FR3131538A1 - NO delivery device with emergency dosing system - Google Patents

Abstract

Title of the invention NO delivery device with emergency dosing system The invention relates to an NO delivery device (1) for supplying a gas containing NO comprising a valve device (113) and a flow measurement device (112) arranged on an injection line (111), an emergency NO dosing system (200), and control means (130). The emergency NO dosing system (200) comprises an emergency line (201) fluidly connecting to the injection line (111) and comprising an emergency solenoid valve (202) and a flow control device (210) controlled by the control means (130). Figure of the abstract: Fig. 1

Description

NO delivery device with emergency dosing system

The invention relates to a device for delivering 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. i.e. a medical device for administering gas to a patient.

NO is a gas which, when inhaled, dilates the pulmonary vessels and increases oxygenation by improving gas exchange.

The properties of NO are used to treat different medical conditions, such as Pulmonary Hypertension of the Newborn or PPHN (for Persistent Pulmonary Hypertension of the Newborn ), Acute Respiratory Distress Syndrome or ARDS observed mainly in adults or even pulmonary hypertension in cardiac surgery, as taught in particular by EP-A-560928, EP-A-1516639 or US-A-10,201,564.

Usually, a small quantity of NO gas (ie a few ppm vol.), diluted in nitrogen (N ₂ ) is injected into a gas flow containing oxygen (O ₂ ) which is then inhaled by the patient. The concentration of NO, which corresponds to a dosage, is determined by the doctor or the like. Typically, the gas containing the O ₂ is typically an N ₂ /O ₂ mixture or air, such as medical grade air. In general, the concentration of NO in the gas inhaled by the patient is between 1 and 80 ppm by volume (ppmv), depending on the population treated, ie newborns or adults, and therefore the disease to be treated.

The gas inhaled by the patient can be delivered through an NO delivery device associated with a mechanical ventilator, as described by US-A-5,558,083. The NO delivery device is fluidly connected to one or more gas cylinders containing a mixture of N ₂ /NO whose NO concentration can typically be between 200 and 800 ppmv. Generally, the NO delivery system comprises an NO injection module placed in the inspiratory branch of a patient circuit fluidly connected, on the one hand, to the mechanical ventilator and, on the other hand, to a respiratory interface delivering the NO-enriched gas to the patient, for example a breathing mask, a tracheal intubation tube or the like.

The NO delivery system also includes a flow sensor which measures the gas flow delivered by the mechanical ventilator (ie air or N ₂ /O ₂ mixture) in order to determine the quantity of NO to be delivered to respect the dosage set by the doctor .

The NO delivery system can ensure the NO dosage by means of a proportional solenoid valve delivering a continuous flow of gas containing NO, which is associated with a flow sensor, the two components being arranged in the delivery system, as well as an injection line connected to the NO injection module, as described in US-A-5,558,083.

Other systems are available where the proportional solenoid valve is replaced by a plurality of “all or nothing” type solenoid valves, delivering the gas intermittently, that is to say in the form of pulses, generally at high frequency. , whose amplitude and duration make it possible to guarantee the right quantity of gas circulating in the injection line connected to the NO injection module.

In all cases, known NO delivery systems receive the measurements from the flow sensor placed in the inspiratory branch of the patient circuit and adjust in real time the quantity of NO to be delivered, according to the desired dosage, by controlling the flow of NO. NO in the injection line.

NO being an effective therapeutic agent, that is to say that very low concentrations (i.e. a few ppmv) produce a therapeutic effect, its correct dosage is of critical importance and medical teams must constantly adapt the dosage according to the condition of the patient.

As the patient's condition changes, the NO concentration should be gradually decreased or increased. For example, in a situation of weaning a newborn whose condition is improving, it is usual to gradually decrease the dosage, for example in steps of 1 ppm, until reaching a zero value which then allows the system to be stopped. delivery of NO.

A gradual reduction in the NO concentration makes it possible to avoid the “rebound effect”, which can occur in the event of a rapid variation in the concentration, for example in the event of sudden discontinuation of treatment, with the effect of seriously worsening the condition of the patient.

However, NO delivery systems are sophisticated electro-medical systems susceptible to failures that can have a significant impact on the therapy in progress. For example, a major electronic fault can lead to a breakdown of the device and therefore a complete shutdown of NO delivery, with the negative consequences mentioned above.

In such circumstances, the device must warn the user by means of an audible alarm signal that rapid action is required, for example to switch to an emergency pneumatic injection mode in order to limit, as much as possible, adverse effects linked to discontinuation of therapy.

Such a switch to emergency mode is usually done by actuation of a rotary button controlling the transition from the normal NO administration mode to an emergency mode, in which for example a continuous delivery of a fixed flow rate of mixture is carried out. N ₂ /NO, ie of the order of 250 mL/min.

