EP3503953A1

EP3503953A1 - Medical device for the closed-circuit administration of a gaseous mixture to a spontaneously breathing patient, and associated adjustment system

Info

Publication number: EP3503953A1
Application number: EP16763926.9A
Authority: EP
Inventors: Hélène DAVID
Original assignee: Monatomics Technology
Current assignee: Monatomics Technology
Priority date: 2016-08-25
Filing date: 2016-08-25
Publication date: 2019-07-03
Also published as: JP2019524345A; US20190167928A1; CA3033444A1; WO2018037166A1; AU2016420621A1; CN109689143A

Abstract

The invention relates to a medical device (1) for the closed-circuit administration of a gaseous mixture to be delivered to a spontaneously breathing patient, comprising a gas recycling system (4) disposed on a closed administration circuit (2). The recycling system (4) can comprise in particular an input for an exhaled gaseous mixture and an output for the gaseous mixture to be supplied to the patient, the orientation of which defines a direction of circulation (8) from the input to the output, as well as a zone (Z1) for treating the exhaled gaseous mixture housing a compound (5) capable of retaining carbon dioxide, as well as at least one zone (Z3) for adjusting the composition of the gaseous mixture, in which zone the concentration of each gas forming the gaseous mixture is adjusted to a setpoint value.

Description

MEDICAL DEVICE FOR CLOSED CIRCUIT DELIVERY OF A GAS MIXTURE TO A SPONTANEOUS BREATHING PATIENT AND SETTING SYSTEM

The field of the present invention is that of medical devices for the closed-loop administration of a gaseous mixture for therapeutic purposes to a patient breathing spontaneously.

The administration of a gaseous mixture to a patient by means of a breathing apparatus operating in a closed circuit requires the possibility of recycling the gaseous mixture, that is to say, on the one hand, to be able to purify the gas mixture and to secondly to be able to accurately adjust the composition of the gas mixture inspired by the patient to defined set values for each gas component of the gas mixture. The administration of a gas mixture to a patient by means of a breathing apparatus operating in a closed circuit can be done either aided when the patient is anesthetized, or unassisted, said on demand, when the patient is not anesthetized and breathes spontaneously. In the latter case, the administration of the gas mixture to the patient follows the respiratory rhythm of the patient. The gaseous mixture is dispensed to the patient when the patient inhales, then, after being exhaled by the patient, is recycled, i.e., purified and adjusted to the desired composition, before being again inspired by the patient. patient. The present invention is in the context of the closed-loop administration of therapeutic gas mixtures composed of oxygen and one or more inert gases to a non-anesthetized patient breathing spontaneously, with the aim of protecting medical use. of this type of gas recycling equipment. The medical device according to the invention makes it possible to administer in a controlled and safe manner a gaseous mixture composed of oxygen and inert gas (s) to a patient breathing spontaneously. According to a first aspect, the invention relates to a system for recycling the gaseous mixture configured to be disposed on a closed circuit for administering said gaseous mixture. According to a second aspect of the invention, it relates to a closed circuit for administering a gaseous mixture to a patient which comprises the system for recycling the gaseous mixture and a member for administering the gaseous mixture to the patient, and according to a third aspect of the invention a medical device for administering a gas mixture to be delivered to a spontaneously breathing patient comprising the closed administration circuit.

The system for recycling a gaseous mixture described in the present invention is a device intended to equip a closed circuit for administering a gaseous mixture to a patient. It has an inlet through which the gas mixture exhaled by the patient enters the device and an outlet through which the gaseous mixture recycled, that is to say purified and adjusted to the desired composition, is supplied to the patient , thus defining a flow direction of the gaseous mixture from the inlet to the outlet of the recycling system. This recycling system comprises at least one treatment zone of the exhaled gas mixture containing a compound capable of retaining carbon dioxide.

According to the first aspect of the present invention, the gaseous mixture recycle system comprises an adjustment zone of the gaseous mixture composition wherein the concentration of each gas comprising the gaseous mixture exhaled by the patient is adjusted to a value. deposit.

