FR3023487A1 - IMPROVED DEVICE FOR DISPENSING A GAS MIXTURE OF OXYGEN O2 AND ANOTHER MEDICAL GAS - Google Patents

Abstract

The dispensing device (12) according to the invention comprises a gas mixture outlet (14) connected to, on the one hand, a first gas source (16) comprising O2 oxygen and, on the other hand, a second gas source (17) comprising, for example, nitrous oxide N2O, by means of gas mixing means (18, 19). The device also comprises means for controlling the mixture (20) as a function of at least a first parameter (21) measured by a first sensor. This sensor (30) is a sensor for measuring a physiological parameter (21) of a patient to whom it is desired to administer the gaseous mixture distributed by the device (12).

Description

The present invention relates to the distribution of gaseous mixtures. More particularly, the invention relates to the distribution of a gas mixture for medical purposes, including sedative. In known manner, to sedate a patient, he is for example inhaled a gaseous mixture of medical oxygen O2 and nitrous oxide N20 medical. A medical gas is a gas for medical use constituting a health product. Sedation by inhalation of a gas mixture of 02 and N20 is the technique of choice for most medical or paramedical procedures that require to be performed under sedation. Since most care is achievable under sedation and sedation by gaseous 02 / N20 has no disabling side effects, the use of the mixture of these gases is becoming more common. Gaseous mixture sedation of O2 / N20 is suitable for the treatment of most patients: the disabled, children, those with particular anxieties, or those with long and / or complex procedures. In particular, dentistry, more and more technical, requires long sessions that are tiring without sedation. This leads more and more practitioners to turn to gaseous sedation of 02 / N20 to increase the comfort and / or safety of their patients. However, like any sedation method, gaseous sedation of O2 / N20 requires precautions in order not to threaten the health of the patient. Thus, for the safety of the sedated patient, it is desirable not to exceed a concentration of more than 70% by weight of N 2 O in the administered mixture. Conventionally, prior art O2 / N20 gas mixture delivery devices mix from a pure O 2 source and a pure N 2 O source. Since a dentist must generally monitor the concentrations of the sedation mixture administered while operating his patient, he may be overwhelmed by the situation and put his patient at risk. The dispensing device may include an integrated alarm that triggers when the device calculates an N20 content exceeding the maximum concentration. But the practitioner can be busy with something else when the alarm is triggered or having no hand available to quickly reduce the flow of N20. FR 2 850 874 B1 overcomes this disadvantage by proposing a gaseous mixture dispensing device comprising a first source of pure gaseous O 2 and a second source of gas which is a mixture of O 2 and N 2 O comprising at least - 2 - 20% by mass d02. The practitioner avoids administering a gas mixture that is too concentrated in N20. Indeed, the N20 content in the final mixture can not exceed the N20 content of the second gas source. However, if this solution improves the safety of the patient, it does not completely guarantee it: indeed, it is possible that more sensitive patients than average do not support the maximum concentration usually accepted. Furthermore, this device also does not allow the practitioner to accurately adjust the N20 content of the mixture to the specific needs of each patient. Indeed, since each organism is different, optimal O 2 and N 2 O concentrations to achieve effective and comfortable sedation may vary from patient to patient. The invention overcomes this drawback by providing a device for dispensing a mixture of medical gases comprising: a gas mixture outlet connected to, on the one hand, a first source of a first medical gas comprising oxygen 02 medical source, and secondly, a second source of a second medical gas, through means of mixing medical gases, and - means for controlling the mixture as a function of at least a first measured parameter by a first sensor, characterized in that the first sensor is a sensor for measuring a physiological parameter of a patient to whom it is desired to administer the gaseous mixture dispensed by the device. The physiological parameter measured by the first sensor makes it possible to adjust the device in real time according to the specific state of each patient and no longer only according to theoretical gas mixing rules. Thus the practitioner can detect very quickly an abnormal state of his patient even when the practitioner has scrupulously respected the theoretical rules of mixing gases. The invention thus enables the practitioner to take into account the real and real needs of each of his patients while fully ensuring their safety. Preferably, the control means comprise a microcontroller 30 for controlling the mixing means according to the parameter measured by the sensor. Advantageously, the first sensor is a pulse oximeter for measuring the patient's Sp02 oxygen saturation. Sp02 is easily measured, non-invasively. Conventional sensors 35 performing such a measurement are generally placed around a finger and are not traumatic. This is a great advantage when one considers that sedation is used on anxious patients. Advantageously, the mixing means comprise at least one solenoid valve chosen from: a first solenoid valve connected to the first gas source, a second solenoid valve connected to the second gas source, each solenoid valve being controlled by the control means . Advantageously, the control means control the mixture as a function of at least a second parameter measured by a second sensor selected from: a first static pressure sensor connected to the first gas source, a second static pressure sensor connected to the second gas source, - a first flow meter connected to the first gas source, - a second flow meter connected to the second gas source, and - a third flow meter connected to a mixing branch of the medical gases from the first and second gas sources; - a composition composition sensor. The practitioner can thus more easily monitor the proper functioning of the device and find a solution to a possible problem detected by the pulse oximeter. Advantageously, the dispensing device comprises interface means between a user of the device and the gaseous mixture control means, this interface enabling: the user to read at least one parameter value measured by at least one a sensor, - the recording in the control means of a set point for the gas mixture.