However, an emergency dosing mechanism or system is not without risk, in particular for the following reasons:

• its activation requires the presence of a person with authority to undertake this action, for example a neonatology doctor. It may therefore take several minutes before this person arrives and therefore before the emergency dosage is established, which leads to discontinuation of therapy and exposes the patient to a rebound effect.
• this emergency dosage, ie a single flow rate of N ₂ /NO mixture, does not guarantee that the desired dosage is respected. In particular, when the rescue dosage is much lower than the desired dosage, the patient may be exposed to an abrupt change in concentration and potentially subject to significant adverse effects.
• Backup dosing is incompatible with certain types of ventilators delivering very low volumes, such as high-frequency oscillation (HFO) ventilators, because it can result in an excessively high inhaled NO concentration that can reach dangerous levels for the patient. Therefore, if the patient is treated with such a ventilator (i.e. HFO), we then find ourselves without means of administering NO to the patient, which leads to the aforementioned risks linked to the abrupt cessation of treatment.

It therefore appears that the current emergency dosing mechanisms do not guarantee a satisfactory level of safety and that it would be desirable for the patient, in the event of setting up an emergency dosage due to a malfunction. of the NO delivery system, to be able to maintain an initially set dosage, without interrupting the therapy, and without worrying about the type of ventilator, i.e. HFO or other, with which the NO delivery system cooperates.

A solution according to the invention relates to a device, i.e. an apparatus, for delivering NO to supply a gas containing NO comprising

• a NO injection line to convey the gas containing NO,
• a valve device arranged on the injection line to control the circulation of gas containing NO in the injection line,
• a flow measuring device arranged on the injection line, downstream of the valve device,
• an emergency NO dosing system, and
• means of control.

According to the invention, the NO emergency dosing system comprises an emergency line connecting fluidly to the injection line upstream of the valve device and downstream of the flow measurement device, said emergency line comprising a emergency solenoid valve and a flow control device, the emergency solenoid valve and the flow control device being controlled by the control means.

In the context of the invention:

• “ppmv” means parts per million by volume,
• " %flight. » » means percentage by volume.
• “NO” stands for nitric oxide.
• “N ₂ ” designates nitrogen.
• “O ₂ ” designates oxygen.

Depending on the embodiment considered, the NO delivery device of the invention may comprise one or more of the following characteristics:

• the NO conveying line conveys a gas mixture formed of NO and nitrogen.
• the emergency solenoid valve is configured and/or controlled to be normally open.
• 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 card carrying said at least one microprocessor.
• the injection line is fluidly connected to a high pressure line via a pressure regulator device, the high pressure and the pressure regulator device being arranged in the NO delivery device.
• the NO delivery device comprises a housing.
• the emergency NO dosing system is arranged in the box.
• the emergency line is fluidly connected to the injection line between the pressure regulator device and the valve device.
• the valve device includes a proportional solenoid valve.
• the flow control device comprises actuator means cooperating with a movable element comprising a through recess, said movable element being able to be moved angularly by the actuator means.
• the actuator means comprises an electric motor driving a rotary axis, the movable element being integral with said rotary axis.
• the electric motor is a stepper motor.
• the mobile element is arranged mobile in an internal housing comprising an input port and an output port in fluid communication with the emergency line.
• the movable element is a sphere, that is to say spherical, for example a ball or the like.
• the internal housing has a spherical shape complementary to that of the spherical mobile element.
• the control means are configured to control the actuator means to effect an angular movement of the mobile element between at least:
  • a fully open position in which all the gas flow supplied by the emergency line enters the through recess of the mobile element, that is to say a maximum flow rate,
  • a completely closed position in which no gas flow can pass through the through recess of the mobile element, that is to say zero flow, and
  • at least one intermediate position located between said total open position and total closed position, in which only part of the gas flow brought by the emergency line enters the through recess of the movable element, that is to say -say one or more reduced flow rates.
• the control means are configured to control the actuator means to effect an angular movement of the movable element between several intermediate positions, angularly offset from each other, each corresponding to a given gas flow, that is to say reduced flow rates between maximum flow and zero flow.
• it comprises electrical power supply means supplying electrical current to the components requiring electrical energy to operate, in particular the control means.
• the electrical power supply means includes means of connection to the mains (110/220V) and/or a battery or the like.
• the flow control device of the NO emergency dosing system constitutes a proportional calibrated orifice system.

The invention also relates to an installation for supplying gas to a patient comprising:

• at least one NO source containing a NO/N ₂ gas mixture,
• a NO delivery device according to the invention, supplied with a NO/N ₂ gas mixture by said at least one NO source,
• an inspiratory branch of a patient circuit supplied with a NO/N ₂ gas mixture by 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 21% oxygen.

