EP3558106A1

EP3558106A1 - Equipment for monitoring blood flow and respiratory flow

Info

Publication number: EP3558106A1
Application number: EP17803903.8A
Authority: EP
Inventors: Philippe Lange; Giovanni AMOROSO; David Lawrence CAMP; Gabriele BUTTIGNOL; Gerrit De Vries
Original assignee: Idahealth Inc
Current assignee: Idahealth Inc
Priority date: 2016-12-21
Filing date: 2017-11-21
Publication date: 2019-10-30
Also published as: US20200093378A1; US11426083B2; BE1024423B1; JP2022120192A; WO2018114180A1; JP7093777B2; JP2020513892A; CN110650680A; CN110650680B

Abstract

The invention of the present application relates to non-invasive equipment for monitoring blood flow and/or respiratory cycles of a human or animal body, comprising at least one segment of conductive elastomer of variable resistance, which is arranged to extend about the circumference of the body element and is sensitive to the length of the circumference of said element, means for capturing said length by virtue of said variable resistance and supplying a signal representative of said length, and means for processing said signal, having means of extracting the parameters of the blood flow and/or of the respiratory cycles that are to be monitored.

Description

Equipment for monitoring blood and respiratory flows

BACKGROUND OF THE INVENTION Plethysmography, developed at the beginning of the 20th century, makes it possible to measure changes in volume in an organ or the whole body, whether human or animal, and is, among other things, used to measure peripheral blood flows. or superficial. In particular, R. J. Whitney developed, in the late 1940s, a double cord deformation gauge system consisting of a mercury-containing rubber casing (J. Physiol., 121, 1-27, 1953). The technology has since been improved. Various techniques are described using for example a photoelectric sensor illuminating the arteries of the wrist to measure the variation of the arterial volume and allowing the generation of an electrical signal which can then be analyzed by various methods to obtain the hematological information. A review of plethysmography methods is available on the internet (http://levelldiagnostics.com/ research / P / LlD-

PulseWaveMonograph. pdf). However, although very simple and practical to use, currently available plethysmography techniques suffer from a lack of precision. The development of the sphygmomanometer, better known as a sphygmomanometer, led to the gradual abandonment of plethysmography. The tensiometer is based on the principle of a manometer that records the reaction of the arteries, subjected to both the pressure of the heart and that of the air produced by the device. Although giving a less accurate result and a shorter duration than the plethysmograph, the tensiometer has become essential for its simplicity of use in medical practices. However, it allows only a rough estimate of the voltage, representative of blood flows, over a short period.

At the same time, electrocardiography has become the cardiologist's exam of choice for representing the electrical activity of the heart. This examination nevertheless requires the installation of several electrodes at various locations of the body, connected to a unit of analysis, monitoring, signals collected.

Doppler ultrasound is also used to explore intracardiac and intravascular blood flow. The practitioner moves a probe along the organs to be analyzed to determine the direction and speed of blood flow. However, this test is not compatible with prolonged use and requires the active presence of a practitioner.

Cardiovascular disease is the leading cause of death in the world. Over the last thirty years, research has led to the development of many drug treatments for some of the heart diseases. At the same time, the surgical techniques have been considerably improved, making it possible in particular to avoid open heart surgery as much as possible by, for example, encouraging the placement of arterial support devices, such as stents, by the arterial route, in particular via the radial artery.

Faced with the increase in the number of interventions for the installation of such devices, the legislation has allowed the expansion of the number of practitioners likely to perform this act previously reserved for the only cardiac surgeon. The increase in the number of these interventions was also accompanied by an increase in the number of post ^¬ operative problems.

It turns out that breathing cycles, that is, the number of breaths and expirations per unit of time, also affect blood flow.

In particular, a frequent complication is the narrowing or even the postoperative occlusion of the artery (stenosis) via which the medical device has been inserted, making a new intervention, via the same artery, ineffective or even dangerous. But it is not uncommon for the same patient to require several interventions of the same type during his life. This problem is described in detail by Muhammad Rashid et al. (J Am Heart Assoc 2016, doi: 10.1161 / JAHA.115.002686). One of the possible causes advanced to explain this occlusion / arterial stenosis is the inadequate compression time and pressure of the wound resulting from the incision of the artery performed at the beginning of the procedure. A correctly performed compression indeed makes it possible to reduce the risks of occlusion, as it is described in the article http: // www. invasivecardiology. corn / articles / ulnar-artery-transient-compression-facilitating-radial-artery-patent-hemostasis-ultra-novel. To date, no technique has been used to monitor arterial function in the wound environment, during the surgical procedure, or during the compression phase of the wound following the procedure, except for monitoring. ultrasound which is not practical to implement in this context. So there is currently a real lack of a simple device, autonomous, space-saving, which would allow the precise monitoring of the arterial function in real time during the surgical intervention and, after the intervention, during the phase compression of the wound. This monitoring could allow the practitioner to adapt in real time and its operative technique and the pressure exerted on the wound to minimize the risks of post-operative problems, such as arterial occlusion.