The dispensing device may comprise alarm means activated at least when the first parameter reaches an undesired value, for example not respecting a particular standard. The attention of the practitioner may be retained by a delicate step of his intervention on the patient, he may momentarily not pay attention to the values 30 displayed by the interface means. The alarm means can attract his attention when needed. The practitioner can then concentrate entirely on his patient, needing to focus on the device only in case of problems. Advantageously, the device comprises means for automatically controlling the mixing means that can be activated in predetermined undesired conditions, such as, for example, maintaining the activation of the alarm means beyond a predetermined duration, these automatic control means may include support for a computer program.

The practitioner can be busy when triggering the alarm means, it is reassuring and reassuring for the patient and the practitioner to know that the device can take the hand and trigger an emergency action. The invention also relates to a carriage characterized in that it carries a device according to the invention. This carriage makes it easy to move the dispensing device according to the invention. Advantageously, the carriage carries power supply means of the device according to the invention.

The invention will be better understood on reading the appended figures, which are provided by way of example and are not limiting in nature, in which: FIG. 1 is a perspective view, three quarter front view, of a carriage carrying a device for dispensing a gaseous mixture according to the invention, FIG. 2 is a perspective view, three quarter rear, of a carriage carrying a device for dispensing a gaseous mixture according to the invention, FIG. a schematic view of a device for dispensing a gas mixture according to the invention, FIG. 4 is a front view of the interface means of a device according to the invention, FIG. 5 is an evolution curve. Sp02 as a function of time in automatic operation of a device according to the invention, at the beginning of sedation. FIGS. 6 and 7 are curves of evolution of the Sp02 as a function of time in automatic operation of a device according to the invention, with the intervention of a user, FIGS. 8 and 9 are curves of evolution of the Sp02 as a function of time in automatic operation of a device according to the invention, without the intervention of a user. Referring now to FIGS. 1 and 2, showing a carriage 10 according to the invention 30 carrying a delivery device 12 of FIG. a gaseous mixture according to the invention as well as in FIG. 3 presenting the dispensing device 12 in detail. As can be seen in FIG. 3, the device 12 comprises an electropneumatic circuit 13 which has a gaseous mixture outlet 14 intended to be connected to conventional means allowing a patient to be sedated by inhaling the distributed gas mixture. . This outlet 14 is also connected, by means of gas mixing means, on the one hand, to a first medical gas source 16 comprising medical oxygen 02 and, on the other hand, to a second source of medical gas 17 comprising, in this example, medical N20 nitrous oxide. Conventionally, the two medical gas sources 16, 17 comprise insulatable gas bottles of the electropneumatic circuit 13 of the device 12 by closing two solenoid valves 16A, 17A.

