Portable circuit and method for performing a time study and analysis of bodily ionic characteristics

• US 4,618,929 A
• Filed: 05/04/1983
• Issued: 10/21/1986
• Est. Priority Date: 05/04/1983
• Status: Expired due to Fees

• Current Assignee: Akron City Hospital
• Original Assignee: Akron City Hospital
• Inventors: Miller, Joseph M., Steiner, Paul R., Fannin, Stephen W.
• Primary Examiner(s): Smith, Jerry
• Assistant Examiner(s): Meyer, Charles B.
• Application Number:
  US06/491,455
• Time in Patent Office: 1,266 Days
• Field of Search: 364/415, 128/631, 128/635, 374/438, 374/444
• US Class Current: 600/348
• CPC Class Codes: A61B 5/0538 invasively, e.g. using a catheter
• CPC Class Codes: A61B 5/14539 for measuring pH
• CPC Class Codes: A61B 5/14542 for measuring blood gases A61B5/14551 takes precedence
• CPC Class Codes: A61B 5/1473 invasive, e.g. introduced into the body by a catheter A61B5/1482 takes precedence

Abstract

A portable circuit and method for performing a time study and analysis of bodily ionic characteristics as esophageal pH includes a transducer 11 for measuring pH and generating a proportional analog signal and an interface 12 for converting this signal into a representative digital signal including offset and gain controls 23,24 for permitting correction for transducer 11 calibration drift during the study period. A processor 14 receives and stores all digital signals for rapid transmission to a data analysis after the study period is ended. Esophageal pH values are measured and stored for a plurality of pre-study and post-study known conditions.

Claims

1. A circuit for monitoring over a period of study time a bodily ionic characteristic comprising:

transducer means for measuring the ionic characteristic and generating an analog signal proportional thereto;

interface means for receiving said analog signal from said transducer means and converting said analog signal into a representative digital signal, said interface means including adjustment means for permitting correction for drift in calibration of said transducer means;

processor means for receiving said digital signal, sampling and storing said digital signal at preselected occasions over the period of study time, and upon the conclusion of the period of study time rapidly transmitting all said stored digital signals to a data analysis device, said processor means including means for determining the orientation of the patient from which the bodily ionic characteristic is being monitored; and

,

housing means for portably carrying said interface means and said processor means, said transducer means electrically connected to said interface means.

2. A circuit, as set forth in claim 1, wherein said processor means further includes mode selector switch means for selecting the operating mode of the circuit.

3. A circuit, as set forth in claim 2, wherein said processor means further includes pushbutton means for causing said processor means to record data from which drift in the calibration of said transducer means may be determined.

4. A circuit, as set forth in claim 3, wherein said interface means further includes transducer type selector means for facilitating connection to different types of said transducer means.

5. A circuit, as set forth in claim 4, wherein said transducer type selector means includes switch means for receiving said analog signal from said transducer means and reversing the polarity of said analog signal from said transducer means.

6. A circuit, as set forth in claim 6, wherein said adjustment means includes means for adjusting the amplitude and DC offset of said analog signal from said transducer means.

7. A circuit, as set forth in claim 6, wherein said interface means further includes amplifier means for receiving said analog signal from said transducer means, amplifying said analog signal;

said amplifier means in electrical communication with said means for adjusting the amplitude and DC offset of said analog signal from said transducer means, thereby inducing said amplifier means to adjust the amplitude and DC offset of said analog signal.

8. A circuit, as set forth in claim 7, wherein said interface means further includes

filter means for receiving the output signal from said amplifier means, removing the high frequency noise contents thereof, and providing an output signal,

converter means for converting said output signal from said filter means into a representative digital signal, and,

voltage clamp means for receiving said output signal from said filter means and adjusting its voltage magnitude to be within a range suitable for receipt by said converter means.

9. A circuit, as set forth in claim 8, wherein the bodily ionic characteristic is gastrointestinal pH.

10. A method for monitoring over a period of study time a bodily ionic characteristic comprising the steps of:

determining the ionic characteristic for a plurality of pre-study conditions and recording first digital signals representative thereof including the steps of

measuring with a transducer the ionic characteristic and generating an analog signal proportional thereto throughout the study period;

converting said analog signal into said second digital signal; and

,

sampling and storing said second digital signal at preselected occasions during the study period;

measuring by transducer the ionic characteristic throughout the study period and at preselected occassions recording second digital signals representative thereof including the steps of

measuring with a transducer prior to commencement of the extended period of time the ionic characteristic and generating an analog signal proportional thereto for a plurality of pre-study known conditions;

converting said analog signals for said plurality of pre-study known conditions into said first digital signals; and

,

storing said first digital signals representative of said plurality of pre-study known conditions;

determining the ionic characteristic for a plurality of post-study conditions and recording third digital signals representative thereof including the steps of

measuring with said transducer subsequent to conclusion of the extended period of time the ionic characteristic and generating an analog signal proportional thereto for a plurality of post-study known conditions;

converting said analog signals for said plurality of post-study conditions into said third digital signals, and;

storing said third digital signals representative of said plurality of post-study known conditions;

providing said first digital signals, said second digital signals and said third digital signals to a data analysis device; and

,

correcting said measured ionic characteristic for drift in calibration of said transducer with respect to time.

11. A method, as set forth in claim 10, further including the step of adjusting said analog signal from said transducer to permit correction for drift in calibration of said transducer.

12. A method, as set forth in claim 11, further including the step of determining and recording the orientation of the patient from which the bodily ionic characteristic is being monitored at the time of sampling for each said second digital signal.

13. A method, as set forth in claim 12, further including the step of selecting different modes of operation to effect the various steps of the method, including calibration and automatic data acquisition and storage.

14. A method, as set forth in claim 13, wherein said steps of determining the ionic characteristic for a plurality of pre-study conditions, measuring the ionic characteristic throughout the study period, and determining the ionic characteristic for a plurality of post-study conditions include the respective steps of determining, measuring and determining gastroesophageal pH.