NO delivery device with emergency dosing system

Abstract

The invention relates to a NO supply apparatus (1) for supplying a gas containing NO, comprising an NO injection line (111) with a normally closed valve device (113) and a flow metering device (112); a backup circuit (200) comprising a backup line (201) connected to the injection line, with a normally open backup solenoid valve (202); and control means (130). In the event of a malfunction of the control means, the flow control device (210) supplies the gas at a predetermined backup gas flow rate, which was set prior to the malfunction. A multidirectional solenoid valve (205) is arranged downstream of the flow control device and feeds the metering lines (206, 207) with calibrated orifice devices (208, 209).

Description

NO delivery device with emergency dosing system The invention relates to a device for supplying gaseous nitrogen monoxide (NO) to a patient, comprising an emergency NO dosing system and intended to be connected to the patient circuit of a mechanical ventilator, i.e., a medical device for administering gas to a patient, which allows gas to be supplied at a predetermined flow rate in case of failure, in particular, of the control means. Nitric oxide (NO) is a gas that, when inhaled, dilates the pulmonary vessels and increases oxygenation by improving gas exchange. It is used to treat various medical conditions, such as pulmonary arterial hypertension of the newborn (PPHN), acute respiratory distress syndrome (ARDS), which is seen primarily in adults, and even pulmonary hypertension in cardiac surgery, as taught, in particular, in documents EP-A-560928, EP-A-1516639, and US-A-10.201.564. Typically, a small amount of gaseous NO (i.e., a few ppm by volume), diluted in nitrogen (N2), is injected into a gas stream containing oxygen (O2), which is then inhaled by the patient. The NO concentration, which corresponds to a specific dosage, is determined by a physician or similar healthcare professional. The gas containing O2 is usually a mixture of N2 / O2 or air, such as medical-grade air. Generally, the NO concentration in the gas inhaled by the patient ranges from 1 to 80 ppm by volume (ppmv), depending on the patient population (i.e., newborns or adults) and, consequently, the specific condition being treated. The gas inhaled by the patient may be delivered through a NO delivery device associated with a mechanical ventilator, as described in US-A-5,558,083. The NO delivery device is fluidly connected to one or more gas cylinders containing an N2 / NO mixture, the NO concentration of which may typically be between 200 and 1000 ppmv. In general, the NO delivery system comprises a NO injection module located in the inspiratory limb of a patient circuit fluidly connected, on one side, to the mechanical ventilator and, on the other side, to a respiratory interface that delivers the NO-enriched gas to the patient, for example, a respiratory mask, a tracheal intubation tube, or similar devices. The NO delivery system also includes a flow sensor that measures the gas flow supplied by the mechanical ventilator (i.e., air or N2 / O2 mixture) to determine the amount of NO to be delivered to meet the dose set by the physician. The NO supply system can guarantee NO dosing by means of a proportional solenoid valve that supplies a continuous flow of gas containing NO, which is associated with a flow sensor, the two components being arranged in the supply system, as well as an injection line connected to the NO injection module, as described in document US-A-5,558,083. Another NO supply system is known, for example, from document FR 3131538 A1. Other systems are available in which the proportional solenoid valve is replaced by a plurality of "all or nothing" type solenoid valves, which supply the gas intermittently, i.e., in the form of pulses, generally at high frequency, whose amplitude and duration ensure the correct amount of gas circulating through the injection line connected to the NO injection module. In all cases, known NO delivery systems receive measurements from the flow sensor placed in the inspiratory branch of the patient circuit and adjust in real time the amount of NO to be administered, according to the desired dose, by controlling the NO flow in the injection line. Since NO is an effective therapeutic agent, meaning that very low concentrations (i.e., a few ppmv) produce a therapeutic effect, its correct dosage is of vital importance and medical teams must constantly adjust the dosage according to the patient's condition. As the patient's condition changes, the NO concentration should be gradually decreased or increased. For example, when weaning a newborn whose condition is improving, it is common practice to gradually decrease the dosage, for example, in 1 ppm increments, until reaching zero, at which point the NO delivery system can be stopped. A gradual decrease in NO concentration helps to avoid the "rebound" effect that can occur in the event of a rapid change in concentration, for example, in the event of a sudden interruption of treatment, with the effect of seriously worsening the patient's condition. However, nitric oxide (NO) delivery systems are sophisticated electromedical systems that can suffer breakdowns or malfunctions, which can significantly impact ongoing therapy. For example, a major electronic breakdown or failure, particularly in the control system, can lead to a complete breakdown of the device and, consequently, a total interruption of the NO delivery, with the negative consequences mentioned above. In such circumstances, the NO delivery device must warn the user, for example by means of an audible alarm signal, that prompt action is required, normally a switch to an emergency pneumatic injection mode, i.e. the so-called "emergency" mode, in order to limit as much as possible the adverse effects associated with an interruption of treatment. Such a change to emergency mode is normally carried out by operating a control element, such as a rotary knob, for example, which controls a continuous supply of a fixed flow rate of NO, normally a mixture of N2 / NO, for example, on the order of 250 ml / min. However, an emergency dosing mechanism or system is not without risks, particularly for the following reasons: - Its activation requires the presence of a person with the authority to take this action, for example, a neonatologist. In a hospital setting, several minutes may pass before this person arrives in the treatment room and the emergency dosage is administered, which may temporarily halt therapy and expose the patient to a rebound effect. - The emergency dose, as a predetermined flow rate of the N2 / NO mixture, does not guarantee that the desired dosage will always be achieved. In particular, when the emergency dose is much lower than the desired dosage, the patient may be exposed to a sudden change in concentration and potentially subject to significant adverse effects, which is undesirable for obvious reasons of patient safety and treatment efficacy. Emergency dosing is incompatible with certain types of ventilators that deliver very low volumes, such as high-frequency oscillation (HFO) ventilators, because it can lead to an excessively high concentration of inhaled nitric oxide (NO), which can sometimes reach levels dangerous to the patient. Therefore, if the patient is being treated with an HFO ventilator, there is no way to administer NO to the patient, which carries the aforementioned risks associated with abrupt treatment interruption. Therefore, it appears that current emergency dosing mechanisms do not guarantee a satisfactory level of safety, and it would be desirable for the patient, in the event of an emergency dose being established due to a failure of the NO delivery device, to be able to maintain NO therapy without interrupting the therapy and / or without worrying about the type of ventilator, i.e., an HFO ventilator or another, with which the NO delivery device cooperates. In other words, one problem is being able to maintain a dosage, i.e., the treatment of the patient with inhaled NO, even in the event of a breakdown or failure of the NO delivery device, in particular, a total interruption of the operation of the control means of the NO delivery device, in particular, due to a breakdown, failure or defect in the electrical supply. A solution according to the invention relates to a NO supply device or apparatus for supplying a gas containing NO, typically a gaseous mixture of NO / nitrogen, comprising: - a NO injection line to transport the gas containing NO, - a valve device disposed in the injection line to control the circulation of NO-containing gas in the injection line, said valve device being configured to be normally in a closed position to prevent any gas circulation in the injection line, - a flow measurement device arranged in the injection line to perform one or more flow measurements of the NO-containing gas flowing through the injection line, - an emergency circuit comprising an emergency line that is seamlessly connected to the injection line, upstream and downstream of the valve device, said emergency line comprising an emergency solenoid valve configured to be normally in an open position to allow circulation of gas in the emergency line, and a flow control device, and - control means, i.e., a control unit, configured to cooperate with the emergency solenoid valve, the flow control device, the valve device, and the flow measuring device. In the event of a breakdown that causes an interruption in cooperation with the control means, i.e., in the event of a breakdown of the control means, for example, due to a failure in the power supply: - The emergency solenoid valve is configured to switch to the open position to allow gas circulation in the emergency line of the emergency circuit. - the valve device is configured to switch to the closed position in order to stop any gas circulation in the injection line, and - the flow control device is configured to supply gas at a preset emergency gas flow rate, where said emergency gas flow rate: is determined by the control means from at least one gas flow measurement provided by the flow measuring device, during normal operation of the apparatus preceding said failure, and It is pre-established by controlling said flow control device by means of the control, during said normal operation of the apparatus. Besides: - A multi-way solenoid valve is provided in the emergency line, downstream of the flow control device, - comprising said multi-way solenoid valve: an inlet seamlessly connected to the emergency line downstream of the flow control device, a first outlet seamlessly connected to a first dosing line comprising a first calibrated orifice device, and a second outlet seamlessly connected to a second dosing line comprising a second calibrated orifice device, - the first dosing line and the second dosing line are connected to the emergency line, downstream of said first and second calibrated