WO1986002819A1 - Apparatus and method for monitoring organs of the body - Google Patents
Apparatus and method for monitoring organs of the body Download PDFInfo
- Publication number
- WO1986002819A1 WO1986002819A1 PCT/GB1985/000521 GB8500521W WO8602819A1 WO 1986002819 A1 WO1986002819 A1 WO 1986002819A1 GB 8500521 W GB8500521 W GB 8500521W WO 8602819 A1 WO8602819 A1 WO 8602819A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- signals
- impedance
- recorder
- organ
- electrodes
- Prior art date
Links
- 238000000034 method Methods 0.000 title claims abstract description 13
- 238000012544 monitoring process Methods 0.000 title claims abstract description 9
- 210000000056 organ Anatomy 0.000 title claims description 19
- 210000001835 viscera Anatomy 0.000 claims abstract description 5
- 230000010355 oscillation Effects 0.000 claims abstract description 3
- 230000008602 contraction Effects 0.000 claims description 11
- 238000006073 displacement reaction Methods 0.000 claims description 5
- 238000004458 analytical method Methods 0.000 claims description 2
- 230000002596 correlated effect Effects 0.000 claims 1
- 230000000875 corresponding effect Effects 0.000 claims 1
- 210000002784 stomach Anatomy 0.000 description 10
- 230000000747 cardiac effect Effects 0.000 description 4
- 210000002216 heart Anatomy 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 230000007423 decrease Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000002955 isolation Methods 0.000 description 2
- 210000004072 lung Anatomy 0.000 description 2
- 210000003932 urinary bladder Anatomy 0.000 description 2
- 210000004291 uterus Anatomy 0.000 description 2
- 239000008280 blood Substances 0.000 description 1
- 210000004369 blood Anatomy 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 230000002496 gastric effect Effects 0.000 description 1
- 230000000155 isotopic effect Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 235000012054 meals Nutrition 0.000 description 1
- 210000004165 myocardium Anatomy 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/05—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves
- A61B5/053—Measuring electrical impedance or conductance of a portion of the body
- A61B5/0535—Impedance plethysmography
Definitions
- This invention relates to apparatus for monitoring hollow visceral organs of the body.
- This invention is based on the observation that it is possible to monitor body function, for example, the function of hollow visceral organs such as the stomach including measuring the volume of the heart, lungs, bladder and uterus dand the volume of fluid within any of these organs, electronically, by measuring differences in impedance across the body through the organ in question using a plurality of electrodes.
- apparatus for monitoring body functions comprises oscillator means for generating a high frequency oscillation, an oscillator driven constant current generating source, at least one pair of current driven electrodes for attachment to the body of a patient, at least two pairs of voltage sensing electrodes for attachment to the body of the patient, tuner/voltage amplifier means tuned to the frequency of the generator means, converter means for measuring impedance changes registering between pairs of voltage sensing electrodes, impedance indicator means isolating circuit means for receiving signals from the impedance converter, filter means for excluding electronic or biological fluctuations from the equipment or the subject and an impedance offset control, and recorder means for recording the subject signals, the subject signals being received by the recorder means as separate signals.
- the recorder means may, for example, comprise a chart recorder or oscilloscope, a tape recorder or a microcomputer and preferably in addition to having the capability for receiving the signals from the different electrode pairs separately also has the capability of correcting phase displacement between the signals and recording a combination of the signals.
- the apparatus can be used to monitor, for example, size, rate of filling or emptying and wall contraction in hollow visceral organs of the body, for example, the stomach, heart, lungs, bladder and uterus.
- the recording produced by the recorder gives a continuous reading of impedance changes. It shows a base line with fluctuations indicating contractions in the wall of the organ causing changes in impedance.
- the organ fills the trace rises to a maximum and then decreases towards a base level value, the subsiding trace similarly being superimposed by fluctuations indicating contractions in the wall of the organ.
- Filling and emptying times of the organ are shown by the speed of ascent to a peak and subsequent decline.
- Volume can be determined as a function of the magnitude of change of impedance.
- the magnitude of contractions of the wall are shown as a function of the area of the minor peaks superimposed on the main trace.
- Processing for example, by Fourier analysis of the signals indicates contractions of the organ in different regions covered by the electrode and by dividing the trace into, for example, time intervals, differences in contractions at different times can be determined giving an indication of, for example, response to a meal or drugs or other stimulus.
