GB2356250A - Determining the amount of pressure wave reflection in a person's arterial tree - Google Patents
Determining the amount of pressure wave reflection in a person's arterial tree Download PDFInfo
- Publication number
- GB2356250A GB2356250A GB9926870A GB9926870A GB2356250A GB 2356250 A GB2356250 A GB 2356250A GB 9926870 A GB9926870 A GB 9926870A GB 9926870 A GB9926870 A GB 9926870A GB 2356250 A GB2356250 A GB 2356250A
- Authority
- GB
- United Kingdom
- Prior art keywords
- person
- red light
- amount
- pressure wave
- infra
- 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.)
- Granted
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Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/02—Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
- A61B5/02007—Evaluating blood vessel condition, e.g. elasticity, compliance
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/02—Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
- A61B5/021—Measuring pressure in heart or blood vessels
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/02—Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
- A61B5/021—Measuring pressure in heart or blood vessels
- A61B5/02108—Measuring pressure in heart or blood vessels from analysis of pulse wave characteristics
- A61B5/02116—Measuring pressure in heart or blood vessels from analysis of pulse wave characteristics of pulse wave amplitude
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/72—Signal processing specially adapted for physiological signals or for diagnostic purposes
- A61B5/7235—Details of waveform analysis
- A61B5/7239—Details of waveform analysis using differentiation including higher order derivatives
Abstract
Apparatus for determining the amount of pressure wave reflection in a person's arterial tree comprises a transmitter (<B>4 in fig. 1</B>) for transmitting red or infrared light through a part of the person's body, such as a finger or ear lobe, and a sensor (<B>8 in fig. 1</B>) for measuring the amount of light passing through the part of the person's body, the measurement providing a digital volume pulse waveform. The amount of pressure wave reflection is estimated by measuring the height (<B>IP</B> <SB>DVP</SB>) of an inflection point (<B>18</B>), this point being the point after the first peak (<B>16</B>) in the digital volume pulse waveform at which a first derivative of the waveform with respect to time is at a local maximum.
Description
2356250 APPARATUS FOR DETERMINING THE AMOUNT OF PRESSURE WAVE REFLECTION
IN A PERSON'S ARTERIAL TREE This invention relates to apparatus for determining the amount of pressure wave reflection in a person's arterial tree.
In a person, the aortic root of the person's arterial tree is the main artery conveying blood to the heart from the rest of the person's body. Blood pressure at the aortic root is influenced by the reflection of pressure waves from the periphery of the circulation back to the heart. The amount of reflection is influenced by the tone (ie the degree of contraction) of small arteries which are mainly in the person's lower body where pressure waves are reflected. Measurement of the amount of reflection provides useful information relating to the load against which the heart pumps, and also the tone of small muscular arteries. The information may be used to assess the effects of drugs on these parameters. Known methods for estimating the amount of pressure wave reflection are based on the measurement of the contour of the arterial pressure pulse. This is technically demanding and it requires an experienced investigator. Also, the known apparatus for carrying out these methods is expensive.
It is an aim of the present invention to obviate or reduce the above mentioned problems.,.--.- 2 Accordingly, in one non-limiting embodiment of the present invention there is provided apparatus for determining the amount of pressure wave reflection in a person's arterial tree, which apparatus comprises transmitter means for transmitting infra-red light or red light through a finger, thumb, toe or ear lobe of the person, measuring means for measuring the infra-red light or red light passing through the finger, thumb, toe or ear lobe and providing a digital volume pulse waveform consequent upon the measured infra-red light or red light, and estimating means for estimating the pressure wave reflection by measuring the height of an inflection point, the inflection point being the point after a first peak in the digital volume pulse waveform at which a first derivative of the digital volume pulse signal with respect to time is at a local maxima.
The apparatus of the present invention is simple to use and it can be produced more cheaply than the known apparatus. The height of the inflection point may be expressed relative to the amplitude of the digital volume pulse signal. The infra-red light or the red light is able to pass easily through the person's finger, thumb, toe or ear lobe. The fleshy part of the finger, thumb or toe will normally be used. The red light is preferably obtained from a light emitting diode but it may be obtained from any other suitable and appropriate light source.