This is the problem solved by the present invention. The present invention provides an improvement in plethysmography techniques, advantageously taking advantage of technological advances in the field of conductive materials.

Heeger, MacDiarmid and Shirawa have shown that nonconductive polymers can be "doped" to promote the displacement of electrons along the conjugated double bonds of the polymer and to make this polymer conductive. The document WO2015 / 049067 details a method for doping polymers, and in particular elastomers, with nanomaterials, in particular graphene-type carbon-based nanomaterials, in order to render these polymers conductive. These conductive elastomers have the property of having a resistance varying according to their length, that is to say the stress applied to them. This is detailed in the above patent document which suggests the use of this property to measure subtle physiological movements such as pulse or respiration.

The present invention relates to non-invasive plethysmographic equipment including an elastomer variable resistive conductor usable especially in the operating room, not causing any inconvenience to the practitioner or practitioners. Solution of the invention

Thus, the invention of the present application firstly relates to a non-invasive equipment for monitoring the blood flows of a body element comprising a network of channels traversed by said blood flows comprising:

at least one variable-resistance conductive elastomer segment arranged to extend around the perimeter of the body element and sensitive to the length of the periphery of said element, means for gripping said length by virtue of said variable resistor and providing a signal representative of said length, and

means for processing said signal comprising means for extracting the parameters of the blood flows to be monitored. The invention of the present application also relates to a non-invasive equipment for monitoring the breathing cycles of a human or animal body inducing a variation in the length of the periphery of a body element comprising: at least one segment of elastomer variable resistance conductor arranged to extend around the periphery of the body element and sensitive to the length of the periphery of said element,

means for capturing said length by said variable resistor and providing a signal representative of said length, and processing means of said signal comprising means for extracting the parameters of the respiratory cycles to be monitored. The applicant is therefore part of WO2015 / 049067 to solve the problem presented above. This document, however, does not describe the application of conductive elastomers with variable resistance to plethysmography equipment and is therefore legally excluded from the field of the prior art. A person skilled in the art reading this document, in particular the paragraph relating to sensors (page 24, 1. 24-33), faced with the wide scope of the possibilities of implementing such sensors, could not be guided towards the particular realization of plethysmography equipment using conductive elastomers with variable resistance.

Blood flow is the flow of blood through the blood vessels and the heart. Blood vessels are all conduits that carry blood and include arteries, veins, venules and capillaries.

Non-invasive monitoring equipment is equipment that allows one or more parameters to be monitored, without the need for any infringement of the skin. It is generally accepted that a simple blood test and a product injection are also non-invasive. The non-invasive nature of an equipment generally implies an absence of danger. In a preferred embodiment, the variable resistance conductive elastomeric segment is arranged to surround the body member and responsive to the tower length of said member. In another interesting embodiment, the variable resistance conductive elastomeric segment is secured to an adhesive part. In all cases, the conductive elastomer is, obviously, placed in contact with the skin itself. Placing the elastomer on a fabric covering the skin, such as clothing, would significantly reduce the sensitivity of the device. By body element, it is in fact understood here any body part likely to be covered or surrounded, in whole or in part, by the elastomer segment. These bodily elements may include bodily limbs, trunk or throat. They can belong to a human or an animal.

The perimeter of the body element refers to a line that forms the boundary of the surface of this element. The elastomer segment may for example extend over a portion of the trunk or neck. The length of the periphery may be only a fraction of the length of the perimeter of the body element. In addition, "surround the member" does not necessarily mean that the segment is closed around itself around the member, since around the member are arranged the input means and processing means. The terms "tower" and "perimeter" will be used interchangeably later in this document.

An adhesive piece here designates a thin layer, made of polymer fabric or any other suitable material, covered on at least one of its faces with an adhesive or sticky substance which allows the piece to adhere in a durable manner to the skin. at the level of the body element where it is placed. Such Adhesive pieces are especially used in dressings or in what is commonly called a "patch".

In the preferred embodiment of the invention, the gripping means of said length comprise at least one measuring bridge, at least one of the resistors is constituted by the conductive elastomer variable resistance. The electrical signal at the output of the measurement bridge is an image of the said length of periphery.

A measuring bridge here designates an electronic assembly, comprising at least one resistor whose value varies as a function of a parameter to be measured, here a length. A well-known example of a bridge is the Wheatstone bridge, but there are also many variants such as AC bridges, Owen Bridge, Schering Bridge, Robinson Bridge, which improve measurement accuracy. The variation in the length of the conductive elastomer, that is to say the variation in the length of the perimeter of the body limb to be monitored, induces a variation in the resistance of the conductive elastomer that is evaluated using the measuring bridge and which is an image of the blood flow at the limb around which the conductive elastomer is placed. The principle of the Wheatstone bridge is well known to those skilled in the art. Its application to strain gauges is widely documented (What's The Difference Between Operational Amplifiers and Instrumentation Amplifiers, Electronic Design, August 26, 2015; Signal Conditioning Wheatseat Resistive Bridge Sensors, Texas Instruments, Application Report SLOA034, September 1999). In general, the measuring bridge provides the function electronic amplifier, and may be an operational, differential or instrumentation amplifier. The measuring bridge can also be called measuring circuit, the concept of bridge being related to the presence of the conductive elastomer variable resistance.