- the trace produced by combining the signals from a large number of electrodes gives an indication of the full impedance displacement of the organ and therefore gives a more sensitive indication of the volume that can be derived from the separate signals.
- the generator means is a 100 kHz oscillator and the current control means produces a 4 milliamp peak-to-peak constant current drive.
- a non-invasive method for monitoring stomach volume and rate of filling and/or emptying has long been sought by gastroenterological physicians.
- a non-invasive method has the advantages of repeatability unlike X-ray or isotopic methods so that the progress of illness or the effects of treatment can be measured.
- the new device proposed has this capability and has proved so sensitive in practice that it may also be used to quantify the contractions of the stomach. Because pairs of electrodes can be used separately to monitor stomach contractions the progress of contractions through the stomach can be assessed. At the same time because a plurality of electrodes is used the accuracy of the volume measurement is enhanced by surveying an increased region of the body thus including the entire region of the stomach even though the exact position of the stomach cannot be identified from without.
- the use of at least two pairs of voltage sensing electrodes increases the possibility of recording signals from the region of interest, within the body, which cannot be identified from without.
- 2 is a 4 milliamp peak-to-peak constant current drive
- 3 is the stomach
- 4 is a pair of current driving electrodes
- 5 is a pair of voltage sensing electrodes
- 6 is a 100 kHz tuner/voltage amplifier
- 7 is a detector to recover impedance changes
- 8 is an impedance meter
- 9 is a subject signal isolation amplifier
- 10 is a low pass filter and impedance offset control
- 11 is a chart recorder
- 12 is a tape recorder or microcomputer.
- the current driving and voltage sensing electrodes 4 and 5 are placed on the body of the patient around the organ to be monitored.
- the signal recorded by the voltage sensing electrodes 5 is passed to the amplifier 6 and converted to impedance by detector/converter 7.
- the signal from the detector/converter 7 is passed both to impedance meter 8 which gives a direct read out of impedance and to trhe signal isolation amplifier 9 and thence to the low pass filter and recorder.
- the signals from the separate pairs of voltage sensing electrodes are maintained separate and are individually passed to the recorder so that impedance changes detected by each pair of voltage sensing electrodes can be recorded individually.
- the recorder preferably also includes means for correcting phase displacement of the individual signals and combining the signals so that the total of the impedance changes recorded by a number of electrodes can also be indicated by the recorder.
- Figs. 2 and 3 are more detailed self-explanatory circuit diagrams in which like reference numerals have been used to indicate the various components of the apparatus. It will be appreciated that only one set of electrodes 5 is shown in these figures and the circuitry will be duplicated as appropriate to accommodate from the sets of electrodes 5.
- circuitry shown is merely exemplary of one especially preferred embodiment of the invention - 5 - and the invention is not to be regarded in any way as limited to the arrangement shown.
Landscapes
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Heart & Thoracic Surgery (AREA)
- Medical Informatics (AREA)
- Physics & Mathematics (AREA)
- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Biophysics (AREA)
- Pathology (AREA)
- Engineering & Computer Science (AREA)
- Biomedical Technology (AREA)
- Hematology (AREA)
- Radiology & Medical Imaging (AREA)
- Molecular Biology (AREA)
- Surgery (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Measurement And Recording Of Electrical Phenomena And Electrical Characteristics Of The Living Body (AREA)
- Measuring And Recording Apparatus For Diagnosis (AREA)
Abstract
Apparatus for monitoring body functions comprises oscillator means (1) for generating a very high frequency oscillation, an oscillator driven constant current generating source (2), at least one pair of current driven electrodes (4) for attachment to the body of a patient, at least two pairs of voltage sensing electrodes (5) for attachment to the body of the patient, tuner/voltage amplifier means (6) tuned to the frequency of the generator means (1), converter means (7) for measuring impedance changes between pairs of voltage sensing electrodes (5), impedance indicator means (8), isolating circuit means (9) for receiving signals from the impedance converter (7), filter means (10) for excluding electronic or biological fluctuations from the equipment or the subject and a impedance offset control, and recorder means (11 or 12) for recording process and analysing the subject signals, the subject signals being received by the recorder means (11 or 12) as separate signals. Methods of producing a record of the function and volume of a hollow visceral organ are also described.
Description
- 1 -
APPARATUS AND METHOD FOR MONITORING ORGANS OF THE BODY
This invention relates to apparatus for monitoring hollow visceral organs of the body.