This zone for adjusting the composition of the gaseous mixture may in particular comprise at least one fan, which may be at adjustable speed, the dual function of which is on the one hand to optimize the homogenization of the gaseous mixture before it is distributed to the patient and, on the other hand, to relieve the inspiratory work of the patient; the fan may for example be controlled according to the inspiratory rhythm of the patient, in particular by being triggered at each inspirational session detected, and / or be controlled according to the inspiratory effort of the patient, in particular by increasing the speed of rotation of the patient. fan.

This zone for adjusting the composition of the gaseous mixture may further comprise intake orifices making it possible to inject into the recycling system the different gases constituting the gaseous mixture in order to adjust the composition of the gaseous mixture exhaled by the patient to defined setpoints for each gas constituting the gas mixture.

The injection of the various gases constituting the gaseous mixture can be controlled according to the concentration values of each gas constituting the gaseous mixture. These values can be determined by measurements made by gas sensors arranged either in situ in the closed circuit of administration, advantageously in the control system. gas recirculation, connected to gas analysis systems, either ex situ outside the closed administration circuit, in which case the sensors are supplied with gas by means of micropumps or microturbines and a tubing of suitable diameter connecting the closed circuit of administration, or preferably the gas recycling system, to the gas sensors. The choice of the location of the sensors may in particular depend on the type of gas to be detected and the type of sensor that results.

According to the present invention, the gas recycling system may comprise a filtration zone, housing a particle retention member, configured to retain in particular particles emanating from the compound capable of fixing carbon dioxide such as, for example, lime soda. This filtration zone may in particular be located inside the recycling system after the gaseous mixture treatment zone and before the gaseous mixture adjustment zone mentioned above. Alternatively, it can be provided that the filtration zone is offset outside the recycling system and in particular at the outlet thereof, or directly before the administration member of the gas mixture to the patient.

According to the first aspect of the present invention, the system for recycling the gaseous mixture may also comprise a heat exchange zone, in particular for cooling the gaseous mixture, housing for example a heat exchanger.

In other words, the system for recycling a gaseous mixture according to the first aspect of the present invention advantageously has a gaseous mixture treatment zone housing a compound capable of retaining carbon dioxide, an adjustment zone of the composition of the gas mixture, which may include gas inlet ports in the recycling system and, optionally, at least one adjustable speed fan. The system for recycling a gaseous mixture also comprises at least one of the following characteristics, taken alone or in combination:

a heat exchange system, in particular for cooling the gaseous mixture, housing, for example, a heat exchanger;

a filtration zone of the gaseous mixture housing a particle retention member;

gas analysis sensors chosen to enable the various gases comprising the gas mixture to be analyzed. In particular, it may be provided that: the treatment zone of the gaseous mixture is situated upstream of the filtration zone with respect to the direction of circulation of the gaseous mixture;

- The gas mixture treatment zone is located upstream of the adjustment zone with respect to the flow direction of the gaseous mixture;

the filtration zone of the gaseous mixture is situated upstream or downstream of the adjustment zone with respect to the direction of circulation of the gaseous mixture.

The present invention also relates to a closed circuit for administering a gaseous mixture to a patient, which comprises the gaseous mixture recycling system previously described, one or two flexible and deformable enclosures, generally called false-lungs, intended to facilitate the inspiratory and / or expiratory work of the patient, and an organ for administering the gas mixture to the patient.

The closed circuit for administering a gas mixture to a patient advantageously has at least one of the following characteristics, taken alone or in combination:

the closed circuit comprises at least one false-lung arranged upstream or downstream of the recycling system with respect to the direction of circulation of the gas mixture inside the closed circuit; or the closed circuit advantageously comprises two false-lungs arranged for one upstream and the other downstream of the recycling system with respect to the direction of flow of the gas mixture inside the closed circuit; if a false lung is placed downstream of the recycling system, it may be equipped with a pressure relief valve;

the closed circuit comprises a member for administering the gas mixture to a patient; this administration member is for example a bucco-nasal mask, a face mask, or a hood wrapped around the patient's head;