3 Preferably, the transmitter means is an. infra-red light emitting diode. Other transmitter means may be employed.
Preferably, the measuring means is an infra-red light detector. other measuring means may be employed.
The apparatus of the present invention may include a housing for receiving the finger, thumb, toe or ear lobe of the person.
The housing may have an open end and a closed end. The finger, thumb, toe or ear lobe can then be inserted into the housing from the open end. The housing is preferably a tubular housing but housings of other cross sectional shapes may be employed.
An embodiment of the invention will now be described solely by way of example and with reference to the accompanying drawings in which:
Figure 1 shows apparatus for determining the amount of pressure wave reflection in a person's arterial tree; Figure 2 illustrates digital volume pulse waveforms; and Figure 3 shows schematically a forward going wave of a person, a reflected wave from the person, and how the two waves are related to digital volume pulse.
Referring to the drawings, there is shown apparatus 2 for determining the amount of pressure wave reflection in a person's arterial tree. The apparatus 2 comprises transmitter means 4 for transmitting infra-red light 4 through f inger pulp in a f inger 6 of the person. The apparatus 2 also comprises measuring means 8 for measuring the infra-red light passing through the finger pulp and providing a digital volume pulse waveform consequent upon the measured infra-red light. The transmitter means 4 is an infra-red light emitting diode. The measuring means 8 is an infra-red light detector.
The apparatus 2 includes a housing 10. The housing 10 has an open end 12 and a closed end 14. As can be seen from Figure 1, the finger 6 is inserted into the housing 10 from the open end 12.
The apparatus 2 also comprises estimating means (not shown) for estimating the pressure wave reflection by measuring the height of an inflection point. The inflection point is the point after a first peak in the digital volume pulse waveform, at which a first derivative of the digital volume pulse signal with respect to time is at a local maxima. The operation of the estimating means is shown in Figure 2 where it can be seen that the illustrated digital volume pulse waveform has two peaks 16, 18. The first peak 16 is formed mainly by the transmission of a pressure wave from the person's heart direct to the finger 6. The second peak 18 is formed by the transmission of a pressure wave reflected mainly from the small arteries in the person's lower body. The height of the second peak 18 provides a simple measure of the amount of pressure wave reflection. However, the second peak 18 is not always clearly defined.
In order to overcome the problem of the second peak 18 not always being clearly defined, the estimating means is employed to make an objective assessment of wave reflection. The objective assessment of wave reflection, closely related to the height of the second peak 18, is determined by measuring the height of the inflection point IPDVP This deflection point is defined as the point, after the first peak 16, at which the first derivative of the digital volume pulse signal with respect to time is at a local maxima. The inflection point-is expressed relative to the amplitude of the digital volume pulse signal.
Referring now to Figure 3, there is shown a forward going wave Fw preceding from the left ventricle (V) of the person's heart along the aorta (Ao). The forward going wave Fw is reflected backwards from small arteries in the periphery at an "apparent site of wave reflection" to form a backward going reflected wave Rw. The digital volume pulse DVP comprises the sum of the forward going wave Fw and the reflected wave Rw. The first peak 16 in the illustrated waveform is due mainly to the forward going wave Fw. The second peak 18 in the waveform is due to the reflected wave Rw. The height of the inflection point IPDVP in the digital volume pulse provides a simple measure of the amount of reflection. The amount of the reflection is then able to be used as useful information related to the load against which the person's heart pumps, and also to the tone of small muscular arteries. The amount of reflection may also be used to asse ss the effects of drugs on these parameters.
It is to be appreciated that the embodiment of the invention described above with reference to the accompanying drawings has been given by way of example only and that modifications may be effected. Thus, for example, other types of transmitter means 4 and measuring means 8 may be employed. Also, the housing 10 may be of a different shape to that shown. The person's thumb, toe or ear lobe may be used instead of the finger 6. Instead of infra-red light, the light may be red light, for example from a light emitting diode.
