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EP-4582124-B1 - NO DELIVERY DEVICE WITH EMERGENCY DOSING SYSTEM

EP4582124B1EP 4582124 B1EP4582124 B1EP 4582124B1EP-4582124-B1

Inventors

  • MARCHAL, Frédéric
  • PATEL, Akshar
  • Boulanger, Thierry

Dates

Publication Date
20260513
Application Date
20241129

Claims (14)

  1. NO delivery device (1) for supplying a gas containing NO, in particular an NO/N 2 gas mixture, comprising: - an NO injection line (111) for conveying the NO-containing gas, - a valve device (113) arranged on the injection line (111) to control 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 measurement device (112) arranged on the injection line (111) to measure the flow rate of the NO-containing gas flowing in the injection line (111), - a backup circuit (200) comprising a backup line (201) fluidly connected to the injection line (111), upstream (111a) and downstream (111b) of the valve device (113), said backup line (201) comprising a backup solenoid valve (202) configured to be normally in an open position to allow gas to flow through the backup 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 measurement device (112), and wherein, in the event of a malfunction causing a failure of cooperation with the control means (130): - the emergency solenoid valve (202) is configured to switch to the open position to allow gas to flow through the emergency line (201) of the emergency circuit (200), - the valve device (113) is configured to switch to the closed position to stop all gas flow 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 measurement device (112) during normal operation of the device (1) preceding said malfunction, and ∘ is preset by control of said flow control device (210) by the control means (130) during said normal operation of the device (1), characterized in that : - a multi-way solenoid valve (205) is arranged on the backup line (201), downstream of the flow control device (210), - said multi-way solenoid valve (205) comprising: ∘ an inlet port fluidically connected to the backup line (201) downstream of the flow control device (210), ∘ a first outlet port fluidly connected to a first metering line (206) comprising a first calibrated orifice device (208), and ∘ a second outlet port fluidly connected to a second metering line (207) comprising a second calibrated orifice device (209), - the first metering line (206) and the second metering line (207) connect (201b) to the backup 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 passage cross-sections 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 metering line (206) or, alternatively, to the second dosing line (207) depending on the gas flow measurement(s) provided by the flow measurement device (112) during normal operation of the device (1) preceding said malfunction.
  2. Device according to claim 1, characterized in that the multi-way solenoid valve (205) comprises 3 ways.
  3. Device 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 calibrated orifice of the second calibrated orifice device (209) has a second passage diameter (D2) such that 1.5.D1 < D2 < 4.D1.
  4. Device according to claim 3, characterized in that the first passage diameter (D1) and the second passage diameter (D2) are such that: 1.8.D1 < D2 < 3.D1, preferably D2 is equal to approximately 2.D1.
  5. Device according to claim 1, characterized in that the backup solenoid valve (202) is of the on/off type that can only adopt an open state in which it allows the gas flow to pass and a closed state in which it interrupts the passage of the gas flow.
  6. Device according to claim 1, characterized in that the flow control device (210) comprising an actuator means (203) cooperating with a pneumatic pressure regulator (204), preferably the actuator means (203) comprises a stepper motor.
  7. Device according to claim 6, characterized in that : - the pneumatic regulator (204) is configured to be adjustable to several pressure levels between 0 and 2 bar relative, preferably less than 1.5 bar relative, and - the actuator means (203) cooperates with the pneumatic regulator (204) to set a desired outlet pressure downstream of said pneumatic regulator (204).
  8. Device according to claim 7, characterized in that : - the pneumatic regulator (204) comprises an internal spring for setting the desired pressure level, and - the actuator means (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), so 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. Device according to claim 1, characterized in that , in normal operation, the control means (130) are configured to control the multi-way solenoid valve (205) to operate a fluidic communication between the inlet port of the multi-way solenoid valve (205) and either the first or second outlet port of the multi-port solenoid valve (205) so as to pass the gas flow through the first or second calibrated orifice device (208, 209).
  10. Device according to claim 1, characterized in that the control means (130) comprise at least one microprocessor.
  11. Device according to claim 1, characterized in that the valve device (113) comprises a proportional solenoid valve.
  12. Device according to claim 1, characterized in that the flow measurement device (112) is configured to perform several successive flow measurements during normal operation of the NO delivery device (1).
  13. Device 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 backup flow rate from a correspondence table stored by storage means, such as a computer memory.
  14. Gas supply system (1, 2) for a patient, comprising: - at least one NO source (250) containing an NO/N 2 gas mixture, preferably an NO/N 2 gas mixture containing between 100 and 2000 ppmv of NO, the remainder being nitrogen (N 2 ), - an NO delivery device (1) according to one of the preceding claims, supplied with 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) to supply said inspiratory branch (31) with a respiratory gas containing at least 20% oxygen, preferably air or an oxygen/nitrogen mixture.

