Detecting pressure pulses in a blood processing apparatus

A monitoring device comprising:

• means for obtaining a first pressure signal (y) from a first pressure sensor, which is arranged in an extracorporeal blood circuit to detect pressure variations in blood which is pumped through a blood processing unit in the extracorporeal blood circuit by a blood pumping device, wherein the extracorporeal blood circuit is connected to a vascular system of a subject;
• means for obtaining a second pressure signal (u) from a second pressure sensor, which is arranged in a treatment fluid supply system to detect pressure variations in a treatment fluid which is pumped through the blood processing unit by the treatment fluid supply system;
• means for generating, as a function of the second pressure signal (u), an emulated first pressure signal (ŷ) which emulates a concurrent signal response of the first pressure sensor;
• means for generating a filtered signal (yf) as a function of the first pressure signal (y) and the emulated first pressure signal (ŷ), so as to suppress, in the filtered signal (yf) compared to the first pressure signal (y), signal interferences originating from the treatment fluid supply system;
• and
• means for processing the filtered signal (yf) for detection of subject pulses originating from the subject.

An apparatus for extracorporeal blood processing comprising:

• an extracorporeal blood circuit for connection to the vascular system of a subject;
• a blood processing unit in the extracorporeal blood circuit;
• a blood pumping device in the extracorporeal blood circuit operable to pump blood through the blood processing unit;
• a treatment fluid supply system operable to pump treatment fluid through the blood processing unit;
• a first pressure sensor arranged in the extracorporeal blood circuit to detect pressure variations in the blood which is pumped through the blood processing unit;
• a second pressure sensor arranged in the treatment fluid supply system to detect pressure variations in the treatment fluid which is pumped through the blood processing unit;
• and
• a monitoring device including
• a first input block configured to obtain a first pressure signal (y) from the first pressure sensor, wherein the extracorporeal blood circuit is connected to a vascular system of a subject,
• a second input block configured to obtain a second pressure signal (u) from the second pressure sensor,
• an emulation block configured to generate, as a function of the second pressure signal (u), an emulated first pressure signal (ŷ) which emulates a concurrent signal response of the first pressure sensor,
• a filtering block configured to generate a filtered signal (yf) as a function of the first pressure signal (y) and the emulated first pressure signal (ŷ), so as to suppress, in the filtered signal (yf) compared to the first pressure signal (y), signal interferences originating from the treatment fluid supply system, and
• a pulse detection block configured to process the filtered signal (yf) for detection of subject pulses originating from the subject.

A monitoring method comprising:

• obtaining a first pressure signal (y) from a first pressure sensor, which is arranged in an extracorporeal blood circuit to detect pressure variations in blood which is pumped through a blood processing unit in the extracorporeal blood circuit, wherein the extracorporeal blood circuit is connected to the vascular system of a subject;
• obtaining a second pressure signal (u) from a second pressure sensor, which is arranged in a treatment fluid supply system to detect pressure variations in a treatment fluid which is pumped through the blood processing unit by the treatment fluid supply system;
• generating, as a function of the second pressure signal (u), an emulated first pressure signal (ŷ) which emulates a concurrent signal response of the first pressure sensor;
• generating a filtered signal (yf) as a function of the first pressure signal (y) and the emulated first pressure signal (ŷ), so as to suppress, in the filtered signal (yf) compared to the first pressure signal (y), signal interferences originating from the treatment fluid supply system;
• and
• processing the filtered signal (yf) for detection of subject pulses originating from the subject.

A computer-readable medium comprising computer instructions which, when executed by a processor, cause the processor to:

• obtain a first pressure signal (y) from a first pressure sensor, which is arranged in an extracorporeal blood circuit to detect pressure variations in blood which is pumped through a blood processing unit in the extracorporeal blood circuit, wherein the extracorporeal blood circuit is connected to the vascular system of a subject;
• obtain a second pressure signal (u) from a second pressure sensor, which is arranged in a treatment fluid supply system to detect pressure variations in a treatment fluid which is pumped through the blood processing unit by the treatment fluid supply system;
• generate as a function of the second pressure signal, an emulated first pressure signal (ŷ) which emulates a concurrent signal response of the first pressure sensor;
• generate a filtered signal (yf) as a function of the first pressure signal (y) and the emulated first pressure signal (ŷ), so as to suppress, in the filtered signal (yf) compared to the first pressure signal (y), signal interferences originating from the treatment fluid supply system;
• and
• process the filtered signal (yf) for detection of subject pulses originating from the subject.