WO2023170342A1

WO2023170342A1 - Ventilator with breathing valve assembly

Info

Publication number: WO2023170342A1
Application number: PCT/FI2023/050134
Authority: WO
Inventors: Johannes Kokkila; Henrik HUPILA; Vesa VAHTILA; Pentti Hyvärinen
Original assignee: Planmeca Oy; Planmed Oy
Priority date: 2022-03-10
Filing date: 2023-03-09
Publication date: 2023-09-14
Also published as: FI20220014A1

Abstract

An arrangement is disclosed comprising a ventilator and a valve assembly. The valve assembly (10) comprises a valve space (20) comprising a ventilator port (11) for receiving breathing gas from the ventilator, a patient port (12) for exchanging gases with a patient and an exhalation port (13) in connection to ambient. The valve space (20) comprises a pouch-like deformable valve member (14) such that it is in contact with structures defining the valve space (20) in an area between the ventilator port (11) and the exhalation port (13), such that the pouch-like deformable valve member (14) divides the valve space (20) into a first subspace (201) and a second subspace (202), whereby the first subspace (201) is in connection with the ventilator port (11) and the second sub-space (202) with the patient port (12). The pouch-like deformable valve member (14) extends from the area between the ventilator port (11) and the exhalation port (13) towards the patient port (12) and is deformable in the valve space (20) to, via its deforming and as dependent on an operational status of the valve assembly (10), partially or completely open and close a flow connection from the second subspace (202) to the exhalation port (13). The pouch-like deformable valve member (14) comprises an opening structure (15) providing, as dependent on an operational status of the valve assembly, a unidirectional flow connection from the first subspace (201) to the second subspace (202).

Description

VENTILATOR WITH BREATHING VALVE ASSEMBLY

FIELD OF THE DI SCLOSURE

This disclosure concerns an arrangement comprising a ventilator and a valve assembly .

BACKGROUND

Pressure responsive respiratory apparatus are known in the art which are designed to enable pos itive pressure from a source of pressure to be applied to a user ' s airway, and to allow for leading an ingress of breathing gas into a user ' s airway during inhalation and egress of expired tidal volume of gases from the user ' s respiratory system to be exited during exhalation, while allowing control of positive end-expiratory pressure ( PEEP) . Many of such known systems are mechanically complex or may e . g . not be able to properly control the PEEP .

BRIEF DESCRI PTION

The arrangements according to this disclosure and embodiments discussed herein relate to e . g . controlling the PEEP and to (non) complexity of a breathing circuit of the system . The arrangement and embodiments thereof presented in this disclosure include features of the valve assembly which are designed to allow for venting gases only during an exhalation cycle while also e . g . providing protection against high lung pres sures and, on the other hand, a basically resistance-free breathing valve in case of ventilator failure .

DESCRI PTION OF FIGURES

The disclosure below will be referring to the attached Figures , out of which Fig. 1 shows, as an example, an overview of an arrangement comprising a ventilator and a valve assembly,

Figs. 2 and 2a show one example of a construction of a valve assembly according to this disclosure,

Figs. 3, 3a and 3b show, as an example, embodiments of features of a frame enclosing a valve space,

Fig. 4 shows, as an example, a pouch-like deformable object designed to be placed within a frame defining a valve space,

Figs. 5a-5c show, as an example, a few different operational statuses of a valve assembly,

Figs. 6a-6b show, as an example, a few operational statuses of a valve assembly relating to safety of the assembly,

Fig. 7 shows a collector casing with an outlet port arranged around the valve assembly,

Fig. 8 is a flow chart showing an example of operation of a system to control an arrangement according to this disclosure,

Fig. 9 shows, as an example, an overview of an arrangement comprising a ventilator and a valve assembly used in connection with an anaesthesia system.

DETAILED DESCRIPTION OF THE FIGURES

Fig. 1 shows one embodiment comprising a ventilator and a valve assembly. The arrangement includes a control system which controls a flow of breathing gas to the valve assembly. The valve assembly is configured to enable providing of breathing gas to a patient, exchange of gases between the valve assembly and the patient as well as to allow for flowing of gases from the valve assembly to atmosphere (ambient) .