In an advantageous embodiment of the invention, the processing means are electronic means and the means for extracting blood flow parameters to be monitored comprise an algorithm arranged to receive the information relating to said length in order to extract the parameters of the parameters. blood flow to watch.

Such algorithms are described in BioMedical Engineering OnLine, 20054: 48 (DOI: 10.1186 / 1475-925X-4-48). In particular, they make it possible to separate information relating to arterial flows from information relating to venous flow and / or respiratory cycles. They also make it possible to analyze the relations between these two flows.

The invention will be better understood with the aid of the following description of several embodiments of the invention, with reference to the drawing in the appendix in which: FIG. 1 represents a schematic view of the blood flow monitoring equipment according to the invention;

Figure 2 shows the equipment of Figure 1 around the wrist of a patient;

Figure 3 is a view of the equipment of Figure 1 with, in detail, the capture box and processing;

FIG. 4 represents another embodiment of the blood flow monitoring equipment, comprising two segments of conductive elastomer and positioned around the wrist of a patient;

Figure 5 illustrates the arrangement of the equipment of Figure 5 on the inside of the wrist, with respect to the arteries of the wrist and an incision made on the radial artery; Figure 6 shows another embodiment of the blood flow monitoring equipment, comprising two segments of conductive elastomer and positioned around the wrist of a patient;

Figure 7 is a view of the equipment of Figure 7 with, in detail, the capture box and processing;

Fig. 8 shows a conductive elastomeric segment form;

Figs. 9a and 9b show another embodiment of the blood flow monitoring equipment, including a system for adjusting the length of the variable elastomer segment;

Figure 10 shows a particular configuration of the conductive elastomeric segment;

Figure 11 illustrates the possible uses of the equipment of the invention;

Figure 12 shows the equipment of the invention integrated in an adhesive part;

Figure 13 illustrates an algorithm of the equipment of the invention;

FIG. 14 illustrates the equipment of the invention comprising an extension member of a conductive elastomer of the equipment of the invention;

FIG. 15 illustrates the equipment of the invention associated with an automatic compression bracelet; and

Figure 16 schematically illustrates the equipment of the invention integrated into the bracelet of a connected watch. With reference to FIGS. 1 to 3, the plethysmographic equipment of the invention comprises a strap 1 for holding a box 2 for capturing and processing signals and, here, housed in a computer system 4, an algorithm 3 whose function combines with those of the processing means of the housing 2.

The bracelet 1 is here an elastomer segment intended to partially surround here a wrist 5 and fixed to the housing 2 to hold the latter on the wrist 5. The connection of the elastomer segment and the housing can be carried out in a simple and standard way, for example with the help of an adhesive tape of the protected trademark "Velcro®" or in the manner of a watch strap holding the watch case. The bracelet 1 is made of conductive polymer intended to be pressed against the skin of the wrist 5.

The housing 2 contains a Wheatstone bridge 6 powered by a power source 7 and connected at the output to a wireless transmitter 8. The bracelet 1 is integrated in the bridge 6 as unknown resistance to be appreciated, and connected in a 9 of the two ends of the diagonal of the bridge 6 in which is disposed a detector 10 which is connected to the transmitter 8 and one 11 of the two ends of the other diagonal of the bridge 6 connected to the energy source 7.

The computer system 4, in which is implanted the algorithm 3, comprises a receiver 12 arranged to be connected to the transmitter 8 of the housing 2. The algorithm 3 thus cooperates with the measurement bridge 6, the wireless transmitter 8 and the wireless receiver 12.

As a source of energy 7, it is possible to envisage an electric battery or a rechargeable battery. The transmitter 8 - receiver 12 link may be a connection "bluetooth", "wifi", or any other wireless technology. As computer system, one can consider a computer, a touch pad, a smartphone or even a connected watch.

Proper positioning and adjustment of the voltage of the conductive elastomer is important to have an optimal quality signal. The length of the elastomer may be adjusted so that the voltage of the conductive elastomer is sufficient for the detection of its variations in length, and therefore of resistance, but not too high, so that the blood circulation is not affected. The adjustment of the length of the bracelet 1 around the wrist can be done manually or automatically.

The structural characteristics of the equipment of the invention having been described, its operation will now be discussed.

During its operation, the length of the conductive elastomer varies depending on the venous flow, the arterial flow and the respiratory volume. The Wheatstone bridge 6 comprising the conductive elastomer bracelet 1 will generate an electrical signal which is the image of these physiological parameters. This signal can then be amplified before being transmitted by the transmitter 8 to the receiver 12 of the computer system 4 comprising the algorithm 3, making it possible to extract the various components from the received signal.