orifice device, and - the first and second calibrated orifice devices have calibrated orifices with different passage sections or diameters, - the control means are configured to control the multi-way solenoid valve to direct the gas flow to the first dosing line or, alternatively, to the second dosing line depending on the gas flow measurement(s) provided by the flow measuring device during normal operation of the device preceding said failure. According to the embodiment considered, the apparatus of the invention may comprise one or more of the following features: - The multi-way solenoid valve comprises 3 ways. - The inlet of the multi-way solenoid valve receives gas via the emergency line, normally a mixture of NO / N2, in case of failure of the NO supply apparatus, in particular the control unit, normally in the absence of a power failure for said control unit. - the failure that causes the interruption of (any) cooperation with the control means comprises a failure of said control means or a failure in the electrical supply of said control means. - In the event of a failure of the NO supply unit, the first outlet of the multi-way solenoid valve feeds the first dosing line comprising the first calibrated orifice device. - Alternatively, in the event of a failure of the NO supply unit, the second outlet of the multi-way solenoid valve feeds the second dosing line comprising the second calibrated orifice device. - The gas inlet path of the multi-way solenoid valve comprises an upstream orifice that receives the gas, normally a mixture of NO / N2 gases, - The first outlet path of the multi-way solenoid valve comprises a first downstream orifice that supplies the gas, normally a mixture of NO / N2 gases, to the first dosing line. - The second outlet of the multi-way solenoid valve comprises a second downstream orifice that supplies gas, normally a mixture of NO / N2 gases, to the second dosing line. - The control means are configured to, during normal operation of the apparatus, control the emergency solenoid valve so that it is in a closed position, preventing any gas flow in the emergency line. The control means are configured to, during normal operation of the appliance, control the valve device to allow gas circulation in the injection line and, preferably, to allow the flow meter to perform at least one gas flow measurement. The control means are also configured to, during normal operation of the appliance, control the flow control device in order to preset the emergency gas flow rate based on at least one gas flow measurement provided by the flow meter. In other words, the adjustment of the flow control device is performed before any failure, i.e., while the NO supply appliance is operating normally. - During normal operation of the device, the flow measurement device is configured to perform several successive flow measurements. - During normal operation of the apparatus, the control means are also configured to determine, for example, calculate, the emergency gas flow rate (i.e., the flow rate of gas containing NO, for example, a NO / N2 mixture) from one or more flow measurements made by the flow measuring device. - The emergency line is smoothly connected to the injection line upstream of the valve device, and upstream or downstream of the flow measuring device, preferably downstream of the flow measuring device. - A flow measurement device is provided in the injection line upstream or downstream of the valve device, preferably downstream of the valve device. - The emergency line is seamlessly connected to the injection line at one end upstream, upstream of the valve device, and at one end downstream, downstream of the valve device, to avoid said valve device. - The emergency line is seamlessly connected to an upstream portion of the injection line located upstream of the valve device, in particular, through its upstream end. - The emergency line is seamlessly connected to a downstream portion of the injection line located downstream of the valve device, in particular, through its downstream end. - comprises storage means for storing at least a portion of the successive flow measurements made by the flow measuring device, i.e., the successive flow measurements are stored by means of storage. - the storage media are configured to also store one or more correspondence tables. - the storage media are configured to also store at least one correspondence table that provides a relationship between the pressure and flow rate of the calibrated orifice device(s). - storage media comprise computer memory, for example, random access memory, or similar. - The NO injection line carries a gaseous mixture consisting of NO and nitrogen, preferably a NO / N2 gas mixture (i.e., nitrogen monoxide / nitrogen) containing between 100 and 2000 ppmv of NO, normally less than 1000 ppmv of NO, the remainder being nitrogen (and possibly unavoidable impurities). - The emergency solenoid valve is set to be normally open, in particular when not controlled by the control means, normally in the event of a failure. - the emergency solenoid valve is of the all or nothing type. - the control means comprise at least one microprocessor. - The control means comprise an electronic board carrying at least one microprocessor. - The injection line is seamlessly connected to a high-pressure line via a pressure regulating device, the high-pressure line and the pressure regulating device being arranged in the NO supply apparatus. - the supply device does NOT include a housing. - The emergency NO dosing system is arranged in the housing, in particular, the emergency line and the emergency solenoid valve. - The emergency line is seamlessly connected to the injection line between the pressure regulating device and the valve device. - The valve device comprises a solenoid valve, preferably a proportional solenoid valve. - The flow control device is configured to form or constitute a system for generating proportional pressure and flow. - The flow control device comprises an actuator means that cooperates with a pneumatic pressure regulator. - The flow control device comprises an actuator means that allows control of the outlet pressure level of the pneumatic pressure regulator. - the flow control device comprises an actuator means that can be adjusted by an angular displacement. - the actuating means comprises an electric motor, in particular, a stepper motor. - the actuator is powered by the electrical power supply, i.e., during normal operation. - the actuating means comprises an electric motor that drives a rotating shaft, fixed to the pneumatic pressure regulator. - The pneumatic pressure regulator comprises an inlet and an outlet in fluid communication with the emergency line. - The control means are configured to control the actuator means in order to effect a displacement, preferably angular, of the pneumatic pressure regulator between at least: A fully open position corresponds to a maximum opening level, meaning it corresponds to the maximum pressure (and maximum flow rate) of the pneumatic pressure regulator. In the fully open position, all the gas flow supplied by the emergency line enters the pneumatic pressure regulator, i.e., a maximum flow rate. A fully closed position corresponds to a total shutdown level, meaning zero pressure (and zero flow) of the pneumatic pressure regulator. In the fully closed position, no gas flow can pass through the pressure regulator; that is, zero flow. And, advantageously, at least one intermediate position located between the maximum opening and maximum closing positions, which corresponds, therefore, to a pressure level at the outlet of the pneumatic pressure regulator between the maximum pressure value and the zero pressure value (i.e., 0 bar). In the intermediate position, only a portion of the gas flow supplied by the emergency line enters the pneumatic pressure regulator, i.e., one or more reduced or limited flows lower than the maximum flow. The control means are configured to control the actuator to perform an angular movement of the pneumatic pressure regulator between several angularly distinct positions, offset from each other, comprising the fully open position, the fully closed position, and several intermediate positions located between the fully open and fully closed positions. Each of these angularly distinct positions corresponds to a given outlet pressure level and gas flow rate, i.e., flow rates between the maximum flow rate, the zero flow rate, and the intermediate flow rates between these maximum and zero flow rates. - The control means are configured to pilot, actuate or control the actuating means, during the normal operation of the device, i.e., before any failure, in order to adjust or regulate the preset emergency gas flow, i.e., the desired flow. - the control means are configured to control the actuator means in order to effect a displacement, preferably angular, of a moving element of said actuator means to a determined position corresponding to the pre-established emergency flow rate. - The moving element comprises a rotating shaft, preferably made of metal or a metal alloy. - The moving element comprises a rotating shaft capable of being driven by an electric motor. - The control means are configured to determine the opening of the pneumatic pressure regulator and / or the preset emergency flow rate from a stored correspondence table. - the control means are configured to determine an opening of the pneumatic pressure regulator corresponding to the preset emergency flow rate. - The correspondence table is stored using storage media, such as computer memory. - comprises electrical power supply means configured to supply electrical current to components that require electrical power to function, in particular, control means or other components, such as solenoid valves, electric motor, etc. - The electrical power supply means comprise means of connection to the mains (110 / 220 V) and / or a battery or similar. - The flow control device of the NO emergency dosing system, which forms a proportional system, allows (pre)establishing or adjusting the preset emergency gas flow rate, before any failure of the apparatus prevents any cooperation between the control means and the emergency solenoid valve, the flow control device, the valve device and / or the flow measuring device. - The emergency gas flow measured by a NO flow sensor located in the NO injection line corresponds to the last flow measurement made by the NO flow measuring device before the failure. - the first calibrated hole of the first calibrated hole device has a first pitch diameter (D1) and the second calibrated hole of the second calibrated hole device has a second pitch diameter (D2), such that 1, 5.D1 < D2 < 4.D1. - the first pitch diameter (D1) and the second pitch diameter (D2) are such that 1, 8.D1 < D2 < 3.D1, preferably D2 is equal to approximately 2.D1. - The emergency solenoid valve is of the on / off type, which can only adopt an open state in which