Fig. 2 shows, as an example, a construction of one valve assembly according to this disclosure. The valve assembly (10) of Fig. 2 comprises a valve space (20) comprising a ventilator port (11) for receiving breathing gas from the ventilator, a patient port (12) for exchanging gases with a patient and an exhalation port (13) in connection to ambient. Within the valve space (20) is arranged a pouch-like deformable valve member (14) such that it is in contact with structures defining the valve space (20) , in an area between the ventilator port (11) and the exhalation port (13) , such that the pouch-like deformable valve member (14) divides the valve space (20) into a first subspace (201) and a second subspace (202) such that the first subspace (201) is in connection with the ventilator port (11) and the second subspace (202) with the patient port (12) . The pouch-like deformable valve member (14) , which could also be referred to as a finger-like valve member, extends from said area between the ventilator port (11) and the exhalation port (13) where it is in contact with structures defining the valve space (20) towards the patient port (12) and is deformable in the valve space (20) such that the pouch-like deformable valve member (14) is able to, via its deforming and as dependent on an operational status of the valve assembly (10) , partially or completely open and close a flow connection from the second subspace (202) to the exhalation port (13) . The pouch-like deformable valve member (14) comprises an opening structure (15) providing, as dependent on an operational status of the valve assembly, a unidirectional flow connection from the first subspace (201) to the second subspace (202) .

In the embodiment of Fig. 2, the valve space (20) and the pouch-like deformable valve member (14) are elongated and the ventilator port (11) is located at the first end of the elongated valve space (20) and the patient port (12) at the second end of the elongated valve space

(20) .

In the context of Fig. 2, the opening structure (15) comprises a disc which opens towards the second subspace (202) but not towards the first subspace (201) . As shown in Fig. 2a, the opening structure (15) may comprise an openable disc (31) and a seat structure (32) to support it in a closed operation mode of the opening structure (15) . The seat structure (32) optionally comprises, instead of one larger hole, more than one orifice to enable the unidirectional flow connection from the first subspace (201) to the second subspace (202) . Regarding the disc (31), in an embodiment it is a piece of the pouch-like deformable valve member (14) partially cut off from the tip thereof. A perforated sheet may be arranged on top of the opening such generated in the pouch-like deformable valve member (14) , to form the seat (32) for the disc (31) . In another embodiment, a tip area of the pouch-like deformable valve member (14) comprises a thicker layer of material than the rest of the pouchlike deformable valve member (14) and such tip is so formed as to function as the seat (32) for a separate disc (31) attached to the pouch-like deformable valve member (14) , wherein the seat (32) again may comprise more than one orifice to allow for the unidirectional flow as discussed above.

In another embodiment not shown in any of the Figs, the opening structure (15) may be a mere opening arranged in the pouch-like deformable valve member (14) at such location that when the pouch-like deformable valve member (14) is in an operational stage in which pressure in the first subspace is higher than in the second, the opening provides a passage between the first and second subspaces but when collapsed, in an operational stage where the situation is reversed and as will be discussed further below, the opening gets pressed against the wall of the valve space and thus preventing flow of gases between the first subspace and the second subspace - particularly, from the second subspace to the first subspace. Further embodiments are now discussed in reference to Figs. 3, 3a, 3b, 4, and 5a-5c. The pouch-like deformable valve member (14) is configured to partially or completely close a flow connection from the second subspace (202) to the exhalation port (13) , when pressure in the second subspace (202) is not higher than pressure in the first subspace (201) , and partially or completely open the flow connection from the second subspace (202) to the exhalation port (13) when pressure in the first subspace (201) is lower than pressure in the second subspace (202) . The pouch-like deformable valve member (14) with the opening structure (15) is designed to provide a unidirectional flow connection from the first subspace

(201) to the second subspace (202) , when pressure in the first subspace (201) is higher than pressure in the second subspace

(202) , and not to provide flow connection between the first subspace (201) and the second subspace (202) when pressure in the first subspace (201) is lower than pressure in the second subspace (202) .