Depending on the embodiment considered, the gas supply installation of the invention may comprise one or more of the following characteristics:

• the medical ventilator delivers air or an oxygen/nitrogen mixture.
• the medical ventilator comprises a motorized blower (i.e. turbine, compressor or the like) delivering the respiratory gas, typically air or an oxygen/nitrogen mixture.
• the medical ventilator comprises a motorized blower controlled by control means, such as an electronic control card.
• the medical ventilator is of the HFO type.
• the NO source contains a NO/N ₂ gas mixture containing between 100 and 2000 ppmv of NO, the remainder being nitrogen (N ₂ ), conditioned at a pressure of between 10 and 250 bar abs, typically at more than 100 bar abs (before start of withdrawal).
• the source of NO is one (or more) pressurized gas cylinders.
• the NO source is one (or more) gas cylinders with a capacity between 0.5 and 50 L (water equivalent).
• the gas cylinder comprises a cylindrical body made of steel or aluminum alloy.
• the gas bottle is equipped with a simple tap (without regulator) or with an integrated regulator or RDI.
• the gas bottle is equipped with an RDI protected by a protective covering, for example made of metal or polymer.
• the patient circuit includes an inspiratory branch and an expiratory branch.
• the inspiratory branch and the expiratory branch are connected to a junction part, such as a Y-shaped part.
• the inspiratory branch and/or the expiratory branch are fluidly connected to a patient respiratory interface, preferably via the junction part.
• the patient respiratory interface includes a tracheal intubation tube or respiratory mask.
• the inspiratory branch and the expiratory branch comprise flexible pipes, for example made of polymer.
• the inspiratory branch and the expiratory branch are further fluidly connected to, respectively, 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.

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

• schematizes a gas delivery installation equipped with an emergency NO dosing system according to the present invention;
• schematizes the association between calibrated orifice and actuator of the emergency NO dosing system of ; And
• has schematize the operation of the calibrated orifice/actuator association .

schematizes an embodiment of a gas delivery installation 1, 2 according to the present invention comprising a NO delivery device 1 comprising an emergency NO dosing mechanism, associated with a mechanical fan 2, i.e. that is to say a respiratory device delivering a respiratory gas, making it possible to deliver NO in gaseous form to a patient at a desired concentration corresponding to a dosage set by a physician-anesthetist or the like, typically between 1 and 80 ppmv of NO (ie ppm in volume).

The medical ventilator 2 delivers a respiratory gas containing at least 21% oxygen, such as air or a NO/N mixture ₂ , into a patient circuit 3, in particular into an inspiratory branch 31 of said patient circuit 3, serving to convey and supply the respiratory gas to a patient P during his inspiratory phases, that is to say to provide respiratory assistance to the patient P, and to convey the gases exhaled by the patient during his expiratory phases.

The medical ventilator 2 is a conventional device comprising for example a motorized blower, also called a turbine or compressor, delivering the respiratory gas into the patient circuit 3 and whose operation is controlled by one (or more) electronic control card or the like. It is electrically powered by power supply means, such as the mains (110/220V) and/or an internal battery.

As visible on , the patient circuit 3 here comprises an inspiratory branch 31 and an expiratory branch 32 fluidly connected to a part Y 33 or similar, in fluidic communication with a respiratory interface 30 making it possible to deliver the gas to the patient P or to collect the gases exhaled by said patient P. The respiratory interface 30 can for example be a facial mask or an intubation probe.

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

The respiratory gas circulating in the inspiratory branch 31 of the patient circuit 3, that is to say going from the mechanical ventilator 2 to the patient P, is inhaled by the patient P while the gases exhaled by said patient P, ie enriched gases in CO ₂ , take the expiratory branch 32 of the patient circuit 3 towards the mechanical ventilator 2 to be discharged to the atmosphere by the mechanical ventilator 2.

Furthermore, a flow sensor 100 as well as an NO injection module 110 are arranged in the inspiratory branch 31 of the patient circuit 3. The flow sensor 100 is preferably arranged in the inspiratory branch 31 between the injection module of NO 110 and the mechanical fan 2.

The inspiratory branch 31 may also include a humidifier (not shown) in order to humidify the gas delivered to the patient P. Preferably, the humidifier is placed downstream of the NO injection module 110, that is to say between said NO injection module 110 and the respiratory interface 30 supplying the gas to the patient P.

The flow sensor 100 is used to measure the gas flow, i.e. a flow rate, delivered by the mechanical ventilator 2 and circulating in the inspiratory branch 31, for example a mass flow sensor or differential pressure measurement.

In the embodiment of , the flow sensor 100 is of the differential pressure measurement type, that is to say that the flow sensor 100 includes an internal restriction 101 which creates a pressure loss generating a differential or pressure gradient when a flow gas passes through this internal restriction 101.

As we see in , the flow sensor 100 comprises upstream 120 and downstream 121 chambers which are separated by a wall 122 through which a gas passage passes so as to form the internal restriction 101.