This invention is based on the observation that it is possible to monitor body function, for example, the function of hollow visceral organs such as the stomach including measuring the volume of the heart, lungs, bladder and uterus dand the volume of fluid within any of these organs, electronically, by measuring differences in impedance across the body through the organ in question using a plurality of electrodes.
According to the invention apparatus for monitoring body functions comprises oscillator means for generating a high frequency oscillation, an oscillator driven constant current generating source, at least one pair of current driven electrodes for attachment to the body of a patient, at least two pairs of voltage sensing electrodes for attachment to the body of the patient, tuner/voltage amplifier means tuned to the frequency of the generator means, converter means for measuring impedance changes registering between pairs of voltage sensing electrodes, impedance indicator means isolating circuit means for receiving signals from the impedance converter, filter means for excluding electronic or biological fluctuations from the equipment or the subject and an impedance offset control, and recorder means for recording the subject signals, the subject signals being received by the recorder means as separate signals.
The recorder means may, for example, comprise a chart recorder or oscilloscope, a tape recorder or a microcomputer and preferably in addition to having the capability for receiving the signals from the different electrode pairs separately also has the capability of correcting phase displacement between the signals and recording a combination of the signals.
- 2 - The apparatus can be used to monitor, for example, size, rate of filling or emptying and wall contraction in hollow visceral organs of the body, for example, the stomach, heart, lungs, bladder and uterus.
The recording produced by the recorder gives a continuous reading of impedance changes. It shows a base line with fluctuations indicating contractions in the wall of the organ causing changes in impedance. When the organ fills the trace rises to a maximum and then decreases towards a base level value, the subsiding trace similarly being superimposed by fluctuations indicating contractions in the wall of the organ. Filling and emptying times of the organ are shown by the speed of ascent to a peak and subsequent decline. Volume can be determined as a function of the magnitude of change of impedance. The magnitude of contractions of the wall are shown as a function of the area of the minor peaks superimposed on the main trace. Processing, for example, by Fourier analysis of the signals indicates contractions of the organ in different regions covered by the electrode and by dividing the trace into, for example, time intervals, differences in contractions at different times can be determined giving an indication of, for example, response to a meal or drugs or other stimulus.
The trace produced by combining the signals from a large number of electrodes gives an indication of the full impedance displacement of the organ and therefore gives a more sensitive indication of the volume that can be derived from the separate signals.
In one specific form of the apparatus, the generator means is a 100 kHz oscillator and the current control means produces a 4 milliamp peak-to-peak constant current drive.
A non-invasive method for monitoring stomach volume and rate of filling and/or emptying has long been sought by gastroenterological physicians. A non-invasive method has the advantages of repeatability unlike X-ray or isotopic methods so that the progress
of illness or the effects of treatment can be measured. The new device proposed has this capability and has proved so sensitive in practice that it may also be used to quantify the contractions of the stomach. Because pairs of electrodes can be used separately to monitor stomach contractions the progress of contractions through the stomach can be assessed. At the same time because a plurality of electrodes is used the accuracy of the volume measurement is enhanced by surveying an increased region of the body thus including the entire region of the stomach even though the exact position of the stomach cannot be identified from without.
Further, the use of at least two pairs of voltage sensing electrodes increases the possibility of recording signals from the region of interest, within the body, which cannot be identified from without.
Moreover, whereas impedance methods have been proposed for monitoring rates of change of cardiac volume and therefore the power of contraction and heart muscle the results have not been quantifiable. Therefore accurate measurements of the volume of blood ejected by the heart, known as cardiac output, have not been feasible. If electrodes of the new device are placed over the stomach and a measured volume of water or other suitable liquid drunk the impedance change can be measured so that impedance changes can be related to the volume drunk. Thus, when other electrodes are used to record the cardiac volume changes the results obtained can be quantified by reference to the recorded gastric change results. In this way a new, non-invasive device for monitoring cardiac performance is available.
Further, in any measurements of function where reference, comparison, or standardisation between signals from the organ being monitored and any other region of the body is required, additional sets of electrodes are used.
The invention will now be described in greater detail by way of example with reference to the drawing which shows a block diagram of
a single channel circuit showing only one pair of voltage sensing electrodes; whereas in practice at least two voltage sensing channels would be used. In the drawing, 1 is a 100 kHz oscillator,
2 is a 4 milliamp peak-to-peak constant current drive, 3 is the stomach, 4 is a pair of current driving electrodes, 5 is a pair of voltage sensing electrodes, 6 is a 100 kHz tuner/voltage amplifier,
7 is a detector to recover impedance changes, 8 is an impedance meter, 9 is a subject signal isolation amplifier, 10 is a low pass filter and impedance offset control, 11 is a chart recorder and 12 is a tape recorder or microcomputer.
