NO delivery device including a piezoelectric pump analysis line

Abstract

Title of the Invention: NO Delivery Apparatus Comprising a Piezoelectric Pump Analysis Line. The invention relates to an NO delivery apparatus (1) comprising a main gas circuit for conveying a gas containing NO, in particular a NO / N2 mixture, an analysis line (110) comprising NO / NO2 measuring means (120, 121) configured to perform NO and / or NO2 concentration measurements within said analysis line (110), and control means (15) connected to said NO / NO2 measuring means (120, 121) and configured to process the NO and / or NO2 concentration measurements performed by said NO / NO2 measuring means (120, 121). Furthermore, the analysis line (110) comprises piezoelectric suction means (141) controlled by the control means (15). Abstract Figure: Figure 3

Description

Title of the invention: NO delivery apparatus comprising a piezoelectric pump analysis line

[0001] The invention relates to a device or apparatus for delivering NO, that is to say an apparatus for supplying a gas containing NO, in particular intended to be connected between a source of gaseous NO, such as a pressurized NO cylinder, and the ventilatory circuit or patient circuit supplied with gas by a medical ventilator, which apparatus includes gas analyzer means intended to be fluidly connected to the patient circuit, typically an NO delivery apparatus comprising a piezoelectric pump analysis line including a piezoelectric suction pump.

[0002] Nitric oxide, or NO, when inhaled, dilates pulmonary vessels and increases oxygenation by improving gas exchange. These properties are used to treat various medical conditions, as described in particular by EP-A-560928, EP-A-1516639 and US-A-10,201,564.

[0003] Usually, a small amount of gaseous NO (i.e. a few ppm vol.), diluted in nitrogen (N2) is diluted in a gas stream containing oxygen, such as an N2 / O2 mixture or air, or even pure oxygen, which is conveyed through the patient circuit of a gas supply installation, and the final gas mixture thus obtained containing NO and oxygen and nitrogen is then inhaled by the patient.

[0004] To do this, the patient circuit is fluidically connected to a NO delivery device providing the NO-based gas flow and also to a medical ventilator, providing the oxygen-based gas flow, as described by US-A-5,558,083.

[0005] Since NO is an effective therapeutic agent at very low concentrations (i.e., a few ppmv or tens of ppmv), it is essential to ensure that its correct dosage is in the final NO / N2 / O2 gas stream in order to be able, if necessary, to adjust the NO dosage according to the patient's condition, i.e., improvement or worsening.

[0006] Conversely, it is also important to ensure that the final NO / N2 / O2 gas stream does not contain, or contains only a negligible amount of, toxic species, in particular NO2 resulting from the oxidation of part of the NO by O2.

[0007] Therefore, to ensure increased patient safety, the NO delivery device generally has a gas sampling line for taking a portion of the final gas mixture intended for the patient, typically gas samples on the order of 250 ml / min, from within the breathing circuit carrying the final NO / N2 / O2 gas flow, as described by US2006 / 207594. These gas samples are then analyzed within the NO delivery device to verify whether the composition of the final NO / N2 / O2 gas flow corresponds to the desired composition, in particular to ensure that:

[0008] - the NO concentration is as close as possible to the desired dosage, by for example, in the range of 10 to 20 ppmv, and

[0009] - the NO2 concentration is as low as possible, typically from 0 to 5 ppmv, because the NO2 is a toxic gas that can cause serious harm to the patient, even at low concentrations.

[0010] Currently, the gas is drawn from the patient circuit using a diaphragm pump, also called a diaphragm pump, such as the reference pump series 2002 available from Thomas or the reference V / P 200 available from Xavitech.

[0011] Diaphragmatic pumps generally comprise two flexible membranes, also called diaphragms, mounted opposite each other and set in oscillation, that is, moving closer to and further away from each other at a given frequency. During the moving-away phase, a suction effect occurs, and a portion of the gas to be analyzed fills the volume separating the two membranes thus created, while during the moving-away phase, the same gas to be analyzed is expelled from the pump. By controlling the frequency of these oscillations, typically between 0 and 50 Hz, it is possible to draw a "constant" flow rate of the gas to be analyzed, for example, 250 ml / min.

[0012] However, in practice, the use of a diaphragmatic pump poses a problem for several reasons.

[0013] First, their operating mode implies that the extracted flow rate is itself inherently oscillating around an average value, for example 250 ml / min. However, these oscillations affect the ventilator's performance, in particular its ability to detect the "inspirations" of a newborn patient. Indeed, since newborn patients have a low respiratory drive, that is, producing low inspiratory efforts and mobilizing similarly low inspiratory volumes of a few ml, ventilators use a proximal flow sensor for this population, that is, a sensor measuring the flow rates inhaled and exhaled by the patient directly at their mouth, for example, at the outlet of the endotracheal tube.This flow sensor serves on the one hand to control and / or measure the flow rates inspired by the patient during an inspiratory phase, but also to detect the start of inspiration and trigger the delivery of a volume in order to assist the said patient.

