WO2021025885A1 - Manchon à pression destiné à être utilisé dans un dispositif de mesure de pression sanguine non invasif - Google Patents

Manchon à pression destiné à être utilisé dans un dispositif de mesure de pression sanguine non invasif Download PDF

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Publication number
WO2021025885A1
WO2021025885A1 PCT/US2020/043678 US2020043678W WO2021025885A1 WO 2021025885 A1 WO2021025885 A1 WO 2021025885A1 US 2020043678 W US2020043678 W US 2020043678W WO 2021025885 A1 WO2021025885 A1 WO 2021025885A1
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WO
WIPO (PCT)
Prior art keywords
light
pressure
body part
detectors
signal
Prior art date
Application number
PCT/US2020/043678
Other languages
English (en)
Inventor
Jacobus Jozef Gerardus Maria Settels
Alexander H. Siemons
Original Assignee
Edwards Lifesciences Corporation
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Edwards Lifesciences Corporation filed Critical Edwards Lifesciences Corporation
Priority to EP20757055.7A priority Critical patent/EP4009859A1/fr
Priority to CN202080051870.5A priority patent/CN114126483A/zh
Publication of WO2021025885A1 publication Critical patent/WO2021025885A1/fr

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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
    • A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
    • A61B5/6801—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be attached to or worn on the body surface
    • A61B5/6813—Specially adapted to be attached to a specific body part
    • A61B5/6825—Hand
    • A61B5/6826—Finger
    • 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
    • A61B5/022—Measuring pressure in heart or blood vessels by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
    • A61B5/02233—Occluders specially adapted therefor
    • A61B5/02241—Occluders specially adapted therefor of small dimensions, e.g. adapted to fingers
    • 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
    • A61B5/022—Measuring pressure in heart or blood vessels by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
    • A61B5/0225—Measuring pressure in heart or blood vessels by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers the pressure being controlled by electric signals, e.g. derived from Korotkoff sounds
    • 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
    • A61B5/022—Measuring pressure in heart or blood vessels by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
    • A61B5/0225—Measuring pressure in heart or blood vessels by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers the pressure being controlled by electric signals, e.g. derived from Korotkoff sounds
    • A61B5/02255—Measuring pressure in heart or blood vessels by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers the pressure being controlled by electric signals, e.g. derived from Korotkoff sounds the pressure being controlled by plethysmographic signals, e.g. derived from optical sensors
    • 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
    • A61B5/022—Measuring pressure in heart or blood vessels by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
    • A61B5/0235—Valves specially adapted therefor

Definitions

  • the present invention relates to a pressure cuff for use in a non-invasive blood pressure measurement device.
  • EP 0 048 060 describes that the pressure of a fluid inside the pressure cuff is controlled on the basis on a signal of a plethysmograph by a pressure valve, in turn controlled by a servo control feedback loop.
  • the signal of the plethysmograph is representing the volume changes of blood inside the blood vessels of the finger under the cuff.
  • the more blood the more light from a light source of the plethysmograph is absorbed, which results in a lower signal of the plethysmograph (and vice versa).
  • blood is propagated through the blood vessels in the finger. This blood flow also causes a blood volume increase of the vessels, and thus a signal decrease of the plethysmograph.
  • the cuff pressure of the pressure cuff is servo controlled using a variable resistance proportional valve, such that the signal of the plethysmograph, and thus the volume of blood inside the blood vessels under the cuff, is kept constant.
  • the pressure exerted on the blood vessel walls from the inside by the heart pulsations is continuously counteracted by a pressure exerted by the pressure cuff.
  • these two pressures are dynamically equal, this results in a constant diameter of the blood vessels and an unloading of the vessels.
  • the counter pressure exerted by the pressure cuff is a direct measure for the actual blood pressure inside the blood vessel, and allows for a continuous non-invasive blood pressure measurement.