In using the apparatus the current driving and voltage sensing electrodes 4 and 5 are placed on the body of the patient around the organ to be monitored. The signal recorded by the voltage sensing electrodes 5 is passed to the amplifier 6 and converted to impedance by detector/converter 7. The signal from the detector/converter 7 is passed both to impedance meter 8 which gives a direct read out of impedance and to trhe signal isolation amplifier 9 and thence to the low pass filter and recorder. When more than one voltage sensing channel is used the signals from the separate pairs of voltage sensing electrodes are maintained separate and are individually passed to the recorder so that impedance changes detected by each pair of voltage sensing electrodes can be recorded individually. The recorder, however, preferably also includes means for correcting phase displacement of the individual signals and combining the signals so that the total of the impedance changes recorded by a number of electrodes can also be indicated by the recorder.
Figs. 2 and 3 are more detailed self-explanatory circuit diagrams in which like reference numerals have been used to indicate the various components of the apparatus. It will be appreciated that only one set of electrodes 5 is shown in these figures and the circuitry will be duplicated as appropriate to accommodate from the sets of electrodes 5.
It will also be appreciated that the circuitry shown is merely exemplary of one especially preferred embodiment of the invention
- 5 - and the invention is not to be regarded in any way as limited to the arrangement shown.
Claims
1. Apparatus for monitoring body functions comprising oscillator means for generating a high frequency oscillation, an oscillator driven constant current generating source, at least one pair current driven electrodes for attachment to the body of a patient, at least two pairs of voltage sensing electrodes for attachment to the body of the patient, tuner/voltage amplifier means tuned to the frequency of the generator means, converter means for measuring impedance changes registering between pairs of voltage sensing electrodes, impedance indicator means, isolating circuit means for receiving signals from the impedance converter, filter means for excluding electronic or biological fluctuations from the equipment or the subject and a impedance offset control, and recorder means for recording the subject signals, the subject signals being received by the recorder means as separate signals.
2. Apparatus according to claim 1, wherein the recorder means comprises a chart recorder or oscilloscope, a tape recorder or a microcomputer.
3. Apparatus according to claim 1 or claim 2, wherein the recorder, in addition to having the capability for receiving the signals from the different electrode pairs separately also has the capability of correcting phase displacement between the signals and recording a combination of the signals, and in addition means to analyse and process signals as required.
4. A method of producing a record of the function of a hollow visceral organ which comprises :
attaching at least one pair current driven electrodes to the body of a patient around the region of the organ to be monitored; attaching at least two pairs of voltage sensing electrodes to the body of the patient around the region of the organ to be monitored; - - passing an oscillated driven constant current through the current driven electrodes; measuring the voltages received by the voltage sensing electrodes; converting said voltages to determine impedance through the organ; separately passing signals correlated to the impedance values recorded by said electrodes to a recorder and producing a continuous record of changes of impedance through the organ.
5. A method according to claim 4, wherein the separate signals produced from the voltage sensing electrodes are corrected for phase displacement and are combined to produce a record corresponding to the combination of the impedance changes across the organ.
6. A method according to claim 4, wherein the separate signals produced from the voltage sensing electrodes are processed separately In order to quantify the changes in impedance, in various regions of the organ of interest, as, for example, in the determination of volume, magnitude and periodicity of contraction, emptying and filling rates.