[0014] However, the oscillations created by the diaphragmatic pump's gas extraction process are also present at the flow sensor, which disrupts the ventilator and leads to what is known as auto-triggering, i.e., the erroneous perception that the patient has begun an inspiration, resulting in the inappropriate delivery of a volume to the patient. Such auto-triggering introduces a detrimental asynchrony between the patient and the ventilator.

[0015] To remedy this, users must "strengthen" the inspiration detection mechanism by making this detection less sensitive. However, this has the effect of requiring the patient to produce an additional inspiratory effort in order to "trigger" the delivery of a volume by the ventilator.

[0016] Furthermore, the oscillations created by diaphragmatic pumps result in significant noise pollution because the oscillation frequencies are within the patients' audible range. The noise generated by such pumps is on the order of 50 decibels (dB), which severely disrupts patients' sleep cycles and potentially affects their recovery.

[0017] From there, one problem is to limit the oscillations in the sampling flow rate in order to optimize the detection of inspiration by the fan, and to limit the noise generated by the gas sampling process.

[0018] One solution according to the invention relates to an apparatus or device for delivering NO comprising: - a main gas circuit for conveying a gas containing NO, in particular a NO / N2 mixture, - an analysis line comprising NO / NO2 measurement means configured to perform concentration measurements of NO and / or NO2 within said analysis line, and - control means linked to said NO / NO2 measurement means, configured to process NO and / or NO2 concentration measurements operated by said NO / NO2 measurement means.

[0019] Furthermore, according to the invention, the analysis line of the apparatus includes piezoelectric suction means (i.e. a device) controlled by the control means.

[0020] Depending on the embodiment considered, the device of the invention may comprise one or more of the following features: - the control means are configured to control the piezoelectric suction means to draw gas at a given suction flow rate. - the given aspiration flow rate is less than or equal to 400 mL / min, preferably at least 50 mL / min, preferably between 100 and 350 mL / min, preferably still between 200 and 300 mL / min. - the given aspiration flow rate is, for example, around 250 mL / min. - the control means are configured to control electric field generation means configured to generate an electric field at an excitation frequency of at least about 20 kHz, preferably between 20 and 30 kHz. - the surface area of ​​the piezoelectric membrane is at least 30 mm2. - The NO / NO2 measurement means include a NO sensor and a NO2 sensor. The piezoelectric suction means (or device) include a piezoelectric suction pump, that is to say, one which, during its operation, exploits the dynamic piezoelectric effect resulting from the frequency excitation. the piezoelectric pump includes at least one piezoelectric material. The piezoelectric material has a crystalline or ceramic structure. The piezoelectric material is chosen from among the materials capable of deforming proportionally to an electric field applied to said material, that is to say under the effect of an electric field that is applied to it. The piezoelectric material comprises at least one metal. the piezoelectric material includes lead zirconate titanate (PZT). The piezoelectric material is subjected to the electric field generated by means of electric field generation. The piezoelectric membrane is powered by an electric current. The generation of the electric field is obtained by dynamic variation of the applied electric current passing through the piezoelectric membrane. The means of generating the electric field are controlled by the control means. The means of generating an electric field include an electric current converter, also called an inverter. The current converter is configured to convert direct current to alternating current at a given frequency. The control means control the value of the frequency of variation of the alternating current. The means for generating the electric field are arranged in the device, the means for generating the electric field are supplied with electric current. said at least one piezoelectric material is deposited in a layer, preferably a thin layer, on a metallic substrate to form a piezoelectric membrane having a surface area of ​​at least 30 mm2, the thickness of the layer of piezoelectric material, preferably a thin layer, is between several tens and several hundreds of pm. the metallic substrate comprising titanium or aluminum. said at least one piezoelectric material has a disc or similar shape. said at least one piezoelectric material is disposed in an enclosure closed including an inlet orifice or port and an outlet orifice or port.