the closed circuit is equipped with a vacuum pump, preferably placed as close as possible to the outlet of the administration member of the gas mixture;

the closed circuit houses at least two, preferably three, nonreturn valves. The present invention according to a particular aspect particularly relates to a medical device for administering a gas mixture to be delivered to a patient breathing spontaneously. This medical device may in particular comprise at least one of the following characteristics, namely:

at least two gas reservoirs, a first reservoir containing pure oxygen, and a second reservoir containing one or more inert gases for the therapeutic purpose of combination or not with oxygen;

- at least two supply lines, each including a mass flow meter coupled to a proportional solenoid valve (DMVP) and / or a single solenoid valve (EVS), connecting the gas tanks to the gas inlet ports in the recycling system of the gaseous mixture;

one of the supply lines may be configured to supply the closed administration circuit with an inert gas for therapeutic purposes, or a mixture of inert gases for therapeutic purposes, this inert gas or these being alone or in combination with oxygen;

an electronic control unit in connection with various sensors, such as gas analysis sensors making it possible to continuously measure the partial pressure of carbon dioxide and of each of the gases constituting the gaseous mixture, sensors making it possible to measure continuously the pressure of the gas tanks, and a sensor for measuring the temperature of the gas administered to the patient; advantageously, the electronic control unit can be configured, for example, to automatically inject one or more gases into the recycling system by means of mass flowmeters - proportional valves and / or solenoid valves in order to adjust the composition of the gas mixture expired by the patient to the desired setpoints, and / or to calculate the volume of expanded gas available in the gas tanks, and / or to adjust the temperature of the gas mixture to a value to maintain the central temperature of the patient at a desired temperature. a predetermined value by a qualified practitioner, and / or to adjust the speed of the ventilator using information relating to the rhythm and / or inspiratory effort of the patient as automatically measured or evaluated by a qualified practitioner; advantageously, the electronic control unit has high alarms and / or low to safely manage the partial pressures of carbon dioxide, oxygen and other gases constituting the gas mixture, the volume of gas expanded available in the gas tanks, the temperature of the gas administered to the patient, and the speed of the ventilator.

Other features, details and advantages of the invention will emerge more clearly on reading the description given below as a representative example in relation to the single figure of this document.

The figure in this document shows a block diagram of a medical device for the closed-loop administration of a gas mixture to a breathing patient spontaneously described in the present invention. Such a medical device 1 of closed circuit administration of a gaseous mixture to a patient breathing spontaneously is adapted to be used in hospital, in a medical office, or in a similar place. The medical device 1 for administering a gaseous mixture is used by a qualified practitioner to administer to a spontaneously breathing patient a gaseous mixture composed of oxygen and inert gases for therapeutic purposes.

The medical device 1 for administering a gaseous mixture, with recycling of the exhaled gas, comprises a closed circuit 2 for administering a gaseous mixture, in particular with a member 3 for delivering the gaseous mixture to the patient, and a system recycling 4 of the gaseous mixture exhaled by the patient.

The medical device 1 for administering a gaseous mixture is furthermore equipped with two feed lines 101 and 102, respectively in relation to the gas reservoirs 201 and 202. The first feed line 101 allows injection into the oxygen recycling system 4 from the tank 201 and the second feed line 102 allows the injection into the recycling system 4 of one or more inert gases, such as for example argon, xenon and helium, combined or not with oxygen, this mixture of inert gases and / or oxygen from the tank 202. Details of the feed lines will be given hereinafter. The closed circuit 2 of the gaseous mixture comprises a delivery member 3 of the gaseous mixture, which is for example an oral-nasal mask, a face mask, or a hood wrapped around the patient's head. The administration member 3 covers at least the patient's mouth and nose. The closed circuit 2 of the gaseous mixture comprises a recycling system 4 of the gaseous mixture, through which the gaseous mixture passes from its inlet to its outlet.

