US-20260123888-A1 - ARTEFACT DETECTION METHOD FOR HEMODYNAMIC PARAMETER MEASUREMENT

Abstract

A means for detecting and classifying artefact-causing events associated with a hemodynamic parameter measurement based on analysis of a tissue pressure signal indicative of a pressure between a surface of the user's body part and a cuff of the measurement apparatus; and an actuator operational signal indicative of an operational parameter of a pneumatic actuator associated with the cuff.

Inventors

• RALPH WILHELM CHRISTIANUS GEMMA ROSE WIJSHOFF
• MARIA ESTRELLA MENA BENITO
• Rene Martinus Maria Derkx
• VALENTINA-GETA DAVIDOIU

Assignees

• KONINKLIJKE PHILIPS N.V.

Dates

Publication Date

20260507

Application Date

20231013

Priority Date

20221018

Claims (20)

1. 1 . A method for use during hemodynamic parameter measurement by a hemodynamic parameter measurement apparatus, wherein the hemodynamic parameter measurement apparatus comprises a cuff for wrapping around a part of the body of a user, and wherein the cuff includes a pneumatic actuator in the form of an inflatable bladder for use in changing a pressure applied to the body part by the cuff, and further includes a tissue pressure sensor arranged for sensing a pressure between a surface of the user's body part and the cuff, and an operational parameter sensor for sensing an operational parameter of the pneumatic actuator; wherein the method comprises: receiving from the hemodynamic parameter measurement apparatus a set of sensor signals, wherein the set of sensor signals includes: a tissue pressure signal indicative of said pressure between a surface of the user's body part and the cuff, and an actuator operational signal indicative of an operational parameter of the pneumatic actuator; processing both signals with an artefact detection module to detect, based on a combination of the signals, the occurrence of any of a pre-defined set of artefact events of different types, each artefact event type corresponding to a physical event affecting sensor readings; and generating a report indicative of the type of any one or more detected artefact events.
2. 2 . The method of claim 1 , wherein the method is performed in real time during a hemodynamic parameter measurement.
3. 3 . The method of claim 1 , wherein the artefact detection is performed based on detecting one or more characteristic features in a waveform of one or more of the received sensor signals.
4. 4 . The method of claim 1 , wherein the artefact detection includes detection of a motion artefact based on: high pass filtering the actuator operational signal, and detecting a signal power level the high-pass-filtered signal which exceeds a pre-defined threshold.
5. 5 . The method of claim 1 , wherein the artefact detection includes detection of a motion artefact based on computing a self-correlation measure of the tissue pressure signal, and detecting that the self-correlation measure falls below a threshold.
6. 6 . The method of claim 1 , wherein the detection includes detection of a motion artefact based on: a first detection comprising high pass filtering the actuator operational signal, and detecting a signal power level in the high-pass filtered signal at any time point which exceeds a predefined threshold; and a second detection comprising computing a self-correlation measure of the tissue pressure signal, and detecting that the self-correlation measure at any time point falls below a threshold; wherein a motion artefact is detected in the event that the time point to which the first detection corresponds and the time point to which the second detection corresponds are within a pre-defined proximity range of one another.
7. 7 . The method of claim 1 , wherein the set of sensor signals further includes a position and/or motion sensor signal indicative of pose and/or motion of the patient, and wherein the method comprises detecting occurrence of an artefact event comprising a motion of the patient or change in pose of the patient.
8. 8 . The method of claim 1 , wherein the artefact detection includes detection of an artefact event corresponding to a user touching a fluid line of the hemodynamic parameter measurement apparatus, and wherein the detection comprises: computing a self-correlation measure of the tissue pressure signal over a time period; and computing a noise measure of the actuator operational signal, the noise measure indicative of a degree of variation of the signal from a smooth ramp function over the time period; wherein said touching is detected responsive to the self-correlation of the tissue pressure signal being below a pre-defined threshold, and the noise measure of the actuator operational signal being below a pre-defined threshold.
9. 9 . The method of claim 1 , wherein the artefact detection includes detection of an artefact event corresponding to a user touching a fluid line of the hemodynamic parameter measurement cuff, and wherein the detection comprises detecting one or more pre-defined characteristic waveform patterns within the waveform of the tissue pressure signal,
10. 10 . The method of claim 1 , wherein the cuff includes a plurality of at least partially overlapping material layer portions; and wherein the artefact detection includes detection of an artefact event corresponding to stick-slip event in relation to said layers, and wherein the stick-slip event is detected based on: detecting an upward inflection in the tissue pressure signal exceeding a first pre-defined gradient threshold, and detecting a downward inflection in the actuator operational signal exceeding a second pre-defined gradient threshold.