7. A method according to claim 4 or claim 5 or claim 6, wherein the impedance changes determined by a plurality of pairs of voltage sensing electrodes attached to the body around the region of the organ of interest are compared, standardised or combined with the signals obtained from an additional set of electrodes attached to a different part of the body.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08711445A GB2190751B (en) | 1984-11-15 | 1985-11-15 | Apparatus and method for monitoring organs of the body |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB848428831A GB8428831D0 (en) | 1984-11-15 | 1984-11-15 | Monitoring organs of body |
| GB8428831 | 1984-11-15 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO1986002819A1 true WO1986002819A1 (en) | 1986-05-22 |
Family
ID=10569750
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/GB1985/000521 WO1986002819A1 (en) | 1984-11-15 | 1985-11-15 | Apparatus and method for monitoring organs of the body |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0235137A1 (en) |
| JP (1) | JPS62501267A (en) |
| AU (1) | AU5069685A (en) |
| GB (2) | GB8428831D0 (en) |
| WO (1) | WO1986002819A1 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0359397A1 (en) * | 1988-08-19 | 1990-03-21 | Hewlett-Packard Company | Device for detection of uterine contractions |
| WO1995035060A1 (en) * | 1994-06-20 | 1995-12-28 | Auckland Uniservices Limited | Brain damage monitor |
| US6631292B1 (en) * | 2001-03-23 | 2003-10-07 | Rjl Systems, Inc. | Bio-electrical impedance analyzer |
| WO2004037082A1 (en) * | 2002-10-25 | 2004-05-06 | Urovid Pty Ltd | Anatomical sensor |
| GB2457365A (en) * | 2008-02-12 | 2009-08-19 | Gen Electric | Uterine activity momitoring using impedance plethysmography |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7758522B2 (en) * | 2007-01-03 | 2010-07-20 | General Electric Company | Combined uterine activity and fetal heart rate monitoring device |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3874368A (en) * | 1973-04-19 | 1975-04-01 | Manfred Asrican | Impedance plethysmograph having blocking system |
| FR2294677A1 (en) * | 1973-11-09 | 1976-07-16 | Thomson Medical Telco | Cardio-pulmonary diagnostic appts using HF current - has electrodes mounted in front and rear of thorax |
| US4059169A (en) * | 1976-02-09 | 1977-11-22 | Hagen Winston H | Monitor for biological volume changes |
| FR2354744A1 (en) * | 1976-06-16 | 1978-01-13 | Commissariat Energie Atomique | OCCLUSION RHEOPLETHYSMOGRAPHY DEVICE |
| WO1983004369A1 (en) * | 1982-06-07 | 1983-12-22 | Healthdyne, Inc. | Respiration or respiration and electrocardiographic monitor |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US387436A (en) * | 1888-08-07 | o neil |
-
1984
- 1984-11-15 GB GB848428831A patent/GB8428831D0/en active Pending
-
1985
- 1985-11-15 EP EP85905646A patent/EP0235137A1/en not_active Withdrawn
- 1985-11-15 WO PCT/GB1985/000521 patent/WO1986002819A1/en not_active Application Discontinuation
- 1985-11-15 AU AU50696/85A patent/AU5069685A/en not_active Abandoned
- 1985-11-15 JP JP60505007A patent/JPS62501267A/en active Pending
- 1985-11-15 GB GB08711445A patent/GB2190751B/en not_active Expired
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3874368A (en) * | 1973-04-19 | 1975-04-01 | Manfred Asrican | Impedance plethysmograph having blocking system |
| FR2294677A1 (en) * | 1973-11-09 | 1976-07-16 | Thomson Medical Telco | Cardio-pulmonary diagnostic appts using HF current - has electrodes mounted in front and rear of thorax |
| US4059169A (en) * | 1976-02-09 | 1977-11-22 | Hagen Winston H | Monitor for biological volume changes |
| FR2354744A1 (en) * | 1976-06-16 | 1978-01-13 | Commissariat Energie Atomique | OCCLUSION RHEOPLETHYSMOGRAPHY DEVICE |
| WO1983004369A1 (en) * | 1982-06-07 | 1983-12-22 | Healthdyne, Inc. | Respiration or respiration and electrocardiographic monitor |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0359397A1 (en) * | 1988-08-19 | 1990-03-21 | Hewlett-Packard Company | Device for detection of uterine contractions |
| WO1995035060A1 (en) * | 1994-06-20 | 1995-12-28 | Auckland Uniservices Limited | Brain damage monitor |
| US6631292B1 (en) * | 2001-03-23 | 2003-10-07 | Rjl Systems, Inc. | Bio-electrical impedance analyzer |
| WO2004037082A1 (en) * | 2002-10-25 | 2004-05-06 | Urovid Pty Ltd | Anatomical sensor |
| GB2457365A (en) * | 2008-02-12 | 2009-08-19 | Gen Electric | Uterine activity momitoring using impedance plethysmography |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8711445D0 (en) | 1987-06-17 |
| EP0235137A1 (en) | 1987-09-09 |
| GB2190751A (en) | 1987-11-25 |
| AU5069685A (en) | 1986-06-03 |
| GB8428831D0 (en) | 1984-12-27 |
| JPS62501267A (en) | 1987-05-21 |
| GB2190751B (en) | 1988-07-13 |
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