The recycling system 4 of the gaseous mixture houses a compound 5 capable of capturing carbon dioxide, such as, for example, sodium lime or a similar product. This is arranged in the recycling system 4 of a treatment zone Z 1, arranged between the inlet of the recycling system 4 and the outlet thereof, inside which is disposed the compound 5 capable of capture the carbon dioxide.

The recycling system 4 can also house a particle retention member 6 configured to retain at least the particles from the compound 5 capable of fixing the carbon dioxide, such as for example soda lime. More specifically, soda lime is in the form of granules which may tend to crumble on contact with the exhaled air by the user. Thus, in the recycling system 4, a filtration zone 2.2 is provided, which consists, for example, of at least one filter through which the gas mixture is able to circulate. Thus, the patient is prevented from breathing particles from compound 5.

The recycling system 4 is equipped, in an adjustment zone of the composition of the gas mixture Z3, with at least one oxygen sensor for measuring the oxygen partial pressure and at least one oxygen dioxide sensor. carbon for measuring the partial pressure of carbon dioxide, placed inside or outside the recycling system 4 (in which case a tubing connects the sensors to said recycling system). Preferably, for safety reasons, the recycling system 4 is equipped with at least two, advantageously three, oxygen sensors 9a, 9b and at least two, advantageously three, carbon dioxide sensors 10a, 10b. Incidentally, the recycling system 4 may be equipped with sensor (s) 1 1, 12 for measuring the partial pressure of the inert gas constituting the gas mixture. The above sensors are coupled to gas analyzers, which can be for example according to the nature of the gas to be analyzed, paramagnetic analyzers or catharometers, arranged outside the recycling system 4.

In the example shown, the sensors are directly arranged in the recycling system 4. In a variant not shown here, a connection may be made to the recycling system 4 or to a closed circuit line 2 to deport the sensors at most. close to the analyzers, and if necessary to integrate them into the housings of these analyzers, it being understood that the measurement principle and the exploitation of these data are not modified according to whether the data to be analyzed are collected outside the analyzer. device or in situ.

The recycling system 4 comprises, in the zone of adjustment of the composition of the gas mixture Z3, as many gas admission port (s) 301, 302 that the medical device for administering a gas mixture 1 comprises of supply lines 101, 102. In other words, the recycling system 4 is the element of the medical device 1 for administering a gaseous mixture inside which the gases intended to be delivered to the user are admitted. . The recycling system 4 is also equipped according to the invention with at least one fan 7 placed in the zone for adjusting the composition of the gas mixture Z3, the role of which is to promote homogenization between the gases admitted to the the interior of the recycling system 4 via the inlet ports 301, 302 and the gaseous mixture exhaled by the patient, previously treated and filtered in zones Z1 and Z2 described above.

The fan 7 is also intended to promote a circulation of the gas mixture in a direction of circulation 8 of the gas mixture inside the closed circuit 2, thus reducing the inspiratory effort of the patient. Indeed, it is understood that the medical device 1 for administering a gas mixture according to the invention applies to medical devices for delivering a therapeutic gas mixture to non-anesthetized patients breathing spontaneously. It is therefore advantageous to provide help with inspiration, especially for the weakest patients. Moreover, the ventilator 7 can operate at variable speeds to adapt to the patient's need for assistance. The speed of the fan 7 can be either set manually by the practitioner or is advantageously automatically adjusted by the machine with one or more sensor (s) measuring the rhythm and / or inspiratory effort of the patient placed (s) for example on or in a false lung, on or in the administration member 3 of the gas mixture or in the recycling system 4 of the gas mixture.

