WO2015107109A1

WO2015107109A1 - Device for measuring blood data in order to estimate the quality of microcirculatory flows

Info

Publication number: WO2015107109A1
Application number: PCT/EP2015/050667
Authority: WO
Inventors: Rémi Bonidal; Bernard ALLAOUCHICHE; Matthias JACQUET-LAGREZE
Original assignee: Apd Advanced Perfusion Diagnostics
Priority date: 2014-01-17
Filing date: 2015-01-15
Publication date: 2015-07-23
Also published as: FR3016509A1; FR3016509B1

Abstract

The invention relates to a mouth probe for measuring blood flow in a patient's oral mucosa, said probe comprising a support (10) on which an optical sensor (101, 102) is mounted that is intended to be applied against a wall of the oral mucosa and that is designed to generate a signal indicative of the blood flow in the oral mucosa, characterised in that the probe also comprises means for securing the optical sensor (101, 102), which are adapted to exert an application pressure from the optical sensor (101, 102) against the wall of the oral mucosa of between 1,000 N/m² and 40,000 N/m².

Description

BLOOD DATA MEASURING DEVICE FOR ESTIMATING THE QUALITY OF MICROCIRCULATORY FLOWS

TECHNICAL AREA

The present invention relates to the general technical field of devices for measuring data representative of the blood flow in an organ and / or a body part of a patient, in particular a human being or an animal. These measured data can then be used in particular to provide a user with information on the local microcirculation to assist him in choosing treatments adapted to the patient by optimizing the tissue perfusion. GENERAL PRESENTATION OF THE PRIOR ART

In the medical field it is often necessary to control the good tissue oxygenation of a patient. Tissue oxygenation is provided by the patient's blood, which delivers oxygen and nutrients to all parts of the patient's body. The blood vessels allow the circulation of blood in the body.

Hemodynamics can be divided into two aspects, namely macrocirculation and microcirculation:

- Macrocirculation includes all vessels with a diameter greater than 150-300 μιτι, such as proximal arteries, elastic, large caliber, as well as more distal arteries of medium size which are muscular in nature;

- The microcirculation includes all vessels with a diameter of less than 150-300 μιτι, such as small arteries, arterioles, capillaries and venules. The only knowledge of the quality of macrocirculatory flows is not sufficient to estimate the quality of a patient's tissue oxygenation. Indeed, in several circumstances encountered in intensive medicine, the presence of microcirculatory flow alterations, at the origin of cellular hypoxia, coexists with the presence of macrocirculatory flows quite adequate.

This is why devices have been developed for measuring blood data allowing an estimate of the quality of a microcirculatory flow of a patient. The document WO 2013/127819 describes in particular a device for measuring blood data in the gastrointestinal tract, these data being able to be used to estimate the quality of a microcirculatory flow of the patient. Such a device comprises in particular a catheter including an optical sensor and an expandable element at its distal end. Even if the results obtained with such a device are very convincing, the installation of the measuring device requires the presence of an expert practitioner for the placement of the optical sensor in the gastrointestinal tract.

An object of the present invention is to propose a device for measuring hemodynamic data in real time which is easy to set up and which allows an estimation of the microcirculatory state of an organ and / or a part of the body of the body. patient.

PRESENTATION OF THE INVENTION

For this purpose, the invention proposes an oral probe for measuring a blood flow of the oral mucosa of a patient, the probe comprising a support on which is mounted an optical sensor intended to be pressed against a wall of the mucosa. buccal and configured to generate a signal indicative of the blood flow of the oral mucosa, characterized in that the probe further comprises optical sensor attachment means adapted to apply a pressure of plating of the optical sensor against the wall of the oral mucosa between 1000 N / m ² and 40000 N / m ² .

