WO1996028207A1

WO1996028207A1 - Facial respirator mask, part and method for the manufacture thereof

Info

Publication number: WO1996028207A1
Application number: PCT/FR1996/000404
Authority: WO
Inventors: Gérard VANDENBROUCQUE
Original assignee: Assistance Publique - Hopitaux De Paris
Priority date: 1995-03-16
Filing date: 1996-03-15
Publication date: 1996-09-19
Also published as: FR2731624B1; JPH10500349A; EP0759792A1; NO964847D0; AU708804B2; NO964847L; AU5113096A; CA2187318A1; FR2731624A1

Abstract

A facial respirator mask having a concave and rigid shell (1) with an aperture for connection to a ventilating apparatus (2), characterised in that the shape of the rigid shell (1) is arranged to encompass, in addition to the nose and mouth, the whole of the adjacent part of the face defined outwardly by the jugal bone, the temporal bone squama and the lower maxilla, so as to provide a continuous engagement between the inner surface of the shell and the bone structure of the face below the forehead. The mask may be made from a material capable of being shaped by moulding on a three-dimensional model of a human face, particularly by direct moulding on the patient's face.

Description

Facial ventilation mask, part and process for its manufacture.

The present invention relates to a facial ventilation mask.

For patients requiring ventilatory assistance, the facial ventilation mask, that is to say a mask covering the nose and mouth, is a non-invasive means of connection which is likely to allow a reduction in the risk of complications related to the use of an endotracheal ventilatory prosthesis, these complications being, for example, laryngeal and tracheal lesions, or pneumonias acquired under mechanical ventilation.

The ventilatory assistance by non-invasive mechanical ventilation can be indicated in particular for the internal pneumatic stabilization of a costal flap, in case of disturbance of the ventilation of the bases post-extubation in a patient having undergone abdominal surgery or for the treatment of distress acute breathing. It allows to breathe into the upper respiratory tract of the patient a gaseous mixture of air enriched with oxygen (breathable) which penetrates into the lungs due to the insufflation pressure applied higher than the internal pressure of the respiratory system. (so-called positive pressure ventilation).

The practitioner currently has at his disposal a standard facial mask, generally offered in different sizes. The latter consists of a rigid shell covering the nose and mouth of the patient, which is placed on the patient's face on either side of the wings of the nose and around the mouth, by pressing the edge of the shell on the nasal bridge, at two points under the cheekbones and an area under the lower lip, the rest of the border being in contact with the cheeks. The rigid shell is provided with a seal ensuring the watertight the fact that the mask is fixed on the face. This seal is most often an inflatable tube applied to the edge of the hull. Masks can also be found where the shell is fitted, inside, with a silicone skirt which deploys under positive pressure so as to ensure sealing.

However, these means of ensuring the tightness of the system are not sufficiently effective under high insufflation pressures and problems of leakage of the gaseous mixture are continuously encountered.

The risk of leakage with a standard mask comes from the play between the surface of the patient's face and the mask.

The risk of leaks further increases when the patient is fitted with prostheses connected to a nasal or oral orifice, such as Salem or Drip probes. The passage of these probes between the patient's face and the edge of the mask creates a detrimental play in the sealing of the system. It is essential to avoid leaks as much as possible. In fact, the regulation of mechanical ventilation is controlled by the pressure measured at the level of the respirator. A leak therefore entails a risk of inadvertent triggering of the ventilator alarm, or of a defect in the quantity of gas mixture delivered, or the impossibility of stopping the insufflation of the gas mixture.

To fight against these leaks, it is often necessary to increase the fixing constraints of the system, namely in general the tension of the harnesses or the tightening of the straps. However, this is almost always accompanied by skin lesions, mainly sores, during prolonged use.

The present invention proposes to provide a solution to the problem of sealing the mask of facial ventilation, so as to ensure effective ventilation, while respecting the comfort of the user and avoiding the risk of skin lesions.