In particular, the algorithm 3 can isolate the electrical signal related to the arterial pulse and the electrical signal related to the venous flow. It can also allow to analyze the difference between these two flows as well as the first or second derivatives of the difference between these two flows. It can, moreover, also include a frequency analysis in order to separate the streams more clearly, for a better quality of signal. This information can then be viewed on the screen 13 of the computer system 4.

The information displayed may be diverse and adapted to the context of use of the equipment of the invention. Typically, the evolution of the physiological parameters, or their relationship between them, calculated by the algorithm 3, as a function of time, will be displayed in a manner easy to analyze by the practitioner.

During a surgical procedure intended to introduce, for example by the radial artery, a stent-type device, an incision in the radial artery is made at the level of the forearm. It is then possible to position the bracelet 1 between the hand and the incision. This is made possible by the small size of the bracelet 1, which is not bulky and does not include electrical connections that may hinder the work of the practitioner. The practitioner can then monitor, in real time, during the introduction of the stent, the arterial and venous flows at the wrist and adapt his intervention accordingly. Similarly, at the end of the procedure, a practitioner will apply pressure to the wound resulting from the incision of the artery, to stop the bleeding. By being able to monitor the arterial and venous flows in real time, the practitioner will be able to adapt the pressure applied to the wound. In the case, illustrated in Figure 15, where this wound compression phase would be managed by an automatic device 14 for wound compression, such as that presented by Terumo TR Band® (http: // www. Medicalexpo. fr / prod / terumo-medical / product-71204-454828.html), it is conceivable that the pressure applied by the automatic compression device is controlled, wirelessly, by an additional algorithm integrated in the computer system 4 according to the analysis of the data provided by the bracelet 1. The medical compression device can be connected wirelessly to the computer system or, as the case may be, by direct wire connection to the case of the bracelet. Different types of compression can be applied and controlled via the measuring device, in direct and / or wireless connection. The compression can for example be effected by pressing an outer element, such as for example a hard or soft sphere, an air chamber or a chamber containing a compressible fluid or not. The correct positioning and correct adjustment of the elastomer segment 1 voltage is important for the quality of the measured signal and, consequently, the quality of the parameters extracted by the detection and analysis algorithms. The operator easily positions the bracelet on the wrist, near the hand, in a position that does not disturb the surgical procedure. The delicate setting then consists mainly in tightening the bracelet to adjust its pressure or tension. This is managed by adjusting the length of the conductive elastomeric tape to an optimum stress or tension at which the elastomer remains sufficiently flexible, but not too loose. It is important to note that the absolute stress of the elastomer does not affect the measurement, but its precision. This is related to the physical characteristics of the elastomer such as, for example, its modulus of elasticity, temperature and dimensions. The elastomer can be made in a specific shape so that it is more flexible, which means that it will give greater precision and its length will be easier to adjust.

The adjustment of the length of the elastomer can be advantageously facilitated by the use of a locking system cooperating with the conductive elastomer segment.

In order to facilitate this cooperation, the conductive elastomeric tape 1 may consist of a continuous material 110 having a particular relief, such as for example a repetitive relief 111 as illustrated in FIG. 8. The relief here is a perforation having a shape of rectangle with rounded corners, but it can take any form compatible with the strength, precision, flexibility and resistance required for the bracelet 1. The relief may, for example, be a pattern of seizing as used, for example, on a hose clamp. This embodiment also makes it possible to improve the electrical contact between the conductive elastomer and the mechanical part connected to the electronic parts of the housing 2.

In the same way, the adjustment of the bracelet 1, at the time of its installation on the wrist, can also be controlled by yet another algorithm integrated in the computer system 4, according to the analysis of the data provided by the bracelet 1, a drive member for clamping the conductive elastomer to its optimum voltage for monitoring. With reference to FIGS. 9a and 9b, the skin 311 of the wrist 310 is surrounded by the conductive elastomer segment 313 and a case 312 containing the electronic elements of the equipment and a clamping member 316. The clamping member 316, comprises a motor 315 which, via a clamping ring 314, allows movement of the conductive elastomer segment at its end 313B, thus adjusting its length, the other end 313B being fixed to the housing 312. The motor 315 can be driven by the computer system 4, and will cause the elastomeric segment 313 to be tightened or loosened to its optimum tension. This voltage is proportional to the resistance of the elastomer and can be extracted from the electrical signal generated by the device. It is conceivable that the end of the adjustment operation is signaled to the operator, for example by means of an apparent light signal on the housing 2, a message on the screen 13 of the computer system 4, an audible signal emitted at the level of the housing 2 or the computer system 4, a vibration of an element of the device or a combination of several of these signals.

An interesting application of the invention is the simultaneous use of several bracelets 1. A second bracelet can be placed between the elbow and the shoulder to generate a second electronic signal, which can be analyzed in relation to the first electrical signal and give to the practitioner additional information about blood flow in the arm as a whole. Similarly, one or more bracelets can be arranged symmetrically on the second arm to obtain a so-called "reference" signal with respect to which the blood flows of the arm undergoing the intervention can be compared. With reference to FIGS. 4 and 5, the non-invasive plethysmographic monitoring apparatus of the invention may comprise two segments of a conductive elastomer arranged to surround the body limb.