  • the invention thereto provides a pressure cuff for use in a non-invasive blood pressure measurement device, comprising: a bladder, for placement around a body part such as a finger, for applying pressure to the body part; at least one light source, for sending light through the body part under the bladder; at least two light detectors, each for detecting light passed through the body part and each for providing a signal in dependence of the amount of detected light; wherein the at least two light detectors and the at least one light source are arranged on the inside of the pressure cuff, and wherein the at least two light detectors are spaced apart; wherein the at least two light detectors are configured to detect light emitted from a single light source at a time, and are each configured to detect light of the same wavelength.
  • the at least one light source and at least one of the at least two light detectors may be arranged in pairs, in use substantially on opposite sides of the body part. Each pair comprises one light source and one light detector.
  • the light detectors are for instance spaced apart such that they follow an artery in the body part under the bladder.
  • the body part is a finger, and the detectors are spaced apart in longitudinal direction of the finger, from the proximal end of the finger towards the distal end (or tip) of the finger.
  • the bladder which is wrapped around the body part such as the finger, applies pressure to the body part which counteracts the pressure fluctuations of the arteries inside the body part that are caused by the heart.
  • the counteracting pressure is applied in dependence of the amount of light received by the light receiver.
  • the bladder, applying pressure to the body part, in particular the finger typically has a certain pressure transfer profile within the body part tissues from the outside - the skin - to the inside, which typically means the outside of the wall of the blood vessel within the body part. For instance, such transfer profile has a full (meaning 1 :1) transfer in the middle of the bladder, whereas the transfer on the outer edges of the bladder is significantly less.
  • the bladder is typically used to put the walls of the arteries inside the body part into an unloaded state, in which for instance the pressure exerted on the inside and outside of the arterial wall is substantially the same.
  • This unloaded state requires a certain counter pressure, which may for instance be achieved at certain locations of the bladder only, typically at the centre, or in the middle, of the bladder.
  • the arteries of the body part are thus typically brought into an unloaded state, wherein the pressure exerted by the bladder equals intra-arterial pressure, which pressure typically is high and closes the veins of the same body part in the middle of the cuff.
  • intra-arterial pressure which pressure typically is high and closes the veins of the same body part in the middle of the cuff.
  • the veins will be left open at least partly, such that in these veins pressure may build up due to entry of blood through the open arteries, but a closed return vein in the middle of the bladder.
  • the arteries may not be brought completely in the unloaded state, such that they may pulsate in diameter upon beating of the heart. Both effects could disturb an optimal measurement of the arterial volume relative to the counter-pressure applied by the cuff, and thus could disturb an optimal measurement of the blood pressure with the cuff.
  • the first effect will increase in time when an unloading cuff is applied to the body part, typically a finger. Because the veins are closed in the middle under the cuff, the finger tip distal to the cuff will increase its volume and the arteriolar, capillary and venular beds will gradually fill up and increase their pressure from capillary pressure to mean arterial pressure of the unloaded artery under the cuff.
  • a third effect is the flow of blood and thus light absorbing red blood cells when the artery is unloaded.
  • the artery When unloaded, the artery is always open - at its unloaded diameter - and with every heart beat blood is flowing in - to the finger tip - during systole and back out - from the finger tip - during diastole because of the positive and negative pressure gradients during these phases.
  • the plethysmograph system may be used to provide input to the servo system maintain an unloaded state of the arteries inside the body part under the cuff.
  • light is emitted from a light source, which light is influenced - scattered and partly absorbed - by the different tissues - including blood - inside the body part.
  • the amount of light subsequently detected by the light receiver is typically less than the amount of light emitted and is a measure of the volume of blood in the blood vessels - arteries and veins - in the body part under the cuff which absorbs or scatters the emitted light.
  • Such scattering for instance occurs upon tissue interaction, when light for instance encounters cell nuclei and mitochondria inside the body part. Scattering in turn increases the distance the light has to travel, which increases likelihood of encountering other tissues and thus the likelihood of being absorbed.