An upstream line 103 and a downstream pressure measurement line 102 are fluidly connected to the flow sensor 100 at connection sites located upstream and downstream of the internal restriction 101, in particular to the upstream 120 and downstream 121 chambers in order to y carry out pressure measurements of the circulating flow, before and after loss of pressure.

The pressure difference created by the internal restriction 101 is determined by a differential pressure sensor 104 connected to the flow sensor 100 via the upstream 102 and downstream 103 lines which form pressure measurement conduits and supply the differential pressure sensor 104, pressure measurements of the circulating flow, before and after loss of pressure.

Preferably, the differential pressure sensor 104 is integrated into the housing 10 of the NO delivery device 1. The sensor 104 can either be electrically connected to a control unit 130, or can transmit the pressure measurements to it so that they are processed electronically.

The control unit 130 comprises a data processing system, i.e. measurements, comprising for example one (or more) microprocessor(s) arranged on one (or more) electronic card and implementing one (or more) algorithms ( s), i.e. one (or more) computer programs.

In other words, the control unit 130 is configured to process and/or exploit the pressure measurement signals or the pressure values transmitted by the differential pressure sensor 104 cooperating with the flow sensor 100.

Of course, the control unit 130 can also be configured to control other electromechanical elements integrated in the housing 10 or external carcass of the NO delivery device 1.

For example, the control unit 130 has a pre-recorded correspondence table which allows the determination of the flow rate of gas circulating in the inspiratory branch 31 and the flow sensor 100, that is to say to transform a value of pressure transmitted by the differential pressure sensor 104 in value of flow passing through the flow sensor 100. Such determination of the flow passing through the flow sensor 100 then makes it possible to calculate the quantity of NO to be added to the gas circulating in the inspiratory branch 31 before reaching patient P.

In other words, by using the pressure measurement returned by the differential pressure sensor 104 and the correspondence table, the control unit 130 can determine the gas flow rate coming from the mechanical fan 2 and the quantity of NO which must be added, via the NO injection module 110, in order to obtain the desired NO concentration, i.e. the dosage defined by the doctor, to be inhaled by the patient P.

The gas mixture obtained at the NO 110 injection module then mainly comprises nitrogen (N ₂ ), oxygen (O ₂ ) in a content of at least 21% vol., and NO at a content typically between 1 and 80 ppmv.

More precisely, depending on the gas flow (ie air or N ₂ /O ₂ ) circulating in the inspiratory branch 31 having been determined using the flow sensor 100, the control unit 130 determines the quantity of NO, typically a mixture of NO and N ₂ , to be added to the gas circulating in the inspiratory branch 31 by the NO injection module 110, in order to obtain the desired concentration.

The NO 1 delivery device is supplied with gaseous NO, typically a gaseous NO/N ₂ mixture, coming from a source of NO 250 fluidly connected to the NO 1 delivery device, in particular to a high pressure line 116 of said device for delivering NO 1, via a supply line 251, such as a flexible conduit or the like.

Typically, the source of NO 250 is one (or more) pressurized gas cylinders containing a mixture of NO/N₂containing a concentration of NO generally between 100 and 2000 ppmv, for example of the order of 800 ppmv, and conditioned at a pressure (when completely full) which can reach 200 to 250 bar abs, or even more.

The NO/N ₂ mixture is supplied to the injection module 110 by the NO 1 delivery device via an injection line 111, such as a flexible gas pipe.

The injection line 111 is fluidly connected to a high pressure line 116 of the NO 1 delivery device, which high pressure line 116 has a high pressure inlet fluidly connected to the NO source to be supplied with NO/N ₂ under pressure , that is to say at a pressure of up to 200 bar abs.

The high pressure line 116, for example a gas passage or conduit, is arranged in the housing 10 of the NO 1 delivery device and includes a pressure regulator 115 which reduces the pressure of the NO/N ₂ mixture to a stable value, for example example 4 bar abs. The outlet port of the pressure regulator 115 provides a stable pressure in the upstream portion of the injection line 111.

A solenoid valve 113, for example a proportional solenoid valve such as the miniature VSO series from Parker, is arranged on the high pressure line 116 in order to control the flow of gaseous NO within the injection line 111. The gas flow circulating in the injection line 111 is measured by a NO flow sensor 112 arranged on the injection line 111, preferably placed downstream of the solenoid valve 113, as visible on .

The pressure regulator 115, the solenoid valve 113, the NO flow sensor 112 and a portion of the injection line 111 are arranged in the housing 10 of the NO delivery device 1.

Furthermore, according to the invention, there is provided an emergency NO dosing system 200 arranged in the housing 10 of the NO delivery device 1.

