Monitoring the blood pressure of a patient
First Claim
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1. A method for monitoring blood pressure of a patient, comprising the following steps:
- (a) determining a pulse arrival time signal from the patient with a pulse wave velocity unit based on a pulse wave velocity method;
(b) determining an accelerometer signal from the patient with an accelerometer sensor after determining the pulse arrival time signal;
(c) detecting a DC component of the accelerometer signal indicative of a posture of the patient with a monitoring device;
(d) normalizing the pulse arrival time signal with a reference pulse arrival time value with the monitoring device by dividing the determined pulse arrival time signal by a reference pulse arrival time value to generate a normalized pulse arrival time signal;
(e) comparing a value of the normalized pulse arrival time signal with predefined upper and lower pulse arrival time threshold values with the monitoring device;
(f) determining if the value of the normalized pulse arrival time signal exceeds the upper reference threshold value or under-runs the lower reference threshold value with the monitoring device;
(g) checking for a change in the posture of the patient based on a change of the DC component of the accelerometer signal;
at least one of;
(h) repeating steps (a)-(g) when the value of the normalized pulse arrival time signal exceeds or under-runs the predefined pulse arrival time threshold values;
(i) in response to the normalized pulse arrival time signal exceeding or under-running the predefined pulse arrival time threshold values and the DC component change not being detected, at least one of;
controlling an alarm to generate an alarm signal; and
controlling a blood pressure cuff to measure the blood pressure of the patient, and(j) in response to the normalized pulse arrival time signal exceeding or under-running the predefined pulse arrival time threshold values and the DC component change being detected, updating the reference pulse arrival time value; and
(k) deriving and displaying a blood pressure value with the monitoring device from the normalized pulse arrival time signal when the value of the normalized pulse arrival time signal does not exceed or under-run the predefined pulse arrival time threshold values.
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Abstract
A method for monitoring the blood pressure of a patient, comprising the following steps: determining a pulse arrival time signal from the patient 2 based on the pulse wave velocity method; determining an accelerometer signal from the patient 2; and triggering an additional measure or deriving a blood pressure value, taking into account the pulse arrival time signal and a DC component of the accelerometer signal. In this way, a possibility for monitoring the blood pressure of a patient is provided with which false alarms and/or unnecessary additional cuff-based blood pressure measurements can be avoided.
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Citations
20 Claims
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1. A method for monitoring blood pressure of a patient, comprising the following steps:
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(a) determining a pulse arrival time signal from the patient with a pulse wave velocity unit based on a pulse wave velocity method; (b) determining an accelerometer signal from the patient with an accelerometer sensor after determining the pulse arrival time signal; (c) detecting a DC component of the accelerometer signal indicative of a posture of the patient with a monitoring device; (d) normalizing the pulse arrival time signal with a reference pulse arrival time value with the monitoring device by dividing the determined pulse arrival time signal by a reference pulse arrival time value to generate a normalized pulse arrival time signal; (e) comparing a value of the normalized pulse arrival time signal with predefined upper and lower pulse arrival time threshold values with the monitoring device; (f) determining if the value of the normalized pulse arrival time signal exceeds the upper reference threshold value or under-runs the lower reference threshold value with the monitoring device; (g) checking for a change in the posture of the patient based on a change of the DC component of the accelerometer signal; at least one of; (h) repeating steps (a)-(g) when the value of the normalized pulse arrival time signal exceeds or under-runs the predefined pulse arrival time threshold values; (i) in response to the normalized pulse arrival time signal exceeding or under-running the predefined pulse arrival time threshold values and the DC component change not being detected, at least one of; controlling an alarm to generate an alarm signal; and controlling a blood pressure cuff to measure the blood pressure of the patient, and (j) in response to the normalized pulse arrival time signal exceeding or under-running the predefined pulse arrival time threshold values and the DC component change being detected, updating the reference pulse arrival time value; and (k) deriving and displaying a blood pressure value with the monitoring device from the normalized pulse arrival time signal when the value of the normalized pulse arrival time signal does not exceed or under-run the predefined pulse arrival time threshold values. - View Dependent Claims (2, 3, 4, 5, 6, 12)
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7. An apparatus for monitoring blood pressure of a patient, comprising:
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a blood pressure cuff; an alarm unit in communication with the blood pressure cuff; a pulse wave velocity unit comprising an ECG sensor and an optical sensor adapted to generate a plethysmographic signal from the patient, the pulse wave velocity unit configured to determine a first measure including a pulse arrival time signal from the patient based on a pulse wave velocity method; an accelerometer configured to be attached to a torso of the patient and to determine a second measure including an accelerometer signal from the patient, the accelerometer signal including a component which is indicative of an orientation of the accelerometer and the patient torso with respect to an earth gravity axis; and a monitoring device wirelessly connected with the ECG sensor, the optical sensor, and the accelerometer, the monitoring device configured to adjust the pulse arrival time signal based on the orientation of the accelerometer and the patient torso and at least one of; trigger the pulse wave velocity unit to again determine the first measure and the accelerometer to again determine the second measure; derive a blood pressure value, based on the pulse arrival time signal; divide the measured pulse arrival time signal by a reference pulse arrival time value to generate a normalized pulse arrival time signal; compare the normalized pulse arrival time signal with upper and lower threshold values of a threshold; detect a change in a DC component of the accelerometer signal; in response to the normalized pulse arrival time signal being outside of the upper and lower threshold values of the threshold and the DC component change not being detected; control the blood pressure cuff to measure the blood pressure of the patient; and control the alarm unit to generate an alarm signal in response to the blood pressure measured by the blood pressure cuff is outside of the upper and lower values of a predefined alarm threshold; and in response to the normalized pulse arrival time signal being outside of the upper and lower threshold values of the threshold and the DC component change being detected, update the reference pulse arrival time value. - View Dependent Claims (8, 9, 10, 11, 17, 20)
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13. A method for monitoring blood pressure of a patient, comprising:
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with an electrocardiogram sensor and a plethysmograph, sensing blood flow of the patient and generating a pulse arrival time signal; with an accelerometer attached to the patient, generating an accelerometer signal indicative of patient motion; with a monitoring device, comparing the pulse arrival time signal normalized by being divided by a reference pulse arrival time value with upper and lower threshold values of a threshold and repeating the sensing and generating until the normalized pulse arrival time signal is outside of the upper and lower threshold values of the threshold; detecting a change in a DC component of the accelerometer signal; in response to the normalized pulse arrival time signal being outside of the upper and lower threshold values of the threshold and the DC component change not being detected, at least one of; controlling an alarm to generate an alarm signal; and controlling a blood pressure cuff to measure the blood pressure of the patient, and in response to the normalized pulse arrival time signal being outside of the upper and lower threshold values of the threshold and the DC component change being detected, updating the reference pulse arrival time value. - View Dependent Claims (14, 15, 18)
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16. A method for monitoring blood pressure of a patient, comprising:
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with an electrocardiogram sensor and a plethysmograph, sensing blood flow of the patient and generating a pulse arrival time signal; with an accelerometer attached to the patient, generating an accelerometer signal indicative of patient motion; with a monitoring device, one of; inputting the pulse arrival time signal and the DC component of the accelerometer signal into a look-up table which was pre-calibrated with blood pressure values to give a blood pressure value based on the input pulse arrival time signal and the input DC component; and operating on the pulse arrival time signal and the DC component with an analytical correction function which was pre-calibrated to provide a determination of the patient'"'"'s blood pressure corrected for an effect of posture; comparing the pulse arrival time signal normalized by being divided by a reference pulse arrival time value with upper and lower threshold values of a threshold; detecting a change in a DC component of the accelerometer signal; in response to the normalized pulse arrival time signal exceeding or under-running the upper and lower threshold values of the threshold and the DC component change not being detected, at least one of; controlling an alarm to generate an alarm signal; and controlling a blood pressure cuff to measure the blood pressure of the patient, and in response to the normalized pulse arrival time signal exceeding or under-running the upper and lower threshold values of the threshold and the DC component change being detected, updating the reference pulse arrival time value. - View Dependent Claims (19)
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Specification