WO2009095601A2

WO2009095601A2 - Mobile recovery device for gas exhaled by a patient

Info

Publication number: WO2009095601A2
Application number: PCT/FR2009/050106
Authority: WO
Inventors: Gilles Cannet; Maxime Dori; Serge Moreau
Original assignee: L'air Liquide, Société Anonyme pour l'Étude et l'Exploitation des Procédés Georges Claude
Priority date: 2008-01-29
Filing date: 2009-01-26
Publication date: 2009-08-06
Also published as: FR2926728B1; FR2926728A1; WO2009095601A3; EP2247332A2

Abstract

The invention relates to a device for the dispensing and recovery of gas, comprising a gas bottle (3) containing a gas or a gaseous mixture containing at least one anesthetic compound and an adsorption container (1) containing at least an adsorbent material for adsorbing at least part of said anesthetic compound. The adsorption container (1) is conformed to form a sleeve around the body of the bottle (3). The bottle (3) and the adsorption container (1) are preferably arranged on a mobile cart (2) fitted with one or more wheels.

Description

Mobile device for recovering gas exhaled by a patient

The present invention relates to a device for recovering nitrous oxide (N ₂ O) or xenon (Xe) found in the gases exhaled by patients, particularly in the care rooms of hospital buildings.

Nitrous oxide mixed with oxygen, for example in an equimolar 50% / 50% ratio, is used in the medical field as an analgesic which is administered to the patient by respiratory mask or the like.

The protoxide is however not metabolized and exhaled by the patient in a volume mixture containing about 48% N ₂ O, 44% O ₂ , 4% CO ₂ and 4% water vapor.

Due to the configuration of the premises in which the care is performed and depending on the presence or absence of a ventilation system of the premises, the medical staff may be exposed to a greater or lesser inhalation of nitrous oxide. ambient, which is not necessarily desirable, especially if this inhalation of N ₂ O is important and / or frequent.

On the other hand, when the premises are equipped with a system of suction of gases to the outside, the nitrous oxide sucked up and then released into the atmosphere can have adverse effects from the point of view of the environment. In particular, it is a gas with a strong "greenhouse effect" and having a destructive action on the ozone layer.

In addition, the dispersion of medical nitrous oxide in a suction or exhaust air system is not simple because the destination of the evacuated gases must be well controlled to avoid further delay the problem solved locally and, moreover, the exhaled mixture is highly oxidizing and its transport requires an analysis of the risks generated by this characteristic and the use of compatible materials and convenient maintenance practices, excluding for example the lubrication of moving parts.

Moreover, xenon is also a gas used in the field of anesthesia and which has very interesting properties for this application. This use is generally done in the operating room but it can also be used in laboratories for research purposes.

For reasons similar to those mentioned above, as well as for economic aspects related to the scarcity of xenon, it may be interesting, even desirable or necessary, to recover the xenon present in the gases exhaled by the patient. As a result, it has been proposed to install a system for capturing patients' expired gases, in particular protoxide or xenon, through the use of an adsorbent adapted to the gas considered in the treatment rooms. to be recovered.

Thus, it has been proposed to use a zeolite of Faujasite type, for example a zeolite of the CaX, NaX, CaLSX or NaLSX type, to adsorb nitrous oxide, as well as CO ₂ and water vapor. lying in the expired gases. Other adsorbents, such as silica gels, activated carbons or zeolites effectively adsorb xenon.

These N ₂ O or xenon molecules present in the exhaled gases actually become selectively and reversibly attached to the pores of the adsorbent material, thus allowing them to be extracted from the gaseous mixture and sequestered before reprocessing. This reaction takes place under good conditions of kinetics and temperature.

To do this, the patient's exhalation tube is connected to a reservoir containing a zeolite or other adsorbent which passes oxygen but adsorbs nitrous oxide, xenon or any other therapeutic or anesthetic gas that is required. recover, thus avoiding that the molecules of this gas spread in the environment. When the adsorbent is saturated, it is reprocessed at the factory, by heating, resulting in the desorption of the adsorbed gases.

However, the problem that arises is that the adsorption capacity of the zeolites, brought back to the volumes expired by a patient during the duration of anesthesia or analgesia, lead to quite large volumes of adsorbent needed. As the density of the adsorbents is of the order of 0.7, the total mass of adsorbent is therefore also important.

