Detecting pressure pulses in a blood processing apparatus

Abstract

A monitoring device () operates on a pressure signal from a blood processing apparatus, e.g. a dialysis machine, which has an extracorporeal blood circuit connected to a vascular system of a subject for pumping blood through a dialyzer, and a treatment fluid supply system for pumping a treatment fluid through the dialyzer. The monitoring device () has a first input block () for obtaining a first pressure signal (y) from a first pressure sensor () in the extracorporeal blood circuit, and a second input block () for obtaining a second pressure signal (w) from a second pressure sensor () in the treatment fluid supply system. An emulation block () generates, as a function of the second pressure signal (w), an emulated first pressure signal (y) which emulates a concurrent signal response of the first pressure sensor (), and a filtering block () generates a filtered signal (y) as a function of the first pressure signal (y) and the emulated first pressure signal (y), so as to suppress, in the filtered signal (}y) compared to the first pressure signal (y), signal interferences originating from the treatment fluid supply system (). A pulse detection block () processes the filtered signal (y) for detection of subject pulses originating from the subject.