Patents by Inventor Ravi K. Narasimhan

Ravi K. Narasimhan has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 11918324
    Abstract: A pulse transit time is measured non-invasively and used to calculate a blood pressure value. A method of determining one or more blood pressure values includes propagating an alternating drive current through a thorax of a subject via electrodes located on a wrist-worn device. Resulting voltage levels of the subject are sensed by the wrist-worn device. The voltage levels are processed to detect when a volume of blood is ejected from the left ventricle. Output from a pulse arrival sensor coupled to the wrist-worn device is processed to detect when a blood pressure pulse generated by ejection of the volume of blood from the left ventricle arrives at the wrist. A pulse transit time (PTT) for transit of the blood pressure pulse from the left ventricle to the wrist is calculated. One or more blood pressure values for the subject are determined based on the PTT.
    Type: Grant
    Filed: August 11, 2020
    Date of Patent: March 5, 2024
    Assignee: Apple Inc.
    Inventors: Thomas J. Sullivan, Wren Nancy Dougherty, Richard C. Kimoto, Erno Klaassen, Ravi K. Narasimhan, Stephen J. Waydo, Todd K. Whitehurst, Derek Park-Shing Young, Santiago Quijano, Zijing Zeng
  • Patent number: 10881307
    Abstract: The present disclosure generally relate s to blood pressure monitoring. In some embodiments, methods and devices for measuring a mean arterial pressure and/or for monitoring blood pressure changes of a user are provided. Blood pressure measured by one or more pressure sensors may be adjusted using one or more correction factors. The use of the one or more correction factors disclosed herein may allow for more compact, convenient, and/or accurate wearable blood pressure measurement devices and methods. In particular, wrist-worn devices may be provided which are less bulky than current devices and may facilitate more frequent and accurate blood pressure monitoring.
    Type: Grant
    Filed: September 23, 2016
    Date of Patent: January 5, 2021
    Assignee: Apple Inc.
    Inventors: Thomas J. Sullivan, Ravi K. Narasimhan, Rui Qiao, Derek Park-Shing Young, Robert K. Montgomery, II, Mohsen Mollazadeh, Zijing Zeng, Vasco D. Polyzoev, Richard C. Kimoto
  • Patent number: 10849555
    Abstract: The present disclosure generally relate s to blood pressure monitoring. In some embodiments, methods and devices for measuring a mean arterial pressure and/or for monitoring blood pressure changes of a user are provided. Blood pressure measured by one or more pressure sensors may be adjusted using one or more correction factors. The use of the one or more correction factors disclosed herein may allow for more compact, convenient, and/or accurate wearable blood pressure measurement devices and methods. In particular, wrist-worn devices may be provided which are less bulky than current devices and may facilitate more frequent and accurate blood pressure monitoring.
    Type: Grant
    Filed: September 23, 2016
    Date of Patent: December 1, 2020
    Assignee: Apple Inc.
    Inventors: Thomas J. Sullivan, Ravi K. Narasimhan, Rui Qiao, Derek Park-Shing Young, Robert K. Montgomery, II, Mohsen Mollazadeh, Zijing Zeng, Vasco D. Polyzoev, Richard C. Kimoto
  • Publication number: 20200367767
    Abstract: A pulse transit time is measured non-invasively and used to calculate a blood pressure value. A method of determining one or more blood pressure values includes propagating an alternating drive current through a thorax of a subject via electrodes located on a wrist-worn device. Resulting voltage levels of the subject are sensed by the wrist-worn device. The voltage levels are processed to detect when a volume of blood is ejected from the left ventricle. Output from a pulse arrival sensor coupled to the wrist-worn device is processed to detect when a blood pressure pulse generated by ejection of the volume of blood from the left ventricle arrives at the wrist. A pulse transit time (PTT) for transit of the blood pressure pulse from the left ventricle to the wrist is calculated. One or more blood pressure values for the subject are determined based on the PTT.
    Type: Application
    Filed: August 11, 2020
    Publication date: November 26, 2020
    Inventors: Thomas J. Sullivan, Wren Nancy Dougherty, Richard C. Kimoto, Erno Klaassen, Ravi K. Narasimhan, Stephen J. Waydo, Todd K. Whitehurst, Derek Park-Shing Young, Santiago Quijano, Zijing Zeng
  • Publication number: 20200367760
    Abstract: Methods and devices for obtaining a blood pressure measurement of a subject measure a transit time of a blood pulse of the subject. A method includes sensing, with a pulse ejection sensor of a wrist-worn device, ejection of blood from the left ventricle. Arrival of a resulting blood pressure pulse at the wrist is sensed via a pulse arrival sensor of the wrist-worn device. A transit time of the blood pressure pulse from the left ventricle to the wrist is determined. A relative blood pressure value of the subject is determined based on the transit time. A reference absolute blood pressure value associated with the relative blood pressure value is received. An absolute blood pressure value for the relative blood pressure value is determined based on the reference absolute blood pressure value and the relative blood pressure value.
    Type: Application
    Filed: August 7, 2020
    Publication date: November 26, 2020
    Inventors: Erno H. Klaassen, Wren Nancy Dougherty, Richard C. Kimoto, Ravi K. Narasimhan, Thomas J. Sullivan, Stephen J. Waydo, Todd K. Whitehurst, Santiago Quijano, Derek Park-Shing Young, Zijing Zeng
  • Patent number: 10646121
    Abstract: The present invention generally relates to the measuring and monitoring of blood pressure. More specifically, embodiments may apply the theory of applanation tonometry for the measurement of blood pressure. Some embodiments provide a method for measuring mean arterial pressure. Some embodiments provide a device that may be worn by a user that may non-invasively measure and monitor blood pressure of a user. In some embodiments, the invention generally relates to sensor arrays for use with a wrist-worn device to measure blood pressure. Embodiments of the sensor array designs described may be configured to improve resolution by decoupling nodes of the sensor array.
    Type: Grant
    Filed: September 23, 2016
    Date of Patent: May 12, 2020
    Assignee: Apple Inc.
    Inventors: Ravi K. Narasimhan, Zijing Zeng, Zhipeng Zhang
  • Publication number: 20170086686
    Abstract: The present invention generally relates to the measuring and monitoring of blood pressure. More specifically, embodiments may apply the theory of applanation tonometry for the measurement of blood pressure. Some embodiments provide a method for measuring mean arterial pressure. Some embodiments provide a device that may be worn by a user that may non-invasively measure and monitor blood pressure of a user. In some embodiments, the invention generally relates to sensor arrays for use with a wrist-worn device to measure blood pressure. Embodiments of the sensor array designs described may be configured to improve resolution by decoupling nodes of the sensor array.
    Type: Application
    Filed: September 23, 2016
    Publication date: March 30, 2017
    Inventors: Ravi K. Narasimhan, Zijing Zeng, Zhipeng Zhang