[0021] Furthermore, according to the embodiment considered, the NO delivery device of the invention may include one or more of the following features: - the NO / NO2 measurement means include a first metal oxide MOS (Metal Oxide Semiconductor) sensor configured to determine the concentration of NO and a second metal oxide MOS sensor configured to determine the concentration of NO2, or alternatively, a combined MOS sensor configured to determine the concentrations of NO and NO2. - each MOS sensor includes a sensitive layer comprising at least one metal oxide, a resistive track subjected to electrical potential and a pair of electrodes, for example a metal oxide selected from titanium dioxide (TiO2) and tin dioxide (SnO2). - according to another embodiment, the means for measuring NO / NO2 include electrochemical sensors. - it includes means of power supply providing electrical current to the various elements or components of the device which need it to function, for example to the control means, the sensors, the pump etc. Preferably, the means of power supply include a connection to the mains (110 / 220V) and / or a rechargeable battery or other, and possibly a current converter. - the electrodes are electrically connected to the control means. - the control systems are configured to determine a concentration in NO and / or NO2. - the measuring means also include an O2 sensor. - it also includes a flow sensor arranged on the analysis line. - it includes an information display, controlled by means of control, to display (at least) the concentrations, i.e. levels, of NO and NO2, and possibly of O2. - the information display includes a screen, in particular the screen of an IGU. - The information display includes a touchscreen display. - The information display includes a color or black and white screen. - The information display is configured to display concentration values operations in NO and NO2, and possibly in O2, having been determined by the piloting means. - the main gas circuit includes flow control means to control the gas flow in the main gas circuit, preferably at least one solenoid valve. - the main gas circuit includes one or more gas passages, such as gas conduits or the like. - the main gas circuit includes at least one gas inlet through which a NO / N2 mixture can enter the main circuit. - the main gas circuit includes at least one gas outlet through which the NO / N2 mixture can exit the main circuit. - the flow control means are controlled by the pilot means to allow or prevent any gas flow in the main gas circuit, in particular said at least one solenoid valve is controlled by the pilot means (i.e. piloted solenoid valve). - the main gas circuit also includes pressure control means, in particular a gas regulator device. - the control means include at least one microprocessor. - said at least one microprocessor is arranged on at least one electronic board tronique. - the control means include at least one microprocessor implementing at least one algorithm. - The NO delivery device includes an external casing or housing. - the gas analysis line, the main gas circuit and the control means are arranged in the device housing.

[0022] Furthermore, the invention also relates to a gas administration installation for a patient, i.e., dedicated to supplying a gas mixture containing NO to a patient, i.e., a person in need of it, comprising: - a NO delivery device for supplying a NO-based gas according to the invention, such as a NO / N2 mixture, - a medical ventilator to supply an oxygen-based gas, such as air or an O2 / N2 mixture, - a patient circuit to which the NO delivery device and the medical ventilator are fluidly connected, - and a proximal flow sensor arranged on the patient circuit and electrically connected to the medical ventilator.

[0023] According to the embodiment considered, the gas supply installation of the invention may include one or more of the following features: - the medical ventilator is a ventilatory support device supplying the patient circuit with a respiratory gas containing oxygen, typically at least 20% vol. about oxygen, preferably at least 20% vol. about oxygen, in particular air or an N2 / O2 mixture. - the NO delivery device is supplied with NO, in particular in a NO / N2 mixture, by one (or more) gas source containing gaseous NO. the gas source(s) contains a NO / N2 mixture containing between 100 and 2500 ppm by volume of NO (ppmv), the remainder being nitrogen, preferably less than 1500 ppmv, the remainder being nitrogen, preferably less than 1000 ppmv, the remainder being nitrogen. Preferably, the gas source contains a NO / N2 mixture containing 250 to 900 ppm by volume of NO, the remainder being nitrogen, for example around 800 ppm by volume of NO, the remainder being nitrogen. The gas source(s) is a pressurized gas cylinder. The patient circuit includes an inspiratory branch and an expiratory branch. The medical ventilator, the main gas circuit, and the analysis line of the NO delivery device are fluidly connected to the inspiratory branch of the patient circuit. The inspiratory branch and the expiratory branch are connected at a junction piece, such as a Y-piece. the patient circuit, in particular the inspiratory branch, feeds a respiratory interface, such as a tracheal intubation tube or a respiratory mask, the proximal flow sensor is arranged on the patient circuit close to the respiratory interface and / or the junction piece, i.e. Y-piece. The proximal flow sensor is arranged between the junction piece and the respiratory interface. a gas humidifier is arranged on the inspiratory branch, preferably downstream of the injection site of gaseous NO, i.e. of the NO / N2 mixture, coming from the main gas circuit of the NO delivery device. The patient circuit is fluidly connected to an outlet port of the medical ventilator in order to recover and convey the oxygen-containing gas delivered by the medical ventilator, such as air or an N2 / O2 mixture. The pressurized gas cylinder(s) contains, when full, a NO / N2 gas mixture at a pressure of at least 150 to 200 bar abs, or even at least 250 to 300 bar abs. The patient circuit includes pipes or conduits used to carry gas. the patient circuit includes a main flow sensor electrically connected to the control means. The analysis line of the NO delivery device is fluidly connected to the inspiratory branch of the patient circuit at a pre-site gas lift located downstream of the main flow sensor, preferably downstream of the gas humidifier. - the main gas circuit of the NO delivery device is fluidly connected to the inspiratory branch of the patient circuit, at an injection site located between the main flow sensor and the gas sampling site. - the main gas circuit of the NO delivery device is fluidly connected to the inspiratory branch of the patient circuit via a gas injection line. - the analysis line of the NO delivery device is connected fluidly to the inspiratory branch of the patient circuit via a gas sampling line. - The gas analysis line of the NO delivery device includes an outlet port communicating with the ambient atmosphere. - the connection of the sampling line to the patient circuit is made by means of a connection device, such as a T-piece, allowing gas sampling to be carried out within the inspiratory branch of the patient circuit in order to check its composition, i.e. the concentrations of NO and NO2. - the connection device is arranged downstream of the NO injection point, i.e. between the NO injection point and the patient interface, e.g. a tracheal intubation probe. - the medical ventilator supplies the patient circuit with a breathing gas containing oxygen, typically at least 20% vol. about oxygen, in particular air or an N2 / O2 mixture. - the NO delivery device supplies the patient circuit with gaseous NO, in particular in a NO / N2 mixture, so as to dilute the gaseous NO (i.e. NO / N2 mixture) in the respiratory gas stream containing oxygen and obtain a final gas mixture intended to be administered to the patient. - the final gas mixture essentially comprises nitrogen (N2), oxygen (O2) at a concentration of at least 20% vol. approximately, and NO at a content between 1 and 80 ppmv, typically in the order of 10 to 20 ppmv corresponding to a desired dosage, i.e. a NO / O2 / N2 gas mixture. - the final gas mixture may include NO2 species resulting from the oxidation of some of the NO.