To this end, the subject of the invention is a facial ventilation mask comprising a concave rigid shell provided with an orifice for connection to a ventilation device, characterized in that the shape of the rigid shell is designed to contain, in addition to the nose and the user's mouth, the entire adjacent part of the face defined externally by the malar bone, the scale of the temporal bone and the lower jaw, so as to ensure continuous support between the internal surface of the shell and bony relief of the face below the forehead. This shape makes it possible to constantly maintain continuous support between the internal surface of the mask and non-deformable structures formed by said bony relief, independently of the possible deformations of the surface of the user's face at the cheeks. This creates a constant hermetic contact between the mask and the face of the user, which makes it possible to avoid leaks in a safe manner, without having to apply strong tightening constraints, unlike the use of traditional masks, which pass through the middle of the cheeks, with which a far from satisfactory result is obtained as regards the reduction of leaks.

Thanks to the advantageous shape of its shell, the mask of the present invention effectively solves the problem of sealing the ventilation while respecting the comfort of the user who no longer suffers from the formation of bedsores.

The connection hole is located at the buccal level on the shell. In this area, the shell can have any shape allowing to adapt a supply pipe in breathable gas delivered by a mechanical ventilation device, and allow the passage of said gas inside the mask through the connection orifice.

According to a preferred embodiment, the shell has a prominence at the buccal level, in which the connection orifice is formed, and such that the user's mouth cannot be in contact with the internal surface of the shell. This avoids the risks of plating the lips or the mouth on the orifice at the buccal level, causing total or partial obstruction of the ventila¬ tion orifice.

The mask can advantageously include a connection piece to a mechanical ventilation device, adapted on the connection orifice.

The connection piece to a ventilation device is then a rigid piece, having a tubular part, making it possible to adapt to the mask a tube for supplying oxygen or a gaseous air-oxygen mixture, sufficiently resistant to withstand handling without damage. gas supply pipe. The tubu¬ lar part of the connection piece is arranged projecting relative to the external surface of the shell at the connection orifice. Advantageously, the connecting piece has at one end of the tubular part, called the internal end, situated on the patient's side, a collar extending radially around the tubular part, bearing on the internal surface of the shell . In a particularly advantageous embodiment, the collar has a concavity oriented in the same direction as the concavity of the shell. In particular, the collar may have the shape of a spherical cap trunk. Such a connecting piece, which makes also the object of the present invention, then easily adapts to the concave shell, by providing a relatively uniform support of the flange on the internal surface of the shell. In addition, due to its concavity, the flange defines a volume between the mouth of the user and the end of the tubular part located inside the mask, so that the risks of obstruction of the orifice ventilation are limited. Such a connecting piece also advantageously fits over a rigid shell provided with a prominence at the connection orifice, as described above.

It is also advantageous for the tubular part of the connecting piece to have a wider internal section at its end furthest from the shell.

Preferably, the facial ventilation mask according to the invention comprises, on all or part of the internal surface of the shell, a seal, in particular at the edge of the shell. The seal makes it possible to perfect the seal of the contact between the mask and the face of the user, and to provide more comfort to the user at the level of the surfaces in support of the mask. This seal can advantageously be in the form of an expanded material, in particular a foam.

In a particular embodiment of a ventilation mask for a patient equipped with a probe connected to a nasal or buccal orifice, the shell has, at the level of the central part of the lower jaw, a projection relative to its external surface providing an internal sheath intended to allow the passage of the probe outside the mask.

This sheath, the internal surface of which is completely lined with a seal, forms a fold projecting into the shell, inside which part of the surface of said seal comes into contact with the complementary part, so that the interior volume of the sheath is completely occupied by the seal. The sheath can therefore be considered as a solid element, which is not likely to affect the sealing of the system. An element such as a probe can be inserted into said sheath in the fold of the seal by compressing the latter elastically, the assembly remaining completely hermetic. The sheath acts as a sealed airlock allowing the probe to exit the mask without disturbing the continuous contact between the internal surface of the mask and the bony relief of the patient's face. The facial ventilation mask according to

1'invention can be provided with means for holding in place on the face of the user. These means can be chosen from known conventional means such as rubber harness or tightening straps fixed on the mask, to exert a restoring force between the shell and the head of the user, sufficient to maintain the hermetic contact but not too much large so as not to inconvenience the user and ensure a tight and comfortable ventilation system. During tightening, the seal is compressed between the bony relief of the face and the rigid shell, uniformly over the entire bony relief.

Preferably, the fixing of these means on the mask is done at the connection area. The components of the mask (shell, connection area, seal) must be made of materials that are not breathable to avoid leaks. Furthermore, they must be biocompatible, that is to say that they are well tolerated by the skin of the face and by the upper respiratory tract. For the hull, plastic materials are preferred which combine solidity and lightness. In particular, advantageously polycaprolactone polymers or mixed transpolyisoprene / polycaprolactone copolymers are used.