  • the pressure cuff relies upon multiple mutually spaced light detectors, and preferably one or multiple spaced light sources.
  • multiple light detectors, and/or sources for instance spaced longitudinally over the pressure cuff and/or along the artery of the body part, the absorption of light in the body part under the cuff may be determined, by measuring where and how much of the light emitted from one light source is received by the multiple detectors.
  • the light detectors may also be arranged in an array of light detectors, to determine where light emitted from the light sources is received by the multiple detectors.
  • the pressure cuff may further comprise at least two light sources, each for sending light through the body part under the bladder; wherein the two light sources and the two light detectors are arranged in pairs.
  • substantially opposite sides of the body part is meant that, in a cross-sectional view of the body part each of the elements of the pairs are located on two more or less opposite sides of the body part. Where one of the elements of the pair would for instance be located on the left side, or left half of the cross-sectional view, the other element of the pair would be located on the right side, of right half of the cross-sectional view.
  • Typical cuff application sites include a phalanx of a human finger, a section of a human upper arm, a human wrist or an animal tail as body part.
  • the body part is a finger, and typically is an index or middle finger.
  • the light detector and light source, forming a pair are located on opposite sides of the finger.
  • the light sources are located on the right and the light detectors on the left.
  • the light sources are on the left side of the cross-sectional view, and the light detectors are on the right side of the cross-sectional view.
  • the light sources may emit light of substantially the same wavelength.
  • each of the light sources of the pressure cuff emits light of the same wavelength the scattering or absorbance of light passing through the body part may be investigated, irrespective of the potential scattering and absorbing differences between light emitted of different wavelengths.
  • Each of the light detectors is further arranged to detect light emitted from the light source(s).
  • the pressure cuff may for instance comprise at least three light sources and at least three light detectors. More sources and more detectors increases the amount of signals and increases the resolution and thus accuracy of the determination of the arterial volume. Three sources and three detectors furthermore is a practical amount which could still be distributed properly over a pressure cuff to be used around a finger. Each light detector may be arranged to measure the light passed through the body part of each of the light sources.
  • a light detector that forms a pair with an emitting light source, or the light detector closest to the light source receives the majority of the light passing through the body part, and that the other light detectors receive less light from the light source, mainly because the light will need to travel longer to the other light detectors, and is thus subjected to more scattering and absorbance.
  • all light detectors measure approximately the same amount of light, which light is emitted from a single light source, it is likely that light is not passing through the body part, or finger, in transmission mode but is passing around the body part in reflection mode between the skin and the cuff.
  • the signals may be used to determine whether or not the pressure cuff is wrapped around the body part sufficiently tight.
  • the wavelength of the light sent or emitted by the light sources may lie around the isobestic point of haemoglobin, and in particular is about 800nm.
  • about 800nm according to the invention is meant wavelengths around 800nm.
  • the effective attenuation coefficient of haemoglobin molecules, a main constituent of red blood cells, is independent, or at least relatively independent, on the oxygenation thereof.
  • Wavelengths falling within the scope of about 800nm include for instance wavelengths between 750 and 950nm, in particular between 750 and 850nm.
  • the light sources may be configured for providing a coherent bundle of light, and for instance comprise coherent light emitting diodes and/or lasers.
  • a coherent bundle is different from a normal bundle of light in that the range of wavelengths is smaller, and in particular photons of a single wavelength are emitted. Additionally, when using lasers for instance, emitted light does not diverge, or at least not as much. Less divergence results in less scattering of light in the body part and should thus result in less contamination of received light from the light detectors which do not form a pair with the emitting light source.
  • the light detectors may be configured to for providing a signal in dependence of the amount of detected light of a certain wavelength, in particular in dependence of a certain range of wavelengths only.
  • This range of wavelengths may for instance coincide with the range of wavelengths, or the single wavelength, as emitted by the at least one light source.
