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The present invention relates to an anaesthetic mask device for gaseous anaesthetics of the type comprising a cup- or hood- shaped part including a connection piece and provided with a border serving as a seal against the patient's face, and means 5 for extraction of excess gas.

During the preparations for anaesthesia as well as during the administration procedure proper in connection with surgical operations and the like an undersired leakage of anaesthetic gas takes place in the operating theatre, and especially the 10 personnel operating near the patient's head is exposed to high concentrations of anaesthetics. When anaesthetics.are to be administered to children the leakage of anaesthetic to the surrounding atmosphere will be still higher because, in order to get. the child used to accept he anaesthetic mask, it is ' 15 often necessary to apply the mask to the child and lift it away repeatedly, which ^" results in large amounts of anae'sthetics flowing out. Although this problem has per se been observed for a long time no useful solution has been found. Neither an im¬ proved general ventilation of the operating theatre nor a con- 20 centrated air extraction, local extraction, at the head of the operating-table have given the desired result.

It has earlier been proposed that the anaesthetic mask should be provided with a sealing device working under vacuum and sucking the mask fast to the patient's face to prevent 25 leakage of anaesthetic gas, and to combine such a device with a valve device provided in the anaesthetic gas supply line to shut off the supply of gas as soon as the mask is removed from the patent's face and the vacuum is eliminated.

However, means for the manipulation of the anaesthetic 30 gas flow are regarded as risky and can, especially in combi¬ nation with vacuum devices, be dangerous to the patients- .

Sucking the mask to the patient's face may make the patient feel uncomfortable and especially so when it is a matter of children who cannot always understand the reasons 35 for the steps taken in connection with the administration of anaesthetics. _Λ ,,

A desire expressed by experts in the field is that devices for the removal of leaking or otherwise escaping anaesthetic gas should be constructed in such a way that they require neithe any change of prevailing anaesthetic administration routines nor any special measures to function. Another desire is that it should be possible to use existing control equipment without changes. Thus it is a main object of the invention to provide a device preventing unintentional spreading of anaesthetic gas outside the anaesthetic mask. The essential characteristic of the device acording to the invention in that there is provided at said border a slot-shaped suction opening into a space situated outside the wall of the anaesthetic mask and connectible to a suction device, that said slot-shaped opening.is so localized relative to the sealing border of the anaesthetic mask that the communication between the interior of the anaesthetic mask and the slot-shaped opening is cut off when the mask is applied to the patient.'s face, while the slot otherwise permits extraction of anaesthetic gas flowing ^* out into the interior of the mask, and that a means deflecting the gas flow towards the wall of the anaesthetic mask is arrange therein to facilitate collection of gas freely flowing out throu the mask.

Embodiments of the device according to the invention will be described more fully below by way of example, reference being made to the accompanying drawings, in which:

Fig. 1 is cross-sectional view of an embodiment of an anaesthetic mask according to the invention;

Fig. 2 is a cross-sectional view of another embodiment thereof; and Fig. 3 is likewise a sectional view of a perferred embodi¬ ment of the device.

The drawings comprise only such details as are essential to the comprehension of the invention and, since the design of the anaesthetic mask proper can vary to a high degree according to manufacturer, anaesthetic system and size, the mask has only ^" been schematically illustrated in two principal embodiments, one with and one without inward-bent border, and in one entirely new embodiment.

The anaesthetic mask proper, generally designated by 1, comprises a connection piece 2 from which the cup- or hood- shaped main part 3 extends. In the embodiment according to Fig. 1 said main part merges in an inward-bent, thinner edge portion which forms a sealing border against the patient's chin, cheeks and nose ridge.

According to the invention an extraction slot 5 is arranged around at least the edge portion of the anaesthetic mask. In the embodiment according to Fig. 1 this slot is formed by anothe hood-shaped means 6 being arranged on the outside of the mask proper 1.

Said means 6 may be connected with the mask 1 by studs or the like 7 which constitute spacing means and keep passages 8 from the slot 5 at the lower edge of the mask open to a connec tion piece 9 which preferably is coaxial with the piece 2 and to which a sucking line is connected.

The body of the hood-shaped means 6 may like the mask 1, be of relatively rigid construction. In the embodiment according to Fig. 1 the body of the means € merges in a collar 10 made of thinner material and terminating in"an edge bead 11. Folding notches 12 are formed in the collar 10 by attenuation of materia or in some other way so that the collar 10, which normally takes the position indicated by dash lines, is apt to fold up to the position shown Fig. 1 when it meets the patient's face. Fitted in a nipple 13, inserted in the connection piece 2 of the anaesthetic mask, 1 is a spreader disk 14 for distributio of inflowing anaesthetic mixture along the inside of the mask so that the gas flow is forced to spread conically within the mask instead of flowing straight out from the nipple as is the case with prior art masks.

