Pulsing flow speed detection arrangement in venous blood vessel e.g. for dialysis

摘要

The arrangement includes an ultrasound unit (10), a signal processing unit (14), and an electronic evaluation unit (18) which comprises devices for continuously generating an electronic index value for a pulse in a reflected signal in the range between 0.3 and 10 Hz, preferably between 0.5 and 3 Hz, as well as comparison devices for a continuous comparison of the electronic index value with a predetermined reference value. The ultrasound unit generates continuous or periodical ultrasound signals for an ultrasound probe (12) put on a human body, and receives a signal reflected by the venous blood vessel. The signal processing unit is coupled to the ultrasound unit for generating a timewise variable processing signal proportional to the flow speed in the blood vessel, from an output signal of the ultrasound unit. The electronic evaluation unit is coupled to the signal processing unit, comprising devices for continuously generating an electronic index value for a pulse in the processing signal in the range between 0.3 and 10 Hz, preferably between 0.5 and 3 Hz, as well as comparison devices for a continuous comparison of the electronic index value with a predetermined reference value. A display unit (22) is coupled to the comparison devices for generating an output signal, if a current electronic index value reaches the reference value. The arrangement is formed in such way, that a detection duration for an application lasts at least one hour, preferably one to six hours.