Preferred but non-limiting aspects of the probe according to the invention are the following:

the fixing means comprise adjustment means for varying the plating pressure in a pressure range of between 1000 N / m ² and 40000 N / m ² ,

the optical sensor comprises at least one emitter for emitting light radiation into the oral mucosa at at least one wavelength, and at least one receiver for receiving light radiation reflected by the oral mucosa,

the optical sensor comprises at least three receivers arranged at an equal distance from the transmitter,

the transmitter and the at least three receivers extend in a plane,

the at least three receivers are arranged on the support so that the force gradient exerted by the fixing means on optical paths between each receiver and the transmitter is equal,

the at least three receivers extend along a quarter circle centered on the transmitter,

the transmitter and the at least three receivers are arranged on the support so that the force exerted on the transmitter by the fixing means is greater than or equal to the force exerted by the fixing means on each receiver,

the fastening means comprise:

a suction element associated with the support and including a hollow portion on one of its faces intended to come into contact with the wall of the oral mucosa, and

a suction system connected to the hollow portion for fixing the suction element against the wall of the oral mucosa by generating a depression in a volume delimited by the wall of the oral mucosa and the hollow portion of the element of sucking so as to press the optical sensor against the wall of the oral mucosa, the fixing means comprise a first jaw on which the support is mounted and a second jaw, the wall of the oral mucosa being intended to be positioned between the first and second jaws, the first and second jaws being arranged so as to apply a clamping force on the wall of the oral mucosa so as to press the optical sensor against the wall of the oral mucosa,

the second jaw comprises a permanent magnet so as to press the optical sensor against the wall of the oral mucosa by magnetic force,

the first and second jaws are connected to one another, the fixing means comprising elastic means serving to urge the first and second jaws towards each other in a closed position,

the surface of the second jaw intended to varnish opposite the support comprises a non-slip material, for example made of silicone, the non-slip material possibly including pimples,

a region of the first jaw intended to come into contact with the wall of the oral mucosa comprises a non-slip material, for example made of silicone, the non-slip material possibly including pimples,

the hardness of the anti-slip material is greater than or equal to 70 Shore A. PRESENTATION OF THE FIGURES

Other features and advantages of the invention will become apparent from the description which follows, which is purely illustrative and nonlimiting and should be read with reference to the accompanying drawings, in which:

FIGS. 1, 3 and 5 illustrate different examples of an oral probe,

- Figures 2 and 4 illustrate different examples of an optical sensor.

DETAILED DESCRIPTION We will now describe in more detail the oral probe according to the invention with reference to the figures. This oral probe is used to measure a blood flow of the oral mucosa of a patient. The oral mucosa covers the inside of the lips and cheeks, the tongue, the floor of the mouth and the palate.

To perform the measurement, this oral probe can advantageously be attached to the cheek or tongue of the patient. However, it will become clear later that this oral probe can be applied to other areas of the mouth - such as the palate - to perform the measurement.

1. General principles

1.1. Presentation of the oral probe

The oral probe includes:

measurement means - in particular an optical sensor such as a photo-plethysmography sensor including one (or more) receiver (s) and one (or more) transmitter (s) - for measuring the blood flow of the oral mucosa d a patient, and

- Fastening means for pressing the measuring means against a wall of the oral mucosa. Advantageously, the fixing means are adapted to apply a plating pressure of the measuring means against the wall of the oral mucosa of between 1000 N / m ² and 40000 N / m ² .

This range of pressure makes it possible to limit the disturbances of the blood flow at the level of the measurement zone. Indeed, unlike other measuring devices such as a pulse oximetry clamp, control of the plating pressure is a very important element in the case of the oral probe according to the invention. It is recalled that a pulse oximetry forceps conventionally comprises first and second branches connected to pivoting between which the tissue for which it is desired to perform an oximetry measurement must be pinched. The first one branch has a light emitter and the second branch has a light-transmitting receiver transmitted through the tissue.

In pulse oximetry, it is the position of the transmitter and the receiver that conditions the quality of the measurement, the measurement being valid as long as the plating pressure does not completely prevent the flow of blood.

On the other hand, in the case of the oral probe according to the invention, the measurement of which is based on reflected radiation, the purpose of which is to measure the blood flow in order to estimate the quality of microcirculatory flow, the slightest change in surface pressure transcribes into an alteration of the microcirculatory flows.