The arrangement of the above-referred Figs, comprises a frame structure (21) comprising an inner wall which delimits the valve space (20) and, concerning a sub-volume within the valve space (20) which extends from the area where the pouch-like deformable valve member (14) is in contact with the structures defining the valve space (20) to an end of the pouch-like deformable valve member (14) , in the direction of the patient port (12) and concerning the pouch-like deformable valve member (14) as not deformed by any external force acting on it, the pouch-like deformable valve member (14) may comprise a section with larger radius than the radius of the inner wall defining the valve space (20) within that section.

Further, the arrangement of these Figs, comprises a frame structure (21) with an inner wall which delimits the valve space (20) and, concerning a sub-volume within the valve space (20) which extends from said area where the pouch-like deformable valve member (14) is in contact with the structures defining the valve space (20) to an end of the pouch-like deformable valve member (14) in the direction of the patient port (12) , and concerning the pouch-like deformable valve member (14) as not deformed by any external force acting on it, concerning a section extending towards the end of the pouch-like deformable valve member (14) in the direction of the patient port (12) from where the exhalation port (13) is located, the pouch-like deformable valve member (14) comprises a section with larger radius than the radius of the inner wall of the valve space (20) within that section. That is, and this also concerns what has been presented in the previous paragraph, to present the matter differently, the pouch-like deformable valve member (14) , when not assembled inside the frame (21) and not squeezed in any way, has a section away from its pouch-like end which has a larger radius than the radius at the section of the inner wall of the valve space (20) whereto that section of the pouch-like deformable valve member (14) gets positioned when assembled. This in turn means that concerning such section of the valve assembly (20) , when there isn't any pressure difference which would cause forces acting on the pouch-like deformable valve member (14) , the pouch-like deformable valve member (14) will be in contact with the inner wall of the valve space (20) .

Above-kind embodiments may be defined such that the pouch-like deformable valve member (14) , when not assembled within the valve space (20) and when no external forces act on it which would squeeze it, has a section of larger radius than that of the inner wall of the valve space (20) along a corresponding section of the valve space whereto said section of the pouch-like deformable valve member (14) gets positioned when assembled, such section starting at the end or from a proximity of the end of the pouchlike deformable valve member (14) which when assembled within the valve space (20) gets positioned beyond a location of the exhala- tion port (13) in the direction of the ventilator port (11) and continuing therefrom towards the patient port (12) , optionally beyond location of the exhalation port (13) .

The above-discussed embodiment is different as compared to an an alternative in which the radius of the valve member at the discussed section would be smaller than that of the frame, and wherein the valve member would be made of such flexible material that pressure provided via the ventilator port would be easily adequate to stretch the valve member enough so as to have a section where it gets into contact with the inner wall of the frame structure .

Particularly the section of the pouch-like deformable valve member (14) , of the particular radius discussed above, is a section which extends over an exhalation port (13) .

Regardless of the radius of the pouch-like deformable valve member (14) as compared to the radius of the valve space within which the pouch-like deformable valve member (14) extends, within the section as discussed above, it is preferable that the radius of the pouch-like deformable valve member (14) is decreasing at the proximity of that end thereof where the opening structure (15) is located. Such embodiment facilitates separating the pouch- like deformable valve member (14) from the inner wall of the frame in an operating situation where pressure gets higher in the second subspace (202) than in the first subspace (201) .

It is to be noted that Figs. 3 and 3a are to be understood concerning an embodiment with three exhalation ports (13) arranged at even distances from each other, while Figs. 2, 5 and 6 are drawn to show an embodiment which is different in this respect. Embodiments in which there are three (or more) exhalation ports (13) opening at different directions from the frame are preferable in that such construction reduces a risk of exhalation being or getting blocked, in a given unusual use-situation of the valve assembly. In an embodiment, there are three exhalation ports at even distances from each other.