Two segments of conductive elastomer 101a and 101b are each connected at one end to a housing 102a and at their other end to a housing 102b and partially surround the wrist 5. The two housings 102a and 102b are each formed in a manner similar to the previously described equipment. During the introduction of the bracelet, the first housing 102a is placed between the radial artery 15 and the ulnial artery 16 and the second housing 102b is placed on the top of the wrist. In this configuration, the variation of the length of the conductive elastomer segment 101a is relative to the radial artery 15 and the variation of the length of the conductive elastomer segment 101b is relative to the ulnial artery 16. This configuration allows to obtain two distinct electrical signals that can be transmitted by the wireless communication units of the housings 102a and 102b to the computer unit 4 comprising the algorithm 3 capable of processing these signals to extract the blood flow parameters, which allows the practitioner to obtain more precise information relating to each artery separately. In particular, if he makes an incision 17 on the radial artery, he can compare the blood flows in the two arteries of the wrist and adapt his intervention if necessary. A Wheatstone bridge-type circuit has been used here, but it is obvious that any suitable analog system, well known to those skilled in the art, for converting elastomer segment length information into electrical current and / or information digital is also possible, as example of other forms of measuring bridge or amplifier, in particular a differential amplifier.

With reference to FIGS. 6 and 7, an alternative variant for separately analyzing the signals relating to the ulnial 16 and radial arteries 17 is to use two segments of conductive elastomer 201a and 201b. These are each connected at one end to a housing 202, and at their other end to a fastener 218 and partially surround the wrist 5. In this case, the housing 202 comprises two Wheatstone bridges 206a and 206b each integrating one of the two elastomer segments 201a and 201b as unknown resistance. Since each end of the elastomer must be connected to the Wheatstone bridge for proper operation, it is necessary to add two lead wires 219a and 219b completing the loop formed respectively by the elastomer segments 201a and 201b within their respective Wheatstone bridge. These Wheatstone bridges are each connected to a detector 210a and 210b, respectively, and are both connected to an emitter 208 and a power source 207. A similar configuration can be envisioned with three or more segments of elastomers each segment being integrated in a measuring bridge, but all being connected to the same transmitter.

Similarly, the use of the equipment of the invention is not limited to the wrist or the arm, it can also be used on other limbs or organs according to the needs of the practitioner, for example when the pose of a stent is done via the femoral artery, the bracelet can be placed at the level of the thigh. The use of the invention is not limited to uses during surgical procedures. It can be applied to any other activity to monitor blood flow and / or respiratory cycles.

An example is the monitoring of sleep apnea. The patient can then be equipped with a device of the invention, in the form of a bracelet or patch, connected during his sleep to an analysis device, such as his smartphone, which contains an application analyzing the signal emitted by the device electronic equipment and that can emit an audible and / or luminous signal intended to wake the patient, if the apnea becomes dangerous for him. Blood flow monitoring equipment and / or breathing cycles, including one or more segments of conductive elastomer, can be used in many parts of the body. It can be used ante, per and post surgery. It can also be used in the longer term, for days, weeks or months to monitor a patient's physiological parameters, such as, for example, arterial and / or venous flow and its cardiac coherence. With reference to FIG. 10, the equipment of the invention can be used at wrist 1606, ankle 1610 or knee 1609 to monitor venous problems in the leg, from the top of the thigh 1607 to monitor the Femoral artery, lower thigh 1608 to detect arterial and / or venous occlusions. It can also be applied to different levels of the upper arms 1603 and 1604 and / or the forearms 1605 and 1606 to detect arterial and / or venous occlusions. It can also be used advantageously to monitor the physiological behavior of the penis to clarify the type of erectile dysfunction. An application of the device at the level of the neck 1602 makes it possible to monitor the respiratory rhythm, the instabilities of the respiratory cycles and the arterial and / or venous flows towards the brain. The monitoring conductive elastomeric segment may also be installed at the trunk, for example around the waist 1627, to monitor the movements of the abdomen, for example to monitor abdominal wall behaviors after intestinal intervention, or at the level of the chest 1626 to monitor the respiratory cycle, cardiac coherence and arterial and venous cardiac activities.

Incidentally, the device of the invention can be arranged aesthetically, as a kind of jewel, to be used during the day and night in an elegant, practical and comfortable.

Another very useful and novel embodiment of the invention is to join the segment (s) of conductive elastomer and the gripping and / or treatment means to an adhesive part, to form a device of the "patch" type. ". With reference to FIG. 12, a conductive elastomer segment 1621 is connected to an input device 1620 by electrical connectors 1623. The elastomer 1621 and the gripper 1620 are disposed on the tacky side of an adhesive piece 1622, the assembly forming a patch 1624.