  • the present invention further relates to a pressure system for use in a non-invasive blood pressure measurement device, comprising: a pressure cuff according to the invention; an actuator, such as a pump, for supplying pressurized fluid to the bladder; a variable flow resistance, located between the actuator and the bladder, to vary the pressure supplied to the bladder by the actuator; and a controller, arranged to provide a controller signal based on the signals of each of the light detectors. If the actuator is made variable, there is no need for variable flow resistance.
  • the controller of the pressure system may be arranged to provide the controller signal based on the light detected by one pair of light detector and light source of the pressure cuff, and correct this signal for the light detected by each of the other light detectors.
  • the light detected by each of the other detectors may for instance be multiplied with a constant value as weight factor, and subsequently be subtracted from the light detected by the light detector forming a pair with the light source.
  • the correction for instance includes the step of providing a new signal, based on a constant times the pair forming detector minus another constant times the detector signal(s) not forming a pair.
  • the controller of the pressure system may be arranged to continuously control the variable flow resistance and/or the actuator, based on the signals of the light detector and/or the controller signal.
  • the controller may be arranged to calculate a set-point based on the signals of the light detectors.
  • the signal of an optical plethysmograph is representing the volume of blood inside the blood vessels under the cuff of the finger. The more blood inside the vessels, the more light from a light source of the plethysmograph is absorbed, which results in a lower signal of the detector side of the plethysmograph (and vice versa).
  • blood is forced through the blood vessels in the finger, causing the vessels to expand and allow more blood to flow through the vessels. This also causes a volume increase of the vessels, and thus a signal decrease of the plethysmograph.
  • the cuff pressure of the pressure cuff is controlled such that the signal of the plethysmograph, and thus the volume of blood inside the blood vessels, is kept constant.
  • the pressure exerted by the heart on the internal blood vessel walls is continuously counteracted by a pressure exerted by the pressure cuff on the external blood vessel walls, which results in a constant diameter of the blood vessels and an unloading of the vessels.
  • the counter pressure exerted by the pressure cuff is a measure for the actual blood pressure inside the blood vessel, and allows for a continuous non-invasive blood pressure measurement.
  • This control is arranged as a servo feedback system such that at any moment the difference between a servo reference level or setpoint value for the diameter of the blood vessels and the actual plethysmograph signal or real value is minimized, ideally to zero.
  • the servo-reference level in the known method is initially determined automatically and the servo feedback control is operated in a way such that the cuff pressure continuously corresponds substantially with the momentary arterial pressure under the cuff both for pulsations and for absolute pressure level.
  • US 4,510,940 for instance describes a method and a device for correcting the cuff pressure in the indirect, non-invasive and continuous measurement of the blood pressure in a part of the body by using a plethysmograph in a fluid-filled pressure cuff, an electronic control circuit, and an electric pressure valve.
  • the cuff pressure is controlled by the plethysmograph signal in closed-loop operation with the aid of a servo- reference level obtained via a memory circuit.
  • the servo-reference level in operation of the device, is adjusted by opening the closed loop of the control circuit for a short interval, after which, in open-loop operation the cuff pressure is adjusted at an intermediate pressure derived from the pressure last measured and the servo-reference level is adjusted via the memory circuit.
  • the set point determination may be improved by restricting the light receiver signals to the areas of the body part that are actually unloaded. This area is typically the middle or centre of the inflatable cuff.
  • the light detector directly opposite this light source would receive light information from the center, which would correspond to the area of the artery which is unloaded, but also from areas more distal or proximal, corresponding to areas of the artery which are not fully unloaded, for instance because the bladder is not large enough to unload the full area of the body part under the cuff or because the veins under the cuff are not fully collapsed and contribute to the absorption of light.
  • the present invention further relates to a method for measuring a volume of blood flowing through a body part, comprising the steps of: placing a pressure cuff according to the invention around a body part; sending light of one of the light sources through the body part; detecting the light, sent by the single light source, with at least two light detectors, wherein each of the light detectors provides a signal based on the detected light; providing the signal of the light detector closest to the emitting light source, and correcting for, or subtracting, the signal of at least one of the other light detectors; and determining a volume of blood flowing through the body part based on the corrected or subtracted signal.