[0024] The invention will now be better understood with reference to the following detailed description, given by way of illustration but not limitation, with reference to the accompanying figures, among which:

[0025] [Fig-1] is a partial schematic view of a gas administration installation at a patient including a NO delivery device including a diaphragmatic pump gas analyzer according to the prior art.

[0026] [Fig.2] Illustrates the flow oscillations generated by a diaphragm pump, part of the gas analyzer according to the prior art.

[0027] [Fig.3] is a partial schematic view of a patient gas delivery installation comprising an NO delivery device including a piezoelectric pump gas analyzer according to the present invention.

[0028] [Fig.4] shows the benefit of replacing the diaphragm pump of [Fig.1] with a piezoelectric pump according to the invention, as illustrated in [Fig.3].

[0029] [Fig.1] schematically illustrates an embodiment of a gas delivery installation 20 used to supply gaseous NO to a patient P, comprising an apparatus or device for delivering NO 1 to supply a gas based on NO and a medical ventilator 2, i.e. a respiratory support device delivering a respiratory gas containing oxygen, typically at least about 20% oxygen (O2), generally at least about 21% oxygen.

[0030] Such an installation 20 makes it possible to deliver a final gaseous mixture containing NO at a desired concentration corresponding to a dosage set by an anesthesiologist or similar physician, typically between 1 and 80 ppmv of NO (i.e. ppm by volume).

[0031] The final gas mixture is formed by mixing a NO-based gas stream, such as a NO / N2 mixture from the NO delivery device 1, and a breathing gas stream containing oxygen, typically at least about 20% oxygen (O2), such as air or an O2 / N2 mixture, from the medical ventilator 2.

[0032] The NO-based gas flow is injected (not shown) into a patient circuit 3, in particular into an inspiratory branch 31 of said patient circuit 3, supplied furthermore with the gas flow containing oxygen supplied by the medical ventilator 2.

[0033] The flow rate of the O2-based gas circulating in the patient circuit 3 is measured by a main flow sensor (not shown), arranged on the patient circuit 3 downstream of the medical ventilator 2, typically on the inspiratory limb 31. The main flow sensor is electrically connected to the control means 15 of the NO delivery device 1 in order to provide them with flow signals or measurements reflecting the flow rate of the oxygen-containing gas supplied by the medical ventilator 2 and circulating in the patient circuit 3 towards patient P, in particular in the upstream part of the inspiratory limb 31. The main flow sensor may be a flow sensor of the mass flow meter or differential pressure type, or other.

[0034] The final gas mixture obtained by mixing the NO / N2 and air streams, or the O2 / N2 mixture for example, consists essentially of oxygen and nitrogen, and of NO at the desired dosage, typically between 1 and 80 ppmv of NO; ​​it may contain unavoidable impurities, for example argon or others. It is administered to patient P, during its inspiratory phases, by means of a respiratory interface 3, for example a respiratory mask, a tracheal intubation tube or any other suitable interface.

[0035] The gases exhaled by the patient during his expiratory phases are collected by an expiratory branch 32 of the patient circuit 3. The inspiratory branches 31 and expiratory branches 32 are fluidly connected to a junction piece 33, such as a Y-piece or similar, which is also connected to the respiratory interface 30.

[0036] The respiratory interface 30 allows the gas to be delivered to patient P, in particular during the inspiratory phases, and the gases exhaled by patient P to be collected, in particular during the expiratory phases.