It is therefore important, in the case of the mouth probe according to the invention, to control the plating pressure rather than the clamping distance.

The inventors have discovered that the application of a plating force of between 0.2 N and 2 N over an area of between 50 and 100 mm ² makes it possible to render the microcirculatory flow alterations negligible. Different plating strategies can be implemented, including:

• A strategy based on a fixed plating pressure allowing a repeatability of the measurement as well as the use of common reference for the diagnosis,

• A strategy based on a veneer pressure that is adaptable to the patient in order to guarantee optimal measurement quality for the patient; in this case, the fixing means comprise adjusting means (such as a setting screw in the case of a passive veneer or control means in the case of active veneer) for varying the veneer pressure. depending on the quality of the measurement made, this quality being able to be determined taking into account the waveform of the signal or its amplitude or a signal-to-noise ratio, etc.

12. Examples of fastening means The fixing means may be of different types considered independently or in combination. In particular, the fixing means may allow active plating of the measuring means against the wall of the oral mucosa by means of, for example, a suction device.

For example, the fastening means may comprise a suction element on which the measuring means are mounted, and a suction system associated with the suction element.

The suction element may for example include a hollow portion such as an annular groove extending at the periphery of the measuring means, the suction system being connected to the hollow portion.

The activation of the suction system induces the generation of a depression in a volume delimited by the wall of the oral mucosa and the hollow portion of the suction element so as to press the measuring means against the wall of the oral mucosa. .

Alternatively, the fixing means may allow passive plating of the measuring means against the wall of the oral mucosa, for example by means of a permanent magnet.

For example, the fastening means may comprise first and second jaws intended to be positioned opposite. The measuring means are for example mounted on the first jaw and a permanent magnet is mounted on the second jaw. In this case, the positioning of the wall of the oral mucosa between the first and second jaws induces the application of a magnetic clamping force of the first and second jaws 1, 2 against the wall of the oral mucosa, resulting in the plating of the measuring means. Alternatively and as will be described in more detail below with reference to Figures 1 to 5, the fixing means may comprise first and second jaws pivotally connected between them to form a clamp for plating the measuring means against the wall of the oral mucosa.

2. Description of Examples of Probes Referring to Figures With reference to FIG. 1, an example of an oral probe for measuring blood flow has been illustrated. The probe fixing means comprise first and second jaws 1, 2 and a biasing spring 3. The measuring means of the probe comprise a cable 4 connected to an optical sensor 101, 102 mounted on a support 10.

2.1 First and second jaws

2.1.1. Functions of the jaws

The first and second jaws 1, 2 are intended to be moved between an open position and a closed position, the first and second jaws 1, 2 being farther apart from each other in the open position than in the closed position.

Each jaw 1, 2 has a specific function.

The first function of the jaw 1 is to carry the optical sensor (described in more detail below). The support 10 including the optical sensor 101, 102 is integrated in the first jaw 1. The area of the first jaw 1 in contact with the wall of the oral mucosa may be lined with a non-slip material (pin, silicone, ..) to ensure good stability of the probe. To improve the stability of the probe, the first jaw may comprise a suction element associated with a suction system as described above. The second jaw 2 has the main function of maintaining the position of the probe. Preferably, the surface of the second jaw 2 facing the optical sensor 101, 102 is at least equal to the surface of the optical sensor 101, 102. This makes it possible to ensure that the emitters and receivers of the optical sensor are in contact with the wall of the the oral mucosa. Advantageously, this surface may be equipped with a non-slip material to allow better adhesion while remaining at a low pressure (pin, silicone, ..). Furthermore, the second jaw may include one (or more) hollow portion (s) connected (s) to a suction system to ensure better stability. Preferably, the jaw comprises an oblong hollow portion or two point hollow portions to limit the risk of pivoting of the probe. 2.12. Jaws movable in rotation relative to each other

In the embodiment illustrated in Figure 1, the first and second jaws 1, 2 are movable in rotation relative to each other between the open and closed positions.

The first and second jaws 1, 2 are rotatably connected at one of their ends to form a collet.

