Blood pressure monitoring using a multi-function wrist-worn device

• US 10,772,512 B2
• Filed: 08/18/2017
• Issued: 09/15/2020
• Est. Priority Date: 09/08/2014
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Klaassen, Erno H., Dougherty, Wren Nancy, Kimoto, Richard C., Narasimhan, Ravi, Sullivan, Thomas J., Waydo, Stephen J., Whitehurst, Todd K., Quijano, Santiago, Young, Derek Park-Shing, Zeng, Zijing
• Primary Examiner(s): Kremer, Matthew
• Assistant Examiner(s): Foley, Avery M
• Application Number:
  US15/680,931
• Publication Number:
  US 20170340209A1
• Time in Patent Office: 1,124 Days
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/02125 of pulse wave propagation time
• CPC Class Codes: A61B 5/11 Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb for measuring pulse A61B5/02 ;A61B5/1038 takes precedence; motion detection to correct for motion artifacts in physiological signals A61B5/721
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/681 Wristwatch-type devices
• CPC Class Codes: A61B 5/6824 Arm or wrist
• CPC Class Codes: G16H 20/00 ICT specially adapted for therapies or health-improving plans, e.g. for handling prescriptions, for steering therapy or for monitoring patient compliance
• CPC Class Codes: G16H 40/67 for remote operation

Abstract

The present invention provides non-invasive devices, methods, and systems for determining a pressure of blood within a cardiovascular system of a user, the cardiovascular system including a heart and the user having a wrist covered by skin. More particularly, the present invention discloses a variety of wrist-worn devices having a variety of sensors configured to non-invasively engage the skin on the wrist of the user for sensing a variety of user signals from the cardiovascular system of the user. Generally, approaches disclosed herein may passively track blood pressure values without any interaction required on the part of the user or may allow for on demand or point measurements of blood pressure values by having a user actively interact with the sensors of the wrist-worn device. Approaches disclosed herein further allow for absolute blood pressure values to be determined directly without the requirement for any periodic calibrations or for relative blood pressure values to be tracked so as to provide relative blood pressure indices.

Claims

1. An electronic band assembly comprising:

an elongate band configured to be releasably coupled with a wrist-worn watch or a wrist-worn heart rate monitor to form a wrist-worn assembly configured for extending around a wrist of a user and non-invasively engaging skin on the wrist of the user;

impedance cardiogram (ICG) electrodes configured for use in measuring cross-body impedance of the user, wherein the ICG electrodes comprising a first pair of electrodes and a second pair of electrodes, wherein the first pair of electrodes is mounted to the elongate band for engaging the skin on the wrist of the user, and wherein the second pair of electrodes is externally mounted to the elongate band for contacting by two fingers of a hand of the user on an arm opposite to the wrist of the user on which the wrist-worn assembly is worn;

a blood pressure pulse sensor configured to generate a blood pressure pulse signal indicative of arrival of blood pressure pulses at the wrist;

a controller coupled to the elongate band, wherein the ICG electrodes are connected to the controller, wherein the controller measures the cross-body impedance of the user via the electrodes, wherein the controller processes the cross-body impedance to determine a ventricular ejection time for a ventricular ejection of blood from a heart of the user, wherein the controller is connected to the blood pressure pulse sensor, wherein the controller processes the blood pressure pulse signal to determine an arrival time at the wrist of a blood pressure pulse generated by the ventricular ejection, wherein the controller determines a pulse transit time (PTT) of the blood pressure pulse from the heart to the wrist based on the ventricular ejection time and the arrival time, and wherein the controller determines a relative or absolute blood pressure of the user based on the PTT;

a power source coupled to the elongate band and the controller; and

a telemetry interface coupled to the elongate band and the controller, wherein the telemetry interface is configured to communicate with the wrist-worn watch or the wrist-worn heart rate monitor via wireless communication.

2. The device electronic band assembly of claim 1, wherein the wrist-worn watch or the wrist-worn heart rate monitor comprises a housing encasing a second controller, second power source, and second telemetry interface, wherein the elongate band further comprises at least one connection feature for securing the elongate band to the housing.

3. The electronic band assembly of claim 1, wherein the blood pressure pulse sensor comprises at least one photoplethysmogram (PPG) sensor or physical pressure pulse sensor coupled to the elongate band, wherein the at least one PPG sensor comprises at least one infra-red, red, or green optical source and a detector configured to be positioned over a radial artery of the wrist of the user, wherein the physical pressure pulse sensor comprises at least one pressure transducer, accelerometer, or strain gauge configured to be positioned over a radial artery of the wrist of the user.

4. The electronic band assembly of claim 1, further comprising at least one height sensor, barometric pressure sensor, gyroscope, or accelerometer coupled to the elongate band so as to generate output that is processed to determine a height difference between the electronic band assembly and the heart of the user that is used to account for hydrostatic pressure effects in the determination of the relative or absolute blood pressure of the user.

5. The electronic band assembly of claim 1, wherein the telemetry interface is configured to transmit the relative or absolute blood pressure signals to an electronic device other than the wrist-worn watch or the wrist-worn heart rate monitor.

6. The electronic band assembly of claim 1, wherein the telemetry interface of the elongate band is configured to transmit the relative or absolute blood pressure signals to an electronic health or medical record or health application software.

7. The electronic band assembly of claim 1, wherein the telemetry interface of the elongate band is configured to transmit trending data for a time period based on the relative or absolute blood pressure, wherein the time period comprises one or more days, weeks, months, or years.