For example, to adsorb all the protoxide contained in a bottle B5, that is to say 750 liters of gas or 2.5 liters of capacity (in water), it takes 10 to 15 kg of adsorbent.

The implementation of such a solution can therefore lead to fairly strong constraints, particularly in terms of volume, weight and difficulty and / or frequency handling by the nursing staff.

In addition, the adsorbent container must be designed to minimize the pressure drop of the gas because it will be felt by the patient as a resistance to exhalation.

In addition, the shape of the container and the adsorbent bed therein must be carefully chosen for homogeneity issues in the adsorption of volatile compounds. In view of this, a problem that arises is therefore to propose an adsorbent container dedicated to the trapping of volatile compounds present in the gases exhaled by the patients, in particular N ₂ O and xenon, which is adapted to these constraints. and which is otherwise easy to implement by the nursing staff.

In other words, the invention aims to provide a device for recovering in particular nitrous oxide (N ₂ O) or xenon (Xe) found in the gas exhaled by patients, which is well suited to a easy implementation in hospitals or the like, especially in treatment rooms in hospital buildings.

A solution according to the invention is a gas distribution and recovery device comprising a gas cylinder containing a gas or a gaseous mixture containing at least one anesthetic compound and an adsorption vessel containing at least one adsorbent material capable of adsorbing at least a portion of said anesthetic compound, characterized in that the adsorption vessel is shaped to form a sleeve around at least a portion of the body of the bottle.

As the case may be, the device of the invention may comprise one or more of the following characteristics:

- A recess is provided in the outer wall of the adsorption vessel, said recess being shaped and dimensioned to receive at least a portion of the body of the bottle.

the adsorption vessel has a recess having a U-shaped cross-section, preferably the recess comprises first and second expansions facing each other.

- The inner wall of the recess of the adsorption vessel is in contact with at least a portion of the body of the bottle when the bottle is positioned in said recess.

the bottle and the adsorption container are arranged on a mobile carriage provided with one or more wheels.

the adsorption vessel comprises a gas inlet port to be purified and at least one purified gas outlet vent, preferably the inlet orifice is in the upper half of the vessel and the outlet vent is found in the lower half of the container.

the adsorption container comprises an internal compartment enclosing the adsorbent material and an external body protecting said internal compartment. the adsorption vessel comprises connection means arranged at the gas inlet orifice adapted to and designed to allow the connection of a gas channel to said inlet port.

The invention also relates to a method for recovering and treating gas exhaled by a patient, wherein: a) a gas exhaled by a patient is recovered, said gas containing at least one anesthetic compound, in particular N ₂ O or xenon, b) introducing the gas recovered in step a) into the adsorption vessel of a device according to the invention, c) adsorbing at least a portion of the anesthetic compound within said adsorption vessel, and d) extracting from the adsorption vessel a purified gas freed from at least a portion of said anesthetic compound.

The invention will now be explained in more detail with reference to the appended figures in which: FIG. 1 represents an embodiment of a device forming a mobile assembly according to the present invention, and FIG. 2 is an exploded view of the whole of Figure 1.

Figures 1 and 2 show a possible embodiment of a device forming a mobile assembly according to the present invention which comprises an adsorbent container 1, also called adsorber, a gas bottle 3 containing anesthetic gas or analgesic comprising N ₂ O or xenon, and a transport carriage 2 carrying the bottle 3 and the adsorber 1, and facilitating the transport of all in hospital buildings or other.

More specifically, the transport carriage 2 comprises a carrying frame 25 provided with a bottom 24 on which is placed the gas bottle 2 and / or the adsorber 1, and a handle, such as a hoop 21. The lower part of the carriage 2 comprises one or more wheels 22 to allow movement of the assembly by rolling on the ground. A stand 23 makes it possible to hold the assembly in the vertical position at its place of use.

The carriage 2 receives the adsorber 1 which is held in position by a suitable fixing device adapted and designed to hold the adsorber 1 in a fixed position on the carriage 2, for example by screwing, by straps, by clipping, by interlocking or other.

