EP1061980A1 - Metabolic gas exchange and noninvasive cardiac output monitor - Google Patents
Metabolic gas exchange and noninvasive cardiac output monitorInfo
- Publication number
- EP1061980A1 EP1061980A1 EP98911713A EP98911713A EP1061980A1 EP 1061980 A1 EP1061980 A1 EP 1061980A1 EP 98911713 A EP98911713 A EP 98911713A EP 98911713 A EP98911713 A EP 98911713A EP 1061980 A1 EP1061980 A1 EP 1061980A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- gasses
- subject
- flow meter
- respiratory
- inhaled
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Definitions
- This invention relates to a respiratory gas analyzer employing a flow
- a sensor and a capnometer which may be interconnected in a first configuration to measure metabolic activity of a patient or in a second configuration to measure
- the integrated flow differences between the inhalations and the carbon dioxide scrubbed exhalations are a measure of the patient's oxygen
- These devices may incorporate a capnometer to measure the carbon dioxide concentration of the
- a computer receiving signals from the flow meter and the
- capnometer may calculate, in addition to the oxygen consumption of the patient,
- the cardiac output of a patient that is the volume of blood ejected from
- cardiac output is routinely measured by invasive techniques 2 including thermal dilution using an indwelling pulmonary artery catheter. This
- the partial rebreathing technique is a known method for cardiac output
- measuring cardiac output requires blood gas values for arterial and mixed venous
- CO. cardiac output
- VO 2 oxygen consumption
- CaO 2 the arterial pressure
- the partial rebreathing method allows 3 computation of cardiac output without invasive blood gas measurements as follows:
- the partial rebreathing technique uses the change in CO 2 production (VCO j ) and
- the present invention is accordingly directed toward a respiratory gas
- respiratory gasses which is typically atmospheric air
- a mouthpiece so that
- the flow meter measures the gas volume during inhalation. During exhalation
- the gas is passed through a capnometer to the carbon dioxide scrubber and the output of the scrubber is fed back through the flow meter to the atmosphere.
- the exhaled breath is not passed through the carbon dioxide scrubber but is
- the analyzer may be formed so that the carbon
- the scrubber may be maintained in position on
- the analyzer further includes valving connected to the circuitry to shift
- exhaled gasses are passed through the capnometer and then directly to the flow
- the conduit volume thus acts as a
- gasses constitutes rebreathed gasses from the conduit dead space having a high
- carbon dioxide content Preferably from 20% to 70% of the inhaled air
- the metabolic measurements are made with the scrubber connected in
- a computer connected to the flow meter
- the valve is in the first configuration in which the exhaled gas is passed through
- Each inhaled breath includes a proportion
- Figure 1 is a schematic diagram illustrating a preferred embodiment of
- Figure 2 is a schematic diagram of the system of Figure 1 in a
- Figure 3 is a schematic diagram of the system of Figure 1 in a
- the analyzer employs a mouthpiece 12
- the mouthpiece 12 connects through a short passage 14 to a capnometer
- the capnometer 16 generates an electrical signal which is a function
- the capnometer may be of a conventional type such as those
- the capnometer provides an electrical output signal to a computation unit 18
- the capnometer is connected by a short passage 24 to a two position,
- the valve has a single input flow
- valve has a first position, illustrated in Figure 1 , in which output is provided to
- a second one-way valve 32 connecting to the input of a carbon dioxide scrubber
- the carbon dioxide scrubber 34 is a container having a central gas
- absorbent materials may include sodium
- the output 38 of the scrubber is located adjacent to a bi-directional
- volume flow sensor 40 which is positioned at the end of the volume 30 opposite
- the flow sensor is preferably of the pressure differential type
- source and sink is typically the atmosphere but may alternatively be a suitable
- the electrical output of the bi-directional volume flow sensor is connected to the computation unit 18.
- the Respiratory Quotient (RQ) which equals VCO 2 divided by VO 2
- the Resting Energy Expenditure (REE) preferably
- the sensor 16 generates an electrical signal which is provided to the
- the carbon dioxide in the exhaled breath and provides its output into the volume 10 30 immediately adjacent the bi-directional volume flow sensor 40 in a direction
- the volume of exhaled air passing through the flow sensor 40 will be described.