In the example illustrated in FIG. 3, the gas mixing means comprise a first solenoid valve 18 connected to the first gas source 16 and a second solenoid valve 19 connected to the second gas source 17. The first solenoid valve 16 makes it possible to adjust the flow rate of 02 circulating in the dispensing device 12 and the second solenoid valve 19 makes it possible to adjust the flow rate of circulating N20 in the device 12. The O2 and N20 are mixed downstream of the solenoid valves 18, 19, in a branch M of the circuit 13 connected to the output 14. The solenoid valves 18, 19 of the device 12 are preferably miniature solenoid valves with thermal compensation according to the European directive RoHS (2002/95 / 0E). They provide the desired adjustment independently of external conditions, in accordance with the usual requirements of a medical device. The device 12 also comprises means for controlling the gas mixture. These control means may, for example, comprise a microcontroller 20 which controls the solenoid valves 16A, 17A, 18, 19 as a function of at least one parameter 21 measured by a sensor 30. This parameter 21 is a physiological parameter of a patient it is desired to administer the gaseous mixture distributed by the device 12. The sensor 30 being, in this example, a pulse oximeter, the physiological parameter 21 measured is the oxygen pulse saturation Sp02 of the patient. Pulse oxygen saturation, Sp02, can be measured simply, reliably, non-invasively and continuously. It corresponds to the oxygen saturation of the arterial blood. In fact, only the blood circulating in the arteries is subjected to heartbeat, the blood circulating in the veins being set in motion by other processes. Pulse oximetry makes it possible to measure Sp02 by emitting two lights through the pulpit of a patient, for example through his finger, namely: a red light (wavelength of 660 nm) infrared light (wavelength 940 nm), and the measurement of their differential absorption by hemoglobin molecules in the blood. The pulse oximeter is a sensor which generally comprises a fingernail bearing two diodes emitting respectively the red light and the infrared light. Oxygen 02 is transported in the blood mainly by the hemoglobin molecules. The absorption of red and infrared light by these molecules is variable depending on whether they are in reduced form (Hb), that is to say non-oxygenated or in the form of oxyhemoglobin (Hb02), that is to say say oxygenated. HbO 2 absorbs infrared light and passes red light while Hb absorbs red light and passes infrared light. The portion of unabsorbed light is collected by the pulse oximeter and analyzed. If the light collected is mainly infrared light, it is deduced that there is little Hb02 present in the blood and therefore that the patient on whom the measurement is made can potentially be in hypoxemia, which is dangerous. Conventionally, it is generally considered that a value of 5% of a patient in a normal state must be greater than 93%. In particular for a patient under anesthesia, the measurement of 5p02 allows the early detection of hypoxaemia, well before the appearance of a cyanosis which may be of very late onset in an anemic patient or difficult observation in a patient. very pigmented. Moreover, the microcontroller 20 controls the gaseous mixture by controlling the solenoid valves 16A, 17A, 18, 19 as a function of other parameters 22, 23, 24, 25, 26 measured by different sensors 32, 33, 34, 35, 36: a first static pressure sensor 32 connected to the first gas source 16 which measures the static pressure of O2 22 in the part of the pneumatic circuit 13 which carries 102, a second static pressure sensor 33 connected to the second source of gas 17 which measures the static pressure of N20 23 in the part of the pneumatic circuit 13 which carries the N20, 25 - a first flow meter 34 connected to the first gas source 16 which measures the flow rate 02 24 of the pneumatic circuit 16, a second flowmeter 35 connected to the second gas source 17 which measures the flow rate of N20 of the pneumatic circuit 16, and a third flowmeter 36 connected to the two gas sources 16, 17 which measures the flow rate of the gaseous mixture 26 which pass e in the pneumatic circuit 16. The various sensors 32 to 36 and valves 16A, 17A, 18, 19 of the pneumatic circuit 13 are analog output components which are usually less energy consuming and more robust than digital output electrical components. . The flow meters 34 to 36 and the static pressure sensors 32, 33 are preferably heat compensated. FIG. 3 also shows a conventional interface between the pulse oximeter 30 and the microcontroller 20. The static pressure sensors 32, 33 make it possible to detect very quickly any unexpected pressure drop in the pneumatic circuit. 13. The transport of gases from the sources 16, 17 to the outlet 14 is by a set of flexible pipes 38 of thermoplastic polyurethane elastomer suitable for the transport of medical gases. The carriage 10 is made mobile by wheels and also carries electrical supply means 40 of the device 12 and interface means 42 between a user of the device 12 and the control means 20 of the gas mixture. The power supply means 40, shown diagrammatically in FIG. 2, comprise means 10 for connection to an electrical network and a battery, so as to make it possible to select a supply of the device 12 from the electrical network or the battery as the case may be. Preferably, conventional current cutting means are integrated with the power supply means 40 to allow adaptability to different electrical networks of different countries. To ensure perfect patient safety, safety loops implemented by conventional electronic means ensure, each time the device 12 is turned on, that the battery is sufficiently charged to allow the device 12 to operate for at least 20 minutes. The interface means 42 allow: the reading by the user of at least one value of the parameter 21 to 26 measured by each sensor 30 to 36, and the recording in the control means 20 of a set point for the gas mixture. The interface means 42 comprise, for example: two segment displays 44A, 44B, an LCD 46, and buttons for reading, controlling and controlling the various parameters 21 to 26. The segment displays 44A, 44B provide the user with a very good visibility of certain selected parameters of the device 12, for example the percentage of N20 in the gaseous mixture and the flow rate of the gaseous mixture 26. The screen 46 displays the values of these selected parameters, as well as the values of parameter 21 measured by the pulse oximeter connected to the patient. The screen 46 also displays device state parameters 12, battery reserves, time elapsed since the start of device 12, etc. Preferably, device 12 can not be turned on. in operation as long as the microcontroller 20 does not receive a desired Sp02 value 21. The proper connection of the pulse oximeter 30 to the electropneumatic circuit 13 is thus made mandatory in order to start the sedation. The device 12 also comprises alarm means 50 activated at least 5 when the first parameter 21 reaches