Device, system and method for monitoring vital signs

• US 7,238,159 B2
• Filed: 09/21/2004
• Issued: 07/03/2007
• Est. Priority Date: 04/07/2004
• Status: Active Grant

• Current Assignee: Sotera Wireless Incorporated
• Original Assignee: Triage Wireless, Inc.
• Inventors: Banet, Matthew J., Visser, Henk
• Primary Examiner(s): Marmor, II; Charles A.
• Assistant Examiner(s): MALLARI, PATRICIA C
• Application Number:
  US10/711,492
• Publication Number:
  US 20050228298A1
• Time in Patent Office: 1,015 Days
• Field of Search: None
• US Class Current: 600/485
• CPC Class Codes: A61B 5/002 Monitoring the patient using a local or closed circuit, e.g. in a room or building A61B5/0017 takes precedence
• CPC Class Codes: A61B 5/0022 Monitoring a patient using a global network, e.g. telephone networks, internet
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters

Abstract

A monitoring device, method and system are disclosed herein. The monitoring device is capable of determine when a user'"'"'s wrist is at rest using a motion sensor disposed within a wrist module that is attached to the user'"'"'s wrist. When at rest, the monitoring device utilizes a vital sign monitor to determine a plurality of vital signs of the user. The vital sign monitor preferably comprises a light source and photodetector in communication with a pulse-oximetry circuit. The motion sensor is preferably an accelerometer.

Claims

1. A device for monitoring a user'"'"'s blood pressure while the user is ambulatory, the device comprising:

a blood pressure sensor comprising;

a motion sensor for monitoring motion of the user and configured to generate motion information in response; and

a blood pressure monitor comprising an optical system comprising a light source and a light detector configured to generate a time-dependent waveform comprising a primary peak and a reflective peak that are, collectively, representative of the user'"'"'s blood pressure; and

a body-worn processing unit, connected to the blood pressure sensor through a cable, comprising;

a microprocessor for receiving the time-dependent waveform from the blood pressure monitor and motion information from the motion sensor, the microprocessor comprising computer code that controls the microprocessor to;

     1) analyze the primary and reflective peaks comprised by the time-dependent waveform from the blood pressure monitor with a mathematical model by varying parameters of the model until they correspond to the amplitudes of the primary and reflective peaks;

     2) analyze the motion information from the motion sensor to distinguish between time-dependent waveforms generated while the user is moving and while the user is at rest; and

     3) calculate a blood pressure value from parameters of the model determined from the time-dependent waveform generated when the user is at rest.

2. The device according to claim 1 wherein the motion sensor is an accelerometer, a piezoelectric device or a mercury switch.

3. The device according to claim 1 wherein the motion sensor is a software algorithm that analyzes the time-dependent waveform from the blood pressure monitor to determine motion.

4. The device according to claim 3, wherein the software algorithm is computer code operating on the microprocessor.

5. The device according to claim 1 further comprising a wireless transmitter.

6. The device according to claim 5, further comprising a wireless transmitter operating a wireless protocol based on 802.15.1, 802.15.4, part-15, or 802.11.

7. The device according to claim 5 further comprising a component adapted to be mounted on a finger of the user.

8. The device according to claim 1 further comprising an analog-to-digital converter in communication with the motion sensor, the optical system, and the microprocessor.

9. The device according to claim 1 wherein the optical system is in communication with a pulse-oximetry circuit.

10. A device for monitoring a user'"'"'s blood pressure while the user is ambulatory, the device comprising:

a blood pressure sensor comprising;

a motion sensor for monitoring motion of the user and configured to generate motion information in response; and

a blood pressure monitor comprising an optical system comprising a light source and a light detector configured to generate a time-dependent waveform comprising a primary peak and a reflective peak that are, collectively, representative of the user'"'"'s blood pressure; and

a body-worn processing unit, connected to the blood pressure sensor through a cable, comprising;

a microprocessor for receiving the time-dependent waveform from the blood pressure monitor and motion information from the motion sensor, the microprocessor comprising computer code that controls the microprocessor to;

     1) analyze the primary peak and the reflective peak comprised by the time-dependent waveform from the blood pressure monitor by taking a derivative of the waveform;

     2) analyzing the derivative of the waveform with a mathematical model by varying parameters of the model until they correspond to the derivatives of the amplitudes of the primary and reflective peaks;

     3) analyze the motion information from the motion sensor to distinguish between time-dependent waveforms generated while the user is moving and while the user is at rest; and

     4) calculate a blood pressure value from the derivative of the time-dependent waveform and the primary and reflected peaks in the waveform generated when the user is at rest.

