# US 11,298,033 B2 · Non-invasive blood pressure monitors and methods of operating the same

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- Number: US 11,298,033 B2
- Document ID: US11298033B2
- Status: Granted
- Kind: B2
- Application number: 16/405,318
- Filed: 2019-05-07
- Published: 2019-10-31
- Granted: 2022-04-12
- Earliest claimed: 2014-10-10
- Assignees: Koninklijke Philips N.V.
- Applicants: Koninklijke Philips N.V.
- Inventors: Jens Muehlsteff; Teun Van Den Heuvel; Erik Bresch; Lars Schmitt; Dieter Woehrle
- Web page: https://patentgrep.com/patent/US11298033B2

## CPC

- A61B 5/022: by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
- A61B 5/02028: {Determining haemodynamic parameters not otherwise provided for, e.g. cardiac contractility or left ventricular ejection fraction}
- A61B 5/02141: {Details of apparatus construction, e.g. pump units or housings therefor, cuff pressurising systems, arrangements of fluid conduits or circuits (A61B5/02233, A61B5/0235 take precedence)}
- A61B 5/02225: {using the oscillometric method}
- A61B 5/024: Measuring pulse rate or heart rate
- A61B 5/7221: {Determining signal validity, reliability or quality (preventing, reducing or removing noise induced by motion artefacts A61B5/7207; noise originating from a therapeutic or surgical apparatus A61B5/7217)}
- A61B 5/7275: {Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor}
- A61B 5/74: {Details of notification to user or communication with user or patient; User input means}
- A61B 2560/0266: for monitoring or limiting apparatus function
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)

## Abstract

According to an aspect, there is provided a method of operating a non-invasive blood pressure, NIBP, monitor to measure the blood pressure of a subject, the NIBP monitor comprising a cuff, a pressure sensor for measuring the pressure in the cuff and for outputting a pressure signal representing the pressure in the cuff and a physiological parameter sensor, the method comprising obtaining a first measurement of a physiological parameter for the subject during inflation of the cuff, the first measurement being obtained from the pressure signal; obtaining a second measurement of the physiological parameter for the subject during inflation of the cuff, the second measurement being obtained from the physiological parameter sensor; comparing the first measurement and the second measurement; and estimating the reliability of a blood pressure measurement obtained by the NIBP monitor during inflation of the cuff based on the result of the step of comparing.

## Claims

### Claim 1

A method of operating a non-invasive blood pressure, NIBP, monitor to measure the blood pressure of a subject, comprising:
determining a pattern of arrhythmias for the subject based on historical pulse or heart rate measurements;
during each of a plurality of blood pressure measurements of the subject:
predicting, based on the pattern of arrhythmias for the subject, a likelihood that the subject will experience an arrhythmia during inflation of a cuff that is placed around a limb of the subject;
in response to a determination that the likelihood that the subject will experience an arrhythmia during inflation of the cuff does not satisfy a threshold:
buffering a pressure signal output by a pressure sensor associated with the cuff, wherein the buffering is performed during inflation of the cuff;
processing the buffered pressure signal across a plurality of heart beats of the subject to estimate an autocorrelation function of the buffered pressure signal;
identifying a plurality of peaks in the autocorrelation function;
determining a heart rate of the subject based on the plurality of peaks;
adapting one or more frequency characteristics of a high-pass filter based on the heart rate;
applying the filter to the buffered pressure signal to generate a filtered pressure signal;
analyzing the filtered pressure signal to determine an inflation-based blood pressure measurement for the subject; and
deflating the cuff over a first time interval without obtaining a deflation-based blood pressure measurement during the deflating; or
in response to a determination that the likelihood that the subject will experience an arrhythmia during inflation of the cuff satisfies the threshold:
causing inflation of the cuff;
deflating the cuff over a second time interval that is longer than the first time interval,
obtaining a deflation-based blood pressure measurement during the deflating, and
providing the deflation-based blood pressure measurement as output.

### Claim 2 (depends on 1)

The method of claim 1, wherein the pattern of arrhythmias are further determined based on one or more past postures of the subject during acquisition of the historical pulse or heart rate measurements, and wherein the predicting is further based on a current posture of the subject.

### Claim 3 (depends on 1)

The method of claim 1, wherein the pattern of arrhythmias are further determined based on past activity levels of the subject during acquisition of the historical pulse or heart rate measurements, and wherein the predicting is further based on a current or recent activity level of the subject.

### Claim 4

A non-invasive blood pressure, NIBP, monitor for measuring the blood pressure of a subject, the NIBP monitor comprising:
a control unit that is configured to:
determine a pattern of arrhythmias for the subject based on historical pulse or heart rate measurements of the subject; and
during each of a plurality of scheduled blood pressure measurements of the subject:
predict, based on the pattern of arrhythmias for the subject, a likelihood that the subject will experience an arrhythmia during inflation of a cuff that is placed around a limb of the subject;
in response to a determination that the likelihood that the subject will experience an arrhythmia during inflation of the cuff does not satisfy a threshold:
buffer a pressure signal output by a pressure sensor associated with the cuff, wherein the buffering is performed during inflation of the cuff;
process the buffered pressure signal across a plurality of heart beats of the subject to estimate an autocorrelation function of the buffered pressure signal;
identify a plurality of peaks in the autocorrelation function;
determine a heart rate of the subject based on the plurality of peaks;
adapt one or more frequency characteristics of a high-pass filter based on the heart rate;
apply the filter to the buffered pressure signal to generate a filtered pressure signal;
analyze the filtered pressure signal to determine an inflation-based blood pressure measurement for the subject; and
deflate the cuff over a first time interval without obtaining a deflation-based blood pressure measurement during the deflating; or
in response to a determination that the likelihood that the subject will experience an arrhythmia during inflation of the cuff satisfies the threshold:
cause inflation of the cuff;
deflate the cuff over a second time interval that is longer than the first time interval,
obtain a deflation-based blood pressure measurement during the deflating, and
provide the deflation-based blood pressure measurement as output.

### Claim 5

At least one non-transitory computer-readable medium comprising instructions that, in response to execution of the instructions by one or more processors of a non-invasive blood pressure, NIBP, monitor for measuring the blood pressure of a subject, cause the one or more processors to perform the following operations:
determining a pattern of arrhythmias for the subject based on historical pulse or heart rate measurements;
during each of a plurality of blood pressure measurements of the subject:
predicting, based on the pattern of arrhythmias for the subject, a likelihood that the subject will experience an arrhythmia during inflation of a cuff that is placed around a limb of the subject;
in response to a determination that the likelihood that the subject will experience an arrhythmia during inflation of the cuff does not satisfy a threshold:
buffering a pressure signal output by a pressure sensor associated with the cuff, wherein the buffering is performed during inflation of the cuff;
processing the buffered pressure signal across a plurality of heart beats of the subject to estimate an autocorrelation function of the buffered pressure signal;
identifying a plurality of peaks in the autocorrelation function;
determining a heart rate of the subject based on the plurality of peaks;
adapting one or more frequency characteristics of a high-pass filter based on the heart rate;
applying the filter to the buffered pressure signal to generate a filtered pressure signal;
analyzing the filtered pressure signal to determine an inflation-based blood pressure measurement for the subject; and
deflating the cuff over a first time interval without obtaining a deflation-based blood pressure measurement during the deflating; or
in response to a determination that the likelihood that the subject will experience an arrhythmia during inflation of the cuff satisfies the threshold:
causing inflation of the cuff;
deflating the cuff over a second time interval that is longer than the first time interval,
obtaining a deflation-based blood pressure measurement during the deflating, and
providing the deflation-based blood pressure measurement as output.