an undesired value, for example not respecting a particular standard. If a disconnection of the pulse oximeter 30 occurs during sedation, the sudden absence of 5p02 value 21 immediately activates the alarm means 50 and an alert message warns the user. Preferably, the activation (see arrow 51 in FIGS. 6 to 9) of the alarm means 50 is also done if the pulse oximeter 30 is connected to the circuit 13 but the values of 5p02 21 received are not exploitable (for example because of a wrong position of the pulse oximeter on the patient's finger). In other cases, the interface means 42 also display messages to explain the reasons for the activation of the alarm means 50 to the user of the device 12. The screen 46 also allows, without any application sedation by the device 12, access to a menu that can be used to: - modify sedation parameters 22 to 26, - reset the device 12, 20 - give access to the operating information of the device 12 and to activation of a 50% clamping at N20 concentration. The alarm means 50 are controlled by safety loops implemented by conventional electronic means which ensure the feedback control of the sedation parameters 22 to 26. If the microcontroller 20 does not detect a response from a user in response to activation of the alarm means 50, the device 12 then goes into automatic operation mode. Indeed, the device 12 comprises automatic control means 52 mixing means 18, 19 activatable under undesired predetermined conditions such as for example the maintenance of the activation of the alarm means 50 beyond a duration predetermined, these automatic control means 52 may include a support for a computer program. This program has two complementary sub-programs, later called the first and second programs. These automatic control means 52 are also preferably triggered in the case where the microcontroller 20 does not receive the values of the 5p02 rate 21 because of a poor connection of the pulse oximeter 30: if at the end of one minute the pulse oximeter 30 is still not detected (or if the information is still not usable), then the device 12 goes into automatic mode and there is trigger (see reference 53 in FIGS. and 9) a mode "02 flush" which consists in isolating the source of N20 17 and dispense only 102 pure. The activation of the alarm means 50 may also be due to a sudden drop in pressure in the pneumatic circuit 16 or in one of the gas sources 16, 17 detected by one of the static pressure sensors 32, 33 The device 12 also comprises automatic control means 52 which can take control of the mixing means 18, 19 following a non-deactivation of the alarm means 50. A user of the device can however also decide not to wait. a state of emergency so that the automatic control means 52 take control of the management of the distributed gas mixture and decide to start the device 12 directly in automatic mode. All sedation is then done according to a fully automated process. This method of dispensing is described below with reference to FIGS. 5 to 9. This method comprises the following steps: an initialization step 61, and a steady state step 62. It is intended to dispense a gaseous mixture 02 and N20 by means of the dispensing device 12. The initialization step 61 of the distribution of the gaseous mixture is carried out by activating a first parameterizable program. As shown in FIG. 5, this program controls the control means 20 so as to follow a predetermined increasing curve 64 of evolution as a function of time of the concentration of N 2 O in the distributed mixture. In the example illustrated in FIG. 5, the predetermined increasing curve 64 is a sedation ramp. This sedation ramp 64 aims to increment the concentration of N20 little by little in order to provide gentle sedation to the patient. The sedation ramp 64 is configurable via three setpoint variables that the user can modify through a menu accessible only when the device 12 is not dispensing the gas mixture. This menu, accessed by the screen 46 of the interface means 42, allows a user to parameterize: the target ramp time 64 RR, the targeted target concentration [N2O] 68, the mixing flow. ) - target. The ramp time 64 t, target 66 is the time at which the target [N 2 O] concentration 68 must be reached in the dispensed mixture. This is the time that the first step 61 of the sedation process lasts. The target mixing rate is defined according to the patient's lung capacity and should remain constant throughout the sedation process. The user thus defines at least one parameter 66, 68 of this first program selected from the duration 66 of the initialization step 61 and the target flow rate 01) of the mixture. During this first step 61 of the dispensing method, the gaseous mixture is administered by the device 12 as follows: at t = 0, the user triggers the beginning of the sedation, by pressing a button of the interface means 42 The gas mixture is then administered at the target flow rate and consists of 100% O 2 and 0% N 2 O. <-> target, I - at t = t (with tt the control means 20 progressively increase the concentration of N20 in the distributed mixture, to go from 0% (at t = 0) to the target value [N20] 68 at the end of the adjustable time at Mcible 66, the device 12 proceeds to the second step 62 of the method and the ramp 64 is transformed into a stage 70, during which the gas mixture is administered at the flow rate (Target and Concentration [N20] c, ble 68. Thus the sedation process allows the realization of a steady state step 62 by activating a second parameterizable program controlling the control means 20 of the device 12 so as to follow a predetermined curve 70 of maintaining over time the concentration of N20 in the mixture at a target value 68. The user defines at least one parameter 68 of the second program selected from the duration of the steady state step, the target value 68 and the flow rate of the target mixture. the device 12 is in autopilot, the user always keeps control over the composition of the gas mixture. Particularly during the first step 61 of the sedation process, the user can, at any moment, influence the evolution of the sedation ramp 64 without forcing the device 12 out of operation in automatic piloting. An action of the user on the buttons 71, 72, 73, 74 of the interface means 42 (FIG. 3) makes it possible to modify the sedation ramp 64 and if the parameters of the sedation ramp 64 are modified by a user. they are, according to strict rules: If at a given instant 76, the user presses the button 71 designated for example by "[N20] +", the device 12 responds by immediately inducing a jump 78 of + 5% the concentration of N20 of the distributed gas mixture. A new sedation ramp 79 is obtained. If at a given instant 80, the user presses the button 72 designated for example by "[N20] -", the device 12 responds by immediately inducing a jump 82 of -5%. the concentration of N20 of the distributed gas mixture. We obtain a new sedation ramp 83. In both cases, the microcontroller 20 continues to evolve the sedation ramp 64 taking into account both the unchanged parameters and the modified parameter.