11. 11 . The method of claim 1 , wherein the artefact detection includes detection of an artefact event corresponding to a loosening or slippage of a cuff securer, and wherein the detection is based on: detecting a downward inflection in the actuator operational signal exceeding a first pre-defined gradient threshold, and detecting a downward inflection in the tissue pressure signal exceeding a second pre-defined gradient threshold.
12. 12 . The method of claim 1 , wherein the operational parameter sensor comprises an actuation pressure sensor for sensing a pressure within the inflatable bladder and the actuator operational signal comprises an actuator pressure signal indicative of a pressure within the inflatable bladder; and/or wherein the actuator operational signal includes an actuator activity signal indicative of a pumping power level or pumping rate of a pump of the pneumatic actuator.
13. 13 . The method of claim 1 , wherein, responsive to detection of an artefact, the method comprises generating a control signal for output to the hemodynamic parameter measurement apparatus for controlling the apparatus to abort a current hemodynamic parameter measurement.
14. 14 . The method of claim 1 , wherein the method further comprises determining a recommended response action to be taken by a user based on application of a recommendation module to the output of the artefact detection module; and wherein the generated report is further indicative of the recommended response action for each detected artefact.
15. 15 . A non-transitory computer-readable medium that stores therein a computer program product comprising code configured for being run on a processor operatively coupled to a hemodynamic parameter measurement apparatus, the hemodynamic parameter measurement apparatus comprising a cuff for wrapping around a part of the body of a user, and wherein the cuff includes a pneumatic actuator in the form of an inflatable bladder for use in changing a pressure applied to the body part by the cuff, and further includes a tissue pressure sensor arranged for sensing a pressure between a surface of the user's body part and the cuff, and an operational parameter sensor for sensing an operational parameter of the pneumatic actuator; and wherein the code is configured, when run, to cause the processor to perform a method in accordance with claim 1 .
16. 16 . A processor for a hemodynamic parameter measurement apparatus, comprising: an input/output for operatively coupling in use with a hemodynamic parameter measurement apparatus, the hemodynamic parameter measurement apparatus comprising a cuff for wrapping around a part of the body of a user, and wherein the cuff includes a pneumatic actuator in the form of an inflatable bladder for use in changing a pressure applied to the body part by the cuff, and further includes a tissue pressure sensor arranged for sensing a pressure between a surface of the user's body part and the cuff, and further includes an operational parameter sensor for sensing an operational parameter of the pneumatic actuator; one or more processors configured to execute a method, the method comprising: receiving from the hemodynamic parameter measurement apparatus, via the input/output, a set of sensor signals, wherein the set of sensor signals includes: a tissue pressure signal indicative of said pressure between a surface of the user's body part and the cuff, and an actuator operational signal indicative of an operational parameter of the pneumatic actuator; processing the signals with an artefact detection module to detect, based on a combination of the signals, the occurrence of any of a pre-defined set of artefact events of different types, each artefact event type corresponding to a physical event affecting sensor readings; and generating a report indicative of the type of any one or more detected artefact events.
17. 17 . A system, comprising the processor in accordance with claim 16 ; and a hemodynamic parameter measurement apparatus, operatively coupled with the processor, the hemodynamic parameter measurement apparatus comprising a cuff for wrapping around a part of the body of a user, and wherein the cuff includes a pneumatic actuator in the form of an inflatable bladder for use in changing a pressure applied to the body part by the cuff, and further includes a tissue pressure sensor arranged for sensing a pressure between a surface of the user's body part and the cuff, and an actuation operational parameter sensor for sensing an operational parameter of the pneumatic actuator, for example an actuator pressure sensor for sensing a pressure within the inflatable bladder.
18. 18 . The method of claim 11 , wherein the detection further comprises: detecting the downward inflection in each of the tissue pressure and actuator operational signals followed by a signal portion of each respective signal representing a negative offset relative to the respective signal prior to the downward inflection; and determining whether a time duration of said signal portion exceeds a pre-defined threshold.
19. 19 . The method of claim 14 , wherein the recommended response action is to repeat the hemodynamic parameter measurement; the recommended response action is to re-wrap the cuff of the hemodynamic parameter measurement apparatus to the user and repeat the hemodynamic parameter measurement; and/or the recommended response action is to replace the cuff of the hemodynamic parameter measurement apparatus with a new cuff and repeat the hemodynamic parameter measurement.
20. 20 . The processor of claim 16 , wherein the method further comprises exporting the report as a data item via the input/output.