The NO emergency dosing system 200 includes an emergency line 201, also called a bypass line. The emergency line 201 connects fluidly to the injection line 111 at a first connection site 111a located upstream of the proportional solenoid valve 113 and downstream of the pressure regulator 115, and at a second connection site 111b located downstream of the NO flow sensor 112.

In other words, the proportional solenoid valve 113 and the NO flow sensor 112 are located between the first and second connection sites 111a, 111b of the emergency line 201, that is to say that the emergency line 201 bypasses the proportional solenoid valve 113 and the NO flow sensor 112 located on the injection line 111.

The emergency line 201 comprises an emergency solenoid valve 202 and a flow control device 210 forming part of the emergency dosing system 200 of the invention.

The flow control device 210 comprises actuator means 203 cooperating with a mobile element 2042 arranged in a compartment 2041, said mobile element 2042 comprising a through recess 2043.

As detailed below, such an arrangement forms a calibrated orifice 204 of proportional type, that is to say a proportional calibrated orifice system.

The emergency solenoid valve 202 is preferably an “all or nothing” type solenoid valve having two possible states, namely an open state and a closed state, for example a solenoid valve from the Picosol series from IMI Norgren. The emergency solenoid valve 202 is normally open, that is to say that in the absence of an electrical command coming from the control unit 130, the emergency solenoid valve 202 is in the open position, which then allows the gas from the NO source to take the emergency line 201 from the first connection site 111a towards the second connection site 111b.

is a sectional diagram of the calibrated orifice 204 formed by the actuator means 203 and the movable element 2041 to a through recess 2043 of the emergency NO dosing system equipping the NO delivery device 1 of the invention.

The actuator means 203, more simply called actuator, of is preferably a stepper type motor 2030, for example like that marketed by the company Portescap, extended by an axis 2031 mechanically coupled in 2031a to the mobile element 2042.

The mobile element 2042 is here a sphere. The sphere forming the movable element 2042 can be metallic, for example stainless steel and has a through recess 2043, that is to say it is diametrically crossed by a drilling or internal passage allowing the passage of gas.

The mobile element 2042, i.e. the sphere, is housed in a compartment or internal housing 2041 forming a sphere chamber which is here of generally spherical shape. Housing 2041 is arranged in a part forming body 2040. The external diameter of sphere 2042 is substantially equal to the internal diameter of internal housing 2041.

The body part 2040 can also be metallic, for example a steel ball or the like. It includes an input port 201a and an output port 201b in fluid communication with the internal housing 2041.

On , we see that the through recess 2043 of the sphere 2042 is aligned with the inlet ports 201a and outlet 201b of the body 2040, which are in fluidic communication with the emergency line 201, that is to say that They are in fluid continuity, so that the gas can flow from the inlet port 201a to the outlet port 201b via the through recess 2043 of the sphere 2042.

As indicated, the actuator means 203 is here a stepper motor 2030 rotating the axis 2031 and therefore the sphere 2042. In response to a command coming from the control unit 130, the stepper motor 2030 will adopt a different position and rotate the axis 2031 which will then cause the sphere 2042 to also rotate.

Considering that the control unit 130 is capable of varying the control value proportionally, it follows that the axis 2031 can undergo more or less significant rotational movements and in a proportional manner, for example between 0 and 90°.

In other words, the rotational movement undergone by the axis 2031 is therefore transmitted to the sphere 2042 which pivots in response, within its housing 2041, as illustrated in has .

So, is a top diagram of the calibrated orifice 204 of showing, as already explained, the axis 2031 which requires the sphere 2042 to present its recess 2043 in continuity with the input ports 201a and output 201b of the body 2040 so as to create a fluid connection between said input ports 201a , 201b and thus authorize the passage of gas through the ports 201a, 201b and the recess 2043. The calibrated orifice 204 is then at its maximum opening, that is to say in the fully open position. In this position, the axis AA of the through recess 2043 of the sphere 2042 is (quasi) coaxial with the axis BB passing through the inlet (201a) and outlet (201b) ports so that the opening is maximum, therefore the maximum flow in the emergency line 201, including through the through recess 2043 of the sphere 2042.

In , the control unit 130 controlled the stepper motor 2030 to cause the axis 2031 to undergo a rotation here of the order of 90° and consequently also the sphere 2042 which also undergoes the same rotation of 90 °. After rotation, the inlet ports 201a and outlet 201b of the body 2040 of the calibrated orifice 204 no longer face the recess 2043 of the sphere 2042 but a non-hollowed out portion 2044, i.e. full, of the sphere 2042 and then find themselves completely blocked by the non-hollowed part 2044 of the sphere 2042. The fluid connection is then broken and no gas can circulate between the inlet ports 201a and outlet 201b of the body 2040 of the calibrated orifice 204. The calibrated orifice 204 is then completely closed.