The connection between the first and second jaws allows their relative displacement in rotation about an axis A-A 'transverse to the first and second jaws.

The connection between the first and second jaws can be a deformable hinge, preferably elastically. It is the ability of this hinge to deform which allows the opening or closing of the angle formed by the first and second jaws.

Alternatively, the connection between the first and second jaws may be a pivot. 2.13. Jaws movable in translation relative to each other

In the embodiment illustrated in Figure 5, the jaws 1, 2 are translational movable relative to each other between the open and closed positions.

The first jaw 1 extends radially at the end of a first barrel 1 1 including a longitudinal slot 1 1 1 for the passage of the second jaw 2.

The second jaw 2 extends radially at the end of a second one 12 and is telescopically slidable inside the first one 1 1 so as to bring the first and second jaws 1, 2 closer or further away. A spring 3 disposed within the first and second barrels 1 1, 12 allows to solicit the first and second jaws 1, 2 to bring them closer to each other.

2.2. Optical sensor

With reference to FIGS. 2 and 4, various examples of optical sensors that can be used in the oral probe are illustrated without limitation.

Each optical sensor 101, 102 is mounted on a support 10 sufficiently rigid so that its deformation is negligible when the plating pressure applied by the fixing means is of the order of 25 N / m ² .

The optical sensor 101, 102 makes it possible to emit light into the tissue and to receive light reflected therefrom.

In the embodiment illustrated in FIG. 2, the optical sensor 101, 102 comprises a transmitter 101 - such as a monochromatic light-emitting diode - and a receiver 102. The wavelength of the transmitter 101 is defined as a function of the absorbance of the hemoglobin saturated with oxygen. Advantageously, the optical sensor 101, 102 may comprise several emitters 101 adapted to emit light radiation at a given wavelength different from the emission wavelength of the other emitters 101. In this case, the emission wavelengths of the different emitters 101 are chosen as a function of the absorptivity of different types of hemoglobin - including in particular saturated hemoglobin or "oxyhemoglobin" and unsaturated hemoglobin or "deoxyhemoglobin". ".

The receiver 102 makes it possible to measure the luminous intensity having passed through the different media of the measurement zone. In the embodiment illustrated in FIG. 2, the optical sensor 101, 102 comprises a single receiver 102. This simplifies the complexity of the probe.

Alternatively, the optical sensor 101, 102 may comprise several receivers 102. The use of several receivers makes it possible to obtain a regional indicator of the blood circulation and also to offset possible measurement problems. Indeed, the receiving device responds to the problem of local measurement of blood flow. The measurement of a blood flow can be disturbed by the presence of an artery / arteriole in the measurement zone. In such a case, the measurement no longer corresponds to a measurement of tissue microcirculation but to a measurement of arterial microcirculation which is no longer the desired parameter. Preferably, the receivers are arranged at equal distance from the transmitter (distance of the order of one centimeter) and extend in the same plane. This makes it possible to simplify the subsequent processing of the signals from the different receivers. Because of this constraint, they can therefore be arranged in a circular manner around the emitter for example over a portion of a circle.

The receivers 102 can be positioned so that the force gradient exerted by the first and second jaws is equal on the different optical paths 103 between the transmitter 101 and each receiver 102. to guarantee a good homogeneity of the measurements between the different receivers 102. Thus within the framework of a pair of 3 receivers / 1 transmitters, preference will be given to an arrangement with the transmitter on the side of the strongest plating force and the receivers on the side of the weakest plating force with a symmetrical distribution.

Advantageously, the support 10 can be removably integrated with the first jaw to allow its replacement, especially when implementing successive measurements on different patients. This avoids contamination of patients. Alternatively, a portion of the first jaw on which the support is mounted may be removable.

2.3. Description of the process Acquisition of the signals can be carried out from analog / digital converters (ADC) directly embarked on the clamp. This solution offering the best signal / noise ratio, however, has the disadvantage of having a high cost. The alternative solution is therefore to have CANs in an acquisition station. The clamp is connected to this station by means of the cable 4. A circular cable 4 will be preferred to a sheet in order to limit the torsion forces generated.