The connection area, in particular the connection piece, must be made of a material hard enough to support the connection to the ventilation unit. Advantageously, hard polymer materials such as polyvinyl chloride or polytetrafluoroethylene are used.

The seal is advantageously made of polyvinyl chloride foam.

The invention also relates to a method of manufacturing a facial ventilation mask as described above.

This process is characterized in that the concave rigid shell is formed from a material capable of evolving between a plastic phase and a rigid phase, by modeling said material in its plastic phase on a model of human face in relief. , such as a mannequin, so as to take the imprint of the relief of the nose bone, malar bones, temporal scales and lower jaw, then stiffening of said material in place on the model.

Among the materials of the type having the requisite qualities set out above, it is preferred to use polymeric materials thermoformable at low temperature, that is to say at a temperature below 70 ^e C, in particular below 60 ° C, in particular polycaprolactones or the transpolyisoprene / - polycaprolactone copolymers.

By having a series of models with the average anatomical characteristics of classes of individuals of defined type, sex and age, we can make masks suitable for individuals of these different classes.

The general manufacturing process comprises the successive stages of (a) cutting a piece of said material, to the dimensions of the model according to a shape spreading over the surface of the part of the face delimited by the nasal bridge, the malar bones, the temporal scales and the lower maxilla, and (b) shaping of said piece, by modeling the piece of material in its plastic phase on the relief model by taking the imprint of the relief of the above bones, (c) stiffening of the modeled material, in place on the model to form the rigid shell (1), and (d) arrangement of an orifice at the buccal level, either on the part before its shaping, or on the rigidified shell.

During the modeling step (b), it is possible to arrange a prominence at the buccal level on the formed shell, by creating a free space between the zone of the model extending around the mouth and the piece of formable material.

When it is desired to manufacture a ventilation mask having a connection orifice provided with a connection piece projecting relative to the shell of the mask, the method comprises a step of placing said connection piece in the connection orifice, if necessary before or after step (b). For the comfort of the user, the connecting piece having a part intended to be disposed inside the shell, in particular a flange intended to come to bear on the internal surface of the shell, is advantageously arranged so that this part is not protruding by compared to the internal surface of the shell after it has been placed in the mask. In this regard, it is preferred to provide the piece of material with the connecting piece before it is shaped on the relief model. The rigid shell then takes a shape which takes account of the connecting piece so that the internal surface of the mask is relatively uniform.

Similarly, the application of a seal can be carried out either on the rigid shell after modeling, or on the part before modeling. The second option is preferred since it allows the shell to be given a shape taking into account the elements which are inside the final mask ready for use. This is particularly advantageous when the mask has a seal over its entire internal surface, so as to avoid the loss of internal volume of the mask due to the thickness of the seal. The mask then remains perfectly adapted to the anatomical type of the model to offer better comfort to the user.

The fixing of the joint can be carried out in particular by gluing. Preferably, the seal is self-adhesive and consists of a layer of expanded material, in particular of foam, and of an adhesive layer. This manufacturing process makes it possible to produce various models of facial ventilation masks according to average anatomical characteristics suitable for various classes of individuals, having the advantages of use described above. The method can also be applied on a case-by-case basis for individuals for whom the average anatomical characteristics are unsuitable or poorly, by performing the operation of modeling the shell directly on the face of the user. So we can optimize the shape of the shell of the mask for patients of particular morphology by modeling on the patient's face the pre-cut piece according to the dimensions of the model. With a series of models having the average characteristics of predefined classes of individuals, it is thus possible to manufacture a series of patterns for cutting a part or else a series of precut parts adaptable to individuals of these different classes.

For even more atypical patients, it is possible to cut said piece directly to the measurements of the patient's face.

In these two cases, it is advisable to arrange a connection orifice at the buccal level in the piece of formable material before its application on the face of the user to allow the latter to breathe normally during the whole modeling operation.

The modeling is advantageously carried out so as to take the exact imprint of the part of the face of the user delimited by the nasal bridge, the malar bones, the temporal scales and the lower jaw.

The mask thus manufactured perfectly matching the relief of the user's face makes it possible to optimize the regulation of ventilation by preventing leaks at the edge of the mask and the creation of dead volume by swelling of the cheeks.