[0037] A proximal flow sensor 35 is also provided for measuring the flow rate delivered to the patient and exhaled by the patient. This sensor is arranged at the respiratory interface 30 and / or the junction piece 33, typically between them. The proximal flow sensor 35 can be of various technologies, such as a hot-wire sensor, and is preferably adapted to the patient population to be treated, i.e., newborns or adults. Here, an electrical cable 34, connected to the medical ventilator 2, provides power to the proximal flow sensor 35. Instantaneous flow measurement is performed in the medical ventilator 2 based on the electrical information returned by the proximal flow sensor 35. This technology is conventional.

[0038] The inspiratory branches 31 and expiratory branches 32 include conduits, pipes, tubes, passages, tubing or the like, for example flexible polymer tubing, suitable for and configured to convey gas flows.

[0039] During the operation of the installation 20, the gas flow circulating in the inspiratory branch 31 of the patient circuit 3, i.e. going from the mechanical ventilator 2 to patient P, is inhaled by patient P, while the gases exhaled by said patient P, i.e. enriched in CO2, are conveyed by the expiratory branch 32 of the patient circuit 3 to the ventilator 2 where they are vented to the atmosphere via a vent or similar.

[0040] Furthermore, the NO 1 delivery apparatus is of conventional architecture and operation with regard to the supply of NO, typically a NO / N2 mixture. It includes (not shown) an internal main gas circuit for conveying a gas containing NO, in particular one (or more) internal gas delivery line, typically a NO / N2 mixture comprising 100 to 2000 ppmv of NO (remaining N2), typically less than 1000 ppmv.

[0041] Flow control means, such as a solenoid valve, and / or gas flow pressure control means, such as a gas pressure regulator, are arranged on the main gas circuit. The flow control means are preferably controlled by the control means 15 of the NO delivery device 1 comprising one or more (Micro)processor(s) carried by an electronic card 150, based on the flow signals or measurements provided by the main flow sensor. The main flow sensor is advantageously arranged on the patient circuit 3, typically the inspiratory branch 31, upstream of the injection site 31a of the inspiratory branch 31 of the patient circuit 3 where NO (i.e., the NO / nitrogen mixture) is injected into the inspiratory branch 31 and mixed with the oxygen-containing gas flow from the medical ventilator 2.

[0042] The NO / N2 mixture comprising for example 100 to 2000 ppmv of NO (rest N2) generally comes from one or more gas sources, e.g. one or more compressed gas cylinders (not shown) containing the NO / N2 gas mixture at a pressure of up to 150 bar, or even 180 to 200 bar, or more.

[0043] The NO delivery device 1 makes it possible to supply / inject NO, i.e. the NO / nitrogen gas mixture, into the patient circuit 3 so that it mixes there with the flow of oxygen-containing gas from the medical ventilator 2, as already explained.

[0044] More specifically, the NO / nitrogen mixture is conveyed by a gas injection line 11, such as a conduit or similar, and the injection of NO (i.e. of the NO / nitrogen mixture) is carried out at an injection site 31a of the inspiratory branch 31 of the patient circuit 3 so as to effect a mixing (i.e. a dilution) of the flow (flow rate) of NO / nitrogen mixture with the flow (flow rate) of gas containing oxygen (i.e. >20% vol. approx.) from the medical ventilator 2, such as air or an O2 / N2 mixture and thus obtain the final NO / O2 / N2 gas mixture.

[0045] The final gas mixture is then administered to patient P via the breathing interface 30 and therefore mainly comprises nitrogen (N2), oxygen (O2) at a content of at least 20% vol. approximately, and NO at a content between 1 and 80 ppmv, typically in the order of 10 to 20 ppmv corresponding to a desired dosage.

[0046] Indeed, nitric oxide or NO, when inhaled, dilates pulmonary vessels and increases oxygenation by improving gas exchange. These properties are used to treat various medical conditions, such as Persistent Pulmonary Hypertension of the Newborn or PPHN, Acute Respiratory Distress Syndrome or ARDS observed mainly in adults, or pulmonary hypertension (PH) in cardiac surgery in adults or children, as described in particular by EP-A-560928, EP-A-1516639 and US-A-10,201,564.

[0047] The concentration of NO in the mixture administered to the patient corresponds to a dosage (i.e., a target concentration) determined by a physician or similar professional. Generally, it is between 1 and 80 ppm by volume (ppmv), typically in the order of from 10 to 20 ppmv, depending on the population treated, i.e. newborns, children, adolescents or adults, and the disease to be treated.

[0048] However, due to the presence of O2 in the final NO / O2 / N2 gas mixture, some of the NO in it will oxidize and form toxic NO2 species.