Thus, during the initialization step 61, the predetermined increasing curve 64 can be replaced at any time by a corrected curve 79, 83 of evolution as a function of time of the concentration of N20 in the distributed mixture. If at the moment when the user presses the button 71 "[N20] +" the value in N20 requested 84 is greater than [N20] target 68, the device 12 passes immediately from the first sedation step 61 to the second step 62, replacing the ramp 64 by a step 84 where the value of [N20] target 68 is replaced by the new value of [N20] 84. A press on the buttons 73 designated for example by "(1) +" or 74 designated for example by "(1) -" immediately changes the output flow of the mixture 26, maintaining the concentration parameters 66, 68 of the ramp 64 unchanged. A user can not change the target parameter 66. The only solution to change this parameter 66 is to output the device 12 from the autopilot mode to enter manual mode. The setting of the target 66 can only be done via the menu, accessible only by the interface means 42 outside of any gas distribution by the device 12. The transition from the automatic mode to the manual mode is done simply by pressing the key. a dedicated button of the interface means 42. If the transition from automatic mode to manual mode is done during the first sedation stage 61, then the ramp 64 stops immediately and the device 12 dispenses a gas mixture with a concentration in N20 stabilized around the value of 25 [N20] 86 which defined the gas mixture dispensed at the time of exit from the automatic mode. Throughout the sedation process, the gaseous mixture control means is controlled according to a physiological parameter of a patient inhaling the mixture. The physiological parameter 21 measured is preferably the pulse oximetry (or pulse oxygen saturation 5p02) of the patient. Several cases of figures are illustrated in FIGS. 6 to 9. In FIG. 6, the evolution, as a function of time, of the 5p02 21 of a patient inhaling a gaseous mixture distributed by the device 12. The variable 5p02 21 is followed over time and its evolution is stored in memory of the microcontroller 20. There is no absolute value to be respected. That is, one patient may have a 5% level of 50% while proceeding perfectly well, while the same value for another patient may mean a critical physiological state. The Sp02 values generally considered "normal" are between 94 and 99%. The dispensing method triggers an alarm 51 when undesired predetermined conditions are realized and, if this alarm 51 is maintained beyond a predetermined time period 92, isolating the second gas source 17 comprising N20. In a conventional manner, the value of Sp02 21 in the patient is noted (Sp02) 090 at the start of sedation, that is to say at t = 0. This value 90 is taken as a reference for the patient in question: if the Sp02 level 21 falls below 0.9x (Sp02) 0 for the predetermined duration 92, then the alarm means 50 is triggered. In this embodiment, the predetermined duration 92 is set to 1 minute. However, an absolute threshold is also fixed: as long as the Sp02 21 is less than 80%, the sedation can not start, because the device 12 considers the patient as poorly oxygenated which could represent a risk for it. Similarly, if during the sedation, Sp02 21 falls below the threshold value of 80%, an alarm 51 is immediately triggered, accompanied by a message on the screen 46. At each instant t, the internal program of the microcontroller 20 compares the value of the Sp02 21 to (Sp02) 0: 20 - if (Sp02) (t)> (Sp02) 0, the device 12 continues to apply the method normally; if (Sp02) (t) <(Sp02) 0 for less than one minute, it is considered that the sedation proceeds normally and has no major impact on the physiological state of the patient and the device 12 continues to apply the process normally; if (Sp02) (t) <(Sp02) 0 for all t for more than one minute, the situation is considered abnormal and an alarm 51 is activated to warn the user. If, within a period of ten seconds after the activation 51 of the alarm means 50, the user presses the button 91 designated for example by "OK" (FIG. 4) to signify his / her understanding of the information then a new delay 96 of 20 seconds is put in place. During this time, if the user changes the sedation parameters 22 to 26 to reduce the N20 concentration of the dispensed mixture and there is a correction 97 of the 5p02 rate 21, i.e. 5p02 21 passes above 90% (5p02) 0, then device 12 continues to apply the second step 62 of the process normally. If, as shown in FIG. 7, the correction 97 of the rate of 5 po 2 21 does not occur following the intervention 95 of the user, then there is triggering 53 of a "02 flush" mode, and sedation resumes only when the 5p02 21 is ironed above the threshold 0.9x (5p02) 0. If, as shown in FIG. 8, there is no intervention 95 of the user after the trigger 51 of the alarm means 50, a delay 98 of one minute is set in place. If during this time the correction 97 of the 5p02 21 takes place, the anomaly is considered resolved, and the device 12 continues to distribute the gas mixture.