  • Correction or subtraction in the method may also comprise the step of processing the signals of the at least one of the light detectors before correction or subtracting.
  • one of the light detectors is arranged opposite to the at least one light source, wherein the other light detectors are arranged at an angle from the at least one light source.
  • the light detector opposite to the light source provides the main signal, wherein the light detectors at an angle provide the signal which is to be subtracted (or corrected for).
  • the light detector and light source providing the main signal are considered to form a pair according to the invention.
  • the method may further comprise the step of repeating, for each light source, the steps of sending light of one of the light sources through the body part; detecting the light, sent by the single light source, with at least two light detectors, wherein each of the light detectors provides a signal based on the detected light; correcting for, or subtracting the signal of the light detectors, which do not form a pair with the single light source from the signal of the light detector which does form a pair with the single light source; and determining a volume of blood flowing through the body part based on the subtracted signal.
  • a cuff, or pressure cuff, used in non-invasive blood pressure measurements may comprise an inflatable bladder provided with an air supply channel for inflating the bladder and for evacuating the bladder.
  • the air channel may for instance be connected to the bladder using a suitable fitting.
  • the inflatable bladder may comprise a top layer arranged to be brought into contact with the body part of the person to be measured, typically a finger.
  • the inflatable bladder may further comprise a back layer attached to a flexible printed circuit.
  • the top layer for instance made of polyurethane (PU), it typically more elastic than the back layer, for instance made of polyvinyl chloride (PVC), which could even be non-elastic.
  • PU polyurethane
  • PVC polyvinyl chloride
  • the inflatable bladder may further comprise at least one, or at least two cut-away areas, to accommodate or position light sources, and at least two cut-away areas to accommodate or position light detectors.
  • the back layer may comprise corresponding cut-away areas for accommodating the light sources and detectors.
  • the printed circuit may for instance be connected to a signalling cable, which may be provided with a suitable connector.
  • the cable and an air supply for the air supply channel may for instance be located in a housing outside the pressure cuff.
  • the printed circuit may for instance comprise an identification unit and/or a module for processing signal received from the light detectors, which module may further be arranged to perform signal processing steps, such as filtering or amplification, on the received signals.
  • the pressure cuff may further comprise fastening means, such as Velcro, to wrap the cuff around a body part, typically around a finger.
  • the cuff may also be placed on an ear, or on the temples of a person, in a nostril or in a body cavity.
  • FIG. 1 schematically shows a device for non-invasive blood pressure measurements according to the prior art
  • FIG. 2 schematically shows a pressure cuff according to the present invention
  • FIG. 3 schematically shows a cross sectional view of a pressure cuff according to the present invention wrapped around a finger;
  • - figure 4 schematically shows a side view on a pressure cuff according to the present invention wrapped around a finger
  • - figure 5 schematically shows the pressure cuff of figure 4, with one light source emitting light
  • figure 6 schematically shows the effective attenuation coefficient of haemoglobin, in its oxygenated and unoxygenated form
  • FIG. 7 schematically shows a pressure system for use in a non-invasive blood pressure measurement device according to the present invention.
  • FIG 1 schematically shows a device (1) for non-invasive blood pressure measurements according to the prior art, comprising a pressure cuff (2), which generates a signal (3) based on the detected light.
  • This signal (3) representative for the volume of blood of the arteries under the cuff in the finger (4) is compared to a set-point (5) by a comparator (6), which comparison is then communicated to a controller (7).
  • the controller (7) controls a control valve (8).
  • the valve (8) regulates the pressure supplied to the pressure cuff (2) by a pump (9).
  • the pressure supplied to the pressure cuff (2) is measured by a transducer (10).
  • the present invention uses a similar device for non-invasive blood pressure measurements, but with an improved pressure cuff.