[0049] It is therefore essential to ensure that the concentration of NO in the final gas mixture corresponds to the dosage desired by the physician and that, moreover, the quantity of toxic NO2 species is limited, typically less than a few ppmv, generally less than 0.5 ppmv.

[0050] To do this, the NO 1 delivery device of [Fig.1] incorporates gas analysis means 10, i.e. a gas analyzer, allowing to monitor, i.e. measure, the concentrations of NO and NO2 in the final gas mixture, as explained below.

[0051] As already stated, the NO 1 delivery device also includes control means 15 comprising, for example, one or more electronic control boards 150 and a control unit 151 with a (micro)processor(s), typically a microcontroller or similar. The control means 15 allow all the electromechanical elements of the NO 1 delivery device to be controlled or commanded. More specifically, the electronic control board 150 preferably integrates the control unit 151, i.e., one or more microprocessors, and is configured to control and also analyze the signals from the various components of the NO 1 delivery device, such as the pump, sensors, etc., including those from the gas analysis means 10.

[0052] The gas analysis means 10, i.e. the gas analyzer, is arranged in the housing 5 or external casing, for example made of polymer, of the NO delivery device 1.

[0053] The gas analyzer 10 includes an inlet port 100 arranged on the outside of the housing 5 of the NO delivery device 1, which is fluidically connected to the inspiratory branch 31 of the patient circuit 3, via a gas sampling line 101.

[0054] The connection of the sampling line 101 to the patient circuit 3 is made by means of a suitable connection device 102, such as a T-piece or similar, allowing gas samples to be taken within the inspiratory branch 31 of the patient circuit 3 in order to check its composition, in particular the concentrations of NO and NO2 species.

[0055] The connecting device 102 is arranged downstream of the NO injection point 31a, i.e. between the NO injection point 31a and the patient interface 30, e.g. a tracheal intubation probe.

[0056] The inlet port 100 of the gas analyzer 10 communicates fluidly with a gas analysis line 110, arranged in the housing 5, within which are arranged successively, from the inlet port 100, a NO2 sensor 120 and a NO sensor 121, a flow sensor 130 and a gas suction device 140, such as a suction pump.

[0057] The gas analysis line 110 terminates in an outlet port 110a connected to the ambient atmosphere A through which the gas is released to the atmosphere after passing through the gas analysis line 110 and coming into contact with, in particular, the NO2 120 and NO 121 sensors.

[0058] The suction pump 140 allows the gas to circulate by creating a flow or gas flux in the gas analysis line 110, as explained below.

[0059] The power supply of the NO delivery device 1, in particular of the control means 15, of the gas analysis means 10 (i.e. the sensors 120, 121, 130), of the diaphragm pump 140, is ensured by an electrical current source and / or electrical supply means (not shown), for example a connection to mains current (110 / 220V) of the type electrical cord and plug connection, and / or one (or more) electrical supply battery, preferably rechargeable, and / or a current transformer.

[0060] The gas flow to be analyzed, which is drawn in by the pump and circulates in the gas analysis line 110, is brought into contact with the NO2 sensors 120 and NO 121, which will then measure the concentration of NO2 and NO in the gas flow and provide these measurements to the control means 15, which will then provide them to the user, such as a doctor or other healthcare personnel, by ordering their display on an information display (not shown), such as a screen, of the graphical user interface (GUI) of the NO delivery device 1.

[0061] The gas analysis line 110 may also include one or more other sensors, such as an oxygen sensor.

[0062] Of course, if necessary, the control means 15 can also process the measurements of NO and NO2 before ordering their display, in particular perform a compensation of these values ​​to take into account environmental factors that may influence the measurements, such as atmospheric pressure, temperature and / or humidity, to which the gas mixture may have been subjected.

[0063] According to the prior art, as already explained, the suction pump 140 is generally of the diaphragm type, also called a diaphragm pump. It is controlled by the control means 15 in order to aspirate, i.e., to draw, a portion of the gas to be analyzed from the patient circuit 3. Preferably, the flow rate circulating in the gas analysis line 110 is kept constant and equal to a given target flow rate, for example, approximately 250 ml / min. This control of the diaphragm pump 140 is based on flow measurements taken by the flow sensor 130 of the analyzer 10 and includes an adjustment, preferably continuous, of the control of the diaphragm pump 140 in the goal of achieving the desired target flow rate.

[0064] In view of the intrinsic oscillatory nature of the diaphragm pump 140, as explained previously, the control means 15, via in particular the control unit 151, can process the signal from the flow sensor 130 in order to "smooth out" the oscillations, by means of low-pass filters, time averages etc... and allows said diaphragm pump 140 to reach and maintain the target flow given, for example 250 mL / min.

[0065] In all cases, since the pump 140 is of the diaphragmatic type, it induces oscillations around the target flow rate value, for example 250 ml / min.

