Isolating ring sensor design

• US 6,402,690 B1
• Filed: 04/18/2000
• Issued: 06/11/2002
• Est. Priority Date: 04/23/1999
• Status: Expired due to Fees

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Rhee, Sokwoo, Yang, Boo-ho, Asada, Haruhiko H.
• Primary Examiner(s): Shaver, Kevin
• Assistant Examiner(s): Astorino, Michael C
• Application Number:
  US09/552,185
• Time in Patent Office: 784 Days
• Field of Search: 600/300, 600/301, 600/309-311, 600/316, 600/323, 600/324, 600/326, 600/328, 600/340, 600/344, 600/345-348, 600/355, 600/361-365, 600/481-510, 600/549, 600/587, 600/595, 128/897, 128/898, 128/903, 128/920
• US Class Current: 600/300
• 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 5/02427 Details of sensor
• CPC Class Codes: A61B 5/0261 using optical means, e.g. infrared light
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: Y10S 128/903 Radio telemetry

Abstract

A monitoring system for monitoring the health status of a patient by performing measurements such as skin temperature, blood flow, blood constituent concentration, and pulse rate at the finger of the patient. The monitoring system has an inner ring proximate to the finger as well as an outer ring, mechanically decoupled from the inner ring, that shields the inner ring from external loads. Measurements are performed in accordance with a protocol that may be preprogrammed, or may be modified on the basis of real-time data or by command from a remotely located medical professional.

Claims

1. A monitoring system for monitoring the health status of a patient, the monitoring system comprising:

a. an inner ring characterized by a first mass, the inner ring adapted to be proximate to a finger of the patient;

b. at least one sensor coupled to the inner ring for providing a signal based on at least one of skin temperature, blood flow, blood constituent concentration, and pulse rate of the patient; and

c. an outer ring characterized by a second mass, the outer ring adapted to be coupled to the finger of the patient substantially externally to the inner ring, the second mass being larger than the first mass, such that the outer ring shields the inner ring from any external loads.

2. A monitoring system according to claim 1, wherein the outer ring further shields the inner ring from ambient light.

3. A monitoring system according to claim 1, wherein the outer ring shields the inner ring from inertial loads.

4. A monitoring system according to claim 1, wherein the outer ring further shields the inner ring from static external forces.

5. A monitoring system according to claim 1, further comprising a flexible electrical coupling for conveying the signal from the sensor to an electronics module in such a manner as to maintain mechanical decoupling of the inner and outer rings.

6. A monitoring system according to claim 1, wherein the pressure of the inner ring against the finger of the patient is adjustable within a specified range.

7. A monitoring system according to claim 1, wherein the pressure of the inner ring against the finger of the patient is within the range of 10-30 mm Hg.

8. A monitoring system according to claim 1, wherein the pressure of the inner ring against the finger of the patient is maintained by a material having a stiffness that is a nonlinear function of extension.

9. A monitoring system according to claim 1, wherein the pressure of the inner ring against the finger of the patient is maintained by an elastomer.

10. A monitoring system according to claim 1, further including a light source and a detector for monitoring a characteristic of arterial blood flow within the finger.

11. A monitoring system according to claim 10, wherein the light source is a light-emitting diode.

12. A monitoring system according to claim 10, further including a control loop for regulating the intensity of light emitted by the light source.

13. A monitoring system according to claim 12, wherein the control loop regulates the intensity of light emitted by the light source in response to a ratio of signal to noise in the detector.

14. A monitoring system according to claim 12, further including a temperature sensor for generating a signal such that the control loop regulates the intensity of light emitted by the light source in response to the signal generated by the temperature sensor.

15. A monitoring system for monitoring the health status of a patient, comprising:

a. an inner ring characterized by a first mass, the inner ring adapted to be proximate to a finger of the patient;

b. at least one sensor coupled to tee inner ring for providing a signal based on at least one of skin temperature, blood flow, blood constituent concentration, and pulse rate of the patient;

c. an outer ring characterized by a second mass, the outer ring adapted to be coupled to the finger of the patient the second mass being larger than the first mass, such that the outer ring shields the inner ring from any external loads;

d. an electronics module disposed on the outer ring for processing the signal provided by the sensor; and

e. a flexible electrical coupling for conveying the signal from the sensor to the electronics module in such a manner as to maintain mechanical decoupling of the inner and outer rings.

16. A monitoring system according to claim 15, wherein the flexible electrical coupling includes a plurality of wires.

17. A monitoring system according to claim 15, further comprising:

a. a transmitter for converting the signal to a wave;

b. at least one receiver for receiving the wave from the transmitter; and

c. a controller for analyzing the wave and determining an abnormal health status.

18. A monitoring system according to claim 15, wherein the mass of the outer ring is at least ten times the mass of the inner ring.

19. A monitoring system according to claim 15, wherein the inner ring includes a flexible material.

20. A monitoring system according to claim 19, wherein the tension on the flexible material is a nonlinear function of extension of the flexible material.