- the computation unit 18 converts the signals from the capnometer 16 and the flow sensor 40 into
- the computation unit 18 otherwise operates in the manner disclosed in my U.S. Patent 4,917,718 to integrate signals representing the difference between the inhaled and exhaled volume for the period of the test
- unit 18 allows storage and display of various factors in the same manner as the
- the unit may incorporate an artificial nose and/or a bacterial filter as
- FIG 2 illustrates the unit with the scrubber 34 physically detached
- valve 32 to the area adjacent the flow meter 40.
- the computation unit 18 may control the two position valve 26 and move
- tidal carbon dioxide etCO 2
- the measurement sequence is as follows:
- the etCO 2 is calculated on a breath-by-breath basis using a
- the inhaled air is not admixed to any appreciable degree with previously exhaled air.
- passage 30 is preferably about 15-25% of the tidal volume of the
- Typical tidal volumes range between 600 ml and 1000
- the volume of the chamber 30 is preferably about 150 ml.
- the subject therefore rebreathes carbon dioxide from the 13 temporary dead space chamber for approximately thirty seconds.
- the unit can thus calculate and display the following parameters: oxygen
- V 2 measured energy expenditure
- MEE measured energy expenditure
- VCO 2 cardiac output
- RER respiratory exchange ratio
- V minute ventilation
- etCO 2 end-tidal carbon dioxide
- the computation unit 18, in the cardiac output mode may employ a
Landscapes
- Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)
Abstract
Description
Claims
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/US1998/005184 WO1999045988A1 (en) | 1997-03-11 | 1998-03-13 | Metabolic gas exchange and noninvasive cardiac output monitor |
Publications (2)
Publication Number | Publication Date |
---|---|
EP1061980A1 true EP1061980A1 (en) | 2000-12-27 |
EP1061980A4 EP1061980A4 (en) | 2002-09-25 |
Family
ID=22266613
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP98911713A Withdrawn EP1061980A4 (en) | 1998-03-13 | 1998-03-13 | Metabolic gas exchange and noninvasive cardiac output monitor |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP1061980A4 (en) |
JP (1) | JP2002505923A (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7135001B2 (en) * | 2001-03-20 | 2006-11-14 | Ric Investments, Llc | Rebreathing methods including oscillating, substantially equal rebreathing and nonrebreathing periods |
EP2785402A1 (en) * | 2011-12-01 | 2014-10-08 | Koninklijke Philips N.V. | Systems and methods for using partial co2 rebreathing integrated in a ventilator and measurements thereof to determine noninvasive cardiac output |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5179958A (en) * | 1988-06-29 | 1993-01-19 | Mault James R | Respiratory calorimeter with bidirectional flow monitor |
-
1998
- 1998-03-13 JP JP2000535399A patent/JP2002505923A/en active Pending
- 1998-03-13 EP EP98911713A patent/EP1061980A4/en not_active Withdrawn
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5179958A (en) * | 1988-06-29 | 1993-01-19 | Mault James R | Respiratory calorimeter with bidirectional flow monitor |
Non-Patent Citations (2)
Title |
---|
CAPEK J M ET AL: "NONINVASIVE MEASUREMENT OF CARDIAC OUTPUT USING PARTIAL CO2 REBREATHING" IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING, IEEE INC. NEW YORK, US, vol. 35, no. 9, 1 September 1988 (1988-09-01), pages 653-661, XP000209300 ISSN: 0018-9294 * |
See also references of WO9945988A1 * |
Also Published As
Publication number | Publication date |
---|---|
EP1061980A4 (en) | 2002-09-25 |
JP2002505923A (en) | 2002-02-26 |
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Legal Events
Date | Code | Title | Description |
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PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
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17P | Request for examination filed |
Effective date: 20001011 |
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AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AT BE CH DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE |
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RIC1 | Information provided on ipc code assigned before grant |
Free format text: 7A 61M 15/00 A |
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A4 | Supplementary search report drawn up and despatched |
Effective date: 20020808 |
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AK | Designated contracting states |
Kind code of ref document: A4 Designated state(s): AT BE CH DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE |
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RIC1 | Information provided on ipc code assigned before grant |
Free format text: 7A 61B 5/083 A, 7A 61B 5/029 B |
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RAP1 | Party data changed (applicant data changed or rights of an application transferred) |
Owner name: HEALTHETECH, INC. |
|
RIN1 | Information on inventor provided before grant (corrected) |
Inventor name: MAULT, JAMES R. |
|
17Q | First examination report despatched |
Effective date: 20040416 |
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STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
|
18D | Application deemed to be withdrawn |
Effective date: 20040827 |