  • FIG. 2 schematically shows a pressure cuff (11) according to the present invention for use in a non-invasive blood pressure measurements.
  • the cuff (11) comprises a bladder (12), for placement around a body part and applying pressure to the body part.
  • the cuff (11 ) shown in figure 2 is one typically used for a finger as the body part.
  • the cuff (11 ) further comprises three light sources (13, 13’, 13”) as well as three light detectors (14, 14’, 14”), each for detecting light and providing a signal in dependence of the amount of detected light.
  • the light sources (13, 13’, 13”) and light detectors (14, 14’, 14”) are arranged in pairs, and in use are substantially on opposite sides of the body part, or finger.
  • the light detectors (14, 14’, 14”) and the light sources (13, 13’, 13”) are arranged on the inside of the pressure cuff (11), and are spaced apart.
  • the inside of the pressure cuff (11 ) is the side of the cuff (11 ) which, in use, is facing towards the body part, or finger.
  • the light sources (13, 13’, 13”) emit light of the same wavelength, which wavelength is about 800nm.
  • the light detectors (14, 14’, 14”) and the light sources (13, 13’, 13”) are arranged on a flexible printed circuit (15), which in turn is arranged on an outer wrap (16).
  • This outer wrap (16) is further provided with Velcro (17), for wrapping the outer wrap (16) around the body part, and securing the outer wrap (16).
  • the bladder (12) is arranged on top, or on the inside of, the outer wrap (16) and the flexible printed circuit (15).
  • the bladder (12) is further connected to a fluid supply (18) via a connector (19).
  • Figure 3 schematically shows a cross section of a pressure cuff (11) wrapped around a finger (F).
  • the finger (F) is schematically represented by muscle (M), bone (B) and two arteries (A).
  • the pressure cuff (11) comprises a bladder (12), wrapped around the finger (F).
  • the cuff (11) further comprises a light sources (13) as well as a light detector (14) for detecting light emitted from the light source (13) and passed through the finger (F), and for providing a signal in dependence of the amount of detected light.
  • the light source (13) and light detector (14) are arranged in a pair, and are located on opposite sides of the finger (F).
  • the light source (13) is located on the right side, and the light detector (14) is located on the left side.
  • the light source (13) and light detector (14) are not on exact opposite locations, but are on opposite sides.
  • the light source (13) and light detector (14) are for instance both placed at an angle (a), typically between 0 and 45 degrees, in particular about 20 degrees.
  • Figure 4 schematically shows a side view on a pressure cuff (11) wrapped around a finger (F).
  • Figure 4 shows that the light sources (13, 13’, 13”) and light detectors (14,
  • Figure 5 shows the pressure cuff (11 ) of figure 4, wherein one of the light sources (13) emits light, of a single wavelength. This light is sent through the finger (F) located inside the cuff (11), and may be scattered or absorbed in the finger (F). Typically, the majority of the emitted light is received by the light detector (14) opposite from the light source (13), which forms a pair with the light source (13). Light which is received by the light detectors (14’, 14”) not forming a pair with the light source (13), may be disregarded, or used to correct for scattering and absorption of light coming from proximal and/or distal regions of not fully unloaded arteries.
  • Figure 6 schematically shows the effective attenuation coefficient of haemoglobin, in its oxygenated and unoxygenated form.
  • the effective attenuation coefficient of haemoglobin, a main constituent of blood is independent, or at least relatively independent, on the oxygenation thereof, since the effective attenuation coefficient of oxygenated and unoxygenated haemoglobin is approximately the same. This is called the isosbestic range.
  • Wavelengths falling within the scope of about 800nm include for instance wavelengths between 750 and 950nm, in particular between 750 and 850nm.
  • FIG 7 schematically shows a pressure system (21) for use in a non-invasive blood pressure measurement device, comprising: a pressure cuff (11) according to the present invention; an actuator (22), such as a pump, for supplying pressurized fluid to the bladder (12); a variable flow resistance (23), located between the actuator (22) and the bladder (12), to vary the pressure supplied to the bladder (12) by the actuator (22); and a controller (24), arranged to provide a setpoint and a controller signal based on the signals of each of the light detectors (14) of the pressure cuff (11).