7
Claims (7)
1 Apparatus for determining the amount of pressure wave reflection in a person's arterial tree, which apparatus comprises transmitter means for transmitting infra-red light or red light through a finger'. thumb, toe or ear lobe of the person, measuring means for measuring the infra-red light or red light passing through the finger, thumb, toe or ear lobe and providing a digital volume pulse waveform. consequent upon the measured infra-red light or red light, and estimating means for estimating the pressure wave reflection by measuring the height of an inflection point, the inflection point being the point after a first peak in the digital volume pulse waveform at which a first derivative of the digital volume pulse signal with respect to time is at a local maxima.
2. Apparatus according to claim 1 in which the transmitter means is an infra-red light emitting diode.
3. Apparatus according to claim 1 or claim 2 in which the measuring means is an infra-red light detector.
4. Apparatus according to any one'of the preceding claims and including a housing for receiving the finger, thumb, toe or ear lobe of the person.
8
5. Apparatus according to claim 4 in which the housing has an open end and a closed end.
6. Apparatus according to claim 4 or claim 5 in which the housing is a tubular housing.
7. Apparatus for determining the amount of pressure wave reflection in a person's arterial tree, substantially as herein described with reference. to the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9926870A GB2356250B (en) | 1999-11-12 | 1999-11-12 | Apparatus for determining the amount of pressure wave reflection in a person's arterial tree |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9926870A GB2356250B (en) | 1999-11-12 | 1999-11-12 | Apparatus for determining the amount of pressure wave reflection in a person's arterial tree |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9926870D0 GB9926870D0 (en) | 2000-01-12 |
| GB2356250A true GB2356250A (en) | 2001-05-16 |
| GB2356250B GB2356250B (en) | 2003-10-15 |
Family
ID=10864461
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9926870A Expired - Fee Related GB2356250B (en) | 1999-11-12 | 1999-11-12 | Apparatus for determining the amount of pressure wave reflection in a person's arterial tree |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2356250B (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6616613B1 (en) | 2000-04-27 | 2003-09-09 | Vitalsines International, Inc. | Physiological signal monitoring system |
| US9649071B2 (en) | 2009-09-29 | 2017-05-16 | Nellcor Puritan Bennett Ireland | Systems and methods for high-pass filtering a photoplethysmograph signal |
| US9687161B2 (en) | 2008-09-30 | 2017-06-27 | Nellcor Puritan Bennett Ireland | Systems and methods for maintaining blood pressure monitor calibration |
| US9949648B2 (en) | 2003-07-07 | 2018-04-24 | Nellcor Puritan Bennett Ireland | Continuous non-invasive blood pressure measurement apparatus and methods providing automatic recalibration |
| US10165953B2 (en) | 2010-11-30 | 2019-01-01 | Nellcor Puritan Bennett Ireland | Methods and systems for recalibrating a blood pressure monitor with memory |
| US11246495B2 (en) | 2014-10-27 | 2022-02-15 | Vital Sines International Inc. | System and method for monitoring aortic pulse wave velocity and blood pressure |
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| US8398556B2 (en) | 2008-06-30 | 2013-03-19 | Covidien Lp | Systems and methods for non-invasive continuous blood pressure determination |
| US8660799B2 (en) | 2008-06-30 | 2014-02-25 | Nellcor Puritan Bennett Ireland | Processing and detecting baseline changes in signals |
| US8506498B2 (en) | 2008-07-15 | 2013-08-13 | Nellcor Puritan Bennett Ireland | Systems and methods using induced perturbation to determine physiological parameters |
| US8532751B2 (en) | 2008-09-30 | 2013-09-10 | Covidien Lp | Laser self-mixing sensors for biological sensing |