In the example illustrated, the recycling system 4 of the gaseous mixture comprises successively three zones, among which the treatment zone Z1 inside which is disposed the compound capable of capturing the carbon dioxide 5, the filtration zone Z2 which accommodates the particle retention member 6, and the intake zone Zs which is provided with the sensors 9a, 9b, 10a, 10b, 11, 12, the intake orifices 301, 302, and the fan 7. More precisely in the illustrated example, these three zones Ζι, Z2, and Z3 follow each other in the direction of circulation 8, from the entrance of the recycling system 4 to its exit. The medical device 1 for administering a gaseous mixture according to the invention also comprises a cooling member 13 for the gaseous mixture. Such a cooling member 13 is able to promote a transfer of calories from the gas mixture to a coolant, such as air, cold water, or the like. Thus, the gaseous mixture to be delivered can be cooled before inspiration by the patient, thus allowing, if necessary, maintaining the patient in a normothermic state or, if necessary, inducing a Controlled hypothermia of the patient in order, for example, to optimize the neuroprotective effects of certain inert gases.

The cooling member 13 of the gaseous mixture can be placed between the recycling system 4 and the administration member 3 of the gas mixture. Advantageously, the cooling member 13 is integrated in the recycling system 4 which in this case has a heat exchange zone Z ₄ , for example consisting of a chamber made of a material having conductive thermal properties exposed to a flow. cold. In the illustrated example, the four zones Zi, Z2, Z3, and Z follow each other in this order of the input of the recycling system 4 at its exit in the direction of circulation 8. It may in particular be provided to dispose the organ 13 in the recycling system directly after the fan 7.

The recycling system 4, which is the subject of a first aspect of the invention, and especially as just described in a preferred embodiment, is advantageous in that it can be arranged in a medical application context on a closed circuit breathing apparatus, with gas recirculation, for administering a therapeutic gas mixture to a patient breathing spontaneously. The recycling system 4 takes the form of a housing in which is housed at least one carbon dioxide capture compound to treat the mixture of gas exhaled by the patient in the closed circuit 2, and at least one adjustment zone of the composition of the gas mixture Z3 in which the concentration of each gas composing the gaseous mixture is adjusted to a set value, and in which there can be provided in particular a fan 7 whose function is to facilitate the homogenization of the newly injected gases in the housing with the gas exhaled by the patient and decrease the inspiratory work of the patient.

The presence in a common housing of each of these components, and if necessary, a particle filter, gas analysis sensors and a heat exchanger, facilitates the integration of each of these components on the closed circuit 2 for administering the gas mixture to the patient.

The closed circuit 2 for administering the gas mixture to the patient also comprises, in addition to the recycling system 4 of the gas mixture, at least one flexible and deformable enclosure, also called false lung, 14a, 14b. More particularly, the closed circuit 2 comprises a first false-lung 14a to facilitate the expiration of the patient and a second false lung 14b to facilitate the inspiration of the patient. Preferably, the first false-lung 14a is placed between the administration member 3 and the inlet of the recycling system 4 and the second false-lung is 14b is placed between the outlet of the recycling system 4 and the organ 3, in the direction of circulation 8. The deformability of the false lungs 14a and 14b facilitates the circulation of the gas mixture by minimizing the inspiratory and expiratory work of the breathing patient through the administration member 3. The second false -Poumon 14b can be equipped with an overpressure valve 15 which is provided to prevent its deterioration in case of overpressure during the injection of the gases in the recycling system 4.

Finally, the closed circuit 2 for administering the gas mixture comprises two nonreturn valves 16a, 16b. A first nonreturn valve 16a is disposed between the delivery member 3 and the first false lung 14a, advantageously at the outlet of the delivery member 3, and a second non-return valve 16b is disposed between the second counter-lung 14b and the administration member 3, advantageously at the entrance of the administration member 3. A third valve, not shown here, may be envisaged to be disposed between the first false-lung 14a and the recycling system 4, advantageously at the inlet of the recycling system 4. The nonreturn valves 16a, 16b are intended to impose a circulation of the gaseous mixture in the direction of circulation 8.

It follows from these provisions that the mixture of gas exhaled by the patient crosses the first nonreturn valve 16a which is housed inside a first exhalation pipe portion 17a, preferably closer to the body of the 3. The gas mixture then continues to flow in the first exhalation pipe section 17a before entering the interior of the false lung 14a and then into a second exhalation pipe section 17b, before entering inside the recycling system 4, and more particularly inside the treatment zone Zi where the carbon dioxide present in the gas mixture exhaled by the patient is retained by the compound 5 so as to be regulated in below the toxicity thresholds. The patient's exhaled gas mixture is also charged with water vapor, which tends to react with the soda lime by an exothermic reaction, so that the exhaled air tends to heat up inside the treatment zone.