The connection piece 9 of the extraction means 6 is coupled to the evacuation or suction line. As long as the mask is kept free outflowing anaesthetic gas will be extracted from the space delimited by the collar 10 in unfolded position. The extraction continues also while the mask is being drawn towards the patient' face and is interupted when the border 4 of the anaesthetic mask seals against the face. Any anaesthetic gas leaking out along the border 4 is extracted all the time the mask is kept applied. When

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the mask is removed from the patient the collar 10 unfolds again and functions as before. To prevent too high a negative pressure from arising in the extraction space around the mask, which might have as a result that the mask would be sucked fast to the patient, the extraction line is provided with a valve means sensing the negative pressure and keeping the negative pressure in said space within an appropriate value adapted to the function.

In the embodiment according to Fig. 2 the anaesthetic mask 1 has no inward-bent border and here the border 4 instead tapers so as to form a sealing lip. Also in this embodiment a cup- or hood-shaped means 6 is arranged on the outside of the mask proper so that an extraction slot 5 will be formed along t the edge of the mask. The means 6 projects somewhat outside the edge 4 of the mask and is made of a"'more elastic material than the mask so that the edge 15 of the means 6 can be displaced backwards as the mask is applied to the patient.

Also in tKis case a spreader disk 14 is provided in the

» ^' « nipple 13 which is inserted in the connection piece 2 of the mask 1 . As the mask 1 -has no inward-bent border the anaesthetic gas will flow along the inside of the mask and can thereby be easil caught and extracted through the slot 5 . When the mask t is applied to the patient, the slot 5 is shut off, whereby the extraction, apart from leaking gas, is interrupted. The mask 1 shown in Fig. 3 comprises, like the masks t I I I described above, an inner part 3 and an outer part 6 between

I I which an extraction passage 8 is formed. In this embodiment the

I I t i parts 3 and 6 are made of comparatively rigid, crystal-clear material and have generally parallel portions making it possible continuously to watch the patient's face and especially his lips without making it necessary to lift away the mask. f I

The inner part 3 is in this case provided with a soft

I I seal 4 , preferably in the form of a closed, tube-like profile, instead of the above-mentioned sealing borders.

I I The outer part 6 has a circu ferentially extending soft

I I I I strip 10 tapering towards the free edge of the part 6 and bent in inward direction when not acted upon, and this strip is

I I adapted to bend towards the sealing profile 4 when it is

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applied to the patient's face, thereby reducing or preventing

I I extraction through the slot 5 . Also in this case the suction source may be provided with control means preventing buildup of too high negative pressure.

• I

5 The inner part 3 of the mask has a central opening

I I surrounded by a bead 2 and entering through this bead is

I I the end of a double nipple 13 to which coaxial lines for anaesthetic gas and exhalation air are connected. The inner end ι ι i i of the nipple 13 is formed as a spreader disk 14 making 10 the anaesthetic gas flow out substantially radially from the nipple end. The gas will thus sweep along-the walls in the

I I mask, which facilitates collection through the slot 5

I I

The nippple 13 is combined with an outer nipple 16 to

I I which the connection piece 9 of the evacuation line is 1.5 connected.

As a rule the adjustment of the anaesthetic gas flow takes place with the mask lifted off the patient, while the outflowing

I I gas is spread in the mask, is collected in the suction slot 5 and removed through the passage 8 . When " he mask is applied to

I I

20 the patient the thin strip 10 will bend inwards, whereby

I I it reaches the sealing profile 4 and prevents extraction of ^{• •} yci§ from the interior of the mask. If some part of the mask is withdrawn from the face of_ the patient then the strip withdraws from the profile to allow extraction. As soon as the mask is 5 entirely removed from the patient the suction slot opens in its entirety, whereby gas is prevented from escaping into the surrounding atmosphere.

Thus, in the embodiments herein described, extraction of anaesthetic gas continues all the time the mask is removed from 0 the patient and any gas that would otherwise have leaked out due to unsatisfactory application along some portion of the mask is collected and extracted. When the mask has been applied to the patient the extraction is interruptedand the mask functions entirely as a conventional mask. The device according to-the 5 invention can thus be used in an entirely conventional manner and as far as the operating personel is concerned it requires no additional steps at all for functioning.

The invention must not be considered limited to that OMPI

described in the foregoing and shown in the drawings but can be modified in various ways within the scope of the appended calims.

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