| US9314168B2 (en) | 2008-09-30 | 2016-04-19 | Nellcor Puritan Bennett Ireland | Detecting sleep events using localized blood pressure changes |
| US9301697B2 (en) | 2008-09-30 | 2016-04-05 | Nellcor Puritan Bennett Ireland | Systems and methods for recalibrating a non-invasive blood pressure monitor |
| US8216136B2 (en) | 2009-03-05 | 2012-07-10 | Nellcor Puritan Bennett Llc | Systems and methods for monitoring heart rate and blood pressure correlation |
| US9198582B2 (en) | 2009-06-30 | 2015-12-01 | Nellcor Puritan Bennett Ireland | Determining a characteristic physiological parameter |
| US8290730B2 (en) | 2009-06-30 | 2012-10-16 | Nellcor Puritan Bennett Ireland | Systems and methods for assessing measurements in physiological monitoring devices |
| US8628477B2 (en) | 2009-07-31 | 2014-01-14 | Nellcor Puritan Bennett Ireland | Systems and methods for non-invasive determination of blood pressure |
| US9220440B2 (en) | 2009-09-21 | 2015-12-29 | Nellcor Puritan Bennett Ireland | Determining a characteristic respiration rate |
| US8463347B2 (en) | 2009-09-30 | 2013-06-11 | Nellcor Puritan Bennett Ireland | Systems and methods for normalizing a plethysmograph signal for improved feature analysis |
| US9451887B2 (en) | 2010-03-31 | 2016-09-27 | Nellcor Puritan Bennett Ireland | Systems and methods for measuring electromechanical delay of the heart |
| US8898037B2 (en) | 2010-04-28 | 2014-11-25 | Nellcor Puritan Bennett Ireland | Systems and methods for signal monitoring using Lissajous figures |
| US9259160B2 (en) | 2010-12-01 | 2016-02-16 | Nellcor Puritan Bennett Ireland | Systems and methods for determining when to measure a physiological parameter |
| US9357934B2 (en) | 2010-12-01 | 2016-06-07 | Nellcor Puritan Bennett Ireland | Systems and methods for physiological event marking |
| US9060695B2 (en) | 2011-11-30 | 2015-06-23 | Covidien Lp | Systems and methods for determining differential pulse transit time from the phase difference of two analog plethysmographs |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1990011043A1 (en) * | 1989-03-24 | 1990-10-04 | Eastern Medical Testing Services, Inc. | A method and apparatus for ascertaining the contour of the pressure pulse in the central arteries from the contour of the pressure pulse in the peripheral arteries |
| WO1992011804A1 (en) * | 1991-01-14 | 1992-07-23 | Jonathan Kraidin | Method and apparatus for determining cardiac output |
-
1999
- 1999-11-12 GB GB9926870A patent/GB2356250B/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1990011043A1 (en) * | 1989-03-24 | 1990-10-04 | Eastern Medical Testing Services, Inc. | A method and apparatus for ascertaining the contour of the pressure pulse in the central arteries from the contour of the pressure pulse in the peripheral arteries |
| WO1992011804A1 (en) * | 1991-01-14 | 1992-07-23 | Jonathan Kraidin | Method and apparatus for determining cardiac output |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6616613B1 (en) | 2000-04-27 | 2003-09-09 | Vitalsines International, Inc. | Physiological signal monitoring system |
| US9949648B2 (en) | 2003-07-07 | 2018-04-24 | Nellcor Puritan Bennett Ireland | Continuous non-invasive blood pressure measurement apparatus and methods providing automatic recalibration |
| US9687161B2 (en) | 2008-09-30 | 2017-06-27 | Nellcor Puritan Bennett Ireland | Systems and methods for maintaining blood pressure monitor calibration |
| US9649071B2 (en) | 2009-09-29 | 2017-05-16 | Nellcor Puritan Bennett Ireland | Systems and methods for high-pass filtering a photoplethysmograph signal |
| US10165953B2 (en) | 2010-11-30 | 2019-01-01 | Nellcor Puritan Bennett Ireland | Methods and systems for recalibrating a blood pressure monitor with memory |
| US11246495B2 (en) | 2014-10-27 | 2022-02-15 | Vital Sines International Inc. | System and method for monitoring aortic pulse wave velocity and blood pressure |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9926870D0 (en) | 2000-01-12 |
| GB2356250B (en) | 2003-10-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20181112 |