcomputer connected to the ultrasonic system digitalizes, stores in a circular memory, and processes a series of 12 signals chosen on screen by the keyboard, using functions also developed here. The signals are summed, using the peak of the QRS complex as trigger, to obtain the average result. Special software was developed to detect the QRS peak and calculate some parameters. All the results, including the averaged curve, are shown on the screen. > |
