Measurement device and method of calibration

• US 5,357,953 A
• Filed: 05/21/1992
• Issued: 10/25/1994
• Est. Priority Date: 05/21/1992
• Status: Expired due to Term

• Current Assignee: Puritan Bennett Corp. (Medtronic Plc)
• Original Assignee: Puritan Bennett Corp. (Medtronic Plc)
• Inventors: Powell, Larry, Jeryes, Amal, Young, Yuan, Merrick, Edwin B., Dowling, Neal B. Jr.
• Primary Examiner(s): Sykes, Angela D.
• Application Number:
  US07/886,636
• Time in Patent Office: 887 Days
• Field of Search: 128/633-634, 128/664-665, 128/666-667, 356/39-41
• US Class Current: 600/331
• CPC Class Codes: A61B 2562/085 combined with means for recording calibration data
• CPC Class Codes: A61B 5/1459 invasive, e.g. introduced into the body by a catheter A61B5/1464 takes precedence
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes

Abstract

A calibration method and apparatus capable of being calibrated according to the method that allows a remote sensor to be transferred from analyzing instrument to analyzing instrument within a group of analyzing instruments without the need to recalibrate. The device includes a separate memory capability associated with the sensor as well as each instrument while the method requires the use of an arbitrarily selected sensor to initially be transferred from instrument to instrument, while being subjected to the same calibration standards in order to generate calibration data for entry into each instrument'"'"'s memory. With such data entered in the instruments'"'"' memories, any remote sensor, calibrated on any one instrument and having such calibration data stored in its own memory, can then readily be interconnected to any instrument of the group to immediately yield accurate results.

Claims

1. A measurement apparatus, including a sensor component and an analyzing instrument component, said components being removably connectable, said sensor component being operative to generate a signal in response to certain environmental conditions and said instrument component being operative to generate an output and calibration data interpretive of said signal, comprising:

first memory means secured to said sensor component and interconnectable to said instrument component for storing calibration data relating to said sensor component, wherein said instrument component stores said calibration data into said first memory means;

second memory means located within said instrument component for storing calibration data relating to said instrument component; and

processing means for correcting said signal in accordance with said calibration data stored in said first and said second memory means.

2. The measurement apparatus of claim 1, further comprising at least two instrument components, each instrument component interchangeable with the other and having respective memory means for storing calibration data relating to said instrument components, said first memory means having calibration data relating to said sensor component and necessary for said signal to be correctly interpreted by said instrument components.

3. The measurement apparatus of claim 2, wherein said first and second memory means are selected from the group consisting of RAM, PROM, EPROM and EEPROM.

4. The measurement apparatus of claim 1 wherein said sensor component generates an optical signal and wherein said first and said second memory means store calibration data electronically.

5. The measurement apparatus of claim 1 wherein said sensor component comprises at least one probe, insertable into a patient'"'"'s vasculature, said probe being responsive to the presence of a certain blood parameter within said patient'"'"'s blood supply and operative to fluoresce with an intensity thereof being a function of the partial pressure of said parameter and wherein said instrument component interprets such fluorescence to generate an output directly in terms of said partial pressure.

6. The measurement apparatus of claim 5, wherein the blood parameter to be measured is selected from the group consisting of PO₂, PCO₂, and pH.

7. The measurement apparatus of claim 1, wherein said first memory means is removably secured to said sensor component.

8. An invasive optical blood gas analyzer, including a probe insertable into a patient'"'"'s blood flow, and an analyzing instrument, said probe and instrument being interconnectable, said probe being operative to generate fluorescent radiation, the intensity of said fluorescent radiation being a function of the partial pressure of a certain gas in the patient'"'"'s blood flow, and said instrument being operative to convert the fluorescent intensity into a measure of partial pressure, said analyzer comprising:

a first, non-volatile, semi-conductor memory device attached to said probe, said first memory device interconnectable to said instrument and operative to store calibration data specific to said probe relating to the conversion of said fluorescent intensity into a measure of partial pressure;

a second, non-volatile, semi-conductor memory device located within said instrument and operative to store calibration data specific to said instrument relating to the conversion of said fluorescent intensity into a measure of partial pressure; and

a data processor located within said instrument for correcting the measure of partial pressure in accordance with the calibration data stored in said first and second memory devices.

9. The analyzer of claim 8, wherein said first and second memory devices are selected from the group consisting of RAM, PROM, EPROM and EEPROM.

10. The analyzer of claim 8 wherein the probe is capable of generating fluorescent radiation which is a function of the pH value of the patient'"'"'s blood.