Indeed, the flexible structures of the face that are the cheeks are contained in the mask and are in contact with the internal surface of the latter. During ventilation, the cheeks are only likely to swell in a limited way under the effect of positive pressure and are thus pressed against the rigid shell of the mask, to ensure an even more tight contact, limiting the swelling of the cheeks limiting dead space. In addition, the large contact surface between the mask and the skin of the user makes it possible, knowing that the pressure exerted thereon is inversely proportional to the contact surface, to obtain pressure constraints of weak support.

The present invention will be illustrated by the example below which describes a facial ventilation mask for a patient equipped with a nasogastric tube of the Salem tube type, as well as the manufacture of this mask by modeling on the face of the patient.

During the description, reference will be made to the appended drawings in which:

- Figure 1 shows a front view of a facial ventilation mask; - Figure 2 shows a right side view of the same mask with cutaway, illustrating a vertical section of the mask in the axis of the nose.

- Figure 3 shows a horizontal sectional view of the central part of the mask at the chin, and illustrates the passage of the nasogastric tube;

- Figures 4A and 4B are two views respe¬ ctively in elevation and in longitudinal section, of a connecting piece to a ventilation device; - Figure 5 shows the shape of a planar pattern made to measure the patient's face.

The facial ventilation mask shown in FIGS. 1 and 2 comprises a rigid shell, symmetrical with respect to the median vertical axis of the face of the user. This shell has a connection orifice 2 at the buccal level. The periphery of the shell is shown in these figures by a flap of the seal 3 which extends over the entire internal surface of the shell. The shape of the shell 1 is designed to build on the bony relief of the patient's face continuously. The periphery of the shell can thus be divided from the nose to the chin into 4 contiguous sections A, B, C and D, which are symmetrical with respect to the median axis of the face. Section A follows the relief of the nose's own bone, from the nasal bridge to the foot of the lateral parts of the nose's own bone, behind the wings of the nose; section B follows the malar bone in the suborbital region; section C follows the temporal scale until the temporomandibular joint but without reaching it; and finally section D follows the lower maxilla going down along the rising branch of the maxilla, crossing the body of the lower jaw in front of the right angle to finally follow the lower edge of the body of the lower jaw under the chin.

The surface of the shell 1 is in continuous support on the nose bone in the area near the edge at the level of section A, the cheekbone in the area bordered by section B, and the cheek in the area bordered by the sections C and D. The shell has a prominence at the connection orifice 2, which provides a free space E between the mouth of the patient and the internal surface of the shell. The S probe connects the patient's stomach to an external power source through the nose.

Inside the mask, it passes next to the mouth so as not to constitute a gene at the level of its lips.

To allow passage outside the mask of the probe S, the shell 1 comprises in the central part of the lower jaw, at the level of the groove of the patient's chin, a projection 4 vertical to the connection orifice 2, and descending up to 'at the lower edge of the shell 1, internally forming a vertical sheath for the probe. Like all the rest of the internal surface of the shell 1, the projection 4 is completely lined with a seal.

As shown in FIG. 3, at the level of the projection 4, the internal surface of the shell follows the body of the lower jaw as far as the point F, where it moves away from the patient's face to form a symmetrical tubular protrusion by relative to the median vertical axis of the mask and joins the body of the maxilla less than the point F ', symmetrical with F with respect to this median axis. The space between points F and F 'is completely filled by the presence of the seal 3, which is folded back on itself.

Inside the sheath, the seal 3 is slightly compressed between the probe S and the rigid shell 1.

The passage of the probe S out of the mask is thus ensured in a completely sealed manner, the projection forming the sheath 4 playing the role of a hermetic airlock.

The use of a thermoformable material at low temperature such as polycaprolactone is advantageous because it leads to a semi-rigid formed shell, that is to say slightly deformable. In this case, a slight deformation of the shell at the level of the projection 4 makes it very easy to disengage the probe when it is necessary to reposition, or to temporarily or permanently remove the mask. The replacement of the probe is just as easy by slight deformation of the shell at the level of the projection.

The seal 3 which is applied to the entire internal surface of the shell 1, is folded over the external surface so as to isolate the edge of the shell from the patient's face. This provides a pleasant touch around the entire periphery of the mask, ensures the patient's comfort when putting it on his face and avoids the risk of cuts or injuries. caused when the facial skin comes to rest on the edge of the shell.