it allows the passage of gas flow and a closed state in which it interrupts the passage of gas flow. - The flow control device comprises an actuator that cooperates with a pneumatic pressure regulator. - the actuator means comprises a stepper motor, preferably an electric motor. - The pneumatic regulator is configured to be adjustable to various pressure levels between 0 and 2 bar relative, preferably less than 1.5 bar relative. - the actuator cooperates with the pneumatic regulator below said pneumatic regulator. - The pneumatic regulator comprises an internal spring that allows adjustment of the desired pressure level. - The actuator comprises a stepper motor configured to adopt several different angular positions, each angular position of the stepper motor corresponding to a given tension of the internal spring of the pneumatic regulator. - The desired outlet pressure level downstream of the pneumatic regulator is determined by the tension of the internal spring of the pneumatic regulator corresponding to the angular position adopted by the stepper motor. - In normal operation, the control means are configured to control the multi-way solenoid valve to achieve smooth communication between the inlet path of the multi-way solenoid valve and either of the first and second outlet paths of the multi-way solenoid valve to cause the gas flow to pass through the first or second calibrated orifice device. The invention also relates to an installation for supplying gas to a patient, i.e., a human being, comprising: - at least one NO source containing a gaseous mixture of NO / N2, - a NO supply device according to the invention, fed with a gaseous mixture of NO / N2 by said at least one NO source, - an inspiratory limb of a patient circuit fed with a NO / N2 gas mixture via the NO delivery device, and - a medical ventilator, i.e., a respiratory assistance device, in fluid communication with the inspiratory branch to supply said inspiratory branch with a respiratory gas containing at least 20% oxygen. According to the embodiment in question, the gas supply installation of the invention may comprise one or more of the following features: - The medical ventilator supplies air or an oxygen / nitrogen mixture, i.e., as a respiratory gas containing at least 21% oxygen by volume. - According to one embodiment, the medical ventilator comprises a motorized fan (i.e., a turbine, compressor, or the like) that supplies breathing gas, typically air or an oxygen / nitrogen mixture. - According to another embodiment, the medical ventilator comprises an internal gas circuit comprising one or more proportional valves for supplying the gas and controlling its delivery, in particular, its flow rate. Such a ventilator typically receives breathing gas via one (or more) wall outlets supplied by a network of pipes in a hospital or facility, typically air or an oxygen / nitrogen mixture. - The medical ventilator comprises control means, such as one (or more) electronic control boards. - The control means, such as an electronic control board, control or actuate the motorized ventilator or, as the case may be, the proportional valves of the medical ventilator. - the medical ventilator is of the HFO type or includes an HFO function, that is, it is capable of producing high-frequency oscillations. - The NO source contains a mixture of NO / N2 gases containing between 100 and 2000 ppmv of NO, the remainder being nitrogen (N2), conditioned at a pressure between 10 and 250 bar abs, normally at more than 100 bar abs (before extraction begins); - The NO source contains a mixture of NO / N2 gases containing between 100 ppmv and 1000 ppmv of NO, the remainder being nitrogen (N2), packaged at a pressure between 10 and 250 bar abs, normally more than 100 bar abs (before extraction begins); - the source of NO is a pressurized gas bottle (or bottles); - The NO source is a gas bottle (or bottles) with a capacity between 0.5 l and 50 l (equivalent in water); - the gas bottle comprises a cylindrical body made of steel or aluminum alloy; - the gas bottle is equipped with a simple key (without a fork) or with an integrated regulator or RDI; - the gas bottle is equipped with an RDI protected by a protective cover, for example, made of metal or polymer; - the patient circuit comprises an inspiratory branch and an expiratory branch. - the patient circuit comprises flexible conduits that form the inspiratory branch and the expiratory branch, usually polymer tubes. - The inspiratory and expiratory branches, for example, flexible ducts, are connected to a splice piece, such as a Y-piece. - the inspiratory and / or expiratory limbs are seamlessly linked to a patient respiratory interface, preferably via the splice piece; - the patient's respiratory interface comprises a tracheal intubation tube or a respiratory mask; - the inspiratory and expiratory limbs comprise flexible tubing, for example, made of polymer; - the inspiratory and expiratory limbs are also seamlessly connected to, respectively, the outlet and inlet ports of the medical ventilator; - the inspiratory branch of the patient circuit may include a gas humidifier; - The gas humidifier is arranged downstream of the NO injection module to humidify the gas before it is administered by inhalation to the patient. According to another aspect, the present description also relates to a method for the therapeutic treatment of a person, i.e., a human patient (i.e., an adult, a child, an adolescent, or a newborn), suffering from pulmonary hypertension and / or hypoxia, which causes pulmonary vasoconstriction or the like, comprising the administration by inhalation to the person in need of a gas mixture comprising 1 to 80 ppmv of NO and at least 20% by volume of oxygen, preferably at least 21% by volume of oxygen, by means of a gas supply installation, such as the one described above, comprising an NO delivery device equipped with the emergency NO dosing system according to the invention, to treat (at least partially) said pulmonary hypertension and / or said hypoxia.which may be caused by one (or more) pathologies or other pulmonary disorders typically of the PPHN type (persistent pulmonary hypertension of the newborn) or ARDS (acute respiratory distress syndrome), or generated by a cardiac surgery operation with the patient on extracorporeal blood circulation (ECC). In general, within the framework of the invention: - "ppmv" means parts per million by volume, - "% vol." means percentage by volume, - "NO" designates nitrogen monoxide, - "NO2" designates nitrogen dioxide, - "N2" designates nitrogen, - "O2" designates oxygen. - the terms "concentration", "dose" and "content" are considered equivalent. - The terms "control", "command" and "drive" are considered equivalent and interchangeable. - The terms "means of / to / for" are considered completely equivalent and interchangeable with the terms "device of / to / for" or equivalent terms such as "unit", for example, the terms "control means" can be replaced by "control device" or "control unit", the terms "measuring means" can be replaced by "measuring device"... - "Normal operation" means the usual operation of the NO supply device during a first period of time (of non-zero duration), in the absence of any malfunction, failure, defect, or other issue. The first period of time typically lasts from one to several minutes, or even hours or days, or even longer. - The term "failure" means a breakdown, anomaly, problem, malfunction, defect, or the like, whether electrical, mechanical, or otherwise, that affects the normal operation of the NO supply device, in particular, that prevents the operation of the device's control means, during a second period of time (of non-zero duration), for example, due to a failure of the control means and / or a power supply fault to them. The second period of time has a variable duration, for example, from a few seconds to one or more minutes, or tens of minutes, or even longer. The invention will now be better understood thanks to the following detailed description, offered for illustrative but not limiting purposes, with reference to the accompanying figures, among which: Fig. 1 schematically shows an embodiment of a gas supply installation comprising an NO supply device equipped with an emergency NO dosing system according to the present invention. Figures 2 to 5 illustrate the operation of the calibrated orifice / actuator combination of the NO emergency dose system in Figure 1. Fig. 1 schematically shows an embodiment of a gas supply installation 50 according to the present invention comprising an NO supply apparatus or device 1 comprising an emergency NO dosing system, associated with a mechanical ventilator 2, i.e., a respiratory apparatus that supplies a respiratory gas. This installation 50 is configured to supply NO in gaseous form to a patient at a desired concentration corresponding to a dosage established by an anesthesiologist or similar, normally between 1 and 80 ppmv of NO (i.e., ppm by volume), in particular, a NO / N2 mixture flow. The medical ventilator 2 supplies a respiratory gas containing at least 20% by volume of oxygen approximately, preferably at least 21% by volume of oxygen approximately, such as air or an O2 / N2 mixture, to a patient circuit 3, in particular to an inspiratory branch 31 of the patient circuit 3, which serves to transport and supply the gas to a patient P and to transport the gases exhaled by the patient through an exhalation branch 32 of the patient circuit 3. Medical ventilator 2 is a conventional respiratory support device that may comprise, according to the desired embodiment, a motorized ventilator, also called a turbine or compressor, or one or more proportional valves, instead of the motorized ventilator, which are supplied with gas, for example, medical air, by means of a wall outlet fed by a hospital network that carries the gas within a hospital establishment. In all cases, when the medical ventilator 2 supplies respiratory gas to the patient circuit 3, its operation is controlled by one (or more) electronic control card(s) or similar arranged in the medical ventilator 2. It is electrically powered by electrical power supply means, such as the mains (110 / 220 V) and / or an internal battery. For example, medical ventilator 2 could be the Getinge Servo-n Neonatal®, a proportional valve ventilator with an HFO function. Of course, another medical ventilator 2 could also be suitable. As shown in Fig. 1, the inspiratory limb 31 and the expiratory limb 32 are seamlessly connected to a connecting piece 33, such as a Y-shaped piece or similar, in seamless communication with a respiratory interface 30 that allows the gas to be delivered to patient P or, conversely, the gases exhaled by patient P to be collected. The respiratory interface 30 can be, for example, a face mask, a tracheal intubation tube, or similar. The inspiratory branch 31 and exhalation branch 32 comprise pipes, channels, tubes, passages, tubules or the like, for example, flexible