11. The blood gas analyzer of claim 8, wherein said first memory device is removably attached to said probe.

12. The blood gas analyzer of claim 8, wherein calibration data is stored in said first memory device via an analyzing instrument interconnected thereto.

13. The blood gas analyzer of claim 8, wherein the calibration data stored in said first memory device is specific to the characteristics of said probe.

14. A method for calibrating a group of instruments, said group including at least a first and second instrument, each instrument operative to interpret signals generated by remote sensors interconnectable thereto and responsive to a certain environmental condition, said sensors including memory means for storing calibration data and said instruments including memory means for storing calibration data as well as processing means for interpreting the sensor signals in accordance with calibration data stored in said sensors'"'"' and said instruments'"'"' memory, said method comprising the steps of:

selecting a first instrument, interconnecting said first instrument to a first sensor, subjecting said first sensor to a first standard of said certain environmental condition to generate a first signal, entering first calibration data into the memory means of said first sensor, generating a first measurement of said first standard;

selecting a second instrument, interconnecting said second instrument to said first sensor and subjecting said first sensor to said first standard to generate a second signal;

entering second calibration data into said second instrument'"'"'s memory means so as to correct said second signal to conform to said first measurement.

15. The method of claim 14 further comprising the step of subjecting said first sensor to at least one additional standard of certain environmental conditions and interconnecting the first sensor subjected to each additional standard to each of the first and second instruments, so as to obtain additional calibration points to be stored in the memory means of the sensor and instruments.

16. The method of claim 14, further comprising the step of entering an interpretation from said first instrument of said first signal into said first sensor'"'"'s memory means for correction of an interpretation from said second instrument of said second signal.

17. A method for calibrating an invasive optical blood gas analyzing system, including a group of analyzing instruments, so as to enable a transfer of probes, interconnectable to such analyzing instruments, from instrument to instrument without recalibration, each of said probes including a memory device for storing calibration data and each of said instruments including a memory device for storing calibration data as well as a data processor for modifying said instrument'"'"'s output in accordance with calibration data stored in said probe'"'"'s memory and said instrument'"'"'s memory, comprising the steps of:

selecting a first probe for use as a transfer probe;

interconnecting said transfer probe to a first instrument of said group of instruments and subjecting said probe to at least one calibration standard;

entering said first instrument'"'"'s output into said transfer probe'"'"'s memory device;

successively transferring said transfer probe, subjected to said calibration standard, to every other instrument in said group, and entering corrective data into each individual instrument memory device such that each individual instrument'"'"'s output is modified to conform to said first instrument'"'"'s output;

selecting a second probe, interconnecting it to any instrument of said group of instruments and subjecting it to a calibration standard of known values;

entering calibration data into said second probe'"'"'s memory device for modifying the output of the instrument interconnected thereto to conform to said known values, whereby said second probe can then be interconnected to any instrument in the group to yield an accurate output.

18. A method for calibrating a group of apparatuses including at least a first and second instrument component and including at least a first and second sensor component, each instrument component and sensor component being associated with its own memory device capable of storing calibration data values, each sensor component being configured to removably connect to each instrument component, each sensor component configured to be subjected to at least a first known standard of analytes for which each sensor component is capable of detecting, said method including the steps of:

connecting a first sensor component to a first instrument component;

subjecting the first sensor component to a first standard;

calculating calibration values associated with the first sensor component when the first sensor component is connected to the first instrument component and subjected to the first standard;

storing calculated calibration values into the memory device of the first sensor component;

repeating said connecting, subjecting, and calculating steps for the second instrument component connected to the first sensor component subjected to the first standard, wherein new calibration values are calculated and stored into the memory device of the second instrument component.

19. The method of claim 18, further comprising the step of repeating said connecting, subjecting and calculating steps for the first sensor component subjected to the first standard sequentially connected to each instrument component, wherein calibration values are calculated and stored into the memory device of each instrument component.

20. The method of claim 18, further comprising the step of repeating said connecting, subjecting, calculating and storing steps, wherein the first instrument component is connected to the second sensor component and the second sensor component is subjected to the first standard.

21. A measurement system, comprising:

a first instrument component having first memory means for storing first calibration data specific to said first instrument component; and

a sensor component removably connectable to said first instrument component, said sensor component having second memory means for storing second calibration data specific to said sensor component,

wherein said first instrument component generates and stores the first calibration data into the first memory means,

wherein said sensor component generates a signal in response to certain environmental conditions, and

wherein said first instrument component further includes processing means for interpreting the signal generated by said sensor component, the processing means utilizing the calibration data stored in the first and second memory means to interpret the signal.

