Devices of this type are known as resuscitators. These are used within the medical field when a patient is un- able to breath correctly, or when the patient does not breath at all, e. g. because of deep unconsciousness. Such devices are used not only at hospitals, but also in many other connections where first aid equipment finds appli- cation.

Such a device comprises a container which defines an in- ner volume with respect to the ambient, and which is pro- vided with a first opening accommodating a valve arrange- ment which allows inflow of air and/or other gases from the outer area to the inner area, a second opening in connection with which there is provided a valve arrange- ment which allows outflow from the container and prevents inflow to the container through the second opening, and a mouthpiece adapted to be fitted over the openings of a patient's air passages for the delivery of the air and/or gas flowing out of the container to the patient. Using a known device, the mouthpiece is held against the pa- tient's face by one hand, while the container is squeezed by the other hand to force the air or gas present in the container out of the container.

However, it has been found that such devices for perform- ing artificial respiration on a patient, where such de- vices are in the hands of persons having no or only little practice, does not provide satisfactory breathing assistance. The reason is that it may be difficult to hold the mouthpiece correctly relative to the patient's

face by one hand to ensure that the area around the air passages is sealed completely, so that no air flows out along the edge of the mouthpiece, while squeezing the container by the other hand to press the air and/or gas present in the container into the patient. Part of the air or gas pressed out is thus lost to the ambient.

Clearly, this may have serious consequences for the pa- tient's health.

The object of the present invention is to provide a de- vice of the type mentioned in the foregoing, by means of which it may be ensured with greater certainty, also when unpractised persons use the device, that the patient re- ceives the maximum intended amount of the air pressed out of the container.

This is achieved according to the invention in that an expansible means is provided in the container and adapted to expand upon action on the outer area to displace air or other gases in the container out through the second opening.

When such an expansible means is arranged in the con- tainer, it is no longer necessary to squeeze the con- tainer by one hand to force the air present in it out through the second opening and into the patient. It is thus possible to use both hands for holding the mouth- piece relative to the patient's face, while expansion of the expansible means displaces the air from the interior of the container and into patient, and it is thus ensured that air does not, or only to a limited extent, get past the edges of the mouthpiece. The intended amount of air is thus delivered to the patient.

In an expedient embodiment, the container may be com- pressible, as the wall of the container is elastic and

flexible, so that, if desired, the device may also be used under more controlled conditions, e. g. at a hospital where experienced staff is present to hold the mask of the device in engagement with the patient's face. After manual compression of the container, air or oxygen is conventionally sucked into the inner volume because of the elasticity of the wall.

In an expedient embodiment, the expansible means is thus formed by an inflatable means. The means involved may be a means which is inflatable by means of the assistant's expiration air. The interior of the expansible means is hereby isolated from the interior of the container, and there is thus no risk of contagious diseases being trans- mitted via this device.

The container used may be of the known compressible type or may be a rigid or relative rigid container. In con- nection with the invention it is exclusively required that the container used can present a counterpressure on the expansion of the expansible element, and that the container is essentially dimensionally stable when air or gas is sucked in from the ambient.

Particularly expediently, the expansible means is a self- contractible means. Hereby the self-contractible means will suck in air through the first opening during its self-contracting function. The self-contracting force of the expansible means must be sufficient to open the valve arranged at the first opening.

In this connection the expansible means may be formed by a bag of a flexible sheet material and an elastic mate- rial, e. g. an elastic net, arranged on the outer side of this sheet material, a balloon of an elastic rubber mate- rial or a bag of a flexible sheet material formed with

corrugations or folds which, when relieved, contract the bag.

The expansible means preferably comprises a connecting element adapted to cooperate with a complementary con- necting element arranged in an opening in the container.

The opening in the container for the connecting element of the expansible means is preferably arranged such that the assistant, when performing the artificial respira- tion, can get access to the mouthpiece with his mouth.

The invention moreover relates to a container for use in connection with a resuscitator described in the forego- ing. Such a container comprises an opening through which a gas can flow into the container, an opening through which a gas can flow out of the container, and an opening through which an expansible means may be inserted into the container. If this container is used in connection with a normal resuscitator which operates by compression by hand, this opening for the insertion of an expansible means may be closed by a cap. In this connection the con- tainer must satisfy the above-mentioned criteria for such a container.

The invention moreover relates to an expansible means for use in a resuscitator as described in the foregoing. Such an expansible means comprises a mouthpiece for the injec- tion of air. The expansible means is expediently shaped as described in the foregoing, viz. either as a bag of a flexible sheet material and an elastic material, e. g. an elastic net, arranged on the outer side of it, a balloon of an elastic rubber material or a bag of a flexible ma- terial formed with corrugations or folds which, when re- lieved, contract the bag.

The invention will be explained more fully below with reference to the drawing, in which figure 1 shows a device according to the invention, seen from the side, figure 2 shows the device of figure 1 in section during the expansion of the expansible means, figure 3 shows the device of figure 1 in section during the contraction of the expansible means, figure 4 shows the device of figure 1 in section along the line 4-4, figure 5 shows an expansible means, as shown in figures 2,3 and 4, in section, figure 6 shows a first alternative embodiment of an ex- pansible means, and figure 7 shows a second alternative embodiment of an ex- pansible means.