In this so-called closed position, the axis AA of the through recess 2043 of the sphere 2042 is (quasi) perpendicular to the axis BB passing through the inlet (201a) and outlet (201b) ports so that no gas passage takes place through the through recess 2043, therefore in the emergency line 201.

Between And , the control unit 130 imposed extreme control values on the actuator 203 (ie between 0° and 90° of rotation) making it possible to obtain either complete communication (cf. ), or complete insulation (cf. ) of the inlet 201a and outlet 201b ports of the body 2040 of the calibrated orifice 204.

However, the control unit 130 is also configured to be able to assign, in a proportional manner, commands causing a rotation of the axis 2031 and the sphere 2042 between these two extreme angular positions, (i.e. 0° and 90° of rotation ), that is to say an angle not zero but less than 90°.

So, gives the example of an intermediate angular position where the sphere 2042 has undergone a rotational movement of around 45°.

In this case, the inlet port 201a of the body 2040 of the calibrated orifice 204 is partially obstructed, that is to say exposed to non-recessed parts 2044 and recessed parts 2043 of the sphere 2042. The passage section gas of the recessed part 2043 of the sphere 2042 in fluidic relation with the inlet port 201a is then defined by a level (or size) of opening O. This gas passage section is always less than the maximum section of fluid connection as shown in . By means of axial rotation, the same opening level O appears between the outlet port 201b and the recessed part 2043 of the sphere 2042 of the body 2040 of the calibrated orifice 204.

In the so-called intermediate positions, the axis AA of the through recess 2043 of the sphere 2042 and the axis BB passing through the inlet (201a) and outlet (201b) ports form between them a variable angle understood strictly here between 0 and 90° so that the passage of gas through the through recess 2043, therefore in the emergency line 201, is limited/reduced but not zero, nor maximum, that is to say depending on of the desired opening O of the calibrated orifice 204.

Thus, depending on the command imposed on the actuator 203 by the control unit 130, the opening level O defined by the intersection of the input ports 201a, output ports 201b and the recessed part 2043 of the sphere 2042, varies by a zero value ( ) to a maximum value ( ), that is to say it can take intermediate values located between these two extreme values, ie between 0 and 90°.

It is easy to understand that each level or opening value O corresponds to an equivalent calibrated orifice whose gas passage diameter is a function of the positioning of the sphere 2042 and consequently of the command sent by the control unit 130 to the actuator 203.

This assembly therefore forms a proportional calibrated orifice since its caliber or opening level O varies as a function of the angular position taken by the sphere 2042 within the body 2040 of the calibrated orifice 204.

However, the pressure prevailing in the upstream portion of the emergency line 201, that is to say upstream of the calibrated orifice 204, is stable and known since it corresponds to the expansion pressure of the pressure regulator 115 fixed for example at 4 bar abs. The gas flow rate circulating in the downstream portion of the emergency line 201, that is to say downstream of the calibrated orifice 204, is therefore a function of the opening level O.

Thus, the control unit 130 can have a correspondence table linking a given control level to an opening level and to a gas flow rate passing through the calibrated orifice 201 towards the injection line 111 and y penetrating at the second connection site 111b.

For reasons of simplification, we admit that the pressure level prevailing in the inspiratory branch 31 of the patient circuit 3, and therefore in the NO injection module 110 and the injection line 111 is negligible with regard to the pressure of relaxation of the pressure regulator 115 and therefore has no impact on the precision of the flow measurements circulating in the emergency line 201 carried out by the control unit 130.

Of course, additional means, such as an additional pressure measurement downstream of the calibrated orifice 204 arranged in the emergency line 201 could be implemented for compensation purposes, without changing in any way the object of the present invention.

Finally, it should be noted that the choice of a stepper motor is particularly recommended because, unlike the solenoid valves 202, 113 which will take a rest position, in the event of a power cut, namely an open position for the on-off solenoid valve 202 and a closed position for the proportional solenoid valve 113, the position of the stepper motor remains permanent and fixed according to the last command imposed. In other words, the calibrated orifice 204 has a fixed opening level corresponding to the last command value received by the stepper motor.

However, the present invention is not limited to a stepper motor type actuator. Indeed, any other actuator maintaining its position in the event of a power supply failure and which can be coupled to a mechanical mechanism making it possible to define a calibrated orifice of variable size can be used, such as for example a linear motor or other.

The NO 1 delivery device is electrically powered by a power supply, such as the sector (110/220V) or an internal battery, in order to allow the proper functioning of its components requiring electric current to operate, in particular the actuator 203, such as a stepper electric motor, the control unit 130, the solenoid valves 202, 113 or others.

Furthermore, the NO 1 delivery device also includes storage means, such as a computer memory, for storing data, information or others, for example correspondence tables or others.

The operation of the emergency NO dosing system 200 of the NO delivery device 1 of the invention is as follows.