polymer tubes, adapted and configured to carry gas flows. Respiratory gas circulates in the inspiratory branch 31 in the direction from mechanical ventilator 2 to patient P, while exhaled gases enriched in CO2 circulate in the exhalation branch 32 in the direction from mechanical ventilator 2 where they are discharged into the atmosphere. A flow sensor 100 and a NO injection module 110 are arranged in the inspiratory limb 31. The flow sensor 100 is generally arranged between the NO injection module 110 and the mechanical ventilator 2 to measure the gas flow rate coming from the mechanical ventilator 2. The inspiratory limb 31 may also include a humidifier (not shown) for humidifying the gas delivered to the patient, which is preferably arranged downstream of the NO injection module 110, i.e., between the NO injection module 110 and the respiratory interface 30, such as a tracheal intubation tube. The flow sensor 100 is used to measure the gas flow rate, for example, air or an O2 / N2 mixture, supplied by the mechanical ventilator 2 and circulating in the inspiratory limb 31. The measurements taken are supplied, directly or indirectly, to the control means 130 of the NO supply apparatus 1, which use them to control or adjust the amount of NO supplied by the NO supply device 1, i.e., the NO flow, normally from a gas mixture of NO / N2, supplied by the NO supply apparatus to the NO injection module 110, as explained below. For example, a mass flow sensor, a differential pressure sensor, or any other suitable sensor can be used. In the embodiment of Fig. 1, the flow sensor 100 is, for example, of the differential pressure measurement type, i.e., the flow sensor 100 comprises an internal restriction 101 that creates a pressure drop which generates a differential or pressure gradient when a gas flow passes through this internal restriction 101. The flow sensor 100 comprises upstream chambers 120 and downstream chambers 121 that are separated by a wall 122 through which a gas passage passes to form the internal restriction 101. The upstream 103 and downstream 102 pressure measurement lines are seamlessly connected to the flow sensor 100 at the connection sites located upstream and downstream of the internal restriction 101, in particular to the upstream 120 and downstream 121 chambers, to perform pressure measurements of circulating gas flow, before and after the pressure drop, i.e., air or an O2 / N2 mixture. The pressure difference created by the internal restriction 101 is determined by a differential pressure sensor 104 connected to the flow sensor 100 through the upstream 102 and downstream 103 pressure lines that form pressure measuring conduits and provide the differential pressure sensor 104 with pressure measurements of the circulating flow, before and after the pressure drop. Preferably, the differential pressure sensor 104 is integrated into the housing 10 of the NO supply device 1, as illustrated in Fig. 1. The sensor 104 is also electrically connected to a control unit 130, also called a controller or control means, and / or transmits pressure measurements to it so that they can be processed by a computer, in particular to regulate or adjust the flow rate of NO, normally from a mixture of NO / N2, supplied by the NO supply apparatus 1 to the NO injection module 110. The NO injection module 110 injects the NO flow rate, i.e., NO / N2, into the gas flow circulating in the inspiratory limb 31 to produce the desired mixture, typically an NO / O2 / N2 mixture containing NO at the desired concentration corresponding to the dosage prescribed by a physician or similar professional. This concentration is usually between 1 and 80 ppmv, generally between 5 and 40 ppmv of NO, with the remainder being oxygen (approximately >20% by volume) and nitrogen, or even unavoidable impurities (e.g., argon) and water vapor, especially when there is a humidifier downstream of the NO injection module 110. Advantageously, a bypass line 105 can be provided, connected to the downstream pressure line 103, to transmit the pressure information present in that downstream pressure line 103 to a pressure sensor 106, typically a relative pressure sensor.This pressure sensor 106 measures the pressure in the chamber upstream 120 of the flow sensor 100 and can return this value, via an electrical connection, to the control unit 130 for compensation purposes. The actual flow rate passing through the flow sensor 100 depends primarily on the differential pressure measurement 104, but is also affected by the relative pressure 106 upstream of the flow sensor 100. The control unit 130 comprises a data processing system, specifically for measurements from sensors 100, 104, and 106. This system typically includes one or more microprocessors arranged on one or more electronic boards and implements one or more algorithms, i.e., one or more computer programs.Of course, the control unit 130 can also be configured to control other electromechanical elements integrated into the housing 10 of the NO supply device 1. More precisely, the control unit 130 is configured to process and / or use the measurements—that is, the pressure measurement signals or pressure values—transmitted by the differential pressure sensor 104, which cooperates with the flow sensor 100, and / or by the pressure sensor 106. Advantageously, the control unit 130 has a pre-recorded, i.e., stored, correspondence table that allows it to determine the gas flow rate circulating in the inspiratory branch 31—that is, passing through the flow sensor 100—in other words, to transform a pressure value transmitted by the pressure sensor 104, such as, in this case, a differential pressure sensor, into a flow rate value passing through the flow sensor 100, possibly compensated by the value returned by the pressure sensor 106. In general, determining the flow rate of the gas flow (e.g., air) passing through the flow sensor 100 then allows calculating the amount of NO (i.e., the NO / N2 flow rate) that the NO injection module 110 will inject into the gas flow circulating in the inspiratory branch 31 in order to deliver NO to the patient at the desired concentration corresponding to the dosage established by an anesthesiologist or similar, normally between 1 and 80 ppmv of NO (i.e., ppm by volume). In other words, using the pressure measurement returned by the differential pressure sensor 104 and the stored correspondence table, the control unit 130 can determine the gas flow rate (e.g., air or N2 / O2 with an O2 content > 21% by volume) of the mechanical ventilator 2 and the amount of NO to be added, via the NO injection module 110, to obtain the desired NO concentration. As already mentioned, the final gas mixture obtained at the level of the NO injection module 110 then comprises mainly nitrogen (N2), oxygen (O2) at a content of at least 20 to 21% by volume, and NO at a content typically between 1 and 80 ppmv, or even unavoidable impurities and / or water vapor, particularly when a gas humidifier is present. More precisely, based on the gas flow rate (i.e., air or N2 / O2) circulating in the inspiratory branch 31, which has been determined with the help of the flow sensor 100, the control unit 130 determines the amount of NO, normally a NO / N2 mixture, that must be added to the gas having an O2 content > 20% by volume (e.g., air or N2 / O2) circulating in the inspiratory branch 31 to obtain the desired final NO concentration. The NO supply device 1 is supplied with gaseous NO, normally a gaseous mixture of NO / N2, from a NO source 250 fluidly connected to the NO supply device 1, in particular, to a high-pressure line 116 of said NO supply device 1, via a supply line 251, such as a flexible conduit or the like. Normally, the NO source 250 is one (or more) pressurized gas cylinder(s) containing a NO / N2 mixture with a NO concentration generally between 100 and 30,000 ppmv. The NO / N2 mixture is supplied to the injection module 110 by means of the NO supply apparatus 1, through an injection line 111, such as a flexible gas pipe, which is fluidly connected to the high-pressure line 116 of the NO supply apparatus 1, comprising a high-pressure inlet 116a fluidly connected to the NO source to which NO / N2 is to be supplied under pressure, for example, at 10 bar abs. The high-pressure line 116, for example, a gas line or pipe, includes a pressure regulator 115 that reduces the pressure of the NO / N2 mixture to a stable value, for example, approximately 2 bar absolute or any other suitable pressure. Therefore, the outlet of the pressure regulator 115 provides a stable pressure in the upstream section of the injection line 111. A valve device 113, such as a solenoid valve, advantageously a proportional solenoid valve, for example, the VSO series miniature solenoid valve available from Parker, is arranged in the NO supply apparatus 1 to control the flow rate of gaseous NO within the injection line 111. The gas flow rate circulating in the injection line 111 is measured by means of a flow measuring device or NO flow sensor 112, arranged in the injection line 111, preferably placed downstream of the valve device 113, as shown in Fig. 1. The pressure regulator 115, the valve or solenoid valve device 113, the NO flow sensor 112 and an upstream portion of the injection line 111 are therefore arranged in the housing 10 of the NO supply apparatus 1. The valve device 113 is configured to be normally in a closed position (i.e., a shut-off state) to prevent any gas circulation in the injection line 111. To change it to the open position, the valve device 113 must be controlled by the control means 130, as is the case during normal operation of the NO supply apparatus 1. In addition, an emergency NO dosage system is provided, i.e., an emergency circuit 200, arranged in the housing 10 of the NO supply apparatus 1, which is configured to operate in the event of a failure of the NO supply apparatus 1, as explained below. The emergency 200 circuit includes (at least) one emergency 201 line, also called a branch line, such as a gas conduit or pipe, or similar. In the embodiment proposed in Fig. 1, the emergency line 201 of the emergency circuit 200 is seamlessly connected to the injection line 111 at a first connection site 111a, i.e., upstream, located between the pressure regulator 115 and the valve device 113, and at a second connection site 111b, i.e., downstream, located downstream of the valve device 113 and, preferably, downstream of the NO flow sensor 112. In other words, the valve device 113 and, preferably, the NO flow sensor 112 are located between the first and second connection sites 111a, 111b of the emergency line 201, i.e., the emergency line 201 is diverted, the valve device 113 and, preferably, the NO flow sensor 112 are arranged in the injection line 111. Alternatively, according to another embodiment, the second connection site 111b can be located between the valve device 113 and the NO flow sensor 112. In all cases, the gas circulates in