  • the controller (24) may further be used to control the variable flow resistance (23), based on the signals of each of the light detectors (14) of the pressure cuff (11).
  • Figure 8 schematically shows the effects of light received by multiple light detectors (14, 14’, 14”), in a cuff (11) as shown in figures 4 and 5, wherein corresponding features have been given the same reference numerals.
  • the finger (F) schematically the artery (A) and vein (V) are indicated.
  • small arterioles and capillaries are indicated as small vessels (S).
  • the area (B) of the artery (A) that is intended to be unloaded by the cuff (11) is encircled (B) in figure 8.
  • the unloading of the artery (A) causes the smaller vein (V) to close or collapse at the same location, such that the flow of blood from the veins is only outwardly, and flow of blood through the artery is both in and out.
  • the middle detector (14) will, due to the collapse of the vein (V), detect light emitted from the light source (13) and influenced by the fully unloaded artery.
  • the left detector (14’) will receive light from the light source (13), but will be influenced by the artery (not fully unloaded) on the left of area (B) ans also be influenced by the vein not fully collapsed to the left of area (B).
  • the right detector (14”) will receive light from the light source (13), but will be influenced by the vein (not fully collapsed) on the right of area (B), and likely be influenced by the artery (not fully unloaded) on the right of area (B) as well.
  • the left detector (14’) for instance receives a mixture of signals from the unloaded artery, a part of the loaded artery and possibly a part of the collapsed vein.
  • the middle detector (14) receives a mixture of signals from the unloaded artery, a part of the loaded artery and possibly a part of the open vein.
  • the right detector (14”) receives a mixture of signals from the unloaded artery and a part of the open vein and possibly a part of the loaded artery.
  • a compensation for the left part of area (B) can be made.
  • a compensation for the right part of area (B) can be made.
  • the signal used, for instance for determining the set point of the system for instance be 2 times the middle signal minus the left signal minus the right signal, wherein it is also envisioned that each of the signals is provided with their own, tailored, weighing factor.
  • Figure 10 schematically shows an example of the volume measurements made with a cuff according to the invention, when the counter pressure in de cuff follows a ramp-like procedure from zero to above systolic pressure, as shown as the straight line in the bottom graph.
  • Figure 10 employs a system with a single emitter (in the middle of the cuff) and 3 sensors. Top panel shows signals from the middle sensor (M), the proximal sensor (P), the distal sensor (D). On the Y-axis light measurements in arbitrary measures are shown. Individual pressure-volume loops are taken at points 1 ,2, 3, 4, 5 and shown in figure 11.
  • FIG 11 shows the PV loops as the volume signal against transmural pressure (which is intra-arterial pressure minus cuff pressure).
  • the individual heart beats at moments 1 ,2, 3, 4, 5 in figure 10 are highlighted in black. They show the detailed information used to calculate the setpoint value, and also show the considerable hysteresis which is typical for human arteries.
  • Figure 12 shows a typical example of the correction information obtained with a cuff according to this invention. Correction signals include differential distal-center (A, on top) and proximal-center (B, on bottom).