However, a permanent message remains on the screen 46 to indicate the past anomaly. If, as shown in FIG. 9, the correction 97 of the 5p02 rate 21 is not done during the minute 98 following the alarm 50, then there is triggering 53 of the "02 flush" mode.

The triggering 53 of the "02 flush" mode can also be done, at any time, manually by the user via the interface means 42. Pressing the button 100 designated for example by "02 flush" isolates the effect immediately. second gas source 17. The deficit in the flow rate 25 of N20 in the flow rate 26 of the gas mixture is compensated by the increase in the flow rate 24 at 02 to reach the previously specified target value 01) - target by the user via the means of 42. This operation aims to rid the patient's body of inhaled N20 during sedation. The trigger 53 of the "02 flush" mode may be used by the user at the end of sedation to ensure a smooth sedation outflow to the patient and enable him to recover from sedation more quickly. It goes without saying that the invention is not limited to the example described above and other embodiments of the invention will become apparent to those skilled in the art. It is in particular possible to replace the N20 with another medical gas comprising, for example, at least one gas among nitrogen monoxide NO, helium He, carbon dioxide CO2, compressed air, a control gas. , a tracer gas, Heliox, and MEOPA. It is also possible to use the device 12 in an application that would not be dentistry. Indeed, sedation of an agitated or anxious patient can also be very useful in pediatrics, psychiatry or geriatrics for example. The use of the device 12 may also be conceived as a way of encouraging outpatient care, to increase the threshold of tolerance to pain and to simply perform non-invasive but painful or anxiety-provoking acts. One could also consider that the device 12 can operate in complete autonomy, without involving the intervention of a practitioner. Indeed, instead of triggering the alarm means 50, the device 12 could, via conventional control means, automatically make the correction that is required.