the emergency line 201 in the direction from the first connection site 111a to the second connection site 111b. The emergency circuit 200 also comprises an emergency solenoid valve 202 and a flow control device 210 which are arranged in the emergency line 201 and serve to control the gas flow within the emergency circuit 200, normally within the emergency line 201. A 3-way solenoid valve 205, i.e., a 3:2 type solenoid valve, is arranged in the emergency line 201, downstream of the flow control device 210. It is controlled by control means 130. The 3-way solenoid valve 205 comprises an upstream orifice 201a, a first downstream orifice 205a, and a second downstream orifice 205b, in fluid communication. The selection of fluid communication between the upstream orifice 201a and the first downstream orifice 205a, and alternatively, the second downstream orifice 205b, is effected by control means 130, as described below. The 3-way solenoid valve 205 is of the bistable type, that is, in the event of absence of electrical control by the control means 130, for example, in the event of a failure, normally in the event of loss of electrical power, the fluid communication existing between the upstream orifice 201a and the first downstream orifice 205a or the second downstream orifice 205b is maintained, that is, it remains in the state it was in before the failure. As an example, it is possible to use the HDI-referenced solenoid valve 205 available from The Lee Company®. The first downstream orifice 205a of the solenoid valve 205 is in fluid communication with a first dosing line 206, where a first calibrated orifice 208 is provided, while the second downstream orifice 205b of the solenoid valve 205 is in fluid communication with a second dosing line 207 where a second calibrated orifice device 209 is provided. The first and second calibrated orifice devices 208 and 209 have different characteristics in terms of the cross-sectional area of ​​their respective calibrated orifices, for example, different diameters. Therefore, the first calibrated orifice of the first calibrated orifice device 208 may have a first diameter D1, and the second calibrated orifice device 209 has a second diameter D2, such that D1 < D2, preferably 1.5D1 < D2 < 4D1. For example, the first calibrated hole of the first calibrated hole device 208 may have a first pitch diameter D1 of the order of 25 µm and the second calibrated hole of the second calibrated hole device 209 has a second pitch diameter D2 of the order of 50 µm, i.e., D2 is preferably equal to approximately 2.D1. As an example, you can use available calibrations from O'Keefe Control® with the references BLP-1-SS and BLP-2-SS. Of course, you can use other calibrated holes of different diameters and / or shapes. Downstream of the first and second calibrated orifice devices 208, 209, the first and second dosing lines 206, 207 are located at connection site 201b and are also connected, at this same site 201b, to the downstream portion of the emergency line 201, which is seamlessly connected (downstream of site 201b) to the injection line 111 at the level of the second connection site 111b. In other words, the first dosing line 206 and the second dosing line 207 are connected at node 201b to form the downstream portion of the emergency line 201. The emergency solenoid valve 202 is normally set to be in an open position (i.e., an open state) to allow gas to flow in the emergency line 201; that is, it allows gas flow when it is not controlled or is no longer controlled by the control unit 130. During normal operation of the NO supply device 1, the emergency solenoid valve 202 is controlled by the control means 130 to be in a closed position (i.e., a shut-off state) to prevent the flow of NO / N2 from using the emergency line 201. The emergency solenoid valve 202 is preferably an "on / off" type solenoid valve with two possible states: an open state allowing gas flow and a closed state preventing gas flow. It is controlled by the control unit 130. For example, a solenoid valve from the IMI Norgren® Picosol series or the The Lee Company® HDI series can be used. As previously stated, the emergency solenoid valve 202 is normally open. In the absence of an electrical command from control unit 130, the emergency solenoid valve 202 is in the open position, allowing gas from the NO source to flow through the emergency line 201 from the first connection point 111a to the second connection point 111b. Conversely, control unit 130 controls the closing of the emergency solenoid valve 202, that is, its transition from the open to the closed position. In the closed position, any gas flow in the emergency line 201 is prevented, particularly when flow is undesirable, which is the case during normal operation.In other words, the control means 130, i.e., the control unit, are configured to cooperate with the emergency solenoid valve 202, the flow control device 210, the valve device 113, and the flow measuring device 112, during normal operation of the NO supply device 1, to direct the gas flow to the injection line 111 and prevent it from circulating through the emergency line 201, and vice versa, in case of a failure, as explained below. In the embodiment of Fig. 1, the flow control device 210 comprises an actuator means 203, preferably adjustable by an angular displacement, normally a stepper motor, which cooperates with a pneumatic pressure regulator 204 and thus forms a variable pressure system that allows control of the flow rate and pressure of the gas flow. When the emergency solenoid valve 202 is open, i.e., not controlled by the control unit 130, typically in the event of a power failure or a failure of the control unit 130, the pressure in the upstream section 201c of the emergency line 201 (i.e., between the first connection point 111a and the pneumatic regulator 204) is equal to the expansion pressure of the pressure regulator 115, for example, here equal to 2 bar rel. (14 psig). This same pressure is also exerted at the inlet of the pneumatic regulator 204, which is located on the emergency line 201. The 204 pneumatic regulator can be adjusted to several different pressure levels, typically up to 2 bar relative pressure, for example, between 0 and approximately 1.4 bar relative pressure (i.e., 0-20 psi), depending on the tension of its internal spring. For example, a pneumatic regulator available from Beswick Engineering® with the reference PRDB can be used. The actuating means 203, in this case a stepper motor, is mechanically coupled to the pneumatic regulator 204 in such a way that a given angular position of the stepper motor influences the tension of the internal spring of the pneumatic regulator 204 and thus establishes an output pressure downstream of said pneumatic regulator 204. In other words, the stepper motor can, depending on its angular position, determined by the control means 130, control the pneumatic regulator 204, in particular, by acting on the tension of its internal spring, so that it goes from a closed position, i.e., supplying zero pressure at its output, to an open position, which supplies a maximum pressure at its output, normally less than 2 bar relative, for example, on the order of 1.4 bar relative (i.e., approximately 20 psig). Of course, depending on the angular position of the stepper motor, i.e., depending on its "number of steps", the pneumatic regulator 204 can adopt one (or several) intermediate positions, thus supplying a pressure between a minimum, for example, 0 bar relative, and a maximum normally less than 2 bar relative, for example, 1.4 bar relative. Therefore, the resolution in terms of adjustable downstream pressures of the pneumatic regulator 204 depends on the accuracy and the number of steps that define a given position of the stepper motor, i.e., of the actuator 203, and its next position. Therefore, Figure 2 shows the evolution of the output pressure of the pneumatic regulator 204 as a function of a series of steps (i.e., the stepper motor position), determined by the control means 130, which allows us to observe that the pressure increases linearly with the number of steps. More precisely, it can be observed that the maximum output pressure of the pneumatic regulator 204 is limited to 12 psig (830 mb rel.), but that it could be higher, typically up to 20 psig (1.4 bar rel.), by increasing the number of steps. More generally, the pressure at the outlet of the pneumatic regulator 204 is then at the level of the upstream orifice 201a of the solenoid valve 205 that is arranged in the emergency line 201 downstream of the pneumatic regulator 204. In normal operation, the multi-way solenoid valve 205, in this case a three-way valve, is also controlled by the control means 130 to produce smooth communication between its inlet path, which is smoothly connected to the emergency line 201 downstream of the flow control device 210, and one or the other of its first outlet path, which is smoothly connected to the first dosing line 206, and its second outlet path, which is smoothly connected to the second dosing line 207, i.e., between its upstream orifice 201a and one of its downstream orifices 205a, 205b. The outlet pressure of the pneumatic regulator 204 is then propagated to the upstream portion 206a, from the first dosing line 206 located upstream of the first calibrated orifice 208 or, as the case may be, to the upstream portion 207a of the second dosing line 207 located upstream of the second calibrated orifice 209. In other words, during normal operation of apparatus 1, the control means 130 control the 3-way solenoid valve 205 to effect smooth communication between the inlet path of said solenoid valve 205 and one or the other of the first and second outlet paths of the 3-way solenoid valve 205 to cause the gas flow to circulate in one or the other of the dosing lines 206, 207, thereby through the first or second calibrated orifice device 208, 209 comprising different passage sections or diameters of its calibrated orifices D1, D2. However, in general, for any calibrated orifice, there is a relationship between the upstream pressure and the flow rate through it, since the flow rate depends on the orifice's dimensions. In fact, the flow rate through a calibrated orifice is related to the pressure differential between the upstream and downstream pressures of that calibrated orifice. Therefore, Fig. 3 represents the relationship between the pressure (in psig) upstream of the first orifice of the first calibrated orifice device 208 and the flow rate (in ml / min) that passes through it, i.e., that circulates in the downstream part 206b of the first dosing line 206. It can be observed that the flow rate increases as the upstream pressure increases. This increase does not follow a linear law, but rather a "square root" type law, as is widely documented in the literature. Therefore, in this case, depending on the position of the solenoid valve 205, the flow rate passing through the first calibrated orifice of