The objective of the device is to measure the pulsatile part of the blood flow, that is why it is necessary to control the plating pressure (so that it does not disturb the measurement).

When the acquisition device comprises a plurality of receivers, the processing will use the signals from this plurality of receivers to construct a composite indicator using the redundancy to improve the quality of the signal (signal-to-noise ratio, compensation of failure / local perfusion variation / ...). The measurement of this pulsatile part of the blood flow makes it possible to detect pathologies where the microcirculation is impacted. Such pathologies may correspond to a shock. The reader will have understood that many modifications can be made to the probe described above without physically going out of the new teachings described above and defined in the appended claims.

Claims

Oral probe for measuring a blood flow of the oral mucosa of a patient, the probe comprising a support (10) on which is mounted an optical sensor (101, 102) to be pressed against a wall of the oral mucosa and configured to generate a signal indicative of the blood flow of the oral mucosa, the probe further comprising optical sensor attachment means (101, 102) adapted to apply a plating pressure of the optical sensor (101, 102) against the wall oral mucosa of between 1000 N / m ² and 40000 N / m ² , characterized in that the optical sensor (101, 102) comprises at least three receivers (102) arranged at an equal distance from the emitter (101), the receivers being arranged so that the force gradients exerted by the fixing means on optical paths between each receiver (102) and the transmitter (101) are equal.

An oral probe according to claim 1, wherein the fixing means comprises adjusting means for varying the plating pressure in a pressure range of 1000 N / m ^{2 to} 40000 N / m ² .

An oral probe according to any one of claims 1 or 2, wherein the optical sensor (101, 102) comprises at least one emitter (101) for emitting light radiation into the oral mucosa at at least one wavelength, and at least one receiver (102) for receiving light radiation reflected by the oral mucosa.

An oral probe according to claim 1, wherein the transmitter (101) and the at least three receivers (102) extend in a plane.

An oral probe according to any one of claims 1 to 4, wherein the at least three receivers (102) extend along a quarter circle centered on the emitter (101). An oral probe according to any one of claims 1 to 4, wherein the emitter (101) and the at least three receivers (102) are disposed on the support (10) so that the force exerted on the emitter (101) ) by the fixing means is greater than or equal to the force exerted by the fixing means on each receiver (102).

An oral probe according to any one of claims 1 to 6, wherein the attachment means comprises:

a suction element associated with the support (10) and including a hollow portion on one of its faces intended to come into contact with the wall of the oral mucosa, and

a suction system connected to the hollow portion for fixing the suction element against the wall of the oral mucosa by generating a depression in a volume delimited by the wall of the oral mucosa and the hollow portion of the element of sucking so as to press the optical sensor (101, 102) against the wall of the oral mucosa.

An oral probe according to any one of claims 1 to 7, wherein the securing means comprises a first jaw (1) on which the support (10) is mounted and a second jaw (2), the wall of the oral mucosa being intended to be positioned between the first and second jaws (1, 2), the first and second jaws (1, 2) being arranged to apply a clamping force to the wall of the oral mucosa so as to press the optical sensor (10) against the wall of the oral mucosa.

An oral probe according to claim 8, wherein the second jaw (2) comprises a permanent magnet so as to press the optical sensor (10) against the wall of the oral mucosa by magnetic force.

An oral probe according to any one of claims 8 or 9, wherein the first and second jaws (1, 2) are connected to each other, the fastening means comprising elastic means (3) for urging the first and second jaws (1, 2) towards each other in a closed position.

1 1. An oral probe according to any one of claims 8 to 10, wherein the surface of the second jaw (2) for varnishing opposite the support (10) comprises a non-slip material, for example silicone, the non-slip material may include pimples.

12. A mouth probe according to any one of claims 8 to 11, wherein a region of the first jaw (1) intended to come into contact with the wall of the oral mucosa comprises a non-slip material, for example silicone, the non-slip material which may include pimples.

13. Buccal probe according to any one of claims 1 1 or 12, wherein the hardness of the anti-slip material is greater than or equal to 70 Shore A.