A connection piece 5 is placed in the connection orifice 2. It is shown in FIGS. 4A and 4B, on a slightly enlarged scale for reasons of clarity. It has a tubular part 5a and a concave flange 5b. The tubular part 5a has a cylindrical outer shape and a frustoconical inner shape, the inner diameter being less than the end where the flange is located relative to the inside diameter at the connection end.

The tubular part 5a has at its end a collar in the form of a sphere cap trunk. The dimensions of such a part can be for example, for the tubular part 5a, of the order of 2.6 cm for the outside diameter, 2.2 cm for the inside diameter at the end opposite to the flange and 2 cm for the inside diameter at the collar.

The sphere on which the interior surface of the collar 5b rests has a radius of approximately 4.5 cm. The collar rests on this sphere on the surface of a cap trunk whose large diameter is approximately 4 cm and the small diameter corresponds to the small internal diameter of the tubular part 5b, ie 2 cm.

The collar 5b is placed in abutment on the internal surface of the shell 1. It can be assembled to the latter, in particular by bonding using a thermoformable material compatible with the materials constituting the part 5 and the shell 1.

In general, depending on the shape of the connecting piece 5, it is possible to envisage very different fixing methods. A hook ring 6 is fitted on the tubular part 5a of the part 5. It is in the form of a flat ring whose internal diameter corresponds to the external diameter of the connecting part 5, provided with four hooks 6a, 6b, 6c and 6d projecting from the plane of the 'ring.

A harness 7 with four elastic strands 7a, 7b, 7c and 7d allows the mask to be held in place on the patient's face. Each strand is provided with clamping holes and is fixed to the ring 6 by inserting a hook in one of the holes provided on said strand. The four strands meet, at the opposite end to that pierced with holes, to form a surface which is placed at the back of the patient's head.

The positioning of the mask on the patient's face is adjusted by adjusting the point of attachment of each of the strands 7a to 7d on the hooks 6a to 6d of the ring 6. The restoring force exerted by the strands securely holds the mask on the patient's face.

The manufacturing process for this mask is as follows:

Firstly, a flat pattern is made, in a flexible sheet of transparent plastic, cut to the measurements of the patient's face, following the bony relief located under his forehead. The pattern, shown in Figure 5, is symmetrical with respect to its median vertical axis and its outline can be divided into 4 contiguous sections G, H, I and J.

Once applied to the patient's face, the pattern covers the surface of the nose from the nasal bridge to the foot of the nose bone along section G, from the cheekbone along section H, extends up to '' at the temporomandibular joint along section I. It also covers the cheek and half of the chin on the rest of its surface bordered by section J, which follows the lower edge of the lower jaw body under the relief of the chin, across the finger behind it.

A hole K is drilled at the location of the mouth on the pattern. The shape and dimensions of the hole K depend on the shape and dimensions of the connecting piece 5.

A piece P is cut from a rigid polycaprolactone sheet approximately 3 mm thick, sold by the company Fish under the name of "AQUAPLAST", following the outline of the pattern. The outline of the part P, identical to that of the pattern, can therefore be divided into sections G to J in the same way. The contour of the hole K is noted, representing the position of the buccal orifice which will be drilled later. Alternatively, the mouth can be pierced at this stage of operations.

The part P is immersed in a water bath thermostatically controlled at 60 ^β C until it is sufficiently softened. The part is removed from the water bath, dried on a cloth and the oral opening is drilled on the hot part P, following the outline of the hole K.

Polycaprolactone thermoplastic at 60 ^β C is very advantageous to use, because it remains plastic in a wide temperature range up to 30 ^β C. After sufficient cooling to be able to be applied directly to the patient's face without risk of burns , it can still be easily modeled. All other thermoplastic materials which remain plastic up to temperatures low enough for application to the skin to remain tolerable can be advantageously used. As other examples, mention may be made of transpolyisoprene / - polycaprolatone copolymers.

The connecting piece 5 is then put in place by passing the tubular part 5a through the buccal orifice, the flange 5b coming to bear on one face of the part P, which will be referred to below as the internal face of the part P.

Then applied to the internal face of the hot part P a sheet of gasket 3 made of self-adhesive polyvinyl chloride foam, roughly cut roughly to dimensions greater than those of the transparent plastic pattern, pierced a hole at the location of the oral opening identified on the pattern. The self-adhesive seal is placed so that the mouth openings coincide.