the first calibrated orifice device 208 depends on the pressure difference existing, respectively, in the upstream 206a and downstream 206b parts of the first dosing line 206, and vice versa, the flow rate crossing the second calibrated orifice of the second calibrated orifice device 209 depends on the pressure difference existing, respectively, in the upstream 207a and downstream 207b parts of the second dosing line 207. Preferably, the pressure downstream of the first and second calibrated orifices, i.e., downstream of the two calibrated orifice devices 208 and 209 (i.e., in the downstream sections 206b and 207b), is also considered negligible. However, additional measuring means, such as an additional pressure measuring device, may be provided to perform a pressure measurement downstream of the first and second calibrated orifices, for example, in the region from node 201b of the emergency line 201, and used for pressure compensation to increase the accuracy of the flow control device 210, as detailed below. Furthermore, the expression of the flow rate also corresponds to a step-by-step position of the motor 203, expressed in steps, as shown in Fig. 4, as a function of the linear relationship that connects the position of the motor 203 with the outlet pressure of the pneumatic regulator 204, as illustrated in Fig. 2. Therefore, Fig. 4 shows that a number of steps equal to 0 corresponds to a closed position of the pneumatic regulator 204, and each step corresponds to a change in position of the stepper motor 203, which opens the pneumatic regulator 204 a little more to allow the gas flow to pass. For example, for 50 steps, a flow rate of approximately 4 ml / min is obtained, while for 100 steps, the flow rate is approximately 5.5 ml / min. From there, by introducing a correspondence table that links a series of steps (i.e., a stepper motor position 203) and the resulting flow rate, the control means 130 can "(pre)set" the emergency dose system or circuit 200, during normal operation of apparatus 1, as explained below, so that it is operational in the event of a failure of the control unit 130, typically in the event of a power failure of the control unit 130. In other words, during normal operation of apparatus 1, the control means 130 control the pneumatic regulator 204 to adjust or fix the position of the motor 203 step by step in a certain number of steps corresponding to a desired gas flow rate. Similarly, during normal operation of apparatus 1, when the control means 130 control the 3-way solenoid valve 205 to achieve smooth communication between its upstream orifice 201a and, for example, its second downstream orifice 205b, it is possible to establish, as before, a correspondence table linking a series of steps (i.e., a position of the stepper motor 203) and a resulting gas flow rate, which then circulates in the downstream portion 207b of the second dosing line 207, as illustrated in Fig. 5. Since the diameter of the second calibrated orifice 209 is larger than that of the first calibrated orifice 208, the resulting flow rate with a similar "step" (i.e., a similar position) is greater. For example, for 50 steps, a flow rate of approximately 15 ml / min is obtained (4 ml / min for the first calibrated orifice 208). In other words, depending on the configuration of the 3-way solenoid valve 205, the control unit 130 may have a mapping that connects a given control level (i.e., a step) to a gas flow rate passing through the first or, alternatively, the second calibrated orifice 208, 209 in the direction of the injection line 111 and penetrating there to the second connection site 111b. All these (pre)adjustments are made during the correct operation of device 1, i.e., during its normal operation before any failure of the control unit 130, in particular, when it no longer receives electrical current and therefore no longer functions. This is then used to ensure the supply of an emergency NO flow (i.e., a NO / N2 flow), even in the event of a failure of the control unit 130, i.e., when it no longer receives electrical current and therefore no longer functions, since all adjustments have already been made before the failure. Therefore, during normal operation of the NO supply device 1, i.e., when the control unit 130 is operational and normally supplied with electrical current, the emergency solenoid valve 202 is controlled by the control unit 130 to close, preventing any gas circulation in the emergency circuit 200 of Fig. 1. However, in the event of a failure of device 1 that causes the control unit 130 to not function, such as an electrical failure, the emergency solenoid valve 202 can no longer be controlled by the control unit 130 and therefore opens to allow gas to pass into the emergency circuit 200, while the solenoid valve 113 closes, as already explained.The gas flow circulating in the emergency circuit 200 is then subjected to the (pre) adjustments made before the failure, i.e., the position of the stepper motor, sending the flow to the first or second calibrated orifice device 208, 209. In general, it is particularly recommended to use a stepper motor as the actuator 203 because, unlike the solenoid valves 202, 113 which take a rest position in the event of a power outage, i.e., an open position for the all-or-nothing solenoid valve 202 and a closed position for the proportional solenoid valve 113, the position of the stepper motor does not change, i.e., it remains permanent and fixed according to the last command imposed, and this regardless of any power supply. In other words, the tension of the internal spring of the pneumatic regulator 204 has a fixed value equal to the last control value from the control means 130 received by the stepper motor, i.e., a given position corresponding to a given number of steps, during normal operation of the apparatus 1. In the event of gas supply to the pneumatic regulator 204, i.e., when the emergency solenoid valve 202 opens due to the absence of control by the control means 130, the tension of the internal spring of the pneumatic regulator 204 generates a fixed pressure downstream of the pneumatic regulator 204, which is then at the level of the upstream orifice 201a of the solenoid valve 205. Of course, the present invention is not limited to a stepper motor actuator. In fact, any other actuator that maintains its position in the event of a power failure and that can be coupled to a mechanical mechanism that defines or constitutes a variable pressure system, such as a linear motor or similar device, can be used. In general, during normal operation, the NO supply device 1 is also electrically powered by an electrical supply, such as the mains (110 / 220 V) or an internal battery, to allow the proper functioning of its components that require electrical current to operate, in particular, the actuator 203, such as a stepper motor, the control unit 130, the solenoid valves 202, 113, 205, or others. In addition, the NO supply device 1 also comprises storage means, such as a computer memory, for storing data, information or other, for example, one or more correspondence tables, as explained above, gas flow measurements made by the flow measurement device 112, or other. In general, in the event of a major failure in the operation of the NO delivery device 1, such as a power supply failure, for example, caused by a break in its power cable due to vibrations during patient transport, for example, it should be possible to continue treating the patient with inhaled NO, even though the failure causes an interruption in the operation of the control means 130, normally due to a fault in the power supply. To this end, device 1 of the invention is configured so that, in the event of such a failure, the emergency solenoid valve 202 moves to the open position to allow gas to flow through the emergency line 201, while, simultaneously, the valve device 113 moves to the closed position to stop any gas flow in the injection line 111. This allows gas to be supplied, via the emergency line 201 and the flow control device 210, at a predetermined emergency gas flow rate. In fact, during the normal operation of device 1 prior to the failure, this emergency gas flow rate is determined by the control means 130 from one or more gas flow measurements supplied to the control means 130 by the flow measurement device 112.The control means 130 can then preset the flow control device 210 and the solenoid valve 205 so that they can supply the gas at the preset emergency gas flow rate. In other words, the control means 130 determine the emergency gas flow rate to be supplied in the event of a breakdown or other failure, based on the gas flow measurements provided by the flow-measuring device 112 during the normal operation of device 1, and act on the flow control device 210 and the 3-way solenoid valve 205 to adjust this preset emergency gas flow rate, for example, by acting on the pneumatic regulator 204, as explained above. More generally, the operation of the gas supply installation 50 comprising the NO supply device 1 of the invention is generally as follows. As illustrated in Fig. 1, the NO delivery device 1 cooperates with a mechanical ventilator 2 to provide therapeutic support to patient P. As previously explained, the gas flow rate (i.e., air or N2 / O2) from the mechanical ventilator 2, circulating in the inspiratory limb 31 of the patient circuit 3, is continuously measured by the flow sensor 100 and the control unit 130. The flow rate measurement(s) from the flow sensor 100 allow the control unit 130 to determine, in real time, the NO flow rate that must be delivered through the injection line 111 to the NO injection module 110. This determines the amount of NO that must be injected into the airflow from the ventilator 2, thus achieving the desired final NO concentration, typically between 5 and 80 ppmv, in the final N / O2 / N2 gas mixture administered to patient P.In normal operation, i.e., without breakdown or failure, in order not to introduce an additional flow from the emergency line 201 to the injection line 111, the control unit 130 controls the solenoid valve 202, which is preferably of the on / off type, in the closed position and, in parallel, will control the actuator 203, as a stepper motor, to pre-set the pneumatic regulator 204 by defining an internal spring tension level, preferably based on the position adopted by the stepper motor 203, as explained above. This is done by the control unit 130 from one or more flow measurements from the flow measuring device 112. More precisely, the control unit 130 first averages the flow rate of NO (i.e., of the NO / N2 mixture) that has circulated in the injection line 111 for a given time, for example, for 1 minute or for a longer period of time (but the flow rate must then be converted to l / min or ml / min), during normal operation of device 1. Therefore, the control unit 130 estimates a fixed average NO flow rate value (in l / min or ml / min) that allows you to approach