Claims (6)

REVENDICATIONS1. Device for dispensing (12) a mixture of medical gases comprising: - a gaseous mixture outlet (14) connected to, on the one hand, a first source of a first medical gas (16) comprising oxygen O 2 a second source of a second medical gas (17) via means for mixing the medical gases (18, 19), and - control means (20) for mixing the function of at least a first parameter (21) measured by a first sensor (30), characterized in that the first sensor (30) is a sensor for measuring a physiological parameter (21) of a patient to whom it is desired to administer the gas mixture distributed by the device (12). 2. Device (12) according to the preceding claim, wherein the control means (20) comprise a microcontroller for controlling the mixing means (18, 19) according to the parameter (21) measured by the sensor (30). The device (12) according to any one of the preceding claims, wherein the first sensor (30) is a pulse oximeter for measuring the oxygen pulsed saturation Sp02 (21) of the patient. 4. Device (12) according to any one of the preceding claims, wherein the mixing means (18, 19) comprise at least one solenoid valve selected from: - a first solenoid valve (18) connected to the first gas source (16 a second solenoid valve (19) connected to the second gas source (17), each solenoid valve being controlled by the control means (20). 5. Device (12) according to any one of the preceding claims, wherein the control means (20) control the mixture according to at least a second parameter (22, 23, 24, 25, 26) measured by a second sensor (32, 33, 34, 35, 36) selected from: - a first static pressure sensor (32) connected to the first gas source (16), - a second static pressure sensor (33) connected to the second gas source (17), - a first flow meter (34) connected to the first gas source (16), - a second flow meter (35) connected to the second gas source (17), and - a third flow meter ( 36) connected to a mixing arm (M) of the medical gases from the first and second gas sources (16, 17), a mixing composition sensor. 6. Device (12) according to any one of the preceding claims, comprising interface means (42) between a user of the device (12) and the control means (20) of the gas mixture, this interface (42) allowing : - the user reading at least one parameter value (21, 22, 23, 24, 25, 26) measured by at least one sensor (30, 32, 33, 34, 35, 36), - Recording in the control means (20) a setpoint for the gas mixture. Device (12) according to any one of the preceding claims, comprising alarm means (50) activated at least when the first parameter (21) reaches an undesired value, for example not respecting a particular standard. Device (12) according to the preceding claim, comprising automatic control means (52) mixing means (18, 19) activatable under undesired predetermined conditions such as for example the maintenance of the activation (51) of the means of alarm (50) beyond a predetermined time, said autopilot means (52) may include support for a computer program. Device (12) according to any one of the preceding claims wherein the second source of the second medical gas (17) comprises at least one medical gas selected from: - nitrous oxide N20, - nitrogen monoxide NO, - Helium He, carbon dioxide CO2, compressed air, a control gas, a tracer gas, Heliox, MEOPA. Assembly characterized in that it comprises a device (12) for dispensing a mixture of medical gases according to any one of the preceding claims and a carriage carrying this device (12). Assembly according to the preceding claim, wherein the carriage further carries power supply means (40) of the device (12) according to any one of claims 1 to 9. 107. 8. 15 20 9. 25 30 10. 35 11.