The input device 1620 has the same elements as the housings 2 and 202 already described. This patch 1624 can be used for example on the chest or abdomen to measure cardiac coherence, respiratory rate and blood circulation. In particular, this patch can be used to assess whether a patient's breathing is deep or only on the upper part of the lungs (inconsistency), which is an indication of the sympathetic, parasympathetic balance of his metabolism. The 1624 patch can also be used for the measurement of bladder function which is a very important parameter when a patient is in intensive care.

It is possible to manufacture the conductive elastomeric segment of the invention "in layers" in order to reduce the size, the cost of production, the weight and simultaneously increase its sensitivity and measurement accuracy. This multilayer construction consists of alternating layers of conductive elastomer with layers of non-conductive elastomer. This advantageous construction makes it possible to carry out several measurements using a single laminated segment 1500.

With reference to FIG. 10, the elastomer segment 1500 is here alternately constituted by layers of conductive elastomer 1501 (a, b and c) and layers of non-conductive elastomer 1502 (a, b and c), may have the same or different stiffness values. The conductive elastomer layers 1501a, b and c may also have different conductivity values to each other. These layers 1501a, b and c are connected to the rest of the device by electrical connectors. A non-conductive elastomer layer 1502a advantageously forms the outer layer intended to be in contact with the patient's skin in order to electrically isolate the device.

In one embodiment, all the conductive layers cover the entire length of the segment 1500. It is also conceivable that a portion of the conductive layers, here the layer 1501b, can be "fractionated", that is to say, interspersed on its length of non-conductive sections 1503 to form conductive segments 1504, 1505 and 1506. Each conductive segment is connected to the rest of the device by judiciously arranged electrical connectors. This fractionation gives the layer 1501b the previously described properties for bracelets consisting of several segments of conductive elastomers, and makes it possible to isolate signals originating from different venous or arterial flows, such as, for example, the flows relating to the ulnar artery and at the radial artery.

The non-conductive sections 1503 may be made of elastomer or not, and possibly made of different materials.

The segment 1500 may comprise several identical conductive layers, each generating a signal that can be processed separately or statistically or by calculating the interactions of the signals of similar layers.

In general, the electrical connections can be made with any suitable material, both by examples of metals, such as copper, as conductive inks.

An elastomer segment, including a layer or layer of multiple layers, may be used to design equipment designed for specific monitoring. For example, an elastomer segment designed for femoral artery monitoring may have the same construction as an elastomer segment designed for monitoring the radial artery at the wrist, but will be adapted in its dimensions according to the 'use.

The means for extracting the parameters of the blood and / or respiratory flows to be monitored comprise an algorithm implementing a certain number of steps for converting the signal measured at the level of the measurement bridge into an operator viewable signal.

With reference to FIG. 13, in a first step 2001, an electrical signal s, here a voltage v, is measured over time t for each elastomer segment. The electrical signal includes maxima and voltage minima from which the average heart rate fc is extracted. For example, for a human, the heart rate is between 0.25 and 4 Hz. For a correct measurement, a sampling frequency, i.e. the frequency at which heart rate extraction can be performed, of 200 Hz is sufficient. In practice, the 2002 extraction of the heart rate fc comprises several steps from 2003 to 2011. In a first step 2003, the signal S passes into a bandpass filter, that is to say, allowing only one band or frequency range between a low cutoff frequency and a high cutoff frequency of the filter, as for example a filter type RIF (impulse response Finite). From the resulting signal Sf, in a second step 2004, the first derivatives S 'and seconds S''are extracted. In digital mode, the first and second derivatives are conventionally calculated by S '(n) = S (n + 1) -S (n) and S''(n) = S' (n + 1) -S ' (n) where n is the number of

The sample.

In step 2005, the first derivatives S 'are binarized into signals S'b, replacing the positive values of the signals S' by 1 and the negative ones by 0. In a step independent and / or parallel 2006, the second derivatives are rectified into S''p signals by setting all negative values to 0.

In a calculation step 2007, the product of the binarized first derivatives S'b and second derivatives rectified S''p gives the signal W which it is possible, in step 2008, to identify the maximums Wmax. The application of a digital filter called "weight", in step 2009, allows to extract from these maximums Wmax the component Wmaxf relative to the arterial frequency. The signal Wmaxf is then processed again to eliminate the "noise", by a band pass filtering 2010.

It is then possible to detect the time interval between two maxima of an arterial pulsation signal to extract, in step 2011, the heart rate.

Cardiac coherence, that is, the change in heart rate, as defined by the Heartmath Institute, can be inferred.

Cardiac coherence is a follow-up that analyzes the heartbeat rate compared to the previous beat. This dynamics is at the origin of the balancing of sympathetic and para sympathetic systems of the body. This monitoring can make it possible to evaluate in particular the level of stress of an individual and possibly to detect the appearance of pathologies such as burn out, depression, or stroke.

In the case where the equipment comprises several segments of elastomer, the signals corresponding to each segment are treated separately, and each undergoes all the steps 2003 to 2011.