the desired NO concentration. Therefore, in Table 1, the fixed average NO flow rate (in ml / min) is provided for various selected NO concentrations (in ppmv), i.e., dosages, resulting from different entilation minutes (l / min) measured by the flow sensor 100, which use the control means 130 to determine the NO flow rate to be delivered in real time. Table 1 It has been found that, for an average minute ventilation of 2 L / min as measured by the 100 flow sensor, and for a NO dosage of 5 ppmv, the average NO flow rate is 0.1 mL / min and increases with increasing minute ventilation and / or NO dosage. Therefore, the average NO flow rate can vary from 0.1 to 45 mL / min. To account for this significant flow range, as already mentioned, the emergency dosing system 200 is provided with a first and a second calibrated orifice device 208, 209, arranged in the first and second dosing lines 206, 207 downstream of the pneumatic regulator 204. As illustrated in Fig. 4, the first calibrated orifice device 208 is configured to generate relatively low flow rates over a wide pressure range, for example, flow rates of less than 10 ml / min, while the second calibrated orifice device 209 is configured to generate higher flow rates that can exceed 50 ml / min, as illustrated in Fig. 5. However, in the 0-10 ml / min range, it is observed that the relationship between the flow rate and the position of the stepper motor is unfavorable for the device with a second calibrated orifice 209 because a small variation in the position of the stepper motor 203 generates a significant variation in the flow rate, which can affect the accuracy of the generated flow rates. Therefore, the system is configured so that the gas flow passes through the first calibrated orifice device 208 when the average NO flow rate is low, i.e., less than or equal to 10 ml / min, and through the second calibrated orifice device 209, for higher average NO flow rates, i.e., greater than 10 ml / min. Therefore, the control unit 130 operates a specific control of the 3-way solenoid valve 205 based on the average NO flow rate to achieve smooth communication between its upstream orifice 201a and its first downstream orifice 205a (if the flow rate is < 10 ml / min) or, if this is the case, its second downstream orifice 205b (if the flow rate is > 10 ml / min) in order to direct the emergency NO flow to the first dosing line 206 through the first calibrated orifice device 208 or, as the case may be, to the second dosing line 207 through the second calibrated orifice device 209. In normal operation, the control unit 130 averages the NO flow rate and then uses the value thus determined to control the 3-way solenoid valve 205 to select the first or second dosing line 206, 207 and thus the first or second calibrated orifice device 208, 209 intended to manage the NO flow, i.e., to be used to perform the emergency NO dosage in the event of failure of the NO device 1, in particular in the event of a power failure of the flow sensor 100 or of the control unit 130. Furthermore, the control unit 130 performs a conversion using a stored correspondence table or similar, taking into account the selected calibrated orifice, i.e., the first or second calibrated orifice device 208, 209, to control the actuator 203 of the flow control device 210, such as a stepper motor, and define a tension level for the internal spring of the pneumatic regulator 204 to authorize a flow rate of NO circulating in the emergency line 201 of the emergency system 200 that is equal to the calculated value of the fixed average NO. Therefore, this calculated value of average NO serves as an emergency gaseous NO flow rate in the event of a failure of device 1. Under normal operation, no gas flows in the emergency line 201 because the on / off solenoid valve 202 is closed. Gas normally flows in the injection line 111, through the proportional solenoid valve 113 and the flow meter 112, before being supplied to the NO injection module 110, which operates the mixture of NO flow and air or similar flow from fan 2. Therefore, in the event of a major failure of the NO supply device 1 and / or an interruption of its power supply, with the exception of actuator 203, solenoid valve 205, and pressure regulator 115, which operate purely pneumatically, all electromechanical actuators, particularly the solenoid valves, return to their rest position because the control unit 130 is also without power. Furthermore, the various sensors are without power and therefore unable to communicate with and / or control / operate other components. Therefore, the proportional solenoid valve 113 returns to its rest position, i.e., its closed position which prevents any gas flow, while the solenoid valve 202 is simultaneously in its rest position, i.e., its open position, allowing the gas from the NO source to pass into the emergency line 201 of the emergency circuit 200, and its circulation to reach the second junction site 111b, and then to the downstream part of the injection line 111. The NO / N2 mixture then circulates in the emergency line 201 with the preset emergency flow rate, which is controlled by the association of the pneumatic regulator 204, in particular, by its generated pressure, and the selected calibrated orifice, i.e., the first calibrated orifice device 208 or the second calibrated orifice device 209, knowing that, as already explained, the control unit 130 has then determined the last valid value of the fixed average NO flow rate during the normal operation of device 1, before its failure. The emergency flow of NO / N2 that is joined to the injection line 111 (at 111b) can then be injected into the inspiratory branch 31 of patient circuit 3 through the NO injection module 110, as already mentioned. In general, according to the invention, the flow control device 210 is configured to supply the gas, i.e., NO / N2, at a predetermined emergency gas flow rate, where said emergency gas flow rate is determined by the control means 130 from one (or more) gas flow measurements provided by the flow measuring device 112, during normal operation of device 1 preceding the failure, e.g., the last flow rate value being measured before the failure affecting the proper functioning of device 1. The flow rate value is preset within the flow control device 210, for example, by adjusting the internal spring tension of the pneumatic regulator 204 of the flow control device 210, as explained above, by controlling, i.e., presetting, the flow control device 210 using control means 130. The presetting takes place, i.e., is performed or carried out, during the normal operation of device 1. Of course, if the emergency circuit 200 is used in case of a failure of the NO supply device 1, the same accuracy in the concentration of inhaled NO is not guaranteed as when the NO supply system 1 is operating normally, i.e., adjusting the NO flow rate according to the flow rate passing through the flow sensor 100. However, this avoids an interruption in the NO supply to the patient, and, in addition, the buffer volume generated by the portion of the inspiratory branch 31 located downstream of the NO injection module, which may increase in volume in the humidification chamber when present, allows for smoothing out variations in the concentration of NO inhaled by the patient and getting closer to the desired target value, i.e., the NO dosage. Therefore, it is particularly interesting to implement the emergency dosing system of the invention because it increases patient safety, as the patient does not run the risk of being deprived of their NO treatment in the event of a failure of the NO delivery device, and receives a dose of NO very close to, or even equivalent to, the desired dosage. In other words, being able to approximate the desired target NO value thanks to the emergency NO dose system 200 integrated into the NO delivery device 1 of the invention considerably improves patient safety compared to a fixed emergency NO flow rate normally supplied by the safety system of prior art NO delivery devices. Therefore, by way of comparison, with an emergency system based on a fixed flow rate, as conventionally implemented in state-of-the-art NO supply devices: - For an average NO flow rate of 0.05 L / min required to normally guarantee a NO concentration of 10 ppmv (as in neonatology with an HFO ventilator), the resulting concentration with a fixed flow rate is 50 ppmv, which corresponds to a 5x increase in the desired dosage. - Conversely, for an average NO flow rate of 1 L / min required to guarantee a NO concentration of 80 ppmv (when used in adults, for example, in the case of pulmonary hypertension during cardiac surgery), the resulting concentration drops to 20 ppmv, which corresponds to a 75% decrease in the desired dosage. In both cases, significant differences in dosage can lead to unacceptable and dangerous situations for the patient, unlike the NO emergency dose system 200 integrated into the NO delivery device 1 of the invention, which allows the patient to adhere to the desired dosage. As a result, the NO emergency dose system 200 of the invention has undeniable advantages in increasing patient safety by: - automatically inject an emergency NO flow without waiting for the user to realize the situation and intervene by radically switching to the emergency pneumatic dose. - ensure that the concentration of NO inhaled by the patient is similar to the concentration desired by the physician, i.e., the desired dosage. Of course, the switching to the NO emergency dosing system 200 of the invention is only temporary, i.e., it only lasts as long as necessary to replace the faulty equipment or component that triggered the audible and / or visual alarm system in order to alert nursing staff. To prevent misuse of the emergency NO dosing system 200, the control unit 130 is further configured to perform the appropriate start-up and shutdown sequences. For example, if the user wishes to stop the NO therapy, the control unit 130 can control actuator 203 to close the pressure regulator 204. Therefore, in the event of intentional shutdown and the opening of the solenoid valve 202, the "closed" configuration of the pressure regulator 204 then prevents any NO flow in the emergency line 201 until the NO supply device 1 is stopped. The NO delivery device 1 equipped with the NO emergency dose system 200 of the invention is particularly suitable for delivering a gas mixture comprising 1 to 80 ppmv of NO and at least 20% by volume of oxygen to patients (adults, children, adolescents or newborns), preferably at least 21% by volume of oxygen, suffering from pulmonary hypertension and / or hypoxia, which may cause pulmonary vasoconstriction or the like, for example, caused by pulmonary pathologies or disorders such as PPHN (persistent pulmonary hypertension of the newborn) or ARDS (acute respiratory distress syndrome), or even caused by cardiac surgery in which the patient is placed under extracorporeal blood circulation.

