Smart physiologic parameter sensor and method

• US 6,676,600 B1
• Filed: 08/31/2000
• Issued: 01/13/2004
• Est. Priority Date: 09/03/1999
• Status: Expired due to Term

• Current Assignee: Tensys Medical Inc. (Recorders & Medicare Systems Pvt Ltd.)
• Original Assignee: Tensys Medical Inc. (Recorders & Medicare Systems Pvt Ltd.)
• Inventors: Gallant, Stuart L., Conero, Ronald S.
• Primary Examiner(s): Jaworski, Francis J.
• Application Number:
  US09/652,626
• Time in Patent Office: 1,230 Days
• Field of Search: 439/620, 600/437, 600/459, 600/454-456, 600/485-488, 600/491, 73/15.7
• US Class Current: 600/438
• CPC Class Codes: A61B 2018/00178 Electrical connectors
• CPC Class Codes: A61B 2018/00988 Means for storing information, e.g. calibration constants, or for preventing excessive use, e.g. usage, service life counter
• CPC Class Codes: A61B 2560/0252 using ambient temperature
• CPC Class Codes: A61B 2560/0276 Determining malfunction
• CPC Class Codes: A61B 2562/02 Details of sensors specially adapted for in-vivo measurements
• CPC Class Codes: A61B 2562/08 Sensors provided with means for identification, e.g. barcodes or memory chips
• CPC Class Codes: A61B 5/00 Measuring for diagnostic purposes radiation diagnosis A61B6/00; diagnosis by ultrasonic, sonic or infrasonic waves A61B8/00; Identification of persons
• 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 5/02158 provided with two or more sensor elements
• CPC Class Codes: A61B 5/1112 Global tracking of patients, e.g. by using GPS
• CPC Class Codes: A61B 5/6843 Monitoring or controlling sensor contact pressure
• CPC Class Codes: A61B 8/00 Diagnosis using ultrasonic, sonic or infrasonic waves imaging of objects using sonar G01S15/00
• CPC Class Codes: A61B 8/06 Measuring blood flow measuring volume flow in general G01F, e.g. G01F1/66, G01F1/72; measuring speed of fluids in general G01P5/00

Abstract

A sensor assembly used for the measurement of one or more physiologic parameters of a living subject which is capable of storing both data obtained dynamically during use as well as that programmed into the device. In one embodiment, the sensor assembly comprises a disposable combined pressure and ultrasonic transducer incorporating an electrically erasable programmable read-only memory (EEPROM), the assembly being used for the non-invasive measurement of arterial blood pressure. The sensor EEPROM has a variety of information relating to the manufacture, run time, calibration, and operation of the sensor, as well as application specific data such as patient or health care facility identification. Portions of the data are encrypted to prevent tampering. In a second embodiment, one or more additional storage devices (EEPROMs) are included within the host system to permit the storage of data relating to the system and a variety of different sensors used therewith. In a third embodiment, one or more of the individual transducer elements within the assembly are made separable and disposable, thereby allowing for the replacement of certain selected components which may degrade or become contaminated. Methods for calibrating and operating the disposable sensor assembly in conjunction with its host system are also disclosed.

Claims

1. A method of calibrating a transducer element, comprising:

providing a transducer element having a predetermined operating response and an associated storage device, said element adapted to tonometrically measure the pressure associated with a blood vessel;

determining the bridge voltage E_b and signal output voltage E_s of said pressure transducer under varying conditions of temperature and pressure;

determining a plurality of calibration parameters based at least in part on said acts of determining voltage;

storing data representative of said calibration parameters within said storage device; and

calibrating said transducer element based at least in part on said stored calibration parameters.

2. The method of claim 1, wherein said act of calibrating said transducer element comprises at least periodically calibrating said element during use of said element on a living subject.

3. The method of claim 2, further comprising:

applying at least one acceptance criterion during said act of calibrating; and

selectively retaining or discarding, as appropriate, said transducer element and associated storage device based on said act of applying.

4. The method of claim 1, further comprising:

at least periodically replacing said transducer element and associated storage device, said replacement associated storage device having calibration data which is specifically related to said replacement transducer element; and

calibrating said transducer element after said act of replacing at least periodically during use.

5. A method of calibrating a transducer element, comprising:

providing a transducer element having a predetermined operating response and an associated storage device, said element adapted to tonometrically measure the pressure associated with a blood vessel;

determining a bridge voltage and signal output voltage of said pressure transducer under varying conditions of temperature and pressure;

determining a plurality of calibration parameters based at least in part on said acts of determining voltage;

storing data representative of said calibration parameters within said storage device; and

calibrating said transducer element based at least in part on said stored calibration parameters.