[0066] Thus, [Fig.2] represents a flow curve as a function of time showing the oscillations generated by a diaphragm pump 140 used in the gas analysis line 110 of a NO 1 delivery device according to the prior art, and measured by the flow sensor 130 of the gas analysis line 110.

[0067] The instantaneous flow rate INS, derived from the instantaneous flow rate value transmitted by the flow sensor 130, and an averaged value ME, resulting from signal processing performed by the control means 15, via in particular the control unit 151, which controls the diaphragm pump 140 to reach and maintain the target sampling flow rate, are visible. It should be noted that this averaged value ME is well centered on the flow rate of 250 ml / min. However, it is clear that the instantaneous flow rate INS is oscillatory, alternating between values ​​successively higher and lower than the averaged value ME.

[0068] For example, the maximum recorded flow rate of the instantaneous flow rate INS., INS. 1 is on the order of 275 ml / min, while the minimum recorded flow rate of the instantaneous flow rate INS., INS. 2 is on the order of 225 ml / min. This corresponds to flow rate variations of on the order of 50 ml / min over time which "interfere" with the measurement of the proximal flow rate 35 by propagating successively in the sampling line 101, the inspiratory branch 31 of the patient circuit 3 via the connection device 102, and the proximal flow rate sensor 35, causing the aforementioned problems encountered with diaphragm pumps 140 according to the prior art.

[0069] In order to resolve these problems, according to the present invention, the diaphragm pump 140 of the prior art in the NO 1 delivery device of the installation 100 of [Fig. 1] has been replaced by a piezoelectric pump 141, as illustrated in [Fig. 3]. The rest of the installation 100 is unchanged and its operation is identical to that described in relation to [Fig. 1].

[0070] More specifically, the piezoelectric pump 141 used according to the invention has an operation based on a piezoelectric material (or materials), i.e. having piezoelectric properties, for example a crystalline or ceramic-type structure, and responding to excitation by an electric field by deforming proportionally analytically to the electric field to which it is subjected. For example, the piezoelectric material could be lead zirconate titanate, which can deform by up to 0.1% of its dimensions under the influence of an electric field. Of course, the piezoelectric material could be any other suitable material.

[0071] The piezoelectric material is deposited as one or more thin layers, a few tens to hundreds of micrometers thick, on a metallic substrate, for example titanium, aluminum, or any other suitable substrate. This results in a thin "membrane" that can "oscillate" under the effect of a varying electric field.

[0072] In other words, a piezoelectric pump 141 can schematically comprise a surface, for example in the shape of a disc or another suitable shape, comprising a suitable substrate, for example metallic, and a thin piezoelectric layer (or layers) deposited thereon.

[0073] Such a piezoelectric assembly is placed in an enclosure, for example with a circular cross-section, forming a cavity equipped with an inlet port and an outlet port. Means are also provided for generating an electric field to produce a variable electric field (i.e., a conductive material) affecting the piezoelectric material.

[0074] The piezoelectric membrane is supplied with electric current, and the electric field generation means are controlled by the control means 15 to operate dynamic variations over time of the electric current supplied to the piezoelectric membrane. The electric field is then generated by the dynamic variations, over time, applied to the electric current passing through the piezoelectric assembly, i.e., the piezoelectric membrane.

[0075] When the piezoelectric material expands or contracts due to the applied electric field, a suction or expulsion phenomenon occurs through the inlet and outlet ports of the piezoelectric pump 141, respectively. However, the small deformations of the piezoelectric material mobilize only a minute quantity of gas, which then requires: - high-frequency operation of the piezoelectric membrane to significantly increase the number of oscillations of the piezoelectric material; and - dimensions of the piezoelectric membrane, typically of the surface area of ​​the piezoelectric membrane, and therefore of the cavity which contains it, which are sufficient to mobilize "enough" gas by oscillation and achieve the expected flow performance.

[0076] From there, the excitation frequency of the piezoelectric material is preferably an ultrasonic frequency, that is to say at least 20 kHz, typically between 20 kHz and 30 kHz.

[0077] As illustrated on [Fig.3], the control means 15 control the piezoelectric pump 141 in order to aspirate, i.e. to collect, a portion of the gas to be analyzed coming from the patient circuit 3 and passing through the sampling line 101 which is fluidly connected to the inspiratory branch 31.

[0078] Preferably, the control means 15 control, i.e., drive, the piezoelectric pump 141 so that the flow rate circulating in the gas analysis line 110 is maintained constant and equal to a given target flow rate, typically between 50 and 500 ml / min, for example, approximately 250 ml / min. This control of the piezoelectric pump 141 is based on flow rate measurements taken by the flow sensor 130 and includes an adjustment, preferably continuous, of the control of the piezoelectric pump 141 in order to obtain the desired target flow rate.

[0079] When the sampling line 101 is long, for example several meters, it may present a resistance to the flow of the sampled gas, which may affect the performance of the piezoelectric pump 141.