The other parameters of blood flow and respiratory cycles can also be extracted from the same signal Sf from the bandpass filtering step 2003.

In a step 2012, for each segment of elastomer, the signal Sf is processed by vibratory analysis integrating a Fast Fourier Transformation (FFT) from which the spectral power density PSDi is extracted for each frequency group, that is to say say on frequency bands each corresponding to a distinct physiological parameter, such as for example the frequencies of the venous system, the arterial system, the respiratory frequencies. Each physiological function can, indeed, be associated with a set of frequencies which make it possible to characterize it in its cycle, its energy and its dynamics. PDSi signals obtained for each frequency band can then also be weighted by their energy and intensity, in a step 2013, to generate representative signals Wi of each physiological function measured, for example a respiratory signal Wr, a venous signal Wv or an arterial signal Wa. The frequency bands considered, for each segment of elastomer, may depend on the specific placement of the segment on the body element and the dominant signals expected for these locations.

In the case where the equipment comprises several segments of elastomer, the Wi signals obtained for each segment can be compared to facilitate the automatic detection of the types of physiological parameters mainly detected by each segment of elastomer.

All the algorithmic steps 300 described above are managed in real time by the computer system, and the resulting signals can be viewed by an operator.

During the course of the steps of the algorithm 300, all the measured values, the signals or the calculation results can be saved on non-volatile memories, local or remote, such as for example hard disks or the cloud.

The steps of the algorithm 300 are detailed here by way of example. The nature, the number and the ordering of the steps can obviously be different to construct an algorithm making it possible to extract from the measurement of the length of the variable elastomer segment any information that can be used by a practitioner. With reference to FIG. 14, the Applicant was surprised to observe that the insertion of an extension member of the static length of the elastomer segment, here a bead 404, positioned between a segment of conductive elastomer 401 connected to a casing 402 and around the wrist 5, specifically at the level of the radial artery 15, significantly improves the accuracy of the measured signal relative to this radial artery 15.

Indeed, the presence of the bead makes it possible, by geometric effect, by slightly separating the elastomer segment 402 from the arm 5, to amplify the variation in length due to the variation in the diameter of the radial artery, that is, to amplify the amplitude of the signal by increasing the sensitivity.

A pearl is used here. The latter being threaded on the elastomer segment, it is easily movable by sliding and is not likely to dissociate. However, any other rigid positionable element, that is to say capable of being placed stably in time at a specific location of the body member, for example at an artery to monitor, between the skin and the skin. elastomer, is possible. The element may for example have a cubic, semi-spherical shape or any other form that the skilled person deems appropriate. The rigid member may be made of any suitable material, and may for example be of wood or plastic.

In the case of equipment comprising several segments of conductive elastomer, it is conceivable to install several extension members, each positionable on an elastomer segment, in order to monitor several arteries. For example, a device according to the invention, which comprises two elastomer segments each covering the entire periphery of a wrist may comprise an extension member positionable on each segment. When using, a first extension member would be placed between the first elastomeric segment and the skin at the radial artery, a second extension member would be placed between the second elastomeric segment and the skin at the level of the ulnar artery . The equipment can thus measure with great precision the information relating to these two arteries. Other segments with extension member may be added, for example measuring also venous flow. The equipment according to the invention thus comprises at least one extension member positionable between a conductive elastomer segment of the equipment and the perimeter of the body element to be monitored, at a point of interest which is preferably a channel traversed by a blood flow.

It is conceivable to use this extension member to perform other measurements by incorporating a miniaturized complementary measuring instrument. For example, associating with the extension member a sonic or ultrasonic microphone may make it possible to perform doppler-type measurements on the arterial flow, in parallel with the plethysmographic measurement. The result of this measurement could be combined with other information generated by the equipment of the invention, in order to improve its accuracy, quality and range.

It has been mentioned above that the computer system for processing the signal can be, inter alia, a connected watch. With reference to FIG. 16, a connected watch 503 is equipped with a connection port 504, at one of the fasteners of the watch strap 506. It can be envisaged to integrate the equipment of the invention, that is to say at least one conductive elastomer segment 501 (here, two are represented) and a circuit 502 comprising the input means the length of the segments 501, the signal processing means and possibly the battery, to the bracelet 501 of the watch 503. Once the processed signal, it can be transmitted via the connection port 504 of the watch 503 to a software , or an application, 506 installed on the watch. The connected watch 503, that is to say that can communicate in wifi, bluetooth, or 3G or 4G for example, can be programmed to automatically prevent a medical emergency service in case of identification of a problem related to blood flow or breathing cycles of the individual. This configuration is particularly interesting for people at risk of high heart failure, or serious lung problems. The emergency service can not only intervene quickly but, in addition, directly adapt its intervention thanks to the information provided by the equipment integrate into the patient's wristband.

The bracelet and the equipment of the invention form an assembly connectable, mechanically for one and electronically for the other, with the connected watch.