As regards the adsorber 1, the latter is dimensioned so as to contain enough adsorbent, for example zeolite, to adsorb all the protoxide. nitrogen or xenon contained in a bottle B5 having a capacity of 1500 liters of gas (ie 5 1 of water).

As a result, the weight of the adsorbent required is quite substantial, that is to say typically between about 10 and 20 kg, or even more depending on the adsorbent chosen and its adsorption efficiency (capacity, selectivity, activation, possible pollution during repeated uses ...).

To minimize the bulk of the bottle 2 and adsorber 1 assembly, the shape of the adsorber 1 containing the adsorbent is chosen so as to include the gas bottle 3, that is to say that, as visible in FIG. 2, the adsorber 1 has a shape having a "crescent" section, so as to have a compact and integrated shape, and thus to receive all or part of the body of the bottle 3 in its recess 14 forming a hollow space s extending along the outer wall of the adsorber 1.

In other words, the recess 14 of the adsorber 1 has a section "U" and is dimensioned to receive all or part of a gas bottle 3, that is to say that typically the recess 14 ( inside the "U") to a width and a depth of the order of 15 to 17 cm, therefore sufficient to receive a bottle of about 14 cm in diameter.

In addition, with such a shape, the contact surface between the bottle 3 and the wall of the recess 14 of the adsorber 1 is favorable and leads to beneficial heat exchanges: the adsorber 1 heats up due to the adsorption part of the exhaled gas, while the bottle 2 cools due to the relaxation of the gas it contains. For this purpose, the crescent section, that is to say enveloping, of the adsorber 1 is an advantage.

In order to maintain the bottle 3 in the hollow internal space 14 of the adsorber 1, one can:

- Or provide fixing means 13, for example a flange, a collar, one or straps, cooperating with the bottle 3 or the protective cowl 31 mounted thereon, so as to secure the bottle 3 and the adsorber 1;

- Or conform the expansions 15, 16 of the adsorber 1 which face each other (the arms of the "U"), and which surround the bottle 3, so that their free ends are move closer to one another so as to restrict the space between the latter and to prevent the bottle 3 from leaving these two expansions 15, 16. In this case, the insertion and extraction of the bottle 3 in the recess 14 of the adsorber 1 will necessarily be vertically, as shown in Figure 2.

Of course, the adsorber 1 can return other forms, in particular it can form sleeve all around the body of the bottle 3 or only around a part of said 3. Likewise, the entire height of the bottle 3 and / or its protective cover 31 may be covered or only a part thereof, for example only the bottle body 3.

The moment when it becomes necessary to recycle the adsorbent is reported to the user by the depletion of the gas in the bottle, that is to say when the bottle 3 is empty or almost.

The gas bottle 3 can be a conventional medical gas cylinder type B5 provided with a cowling or protective cap 31 from covering and protecting the sensitive organs of the bottle 3, typically the valve or regulator valve 32 serving to control the passage of the gas towards the outside of the bottle (flow and / or pressure), as well as its equipment, such as manometer, steering wheel or operating lever ... A bottle of this type is described for example in the document EP- A-629812 and an expansion valve usable on such a bottle is for example described by the document EP-A-747796.

Moreover, the entry of the exhaled gases by the patient is via an inlet orifice 12 located on the upper face of the adsorber 1 and the discharge to the atmosphere gases freed from their anesthetic compounds, such as N ₂ O or xenon, is via one (or more) vent 11 of gas evacuation is located in the lower zone of the adsorber, that is to say near the bottom 24 of the carriage 2.

As a variant, the outlet 11 for the purified gases can be arranged in such a way that it is easily connectable to an evacuation, preferably in natural or forced depression; the purified gases being free of nitrous oxide or xenon can be simply vented to the outside atmosphere because without significant impact on the environment.

The nature of the adsorbent to be used depends on the gas to be treated and the level of purification of the desired gas. The choice will therefore be made on a case-by-case basis, in particular using empirical tests to test the effectiveness of a particular adsorbent available on the market. By way of example, as mentioned above, to adsorb N ₂ O, a faujasite-type adsorbent can be used, whereas for adsorbing xenon, a silica-gel type adsorbent, activated carbon or zeolite is chosen. Of course, it is also possible to use several different adsorbents which can be either arranged in successive layers in the adsorber 1, or mixed with each other thus forming a composite bed.