It is advantageous to choose a seal such that the adhesive has good hot compatibility with the thermoformable material. In addition, the part having been heated by immersion in a water bath, it is preferable to choose an adhesive capable of forming an effective assembly in the presence of traces of water remaining after drying.

As a variant, the seal can be applied to the internal surface of the shell after the part P has been shaped.

According to another variant, the seal can be applied only at the periphery of the part P or else be applied subsequently to the formed shell 1 to coat the edge of the shell. The piece of thermoformable material P, provided with the connecting piece 5 and covered on its internal face with the seal 3 is applied to the face of the user on the side of the seal 3, while its temperature is high enough for the material is formable, and has dropped enough so that the application of the part to be formed on the user's face does not cause burns for the latter. The part P is positioned so that its outline comes to coincide with the bony structures identified to trace the pattern. The whole is shaped by modeling so as to take the imprint of the relief of the patient's face, so that the shell 1 perfectly matches the shape of the part of the patient's face delimited by the contour of the part P. The periphery of the formed shell 1 , is divided into sections A to D, as described above, which correspond to sections G to J of the outline of the planar part P.

During the modeling, a slight traction is exerted on the connecting piece 5 in the direction opposite to the patient's face to drive the perioral zone of the piece P in this direction, so as to form a prominence which creates between the mouth of the patient and the internal surface of the mask the free space E. The concave shape of the collar 5b of the connection piece 5 is very advantageous for entraining the softened material without risk of tearing while giving prominence to the corresponding concavity.

In addition, this traction makes it possible to integrate the connecting piece 5 in the shell 1, the internal face of the flange 5b and the internal face of the shell 1 forming a continuous surface.

The protruding shape 4 is also produced during the modeling operation of the plastic material. The probe S being brought in front of the patient's face to provide a free space between the probe and the chin, the part of the piece P located below the connection orifice 2 is shaped around the probe. By pinching the material between the probe and the chin, the part is folded back on itself around the probe and a pressure is exerted strong enough for the sealing gasket surfaces 3 facing come into contact with one of the 'other. Contact is maintained throughout the shaping operation.

The formed part is held on the face of the user until it stiffens by cooling. sow thermoformable material. The total duration of the shaping operation is approximately 5 to 10 minutes.

During the modeling and stiffening operations, the oral opening is maintained at the level of the patient's mouth, ensuring a permanent air intake allowing him to breathe normally. The oral orifice, provided with the connection piece, can also be used to bring an oxygen connection and increase the inspiratory fraction of oxygen (Fi0 ₂ ) during the shaping stage.

The shell is then removed from the patient's face and the connection piece is glued to the internal surface of the shell 1. For bonding, a conventional thermoformable material is preferably used. Advantageously, the glue is applied in excess to the internal surface of the mask on and around the collar of the mouthpiece so as to provide a regular internal surface at this location without roughness.

The holding means are then fixed in place on the body of the mask thus produced. The ring with four hooks 6 is fitted to the tubular part 5a of the connection piece and one of the four hooks 6a, 6b, 6c and 6d is attached to each of the four strands 7a, 7b, 7c and 7d of a holding harness rubber 7.

The mask thus produced is placed on the patient's face to provide a completely sealed ventilation system. As a variant, a facial ventilation mask can be made for a patient equipped with a small diameter probe, such as a Salem or Drip probe, connected to a nasal or buccal orifice, the shell of which has instead of the projection constituting a sheath 4, an orifice provided with a grommet for an elastomer probe adapted on said orifice to receive the probe. The inside diameter of the grommet is calibrated as a function of the outside diameter of the probe to ensure the tightness of the contact. The orifice can be drilled on the part P before its shaping, softened or not, or else on the shell 1 shaped by modeling and stiffened.

Although the present invention has been described more precisely in the particular case of mechanical ventilation of patients, in particular in resuscitation or in respiratory assistance, it can also be used in all other applications of mechanical ventilation. For example, the facial mask as described above can be used by a fighter pilot. The particular configurations of the shell such as projecting sheaths or grommet holes can then be used to incorporate various accessories in the ventilation mask.