In the example illustrated, the expired gas mixture then enters the filtration zone Z2 of the recycling system 4 inside which any Compound 5 particles are retained. Then the expired mixture enters the intake zone Zs of the recycling system 4 inside which it can be enriched with gas from the supply lines 101, 102 (ie oxygen and one or more inert gases combined or not with oxygen) so as to maintain the concentration of each gas constituting the gas mixture at predetermined set values. The gas mixture can at this stage be homogenized by the implementation of the fan 7.

Finally, before leaving the recycling system 4, the gas mixture is cooled, if necessary, by a heat exchange zone Z ₄ at a temperature suitable for treating the patient, in particular by swaying the heating of the gas mixture induced by the localized compound 5 in the treatment zone Z1 of the recycling system 4.

During its movement inside the recycling system 4, the gas mixture can be analyzed by means of gas sensors in order to regulate in particular the content of carbon dioxide and oxygen of the gaseous mixture to be administered to the patient, being understood that it may be interesting to place these sensors away from the gas inlet ports to obtain a better analysis of the composition of the mixture to be administered to the patient. At the outlet of the recycling system 4, the gas mixture to be delivered to the patient penetrates inside a first inspecting pipe portion 18a which connects the recycling system 4 to the false lung 14b. Then the gaseous mixture passes through the false lung 14b and finally circulates inside a second part of the inspiration pipe 18b which connects the false lung 14b to the administration member 3. The second part of the 18b inspiration pipe is provided with a non-return valve 16b, advantageously placed at the inlet of the administration member 3. The gas mixture is then delivered to the user via the organ d administration 3 during an inspiration of the patient.

As has been previously described, the gas mixture can be analyzed via sensors arranged outside the recycling system 4. Micro-turbines or micro-pumps will then be provided to suck and direct a part of the gas to the sensors via tubing of suitable diameter.

The gas mixture supply lines of the medical device 1 for administering a gaseous mixture will now be described, with reference to the illustrated example, no limiting of the invention.

The first supply line 101 comprises a line 101a which connects an oxygen tank 201 to a first intake port 301 of the recycling system 4. The tank 201 is equipped with a manual valve 401 which makes it possible to authorize or to prohibit the circulation of the oxygen of the reservoir 201 inside the feed line 101. The reservoir 201 is also equipped with a pressure reducer 501 which makes it possible to lower the oxygen pressure from a high pressure inside the reservoir 201 to a low pressure inside the pipe 101 a. In addition, the pipe 101a is equipped with a mass flowmeter coupled to a proportional valve 601, which will be called later by its acronym DMVP, whose function is to inject into the recycling system 4 of the oxygen reservoir 201 so as to maintain the oxygen concentration of the mixture to be delivered to the patient to a value equal to the set value defined for oxygen. It will be understood that the choice of a DMVP is nonlimiting and that instead of or in addition to a bypass line terminating also in the recycling system 4, it would be possible to use other types of valves such as a simple solenoid valve, which will be called EVS afterwards.

The first supply line 101 also includes a branch 101b, equipped with a manual valve 701, actuated in case of emergency by the practitioner, for example in case of malfunction of the DMVP and / or EVS mentioned above.