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  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Cardiology (AREA)
  • Vascular Medicine (AREA)
  • Surgery (AREA)
  • Medical Informatics (AREA)
  • Physics & Mathematics (AREA)
  • Veterinary Medicine (AREA)
  • Biophysics (AREA)
  • Pathology (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Public Health (AREA)
  • Molecular Biology (AREA)
  • General Health & Medical Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • Physiology (AREA)
  • Ophthalmology & Optometry (AREA)
  • Dentistry (AREA)
  • Measuring Pulse, Heart Rate, Blood Pressure Or Blood Flow (AREA)

Abstract

La présente invention concerne un manchon à pression destiné à être utilisé dans un dispositif de mesure de pression sanguine non invasif, comprenant : une vessie, servant à appliquer une pression à une partie du corps ; au moins une source de lumière, servant à envoyer de la lumière à travers la partie de corps sous la vessie ; au moins deux détecteurs de lumière, chacun servant à détecter la lumière traversant la partie de corps et pour chacun fournissant un signal en fonction de la quantité de lumière détectée ; ladite au moins une source de lumière et au moins l'un desdits au moins deux détecteurs de lumière étant disposés par paires, pour être utilisés sensiblement sur les côtés opposés de la partie de corps ; lesdits au moins deux détecteurs de lumière et ladite au moins une source de lumière étant disposés sur l'intérieur du manchon à pression, et étant espacés ; lesdits au moins deux détecteurs de lumière étant conçus pour détecter la lumière émise par une seule source lumineuse à la fois.
PCT/US2020/043678 2019-08-06 2020-07-27 Manchon à pression destiné à être utilisé dans un dispositif de mesure de pression sanguine non invasif WO2021025885A1 (fr)

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EP20757055.7A EP4009859A1 (fr) 2019-08-06 2020-07-27 Manchon à pression destiné à être utilisé dans un dispositif de mesure de pression sanguine non invasif
CN202080051870.5A CN114126483A (zh) 2019-08-06 2020-07-27 在无创血压测量设备中使用的压力袖带

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US201962883570P 2019-08-06 2019-08-06
US62/883,570 2019-08-06

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0048060A1 (fr) 1980-09-12 1982-03-24 Nederlandse Organisatie voor toegepast-natuurwetenschappelijk onderzoek TNO Dispositif pour la mesure indirecte, non-invasive et continue de la pression sanguine
US4510940A (en) 1981-11-27 1985-04-16 Nederlandse Centrale Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Plethysmograph pressure correcting arrangement
US20080221414A1 (en) * 2007-03-09 2008-09-11 Nellcor Puritan Bennett Llc Method for detection of aberrant tissue spectra
WO2012087634A2 (fr) * 2010-12-23 2012-06-28 Draeger Medical Systems, Inc. Dispositif et procédé pour une mesure non invasive continue de la pression sanguine et une oxymétrie pulsée (spo2) combinées
WO2018085631A1 (fr) * 2016-11-03 2018-05-11 Basil Leaf Technologies, Llc Capteur de tension artérielle non invasif
US20190082982A1 (en) * 2017-09-20 2019-03-21 Edwards Lifesciences Corporation Finger cuff utilizing multiple sensors for blood pressure measurement
US20190133465A1 (en) * 2017-11-03 2019-05-09 Edwards Lifesciences Corporation Device for a non-invasive blood pressure measurement

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0048060A1 (fr) 1980-09-12 1982-03-24 Nederlandse Organisatie voor toegepast-natuurwetenschappelijk onderzoek TNO Dispositif pour la mesure indirecte, non-invasive et continue de la pression sanguine
US4510940A (en) 1981-11-27 1985-04-16 Nederlandse Centrale Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Plethysmograph pressure correcting arrangement
US20080221414A1 (en) * 2007-03-09 2008-09-11 Nellcor Puritan Bennett Llc Method for detection of aberrant tissue spectra
WO2012087634A2 (fr) * 2010-12-23 2012-06-28 Draeger Medical Systems, Inc. Dispositif et procédé pour une mesure non invasive continue de la pression sanguine et une oxymétrie pulsée (spo2) combinées
WO2018085631A1 (fr) * 2016-11-03 2018-05-11 Basil Leaf Technologies, Llc Capteur de tension artérielle non invasif
US20190082982A1 (en) * 2017-09-20 2019-03-21 Edwards Lifesciences Corporation Finger cuff utilizing multiple sensors for blood pressure measurement
US20190133465A1 (en) * 2017-11-03 2019-05-09 Edwards Lifesciences Corporation Device for a non-invasive blood pressure measurement

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