11. A device for monitoring a user'"'"'s blood pressure while the user is ambulatory, the device comprising:

a blood pressure sensor comprising;

a motion sensor for monitoring motion of the user and configured to generate motion information in response; and

a blood pressure monitor comprising an optical system comprising a light source and a light detector configured to generate a time-dependent waveform comprising a primary peak and a reflective peak that are, collectively, representative of the user'"'"'s blood pressure; and

a body-worn processing unit, connected to the blood pressure sensor through a cable, comprising;

a microprocessor for receiving the time-dependent waveform from the blood pressure monitor and motion information from the motion sensor, the microprocessor comprising computer code that controls the microprocessor to;

     1) analyze the time-dependent waveform from the blood pressure monitor by fitting the primary and reflective peaks comprised by the time-dependent waveform with a mathematical model by varying parameters of the model until they correspond to the amplitudes of the primary and reflective peaks;

     2) analyze the motion information from the motion sensor to distinguish between time-dependent waveforms generated while the user is moving and while the user is at rest; and

     3) calculate a blood pressure value from parameters determined by fitting the primary and reflective peaks comprised by the time-dependent waveform generated when the user is at rest.

12. A method for monitoring a user'"'"'s blood pressure while the user is ambulatory, the method comprising:

determining if the user is at rest or in motion using a motion sensor;

generating with an optical system a time-dependent waveform while the user is at rest, the time-dependent waveform comprising a primary peak and a reflective peak that are, collectively, representative of the user'"'"'s blood pressure, the optical system comprising a light source and light detector;

sending the time-dependent waveform to a microprocessor comprised by a body-worn component for processing;

analyzing the primary peak and a reflective peak within the time-dependent waveform with a mathematical model by varying parameters of the model until they correspond to the amplitudes of the primary and reflective peaks; and

calculating a blood pressure value from parameters from the model determined from the time-dependent waveform generated when the user is at rest.

13. The method according to claim 12 wherein determining if the user'"'"'s hand is at rest comprises analyzing a signal sent from a motion sensor to the microprocessor with an algorithm operating on a microprocessor.

14. The method according to claim 13, wherein the motion sensor is an accelerometer.

15. The method according to claim 13, wherein the motion sensor is a piezoelectric device or a mercury switch.

16. The method according to claim 13, wherein the motion sensor is a software algorithm that analyzes the time-dependent waveform from the optical system to determine motion.

17. The method according to claim 13, further comprising wirelessly transmitting the blood pressure value using a radio-frequency transmitter operating a wireless protocol based on 802.15.1, 802.15.4, part-15 or 802.11.

18. The method according to claim 12, further comprising wirelessly transmitting the blood pressure value using a radio-frequency transmitter.

19. A system for monitoring a user'"'"'s blood pressure while the user is ambulatory, the system comprising:

a blood pressure sensor comprising;

a motion sensor for monitoring motion of the user and configured to generate motion information in response, and

a blood pressure monitor comprising an optical system comprising a light source and a light detector configured to generate a time-dependent waveform comprising a primary peak and a reflective peak that are, collectively, representative of the user'"'"'s blood pressure, and

a body-worn processing unit, connected to the blood pressure sensor through a cable, comprising;

a microprocessor for receiving the time-dependent waveform from the blood pressure monitor and motion information from the motion sensor, the microprocessor comprising computer code that controls the microprocessor to;

     1) analyze the primary peak and the reflective peak comprised by the time-dependent waveform from the blood pressure monitor with a mathematical model by varying parameters of the model until they correspond to the amplitudes of the primary and reflective peaks;

     2) analyze the motion information from the motion sensor to distinguish between time-dependent waveforms generated while the user is moving and while the user is at rest; and

     3) calculate a blood pressure value from parameters from the model determined the time-dependent waveform generated when the user is at rest; and

a short-range wireless transmitter for transmitting blood pressure information from the microprocessor to an external receiver.