BODY-WORN SYSTEM FOR MEASURING CONTINUOUS NON-INVASIVE BLOOD PRESSURE (cNIBP)
First Claim
1. A method for monitoring a blood pressure value from a patient, comprising:
- (a) detecting a time-dependent optical waveform comprising a pulse induced by the patient'"'"'s heartbeat with an optical sensor configured to attach to the patient;
(b) detecting a time-dependent electrical waveform comprising a QRS complex induced by the patient'"'"'s heartbeat with an electrical sensor configured to attach to the patient;
(c) determining a pulse transit time which is a measure of a separation in time between a portion of the pulse comprised by the time-dependent optical waveform and a portion of the QRS complex comprised by the time-dependent electrical waveform;
(d) determining a heart rate from portions of QRS complexes in the time-dependent electrical waveform;
(e) determining a mathematical relationship between heart rate, or a first parameter calculated therefrom, and pulse transit time, or a second parameter calculated therefrom;
(f) determining an estimated pulse transit time from a heart rate and the mathematical relationship between heart rate and pulse transit time; and
(g) analyzing the estimated pulse transit time and a blood pressure calibration to determine a blood pressure value.
1 Assignment
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Accused Products
Abstract
The present invention provides a technique for continuous measurement of blood pressure based on pulse transit time and which does not require any external calibration. This technique, referred to herein as the ‘Composite Method’, is carried out with a body-worn monitor that measures blood pressure and other vital signs, and wirelessly transmits them to a remote monitor. A network of body-worn sensors, typically placed on the patient'"'"'s right arm and chest, connect to the body-worn monitor and measure time-dependent ECG, PPG, accelerometer, and pressure waveforms. The disposable sensors can include a cuff that features an inflatable bladder coupled to a pressure sensor, three or more electrical sensors (e.g. electrodes), three or more accelerometers, a temperature sensor, and an optical sensor (e.g., a light source and photodiode) attached to the patient'"'"'s thumb.
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Citations
21 Claims
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1. A method for monitoring a blood pressure value from a patient, comprising:
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(a) detecting a time-dependent optical waveform comprising a pulse induced by the patient'"'"'s heartbeat with an optical sensor configured to attach to the patient; (b) detecting a time-dependent electrical waveform comprising a QRS complex induced by the patient'"'"'s heartbeat with an electrical sensor configured to attach to the patient; (c) determining a pulse transit time which is a measure of a separation in time between a portion of the pulse comprised by the time-dependent optical waveform and a portion of the QRS complex comprised by the time-dependent electrical waveform; (d) determining a heart rate from portions of QRS complexes in the time-dependent electrical waveform; (e) determining a mathematical relationship between heart rate, or a first parameter calculated therefrom, and pulse transit time, or a second parameter calculated therefrom; (f) determining an estimated pulse transit time from a heart rate and the mathematical relationship between heart rate and pulse transit time; and (g) analyzing the estimated pulse transit time and a blood pressure calibration to determine a blood pressure value. - View Dependent Claims (4, 5, 6, 7, 8, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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2. A method for monitoring a blood pressure value from a patient, comprising:
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(a) detecting a time-dependent optical waveform comprising a pulse induced by the patient'"'"'s heartbeat with an optical sensor configured to attach to the patient; (b) detecting a time-dependent electrical waveform comprising a QRS complex induced by the patient'"'"'s heartbeat with an electrical sensor configured to attach to the patient; (c) determining a pulse transit time which is a measure of a separation in time between a portion of the pulse comprised by the time-dependent optical waveform and a portion of the QRS complex comprised by the time-dependent electrical waveform; (d) determining a heart rate from portions of QRS complexes in the time-dependent electrical waveform; (e) determining a mathematical relationship between heart rate, or a first parameter calculated therefrom, and pulse transit time, or a second parameter calculated therefrom; (f) determining that a pulse in the time-dependent optical waveform is not adequate to determine a pulse transit time; (g) determining an estimated pulse transit time from a heart rate and the mathematical relationship between heart rate and pulse transit time; and (g) analyzing the estimated pulse transit time and a blood pressure calibration to determine a blood pressure value.
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3. A method for monitoring a blood pressure value from a patient, comprising:
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(a) determining a pulse transit time which is a measure of a separation in time between a portion of a pulse comprised by a time-dependent optical waveform and a portion of a QRS complex comprised by the time-dependent electrical waveform; (b) determining a heart rate from portions of QRS complexes in the time-dependent electrical waveform; (c) determining a mathematical relationship between heart rate, or a first parameter calculated therefrom, and pulse transit time, or a second parameter calculated therefrom; and (d) determining the blood pressure value from the mathematical relationship, a heart rate, and a blood pressure calibration.
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- 9. The method of step 8, wherein the numerical fitting algorithm is a linear regression algorithm.
Specification