Preferably, the adsorption of the compounds on the adsorbent will be bottom up and desorption against the current adsorption, so from top to bottom. The gas can also be pretreated before adsorbing the N ₂ O, for example to remove all or part of the water vapor that it contains, that is to say to desaturate it in water. In all cases, the inlet port 12 comprises duct connection means for attaching the end of a duct conveying the exhaled gases from the respiratory mask, the intubation probe or any other similar device able to recover expired gases from the patient. For example, the conduit connection means may be a fitting fitted with or without locking or a screw connection with sealing means, such as seals.

In addition, as already said, to make this mobile assembly despite its weight, it is attached to a frame containing wheels 22 and a handle 21 may have a form of arch, as shown in Figures 1 and 2, or any other adapted form.

The nursing staff therefore has, thanks to the movable assembly of the invention, permanently both the means of dispensing the gas and that of sequestering.

Furthermore, the adsorber 1 may consist of an inner container or compartment containing the adsorbent and made of a material supporting the desorption heat treatment and an external bodywork ensuring the aesthetics, fixing it on the carriage 2, as well as the protection of the container or internal compartment and carrying all useful information for use and identification in the form of labels or electronic chip.

The assembly according to the invention can be used both in hospital buildings, such as hospitals or clinics, as in treatment rooms, especially in hospital buildings or in the office of a doctor, a dentist, a veterinarian or the like, only in mobile intervention care units, such as EMS, firefighters, ambulances etc ... or at home.

In use, a first conduit connects the gas cylinder 3 to the upper airways of the patient so as to administer N ₂ O or xenon to said patient, via a respiratory interface, such as a mask or the like, while a second gas duct connects the respiratory interface to the inlet orifice 12 of the adsorber 1 so as to route the exhaled gases to said orifice 12. The first and second gas ducts are preferably flexible gas lines, typically in polymer.

Claims

claims

A gas distribution and recovery device comprising a gas cylinder (3) containing a gas or a gaseous mixture containing at least one anesthetic compound and an adsorption vessel (1) containing at least one adsorbent material capable of adsorbing at least a part of said anesthetic compound, characterized in that the adsorption container (1) is shaped to form a sleeve around at least a part of the body of the bottle (3).

2. Device according to claim 1, characterized in that a recess (14) is arranged in the outer wall of the adsorption container (1), said recess (14) being shaped and dimensioned to receive at least a part of the body of the bottle (3).

3. Device according to one of the preceding claims, characterized in that the adsorption container (1) comprises a recess (14) having a cross-section in the shape of "U", preferably the recess (14) comprises a first and a second expansions (15, 16) facing each other.

4. Device according to one of the preceding claims, characterized in that the inner wall of the recess (14) of the adsorption container (1) is in contact with at least a portion of the body of the bottle (3) when the bottle (3) is positioned in said recess (14).

5. Device according to one of the preceding claims, characterized in that the bottle (3) and the adsorption container (1) are arranged on a carriage (2) movable provided with one or more wheels.

6. Device according to one of the preceding claims, characterized in that the adsorption container (1) comprises a gas inlet port (12) to be purified and at least one purified gas outlet (11), preferably the inlet (12) is in the upper half of the container (1) and the outlet vent (11) is in the lower half of the container (1).

7. Device according to one of the preceding claims, characterized in that the adsorption container (1) comprises an internal compartment containing the adsorbent material and an outer body protecting said inner compartment.

8. Device according to one of the preceding claims, characterized in that the adsorption container (1) comprises connecting means arranged at the inlet (12) of gas suitable for and designed to allow the connecting a gas supply pipe to said inlet port (12).

9. Device according to one of the preceding claims, characterized in that the adsorption container (1) contains at least one adsorbent silica gel type, activated carbon or zeolite.

A method of recovering and treating expired gases from a patient, wherein: a) a breath exhaled by a patient is recovered, said gas containing at least one anesthetic compound, particularly N ₂ O or xenon, b) the gas recovered in step a) is introduced into the adsorption container (1) of a device according to one of claims 1 to 8, c) at least a part of the anesthetic compound is adsorbed in said container of adsorption (1), and d) extracting from the adsorption vessel (1), a purified gas freed from at least a portion of said anesthetic compound.