It appears from figure 1 that the resuscitator comprises a container 1, an inlet valve housing 2 arranged in con- nection with a first opening in the container 1, and a patient valve housing 3 arranged in connection with a second opening in the container 1. A reservoir bag 5 is mounted in connection with the inlet valve housing 2. The inlet valve housing 2 comprises an inlet channel 11 for oxygen or a similar gas. A pressure relief valve 13 is provided on the upper side of the inlet valve housing. A mouthpiece 4 is provided in connection with the patient valve housing 3. The mouthpiece comprises a flexible edge area which can conform to the shape of the patient's face

upon application of pressure. Further an expansible body is mounted in the container 1, with a mouthpiece 6 asso- ciated with this protruding through an opening in the container 1.

Figure 2 shows a sectional view in a situation where air is injected into the expansible means through the mouth- piece 6. In this connection, the flow through the various valve arrangements is shown by arrows. The expansible means comprises a flexible sheet material 7 and a net of an elastic material 8. Upon expansion of the expansible means, the elastic net 8 will offer limited resistance to the expansion. As the expansible means is expanded, the valve body 14 in the inlet valve housing 2 will shut off flow out through the first opening in the container be- cause of the pressure increase in the interior of the container. At the same time, oxygen and/or another gas flows in through the channel 11 and fills the reservoir bag 5. When the bag 5 is filled completely, any addi- tional inflow of oxygen will force the valve 13 to an open position and such oxygen will thus escape through this opening. If oxygen or the like is not admitted through the channel 11, ambient air can be sucked in through the valve arrangement 12. It moreover appears from the figure that the inlet valve housing 2 is con- nected with the container 1 by an annular flange 15 on the inlet valve housing 2. The expansion of the expans- ible means will cause the air or gas present in the con- tainer 1 to be forced out through the second opening and hereby cause the valve body 16 to assume a position in which it permits flow out through openings in a wall 19 in the patient valve housing 3 and further through a branch 17 to the mouthpiece 4 and from there further in- wards through the patient's air passages. In this situa- tion the valve body 16 shuts off the ambient, as the valve body engages the edge of the opening 18 toward the

ambient. It moreover appears that the mouthpiece 6 asso- ciated with the expansible means is mounted in the con- tainer 1 by a groove 9 which cooperates with the edge of an opening 10 in the container.

Figure 3 shows a situation where the expansible means is being contracted. In this situation, the valve body 14 will open because of the self-contractible effect of the expansible means provided by the elastic net 8, and the air or the oxygen present in the reservoir bag 5 will be sucked in through the opening at the valve body 14. The gas simultaneously flowing in through the channel 11 will be sucked into the interior of the container 1 together with the gas already present in the reservoir bag. In this situation, both the pressure relief valve 13 and the suction valve 12 are closed. If no gas were introduced into the reservoir bag through the channel 11, ambient air would in this situation be sucked in through the opening at the valve body 12 and through the opening at the valve body 14 and into the interior of the container.

It moreover appears that in this situation the valve body 16 engages the wall 19 and shuts off access from the am- bient to the interior of the container via the second opening. At the same time, the patient's expiration air will flow past the valve body and toward the ambient through the opening 18.

Figure 4 is a sectional view of the device shown in fig- ure 1, where the expansible means is mounted in an open- ing 10 in the wall of the container 1. The patient valve housing 3 at the second opening is moreover visible be- hind the expansible means.

Figure 5 is a sectional view of an expansible means as shown in figures 2-4. The elastic net 8 is mounted exter- nally on the flexible sheet bag 7. Two annular flanges 9

define a groove between them for receiving the edge of an opening in the container wall. It should be mentioned in this connection that other connections are possible be- tween the expansible means and the container. Thus, a connecting element may be provided in the container where it may cooperate with a complementary connecting element on the expansible means, e. g. on the mouthpiece of the expansible means. A bayonet socket, a threaded connec- tion, a conical frictional connection, a press fit or the like may be involved in this connection.

Figure 6 shows an alternative embodiment of an expansible means for use in a device as shown in figures 1 to 3. The device shown here comprises a corrugated or folded bag which, following expansion and upon relief, will contract the bag, as the folds give rise to an application of force.

Figure 7 shows a further alternative embodiment of the expansible means. A balloon of an elastic material is in- volved here. An expanded form of the balloon is shown in dashed line.

In the embodiment described, the expansible means may be produced at low cost in terms of consumption of material and on automatic machinery and permits an expedient adap- tation of the functional properties.

The means may be made of tubular flexible sheet, e. g. polyethylene, which is pulled inwardly over a rigid plate that forms a support for the sheet. Highly elastic thin rubber thread, preferably surrounded by fabric, is then wound helically around the supported sheet tube with a suitable pitch and with suitable stretching of the thread. The ends of the thread are secured by gluing to the sheet at both ends, and longitudinal sheet strips,

likewise of polyethylene sheet, are spot welded on both sides of each thread cross.

A suitable number of straps for the thread is formed hereby, maintaining the helical position, without pre- venting the thread from sliding through these straps. The sheet tube is then welded and retained at the edges at the other end of the support plate before this is pulled out, and transverse welding is performed to seal the bag.

The bag is then released, whereby the bias of the elastic thread will fold the sheet bag together to a tube shape with a suitably small diameter which allows easy intro- duction through a mounting hole in the ventilation con- tainer.

By adapting the helical pitch of the elastic thread and the degree of the stretching of the thread during wind- ing, the folded-together diameter of the sheet bag, the resistance of the means against inflation and the self- contractible characteristic may be adapted expediently, so that during inflation the net just receives the energy necessary to ensure suitably rapid discharge of the in- flation air and suction of a corresponding amount of fresh air and oxygen into the surrounding ventilation air container.