The second feed line 102 has an architecture similar to the architecture of the first feed line 101, it being noted, however, that no bypass equipped with a manual valve is provided on the feed line 102. Otherwise said second feed line 102 includes a conduit 102a which connects a reservoir 202 containing a gas mixture of oxygen and one or more inert gases to a second inlet 302 of the recycle system 4. The tank 202 is equipped with a manual valve 402 which allows to allow or prohibit the flow of gas from the tank 202 inside the supply line 101. The tank 202 is also equipped with a regulator 502 which allows lowering the gas pressure of a high pressure inside the tank 202 to a low pressure inside the pipe 102a. In addition, the pipe 102a is equipped with a DMVP 602 whose function is to inject into the recycling system 4 the gas mixture of the tank 202 so as to maintain the concentration of the inert gas (s) composing the gas mixture. deliver to the patient at a value equal to their predefined setpoint value (s). We understand that the choice of a DMVP is no limiting and that could be provided instead, or in addition to a bypass line also ending in the recycling system 4, to use other types of valves such as EVS. It will be understood from the foregoing that the medical device 1 for administering a gas mixture could comprise a plurality of supply lines, each in connection with a gas tank, and opening into the recycling system 4.

According to an alternative embodiment, the closed circuit 2 for administering a gaseous mixture to a patient is equipped with a vacuum pump 21 making it possible to purge said circuit of any gas by vacuum before use. More precisely, the closed circuit 2 is emptied with the vacuum pump 21, and the initial filling of the closed circuit 2 is carried out with the gas mixture to be administered to the patient via the control of the DMVPs and / or the EVSs. During this filling of the closed circuit 2 in gaseous mixture, the pressure relief valve 15, which can advantageously be placed on the recycling system 4 or the false lung 14b, makes it possible to avoid an overpressure inside the closed circuit of administration 2.

The medical device 1 for administering a gaseous mixture also comprises an electronic control unit 22 which is in connection with the oxygen sensors 9a, 9b and the inert gas sensors 1 1, 12. The control unit 22 thus essentially manages the oxygen consumption of the gas mixture by the patient, but also possible inert gas leaks that may occur, and thus ensure the distribution of a suitable gas mixture to the patient. By "appropriate" gaseous mixture is meant a gaseous mixture in which the concentrations of the gases that make up the gaseous mixture are equal to, or close to, within acceptable limits set by the practitioner, to the predefined setpoint values for the mixture to be administered to the patient. For this purpose, the electronic control unit 22 comprises, for example, memory means of a mapping of correspondence between the partial pressure and the concentration of each of the gases constituting the gas mixture. Based on all the information collected by the various sensors, the electronic control unit 22 is able to control the implementation of the DMVP 601 and 602, and / or the EVS, in order to deliver to the patient during the entire period of time. duration of treatment a suitable gas mixture, according to the prescription of a doctor.

The electronic control unit 22 is also in connection with a pressure sensor 23a for measuring the pressure inside the tank 201 and with a second pressure sensor 23b for measuring the pressure inside the tank 202. The electronic control unit 22 comprises, for example memory means of a mapping of correspondence between the pressure in the tanks 201, 202 and the volumes of gas available in each of these tanks.

The electronic control unit 22 may, for example, emit an alarm when the amount of free gas available in a tank is less than a predetermined set point value, when the concentration of carbon dioxide is too high compared to a predetermined set point value. when the oxygen concentration is either too low or too high by a predetermined setpoint, or when the inert gas concentration (s) is also too low or too high relative to a predetermined set point value (s). Two types of alarms can be set up, in order to graduate the urgency of the alarm, too high a carbon dioxide content or too low oxygen content can be reported with more force than an inadequate content inert gases.

The electronic control unit 22 is for example also in connection with a temperature sensor 24 of the gas administered to the patient. The electronic control unit 22 can then make it possible, in the case of a treatment combining administration of a gaseous mixture for therapeutic purposes and hypothermia, to regulate the temperature of the gaseous mixture so that the patient's temperature corresponds to a certain temperature. degree of hypothermia sought.

The electronic control unit 22 is preferably connected to a screen 25, such as a touch screen, to display the information delivered by the electronic control unit 22 and to control the implementation of the elements of the medical device 1. administration of a gas mixture.