As illustrated in , the NO delivery device 1 cooperates with a mechanical ventilator 2 in order to provide therapeutic assistance to the patient P.

As already explained, the gas flow (ie air or N ₂ /O ₂ ) coming from the mechanical ventilator 2 and circulating in the inspiratory branch 31 of the patient circuit 3 is continuously measured by the flow sensor 100 and the control unit 130. This flow measurement allows the control unit 130 to determine, in real time, the flow rate of NO to be injected into the injection line 111 and the NO injection module 110 in order to satisfy the concentration of NO desired in the gas supplied to the patient, typically between 5 and 80 ppmv.

In order not to introduce additional flow coming from the emergency line 201 into the injection line 111, the control unit 130 controls the on-off solenoid valve 202 in the closed position and, in parallel, will control the actuator 203, i.e. stepper motor, in order to preset the calibrated orifice 204 by defining a given opening level O.

This is done as follows.

The control unit 130 first averages the flow rate of NO (ie NO/N ₂ mixture) having circulated in the injection line 111 for a given time, for example for 1 minute (or over a period of time longer but the flow rate must then be converted into L/min). The control unit 130 therefore evaluates the fixed average NO flow rate (in L/min) making it possible to get closer to the desired NO concentration.

When this value has been determined, the control unit 130 carries out a conversion via its stored correspondence table so as to control the actuator 203 and consequently define an opening level of the calibrated orifice 204 in order to induce a flow rate of NO circulating in the emergency line equal to the calculated value of fixed average NO. It should be noted that this activity has no physical effect, i.e. no gas flow circulates in the emergency line 201 because the on-off solenoid valve 202 is closed.

In the event of a major failure of the NO 1 delivery device and/or interruption of its electrical supply, with the exception of the actuator 203 and the pressure regulator 115 which has purely pneumatic operation, all of the actuators electromechanical devices, in particular the solenoid valves, return to their rest position and the control unit 130 as well as the various sensors find themselves without a power supply, therefore without the ability to communicate and/or to control/control other components.

As already indicated, the proportional solenoid valve 113 returns to its rest position, namely a closed position thus preventing the NO source from using the upstream portion of the injection line 111, and the solenoid valve 202 then also finds itself in its rest position, namely here an open position allowing the passage of gas coming from the NO source. The NO/N ₂ mixture is then able to take the emergency line 201 at a flow rate set by the calibrated orifice, namely the last valid value of the fixed average NO flow rate determined by the control unit 130.

The flow of NO/N ₂ will then join the injection line 111 (at 111b) to be injected into the inspiratory branch 31 of the patient circuit 3 via the NO injection module 110, as already explained.

Of course, the fact of injecting a continuous flow of NO into the inspiratory branch 31 of the patient circuit 3 does not guarantee the same precision of concentration of inhaled NO as when the NO delivery system 1 operates in normal operation, it is that is to say by adjusting the NO flow rate as a function of the flow rate passing through the flow sensor 100, but the buffer volume generated by the portion of the inspiratory branch 31 located downstream of the NO injection module, which is possibly increased by volume of the humidification chamber when present, makes it possible to smooth out variations in the concentration of NO inhaled by the patient and to get closer to the desired target value, that is to say the NO dosage.

In all cases, being able to approach the desired NO target value thanks to the NO emergency dosing system 200 integrated into the NO delivery device 1 of the invention considerably improves safety for the patient in comparison with a flow rate. of fixed emergency NO (for example 250 mL/min) usually delivered by the safety system of NO delivery devices of the prior art.

Thus, for comparison, while the emergency NO dosing system 200 integrated into the NO delivery device 1 of the invention makes it possible to guarantee a NO concentration substantially equal to the desired dosage, with an emergency system based on a fixed flow rate of 250 mL/min, as conventionally implemented in NO delivery devices of the prior art:

• for an average NO flow rate required of 0.05 L/min to normally ensure an NO concentration of 10 ppmv (case of use in neonatology with HFO type ventilator), the resulting concentration with the fixed flow rate of 250 mL/min is of 50 ppmv, which corresponds to a 5-fold increase in the desired dosage.
• conversely, for a necessary average NO flow rate of 1 L/min to ensure 80 ppmv NO concentration (case of use 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% reduction in the desired dosage.

In both cases, significant dosage deviations can lead to unacceptable and dangerous situations for the patient, unlike the emergency NO dosing system 200 integrated into the NO delivery device 1 of the invention which allows it to respect the desired dosage.

In other words, the NO emergency dosing system 200 of the invention has undeniable advantages by reinforcing patient safety by:

• automatically injecting an emergency flow of NO without waiting for the user to realize the situation and intervene by switching to emergency pneumatic dosing.
• guaranteeing that the concentration of NO inhaled by the patient is similar to the concentration desired by the doctor, i.e. the desired dosage.