[0080] Therefore, at the aforementioned operating frequencies, the surface area of ​​the piezoelectric membrane can be a factor to be taken into account in order to obtain the target flow rate, for example a target flow rate of 250 ml / min, also considering the resistance exerted by the sampling line 101.

[0081] Tests carried out within the framework of the invention have shown that the surface area of ​​the piezoelectric membrane must be at least 30 mm2, when operating at excitation frequencies between 20 and 30 kHz.

[0082] [Fig.4] represents the variations in gas flow within the gas analysis line 110 when gas aspiration is carried out, according to the invention, with a piezoelectric pump 141 and the flow measured by the flow sensor 130 of [Fig.3].

[0083] The instantaneous flow rate INS is shown here, derived from the instantaneous value transmitted by the flow sensor 130, centered on the target flow rate, i.e. here of 250 ml / min, via adequate control of the piezoelectric pump 141 by the control means 15, typically the control unit 151.

[0084] Due to the use of a piezoelectric pump 141 in place of the diaphragm pump 140 according to the prior art, the instantaneous flow rate INS. is perfectly smooth, i.e. not exhibiting oscillations or exhibiting extremely limited oscillations.

[0085] For example, on a 20-second acquisition, only a few local maxima and minima INS.1 and INS.2 occur, the value of which deviates only slightly from the target value, namely by only about 1 ml / min, i.e., more than 50 times lower than in the case of [Fig.2] where a 140 diaphragm pump according to the prior art was used.

[0086] The advantage of using a piezoelectric pump 141 in the line is clear. gas analysis 110 of the ventilator 1 according to the invention. Indeed, the flow variations over time are small and do not "interfere" with the measurement of the proximal flow 35, which makes it possible to improve the sensitivity of inspiratory effort detection of the medical ventilator 2 and thus facilitate the inspiratory effort of patients, in particular when the patients are newborns.

[0087] In addition, the piezoelectric pump 141 also has the advantage of being perfectly silent because the operating frequencies in the ultrasonic range are inaudible to the human ear.

[0088] In general, the gas administration installation 20 comprising the NO delivery device 1 according to the invention is suitable for use in treating various pulmonary pathologies, such as Neonatal Pulmonary Hypertension (NPPH), Acute Respiratory Distress Syndrome (ARDS) and / or pulmonary hypertension (PH) in cardiac surgery, in different patient populations, in particular newborns, adults, adolescents or children.

Claims

Claims

1. NO delivery apparatus (1) comprising: - a main gas circuit for conveying a gas containing NO, in particular an NO / N2 mixture, - an analysis line (110) comprising NO / NO2 measuring means (120, 121) configured to carry out NO and / or NO2 concentration measurements within said analysis line (110), and - control means (15) connected to said NO / NO2 measuring means (120, 121) and configured to process the NO and / or NO2 concentration measurements carried out by said NO / NO2 measuring means (120, 121), characterized in that the analysis line (110) comprises piezoelectric suction means (141) controlled by the control means (15).

2. Apparatus according to claim 1, characterized in that the control means (15) are configured to control the piezoelectric suction means (141) to suck gas at a given suction flow rate.

3. Apparatus according to claim 2, characterized in that the given suction flow rate is less than 400 mL / min, preferably between 200 and 300 mL / min, for example of the order of 250 mL / min.

4. Apparatus according to one of claims 1 or 2, characterized in that the control means (15) are configured to control electric field generation means configured to generate an electric field at an excitation frequency of at least approximately 20 kHz, preferably between 20 and 30 kHz.

5. Apparatus according to claim 1, characterized in that the NO / NO2 measuring means (120, 121) comprise a NO sensor (121) and a NO2 sensor (120).

6. Apparatus according to claim 1, characterized in that the piezoelectric suction means (141) comprise a piezoelectric pump.

7. Apparatus according to claim 6, characterized in that the piezoelectric pump comprises at least one piezoelectric material.

8. Apparatus according to one of claims 4 and 7, characterized in that the

9.

10. piezoelectric material is subjected to the electric field generated by electric field generating means. Apparatus according to claim 7, characterized in that said at least one piezoelectric material is deposited in a layer on a metal substrate to form a piezoelectric membrane having a surface area of ​​at least 30 mm2. Installation for administering gas (20) to a patient (P) comprising: - an NO delivery apparatus (1) for supplying an NO-based gas according to one of claims 1 to 9, such as a NO / N2 mixture, - a medical ventilator (2) for supplying an oxygen-based gas, such as air or an O2 / N2 mixture, - a patient circuit (3) to which the NO delivery device (1) and the medical ventilator (2) are fluidically connected, - and a proximal flow sensor (35) arranged on the patient circuit (3) and electrically connected to the medical ventilator (2).

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