Claims

1. Recycling system for a medical device for administering a gaseous mixture (4) intended to equip a closed administration circuit (2) with a gas mixture to be delivered to a patient breathing spontaneously, the recycling system (4) comprising:

an inlet of an expired gaseous mixture and an outlet for the gaseous mixture to be supplied, the orientation of which defines a flow direction (8) from the inlet to the outlet,

a treatment zone (Zi) of the exhaled gaseous mixture containing a compound (5) capable of retaining carbon dioxide,

characterized in that it comprises at least one adjustment zone of the composition of the gaseous mixture (Z3) in which the concentration of each gas composing the gaseous mixture is adjusted to a set value.

Recycling system (4) according to claim 1, characterized in that the adjustment zone of the composition of the gas mixture (Z3) comprises at least one fan

(7).

3. Recycling system (4) according to claim 2, characterized in that the at least one fan (7) is variable speed.

4. recycling system (4) according to claim 3, characterized in that the at least one fan (7) is controlled according to the rhythm and / or the inspiratory effort of the patient.

Recirculation system (4) according to one of the preceding claims, characterized in that the adjustment zone of the composition of the gas mixture (Z3) comprises inlet openings for injecting into the recycling system ( 4) the different gases constituting the gaseous mixture in order to adjust the composition of the gaseous mixture exhaled by the patient to the set values defined for each gas constituting the gaseous mixture

6. Recycling system (4) according to one of the preceding claims, characterized in that it comprises a filtration zone (Z2) housing a retention member (6) of particles of the compound (5).

The recycling system (4) according to any one of the preceding claims taken in combination of claim 4, wherein the treatment zone (Z1) and the zone Filtration (Z2) are located upstream of the adjustment zone of the composition of the gas mixture (Z3) with respect to the direction of circulation (8).

8. recycling system (4) according to the preceding claim, characterized in that it comprises successively, in the direction of circulation (8), the treatment zone (Z1), the filtration zone (Z2), the zone d adjusting the composition of the gas mixture (Z3) and a heat exchange zone (Z ₄ ).

9. Closed circuit of administration (2) of a gaseous mixture to be delivered to a spontaneously breathing patient, comprising a recycling system (4) defined according to any one of the preceding claims.

10. closed administration circuit (2) according to claim 9, wherein the administration circuit (2) comprises at least one enclosure (14a, 14b) delimited by a flexible wall and deformable.

11. Closed circuit administration (2) according to the preceding claim, wherein the at least one enclosure (14b) is disposed downstream of the recycling system (4) in the direction of circulation (8) of the gas mixture to the inside the administration circuit (2).

12. The closed management circuit (2) according to claim 10, wherein the administration circuit (2) comprises two enclosures (14a, 14b) disposed on either side of the recycling system (4), a first enclosure (14a) being disposed upstream of the recycling system (4) in a direction of circulation (8) of the gaseous mixture inside the administration circuit (2), and a second enclosure (14b) being arranged downstream of the recycling system (4) in the direction of circulation (8) of the gaseous mixture inside the administration circuit (2).

13. Closed administration circuit (2) according to one of claims 9 to 12, characterized in that it comprises a vacuum pump, preferably placed closer to the outlet of the gaseous mixture delivery member. .

14. A medical device for administering (1) in closed circuit a gaseous mixture to be delivered to a spontaneously breathing patient, comprising a gas recycling system disposed on a closed administration circuit.

15. Medical device for administering (1) a gas mixture to be delivered to a patient breathing spontaneously, characterized in that it comprises a closed circuit of administration (2) according to any one of claims 9 to 13.

16. Medical device for administering (1) a gaseous mixture according to the preceding claim, characterized in that it comprises at least two gas supply lines (101, 102) of the recycling system (4).

17. Medical device for administering (1) a gaseous mixture according to claim 15 or claim 16, characterized in that one of the supply lines is configured to supply the closed administration circuit with inert gas for therapeutic purposes, or a mixture of inert gases for therapeutic purposes, this or these inert gases being alone or combined with oxygen.

18. Medical device for administering (1) a gaseous mixture according to any one of claims 15 to 17, characterized in that it comprises an electronic control unit (23) configured to control a speed of operation of the fan. (7) using information relating to a rhythm and / or inspiratory effort of the patient.