22. The measurement system of claim 21, further comprising a second instrument component having third memory means for storing third calibration data relating to said second instrument component,

wherein said sensor component is configured as a transfer probe for calibrating said second instrument component,

wherein said first and second instrument components are interchangeably connectable to said sensor component,

wherein said second instrument component generates and stores the third calibration data into the third memory means, and

wherein the second and third memory means have calibration data necessary for the signal generated by said sensor component to be correctly measured by said second instrument component.

23. The measurement system of claim 22, further comprising a second sensor component removably connectable to said first instrument component and said second instrument component, said second sensor component having fourth memory means for storing fourth calibration data relating to said second sensor component,

wherein said second sensor component generates a signal in response to certain environmental conditions,

wherein the first and fourth memory means have calibration data necessary for the signal generated by said second sensor component to be correctly measured by said first instrument component, and

wherein the third and fourth memory means have calibration data necessary for the signal generated by said second sensor component to be correctly measured by said second instrument component.

24. A method for calibrating at least two instruments, each instrument having memory means for storing calibration data, each instrument being interconnectable to at least one sensor responsive to an analyte, each sensor having memory means for storing calibration data, and each instrument having means for processing the calibration data, said method comprising the steps of:

(a) subjecting the first sensor to a first analyte;

(b) interconnecting a first instrument to the first sensor;

(c) generating a first signal from the first sensor;

(d) calculating first calibration data from a first measurement of the first signal;

(e) entering the first calibration data into the memory means of the first sensor;

(f) interconnecting a second instrument to the first sensor;

(g) generating a second signal from the first sensor; and

(h) entering second calibration data in the memory means of the second instrument to calculate a second measurement from the second signal which conforms to the first measurement.

25. The method of claim 24 further comprising the steps of subjecting said first sensor to a second analyte and repeating steps (b) through (h) to enter additional calibration data into the memory means of the first sensor and the second instrument.

26. The method of claim 24 further comprising the steps of selecting a second sensor and repeating steps (a) through (e), wherein the second sensor is used in place of the first sensor.

27. The method of claim 24 further comprising the steps of configuring the first sensor as a transfer probe for calibrating each of a plurality of instruments, and repeating steps (f) through (h) for each of the plurality of instruments.

28. A method of calibrating a group of instruments including, at least, a first and a second instrument, each instrument operative to measure and interpret signals from remote sensors interconnectable thereto, said sensors being responsive to an analyte partial pressure or concentration, said sensors including memory means for storing calibration constants related to said sensor performance and said instruments including memory means for storing calibration constants relating to the correction of said instruments as well as processing means for correcting the measured intensity signals, said method comprising the steps of:

selecting a first instrument, interconnecting said first instrument to a first sensor, subjecting said first sensor to a first analyte standard to generate intensity signals, storing calibration constants in said first instrument'"'"'s memory means;

selecting a second instrument, interconnecting said second instrument to said first sensor, subjecting said first sensor to said first analyte standard to generate intensity signals; and

entering calibration data into the memory means of said second instrument to correct said intensity signals of said second instrument to conform to the intensity signals of said first instrument.

29. A method of calibrating a group of instruments including, at least, a first and a second instrument, each instrument operative to measure and interpret signals from remote sensors interconnectable thereto, said sensors being responsive to an analyte partial pressure or concentration, said sensors including memory means for storing calibration constants related to said sensor performance and said instruments including memory means for storing calibration constants relating to the correction of said instruments as well as processing means for correcting a measured signals, said method comprising the steps of:

selecting a first instrument, interconnecting said first instrument to a first sensor, subjecting said first sensor to one or more analyte standards to generate intensity signals related to known analyte levels, storing calibration constants into said first instrument'"'"'s memory means;

selecting a second instrument, interconnecting said second instrument to said first sensor and subjecting said first sensor to one or more analyte standards to generate intensity signals related to known standards; and

entering calibration data into the memory means of said second instrument to append said calibration data to the memory means of any sensor subsequently calibrated by the second instrument.

30. A method for calibrating at least two instruments each having memory means for storing calibration data, each instrument interconnectable to at least one sensor responsive to an analyte, each sensor having memory means for storing calibration data, and each instrument having means for processing the calibration data, said method comprising the steps of:

(a) interconnecting a first sensor and a first instrument;

(b) subjecting the first sensor to a first analyte;

(c) generating a first signal from the first sensor;

(d) storing a representation of the first signal into the memory means of the first instrument;

(e) interconnecting the first sensor and a second instrument;

(f) generating a second signal from the first sensor;

(g) storing a representation of the second signal into the memory device of the second instrument; and

(h) utilizing the first signal and second signal representations in the memories of the first and second instruments to maintain the accuracy of calibration of all subsequent sensors calibrated on the first instrument and subsequently moved to the second instrument.