6. A method of calibrating a transducer element, comprising:

providing a transducer element having a predetermined operating response and an associated storage device, said element adapted to tonometrically measure the pressure associated with a blood vessel;

determining a first voltage and second voltage of said pressure transducer under varying conditions of temperature and pressure;

determining a plurality of calibration parameters based at least in part on said first and second voltages;

storing data representative of said calibration parameters within said storage device; and

calibrating said transducer element based at least in part on said stored calibration parameters.

7. The method of claim 6, wherein said act of calibrating said transducer element comprises at least periodically calibrating said element during use of said element on a living subject.

8. The method of claim 7, further comprising:

applying at least one acceptance criterion during said act of calibrating; and

selectively retaining or discarding, as appropriate, said transducer element and associated storage device based on said act of applying.

9. The method of claim 6, further comprising:

at least periodically replacing said transducer element and associated storage device, said replacement associated storage device having calibration data which is specifically related to said replacement transducer element; and

calibrating said transducer element after said act of replacing at least periodically during use.

10. A method of calibrating a sensor means, comprising:

providing a sensor means having a predetermined operating response and an associated means for storing data, said sensor means adapted to tonometrically measure the pressure associated with a blood vessel;

determining a first voltage and second voltage of said sensor means under varying conditions of temperature and pressure;

determining a plurality of calibration parameters based at least in part on said first and second voltages;

storing data representative of said calibration parameters within said means for storing; and

calibrating said sensor means based at least in part on said stored calibration parameters.

11. A transducer element having a predetermined operating response and an associated storage device, said element adapted to tonometrically measure the pressure associated with a blood vessel, said element being adapted for calibration according to the method comprising;

determining a bridge voltage and output voltage of said pressure transducer under varying conditions of temperature and pressure;

determining a plurality of calibration parameters based at least in part on said bridge and output voltages;

storing data representative of said calibration parameters within said storage device; and

calibrating said transducer element based at least in part on said stored calibration parameters.

12. A transducer element having a predetermined operating response and an associated storage device, said element adapted to tonometrically measure the pressure associated with a blood vessel, said operating response comprising a bridge voltage and output voltage which may each vary with temperature and pressure;

wherein a plurality of calibration parameters for said transducer element are;

(i) determined based at least in part on said bridge and output voltages, and

(ii) stored within said storage device;

said calibration parameters comprising at least in part the basis for calibration of said transducer element.

13. A replaceable component of a medical device, comprising:

at least one pressure transducer element adapted to generate an electrical signal;

a storage device, physically co-located and operatively connected to said at least one pressure transducer element, adapted to store therein a plurality of data related to the calibration of said at least one pressure transducer element and said electrical signal, said data being stored prior to use and retrievable from said storage device subsequent to being stored; and

at least one acoustic transducer adapted to generate an acoustic signal and receive an echo resulting therefrom;

wherein said component is adapted for data communication with a host device for measuring the blood pressure of a living organism based at least in part on said electrical signal and echo.

14. The component of claim 13, wherein said at least one pressure transducer element comprises a silicon strain beam pressure transducer capable of generating an electrical signal in response to pressure applied thereto.

15. The component of claim 13, wherein at least a portion of said data comprises prestored data relating to the compatibility of said pressure transducer with said host device.

16. The component of claim 13, wherein said data is utilized to calibrate said pressure transducer at least periodically during the measurement of said blood pressure.

17. A replaceable component of a medical device, comprising:

at least one pressure sensing means adapted to generate an electrical signal;

means, physically co-located and operatively connected to said at least one pressure sensing means, for storing therein a plurality of data related to the calibration of said at least one pressure sensing means and said electrical signal, said data being stored prior to use and retrievable from said means for storing subsequent to being stored; and

at least one acoustic transducer adapted to generate an acoustic signal and receive an echo resulting therefrom;

wherein said component is adapted for data communication with a means for determining the blood pressure of a living organism based at least in part on said electrical signal and echo.

18. A replaceable component of a medical device, comprising:

at least one pressure transducer element adapted to generate an electrical signal;

a storage device, physically co-located and operatively connected to said at least one pressure transducer element, adapted to store therein a plurality of data related to the calibration of said at least one pressure transducer element and said electrical signal, said data being stored prior to use and retrievable from said storage device subsequent to being stored; and

wherein said component is adapted for data communication with (i) at least one acoustic transducer adapted to generate an acoustic signal and receive an echo resulting therefrom, and (ii) a host device for measuring the blood pressure of a living organism based at least in part on said electrical signal and echo.

19. The component of claim 18, wherein said at least one pressure transducer element comprises a silicon strain beam pressure transducer capable of generating an electrical signal in response to pressure applied thereto.

20. The component of claim 18, wherein at least a portion of said data comprises prestored data relating to the compatibility of said pressure transducer with said host device.

21. The component of claim 18, wherein said data is utilized to calibrate said pressure transducer at least periodically during the measurement of said blood pressure.