For uses in wet environments, for example during scuba diving, the watch strap supporting the equipment of the invention could be coated with silicone to ensure sealing.

We have talked about connected watch here, but this means any wearable monitoring system the size of a watch and integrating different technologies such as for example the Apple Watch. The equipment of the invention can also be used to monitor a baby's breathing and / or heart activity. It is even conceivable that it is combined with infant respiratory monitoring monitor, such as a sensor mat to be placed under a mattress. This type of carpet often suffers from a lack of sensitivity leading to false alarms. Combining the information recorded by the carpet with the information from a bracelet of the invention could advantageously increase the sensitivity of the assembly.

Claims

claims

1. Non-invasive blood flow monitoring equipment, of a body element comprising a network of channels traversed by said blood flows, comprising:

at least one variable-resistance conductive elastomer segment (1; 101; 201) arranged to extend around the perimeter of the body element (5) and the resistance being sensitive to the length of the periphery of said element,

means (2; 102; 202) for capturing said length by means of said variable resistor (1; 101; 201) and providing a signal representative of said length, and means (2, 4) for processing said signal comprising means (3) for extracting blood flow parameters to be monitored.

2. Non-invasive equipment for monitoring the breathing cycles of a human or animal body, inducing a variation in the length of the periphery of a body component, comprising:

means (2; 102; 202) for capturing said length by means of said variable resistor (1; 101; 201) and supplying a signal representative of said length, and means (2, 4) for processing said signal comprising means (3) for extracting the parameters of the respiratory cycles to be monitored.

3. Equipment according to one of claims 1 and 2, wherein the resistance elastomeric segment resistance variable (1; 101; 201) is arranged to surround the body member (5) and responsive to the tower length of said member.

4. Equipment according to one of claims 1 and 2, wherein the variable resistance conductive elastomeric segment (1; 101; 201) is secured to an adhesive part.

5. Equipment according to one of claims 1 to 4, wherein the gripping means of said length comprise at least one measuring circuit (6), at least one of the resistors is constituted by the conductive elastomer variable resistance.

6. Equipment according to claim 5 wherein the measuring circuit (6) is connected to a wireless transmitter (8).

7. Equipment according to claim 6 wherein the wireless transmitter (8) is connected to a wireless receiver (12) of a computer system (4) for processing signals received by the receiver (12).

8. Equipment according to one of claims 1 to 7, wherein the processing means are electronic means and the means for extracting blood flow parameters and / or respiratory cycles to monitor comprise an algorithm (3) arranged for receiving the information relating to said length to extract the parameters of the blood flows and / or respiratory cycles to be monitored.

9. Equipment according to one of claims 1 to 7, wherein the processing means are electronic means and the means for extracting blood flow parameters and / or respiratory cycles to be monitored comprise an algorithm (3) arranged to receive the information relating to said length in order to extract cardiac coherence parameters therefrom.

10. Equipment according to one of claims 8 and 9, wherein said algorithm (3) cooperates with the measuring circuit (6), the wireless transmitter (8) and the wireless receiver

10 (12).

11. Equipment according to one of claims 8 to 10, wherein said algorithm (3) is implanted in said computer system (4).

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12. Equipment according to claims 1 to 11, comprising a plurality of conductive elastomer segments (101a, 101b; 201a, 201b; 1501a, 1501b, 1501c, 1504, 1505, 1506).

Equipment according to claim 12, wherein there is provided a housing (202) comprising at least two measuring circuits (206a, 206b) each incorporating a conductive elastomeric segment (201a, 201b).

The equipment according to one of claims 3 and 5 to 13, comprising a clamping member (316) of the conductive elastomeric segment (1).

Equipment according to claim 14, wherein the clamping member (316) comprises a motor (315), driven by the computer system (4) for adjusting the length of the conductive elastomeric segment (1).

16. Equipment according to one of claims 1 to 15, wherein the variable resistance conductive elastomer segment (1; 1500) is a multilayer segment (1500) consisting of an alternation of layers the elastomer

Conductor (1501a, 1501b, 1501c) with layers of non-conductive elastomers (1502a, 1502b, 1502c).

17. Equipment according to one of claims 1 to 16, comprising at least one extension member of the segment.

The conductive elastomer is arranged to be positionable between the conductive elastomeric segment of the equipment and the periphery of the body component to be monitored.

Equipment according to claim 17, wherein the elastomer segment extending member is arranged to be positionable against one of the channels whose blood flow is to be monitored.

Equipment according to claim 17, wherein the rigid element contains a complementary measuring instrument.

Equipment according to claim 5, wherein the measuring circuit (6) is a differential amplifier.

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21. Kit comprising equipment according to one of

claims 1 to 20 and an automatic

Compression arranged to be controlled by the equipment.

22. Equipment according to one of claims 1 to 20, integrated into the bracelet of a connected watch.

23. Equipment according to claim 22, arranged to be connected to a connection port of the watch.

24. An assembly comprising an equipment according to one of claims 1 to 20 and a respiratory monitor monitor mat arranged to cooperate with the equipment.