Of course, the switch to the emergency NO dosing system 200 of the invention is only temporary, that is to say it only lasts the time necessary to replace the faulty equipment or component which triggered the audible and/or visual alarm system in order to alert the nursing staff.

In order to avoid improper activation of the NO emergency dosing system 200, the control unit 130 is also configured to carry out appropriate initialization and shutdown sequences. For example, in the event of a shutdown desired by the user of the NO therapy, the control unit 130 can control the actuator 203 in order to close the calibrated orifice 204. Thus, in the event of voluntary extinction and therefore opening of the solenoid valve 202, the “closed” configuration of the calibrated orifice 204 then prohibits any circulation of NO flow in the emergency line 201, until the NO delivery device 1 is stopped .

The NO 1 delivery device equipped with the NO emergency dosing system 200 of the invention is particularly well suited to the supply of a gas mixture comprising 1 to 80 ppmv of NO and at least 21% vol. of oxygen to patients (adults, children, adolescents or newborns), suffering from pulmonary hypertension and/or hypoxia, which can cause pulmonary or similar vasoconstrictions, for example caused by pulmonary pathologies or disorders of the type PPHN (persistent pulmonary hypertension of the newborn) or ARDS (acute respiratory distress syndrome), or even caused by cardiac surgery with the patient placed on extracorporeal blood circulation.

Claims (12)

NO delivery device (1) for supplying an NO containing gas comprising

• a NO injection line (111) for conveying the gas containing NO,
• a valve device (113) arranged on the injection line (111) to control the circulation of gas containing NO in the injection line (111),
• a flow measuring device (112) arranged on the injection line (111), downstream of the valve device (113),
• a NO emergency dosing system (200), and
• control means (130),

characterized in that the NO emergency dosing system (200) comprises an emergency line (201) fluidly connected to the injection line (111) upstream of the valve device (113) and downstream of the device flow measurement device (112), said emergency line (201) comprising an emergency solenoid valve (202) and a flow control device (210), the emergency solenoid valve (202) and the flow control device ( 210) being controlled by the control means (130). Device according to claim 1, characterized in that the emergency solenoid valve (202) is configured and/or controlled to be normally open, preferably the emergency solenoid valve (202) is of the all-or-nothing type. Device according to claim 1, characterized in that the control means (130) comprise at least one microprocessor. Device according to claim 1, characterized in that the injection line (111) is fluidly connected to a high pressure line (116) via a pressure regulating device (115), the high pressure (116) and the pressure regulating device (115) being arranged in the NO delivery device (1). Device according to claim 4, characterized in that the emergency line (201) is fluidly connected to the injection line (111) between the pressure regulator device (115) and the valve device (113). Device according to one of claims 1 or 4, characterized in that the valve device (113) comprises a proportional solenoid valve. Device according to claim 1, characterized in that the flow control device (210) comprises actuator means (203) cooperating with a movable element (2042) comprising a through recess (2043), said movable element (2042) being able to be moved angularly by the actuator means (203). Device according to claim 7, characterized in that the actuator means (203) comprises an electric motor driving a rotary axis (2031), the movable element (2042) being integral with said rotary axis (2031), preferably a stepper motor. not.
Device according to claim 7, characterized in that the movable element (2042) is arranged movably in an internal housing (2041) comprising an inlet port (201a) and an outlet port (201b) in fluid communication with the line emergency (201), preferably the mobile element (2042) is a sphere.
Device according to claim 9, characterized in that the control means (130) are configured to control the actuator means (203) to effect an angular movement of the movable element (2042) between at least:

• a fully open position in which all the gas flow brought by the emergency line (201) enters the through recess 2043 of the mobile element (2042),
• a completely closed position in which no gas flow can pass through the through recess 2043 of the movable element (2042), and

at least one intermediate position located between said total open position and total closed position, in which only part of the gas flow supplied by the emergency line (201) enters the through recess 2043 of the movable element (2042 ), preferably several intermediate positions, angularly offset from each other, each corresponding to a given gas flow rate. Installation for supplying gas (1, 2) to a patient comprising:

• at least one NO source (250) containing a NO/N ₂ gas mixture,
• a NO delivery device (1) according to one of the preceding claims, supplied with a NO/N ₂ gas mixture by said at least one NO source (250),
• an inspiratory branch (31) of a patient circuit (3) supplied with a NO/N ₂ gas mixture by the NO delivery device (1), and
• a medical ventilator (2) in fluid communication with the inspiratory branch (31) for supplying said inspiratory branch (31) with a respiratory gas containing at least 21% oxygen, preferably air or an oxygen/nitrogen mixture.

Installation according to claim 11, characterized in that the NO source (250) contains a NO/N ₂ gas mixture containing between 100 and 2000 ppmv of NO, the remainder being nitrogen (N ₂ ), conditioned at a pressure between 10 and 250 bar abs.