Description

The invention relates to a device for delivering gaseous nitric oxide (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 makes it possible to supply the gas at a pre-set flow rate in the event of malfunction, 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 Persistent Pulmonary Hypertension of the Newborn (PPHN), Acute Respiratory Distress Syndrome (ARDS), observed primarily in adults, and pulmonary hypertension in cardiac surgery, as taught in particular by... EP-A-560928 , EP-A-1516639 Or US-A-10,201,564 . Typically, a small amount of gaseous nitric oxide (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 dosage, is determined by the physician or similar professional. Typically, the gas containing O₂ is an N₂ / O₂ mixture 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 population being treated, i.e., newborns or adults, and therefore the condition being treated. The gas inhaled by the patient can be delivered via a NO delivery device connected to a mechanical ventilator, as described by US-A-5,558,083 The NO delivery device is fluidically connected to one or more gas cylinders containing a mixture of N₂ /NO₂ with an NO concentration typically ranging from 200 to 1000 ppmv. Generally, the NO delivery system comprises an NO injection module located in the inspiratory limb of a patient circuit fluidically connected, on one side, to the mechanical ventilator and, on the other, to a breathing interface delivering the gas. enriched with NO to the patient, for example a breathing mask, tracheal intubation tube or similar. The NO delivery system also includes a flow sensor that measures the gas flow delivered by the mechanical ventilator (i.e. air or N2 / O2 mixture) in order to determine the amount of NO to be delivered to comply with the dosage set by the doctor. The NO delivery system can ensure NO dosing via a proportional solenoid valve delivering a continuous flow of NO-containing gas, 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 . Another system for issuing NOs is known, for example, from the document FR 3 131 538 A1 . Other systems are available where the proportional solenoid valve is replaced by a plurality of "on or off" type solenoid valves, delivering the gas intermittently, i.e. in the form of pulses, generally at high frequency, whose amplitude and duration ensure the correct amount of gas flowing in 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 delivered, according to the desired dosage, by controlling the flow of NO 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 critically important and medical teams must constantly adjust the dosage according to the patient's condition. As the patient's condition changes, the NO concentration must be gradually decreased or increased. For example, in a newborn weaning situation where the condition is improving, it is common practice to gradually decrease the dosage, for example in increments of 1 ppm, until it reaches zero, at which point the NO delivery system can be stopped. A gradual decrease in NO concentration helps to avoid the "rebound" effect which can occur in the event of a rapid change in concentration, for example in the event of an abrupt discontinuation of treatment, which can seriously worsen the patient's condition. However, nitric oxide (NO) delivery devices are sophisticated electromedical systems susceptible to failures or malfunctions that can significantly impact ongoing therapy. For example, a major electronic malfunction or defect, particularly in the control systems, can lead to device failure and therefore a complete cessation of NO delivery, with the aforementioned negative consequences. In such circumstances, the NO delivery device must warn the user, for example by means of an audible alarm signal, that rapid action is required, typically a switch to a backup pneumatic injection mode, i.e. a so-called "emergency" mode, in order to limit as much as possible the adverse effects associated with