Claims

1. A NO supply apparatus (1) for supplying a gas containing NO, in particular a gaseous mixture of NO / N2, comprising: - an NO injection line (111) for conveying the NO-containing gas, - a valve device (113) disposed in the injection line (111) for controlling the flow of the NO-containing gas in the injection line (111), said valve device (113) being configured to be normally in a closed position to prevent any gas flow in the injection line (111), - a flow-measuring device (112) disposed in the injection line (111) for performing one or more flow measurements of the NO-containing gas flowing in the injection line (111), - an emergency circuit (200) comprising an emergency line (201) seamlessly connected to the injection line (111), upstream (111a) and downstream (111b) of the device (113) valve,said emergency line (201) comprising an emergency solenoid valve (202) configured to be normally in an open position to permit gas circulation in the emergency line (201), and a flow control device (210), and control means (130) configured to cooperate with the emergency solenoid valve (202), the flow control device (210), the valve device (113), and the flow measuring device (112), and wherein, in the event of a failure causing the cessation of cooperation with the control means (130): the emergency solenoid valve (202) is configured to change to the open position to permit gas circulation in the emergency line (201) of the emergency circuit (200), and the valve device (113) is configured to move to the closed position to stop any gas circulation in the injection line (111).and - the flow control device (210) is configured to supply gas at a preset emergency gas flow rate, wherein said emergency gas flow rate: is determined by the control means (130) from at least one gas flow measurement provided by the flow measuring device (112), during the normal operation of the apparatus (1) preceding said failure, and is preset by controlling said flow control device (210) by means of the control means (130), during said normal operation of the apparatus (1), characterized in that: - a multi-way solenoid valve (205) is provided in the emergency line (201), downstream of the flow control device (210), - said multi-way solenoid valve (205) comprising: an inlet path seamlessly connected to the emergency line (201) downstream of the flow control device (210),a first outlet seamlessly connected to a first dosing line (206) comprising a first calibrated orifice device (208), and a second outlet seamlessly connected to a second dosing line (207) comprising a second calibrated orifice device (209), - the first dosing line (206) and the second dosing line (207) are connected (201b) to the emergency line (201), downstream of said first and second calibrated orifice devices (208, 209), - the first and second calibrated orifice devices (208, 209) have calibrated orifices (D1, D2) with different cross-sectional areas or diameters, - and the control means (130) are configured to control the multi-way solenoid valve (205) to direct the gas flow to the first dosing line (206) or, alternatively,to the second dosing line (207) based on the gas flow measurement(s) provided by the flow measuring device (112) during the normal operation of the device (1) preceding said failure.

2. Apparatus according to claim 1, characterized in that the multi-way solenoid valve (205) comprises 3 ports.

3. Apparatus according to claim 1, characterized in that the first calibrated orifice of the first calibrated orifice device (208) has a first passage diameter (D1) and the second calibrated orifice of the second calibrated orifice device (209) has a second passage diameter (D2) such that 1.5D1 < D2 < 4D1.

4. Apparatus according to claim 3, characterized in that the first passage diameter (D1) and the second passage diameter (D2) are such that: 1.8D1 < D2 < 3D1, preferably D2 is equal to approximately 2D1.

5. Apparatus according to claim 1,characterized in that the emergency solenoid valve (202) is of the on / off type, capable of adopting only an open state in which it allows the passage of gas flow and a closed state in which it interrupts the passage of gas flow.

6. Apparatus according to claim 1, characterized in that the flow control device (210) comprises an actuator (203) that cooperates with a pneumatic pressure regulator (204), preferably the actuator (203) comprising a stepper motor.

7. Apparatus according to claim 6, characterized in that: - the pneumatic regulator (204) is configured to be adjustable to various pressure levels between 0 and 2 bar relative, preferably less than 1.5 bar relative, and - the actuator (203) cooperates with the pneumatic regulator (204) to establish a desired outlet pressure downstream of said pneumatic regulator (204).

8. Apparatus according to claim 7,characterized in that: - the pneumatic regulator (204) comprises an internal spring that allows adjustment of the desired pressure level and - the actuator (203) comprises a stepper motor configured to adopt several different angular positions, each angular position of the stepper motor corresponding to a given tension of the internal spring of the pneumatic regulator (204), such that the desired outlet pressure level downstream of the pneumatic regulator (204) is determined by the tension of the internal spring of the pneumatic regulator (204) corresponding to the angular position adopted by the stepper motor.

9. Apparatus according to claim 1, characterized in that, under normal operation,The control means (130) are configured to control the multi-way solenoid valve (205) to operate a smooth communication between the inlet port of the multi-way solenoid valve (205) and either of the first and second outlet ports of the multi-way solenoid valve (205) to cause the gas flow to pass through the first or second calibrated orifice device (208, 209).

10. Apparatus according to claim 1, characterized in that the control means (130) comprise at least one microprocessor.

11. Apparatus according to claim 1, characterized in that the valve device (113) comprises a proportional solenoid valve.

12. Apparatus according to claim 1, characterized in that the flow-measuring device (112) is configured to perform several successive flow measurements during the normal operation of the NO supply device (1).

13. Apparatus according to claims 1 and 6, 7 or 8,characterized in that the control means (130) are configured to determine the opening of the pneumatic pressure regulator (204) and / or the emergency flow rate from a correspondence table stored by storage means, such as a computer memory.

14. Installation (1, 2) for supplying gas to a patient, comprising: - at least one NO source (250) containing a NO / N2 gas mixture, preferably a NO / N2 gas mixture containing between 100 and 2000 ppmv of NO, the remainder being nitrogen (N2), - an NO supply device (1) according to any of the preceding claims, supplied with a NO / N2 gas mixture by said at least one NO source (250), - an inspiratory limb (31) of a patient circuit (3) supplied with a NO / N2 gas mixture by the NO supply device (1),and - a medical ventilator (2) in fluid communication with the inspiratory branch (31) to supply said inspiratory branch (31) with a respiratory gas containing at least 20% oxygen, preferably air or an oxygen / nitrogen mixture.

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