Description

FIELD OF THE INVENTION The present invention relates to artefact detection in the field of measurement of blood pressure and other hemodynamic parameters. BACKGROUND OF THE INVENTION US2021121073A1 relates to an apparatus and a method of operating the apparatus for use with a wearable cuff in determining blood pressure and/or pulse rate. Physiological signals provide an important input to clinical decision-making by health care professionals. However, the accuracy of the information collected depends on the quality of the recorded data. An unreliable signal or a poor signal quality may lead to incorrect measurements, false alarms and/or inappropriate clinical decisions. One source of measurement error is signal artefacts. Some artefacts may be highly transient, while others may be long lasting. Artefacts within the context of cuff-based blood pressure measurement (and/or other hemodynamic parameters) may, by way of non-limiting example, have different causes such as: patient motion; cuff movement during measurement; and measurement technique artefacts due to cuff cracks, where a sudden loosening of the cuff securement leads to a sudden increase in cuff volume, and a consequent reduction in measured pressure signals. In some cases, artefacts may go unnoticed during the procedure by medical care staff, which can result in inaccurate measurements, erroneous data and potentially inappropriate clinical assessment. Inappropriate treatment (or inappropriate lack of treatment) may follow. In some other cases, the artefacts may only be noticed after the measurement has finished. In these cases, the solution depends on each specific situation. For example, it may require repeating the measurement, which adds an additional workflow step and additional time. Moreover, if the actual cause of the artefact is not known, the repeated measurement may result in the same artefact recurring. Furthermore, by repeating a measurement, the comfort of the patient is compromised because the hemodynamic measurement may take on average 90 seconds and can be uncomfortable for the patient. There is a need for a means for detecting artefacts and preferably for taking or recommending actions to remedy them. SUMMARY OF THE INVENTION The invention is defined by the independent claims. The dependent claims define advantageous embodiments. According to examples in accordance with an aspect of the invention, there is provided a method for use during measurement of blood pressure and/or other hemodynamic parameters by a hemodynamic parameter measurement apparatus. The hemodynamic parameter measurement apparatus with which the method might be used may comprise a cuff for wrapping around a part of the body (e.g. arm) of a user, and wherein the cuff includes a pneumatic actuator in the form of an inflatable bladder for use in changing a pressure applied to the body part by the cuff, and may further include a tissue pressure sensor arranged for sensing a pressure between a surface of the user's body part and the cuff, and an operational parameter sensing means for sensing an operational parameter of the pneumatic actuator. For example, the operational parameter sensor may include an actuation pressure sensor for sensing a pressure within the inflatable bladder. For example, the cuff may be configured such that at least a pressure-sensitive part of the tissue pressure sensor is arranged in use between the body part and the cuff. The method itself comprises receiving from the hemodynamic parameter measurement apparatus a set of sensor signals, wherein the set of sensor signals includes: a tissue pressure signal indicative of said pressure between a surface of the user's body part and the cuff; and an actuator operational signal indicative of an operational parameter of the pneumatic actuator. The method further comprises processing both signals with an artefact detection module to detect, based on a combination of the signals, the occurrence of any of a pre-defined set of artefact events of different types, each artefact event type corresponding to a physical event affecting sensor readings. The method may further comprise generating an output based on the detected artefacts event(s). For example, the method may comprise generating a report indicative of the type of any one or more detected artefact events, and preferably exporting the report as a data item. Thus, embodiments of the present invention are based on the idea of detecting physical events, such as physical disturbances, associated with the measurement apparatus or the patient which may lead to signal artefacts based on analysis applied to the tissue pressure signal and at least one operational parameter signal of the pneumatic actuator. The use of both of these signals in detecting artefacts has not before been proposed. Through experimentation and simulation it has been found by the inventors that certain physical disturbance events associated with the apparatus or the patient lead to de