Claims

1. Facial ventilation mask comprising a concave rigid shell (1) provided with an orifice for connection to a ventilation device (2), characterized in that the shape of the rigid shell (1) is arranged to additionally contain the nose and the mouth, the entire adjacent part of the face defined externally by the malar bone, the scale of the temporal bone and the lower jaw, so as to ensure continuous support between the internal surface of the shell and the bony relief of the face below the forehead.

2. facial ventilation mask according to claim 1, characterized in that the connection orifice (2) is provided with a connection piece (5) having a tubular part (5a), the tubular part (5a) being in projection from the outer surface of the shell (1).

3. Facial ventilation mask according to claim 2, characterized in that the connecting piece (5) also has at one end of the tubular part (5a) a flange (5b) extending radially around the tubular part, resting on the internal surface of the shell (1).

4. Facial ventilation mask according to claim 3, characterized in that the collar (5b) has a concavity oriented in the same direction as the concavity of the shell (1), in particular has a shape of a spherical cap trunk.

5. Facial ventilation mask according to any one of claims 1 to 4, characterized in that the shell (1) has a prominence at the buccal level, in which the connection orifice is formed (2), such that the user's mouth cannot be in contact with the internal surface of the shell (1).

6. facial ventilation mask according to any one of claims 1 to 5, characterized in that it comprises over all or part of the internal surface of the shell (1), a seal (3), in particular in expanded material.

7. facial ventilation mask according to any one of claims 1 to 5, characterized in that the shell (1) has, at the central part of the maxilla, a projection (4) relative to its external surface providing a internal sheath, the internal surface of which is completely lined with a seal (3) and inside which said seal (3) is folded back on itself, the facing surfaces of the seal forming a hermetic contact.

8. Connection piece to a mechanical ventilation device for a facial ventilation mask, according to claim 4, having a tubular part (5a) and a flange (5b) extending radially around said tubular part, characterized in that the flange (5b) is concave and turns its concavity opposite to said tubular part.

9. A method of manufacturing a facial ventilation mask characterized in that the concave rigid shell (1) is formed from a material that can evolve between a plastic phase and a rigid phase, by modeling said material in its plastic phase on a model of human face in relief, such as a manne¬ quin, so as to take the imprint of the relief of the nose bone, malar bones, temporal scales and lower maxilla, then stiffening of said material in place on the relief model.

10. Method according to claim 9, characterized in that it comprises the successive steps of: (a) cutting a piece of said material to the dimensions of the model according to a shape spreading over the surface of the part of the face delimited by the nasal bridge, the malar bones, the temporal scales and the lower maxilla, (b) shaping of said part, by modeling the material in its plastic phase on the relief model taking the imprint of the relief of the aforesaid bones, and (c) stiffening of the model material, in place on the model, to form the rigid shell (1), and (d) arrangement of a connection orifice at the buccal level (2), either on the part before it is shaped, or on the stiffened shell.

11. The method of claim 9 or 10, wherein said material is a thermoformable material at a temperature below 70 ° C, the cut piece of thermoformable material being heated to a temperature allowing the softening of said material in its plastic phase , prior to step (b), the shaping of the part in step (b) comprising the modeling of the plastic material on the model and the stiffening of the shell formed by cooling in place on the model.

12. The method of claim 11, wherein step (d) takes place before step (b), and the heating of the piece of thermoformable material is carried out between step (a) and step (d ).

13. Method according to any one of claims 9 to 12, in which during step (b), a prominence is provided at the buccal level on the concave shell (1), by creating a free space between the zone of the face of the model extending around the mouth and the piece of formable material.

14. Method according to any one of claims 9 to 13, further comprising the installation of a seal, in particular a foam self-adhesive, on any part of the internal surface the piece of formable material, before or after step (b).

15. Method according to any one of claims 9 to 14, for the manufacture of a mask for a patient equipped with a probe connected to a nasal or buccal orifice, in which during step (b), arranges at the edge of the shell a projection (4) relative to its external surface, providing an internal sheath for said probe, by pinching the formable part around said probe.

16. Method according to any one of claims 9 to 15, wherein one arranges the connection orifice (2) on the part before 1 step (b), then one sets up a connecting part (5) comprising a collar, by placing said collar in contact with one face of the piece of material corresponding to the internal surface of the shell (1), then the modeling step (b) is carried out.

17. Method according to any one of claims 9 to 16, characterized in that the shaping operation in step (b) is carried out by modeling directly on the patient's face.