In an embodiment, to further facilitate operation of the pouchlike deformable valve member (14) , reinforcement stripes extending axially on its inner surface may be arranged thereto. Such stripes may be, in an embodiment, mere protrusions of the same material as of which the pouch-like deformable valve member (14) itself is made. Location of such stripes, as compared to location of an exhalation ports (13) in an assembled state of the assembly, may be arranged such that there is a difference in distances from a given stripe to its adjacent exhalation ports (13) .

An inner wall of the frame structure (21) which delimits the valve space (20) may comprise a protruding sub-area at and next to a location of the exhalation port (13) , as shown in Fig. 3a showing a (part of a) profile of a cross-sectional cut of the valve space at a location of exhalation ports (13) . Such protruding sub-area optionally extends a distance towards the patient port (12) and thus provides beside it a space for gases to enter between the frame structure (21) and the pouch-like deformable valve member (14) . Such structure may, again, ease collapsing of the pouch-like deformable valve member (14) , i.e. separation of the pouch-like deformable valve member (14) from the frame (21) when pressure increases within the second subspace (202) .

The valve space (20) may be elongated and at least a section of its cross-sections be formed by rotationally symmetrical or elliptic or multi-curved inner wall of the frame (21) . Those crosssections may be triangular circles.

In an embodiment, the valve space (20) has a virtual central axis and the ventilator port (11) and the patient port (12) are located on the virtual central axis at the ends of the frame (21) and at least one exhalation port (13) on the frame (21) at a location or locations between the ventilator port (11) and the patient port ( 12 ) .

The valve space (20) may be delimited as for at least part of its cross-section by a rotationally symmetrical or elliptic or multicurved frame (21) having a virtual central axis and wherein the ventilator port (11) and the patient port (12) are located on the virtual central axis at the ends of the frame (21) , and at least one exhalation port (13) on the frame (21) at a location or locations between the ventilator port (11) and the patient port (12) .

In embodiments, the frame (21) has an area of smaller inner radius at a location in the direction where the patient port (12) is located than at a location closer to where the exhalation port or ports (13) is/are located.

In embodiments, the pouch-like deformable valve member (14) is as for its general overall shape a rotationally symmetrical or elliptic object having a virtual central axis and has an area of smaller outer radius at a location in the direction where the patient port (12) is located than at a location where the exhalation port or ports (13) is/are located.

In one preferable embodiment, cross-section of the inner wall of the frame is multi-curved such that there are three sections, sort of corners where curvature is higher than in three sections between the corners. Such embodiment of the cross-section can be referred to e.g. as a triangular circle (Fig. 3b) .

In an embodiment three exhalation ports (13) are arranged to the frame (21) . In an embodiment of the inner wall shape of a triangular circle, the three exhalation ports may be arranged within sections where the curvature of the wall is smaller. Such arrangement facilitates centering the pouch-like deformable valve member (14) within the valve space (20) , closing of the exhala- tion ports ( 13 ) in operational situations in which pressure gets higher in the first subspace ( 201 ) than in the second subspace ( 202 ) , as well as opening of the exhalation ports ( 13 ) in reverse operational situations . In this sort of preferable embodiment , again, the pouch-like deformable valve member ( 14 ) may comprise a section with larger radius than the radius of the inner wall of the valve space ( 20 ) within at least the section where the exhalation ports ( 13 ) are located .

In reference to what has been discussed above relating to operation of the arrangement disclosed herein, Fig. 5a shows an operational status of the valve assembly (10) in which pressure in the first subspace (201) is greater than in the second subspace (202) and the breathing gas may flow through the opening structure (15) towards the patient port (12) , while the exhalation port (13) is closed. In Fig. 5b the situation as far as pressures in the subspaces (201, 202) is concerned is reversed, whereby the opening structure (15) closes and the pouch-like deformable valve member ( 14 ) collapses , thereby providing a flow channel for gases trough the exhalation port ( 13 ) . Fig . 5c shows a status of the valve assembly ( 10 ) when there is equal pressure in the subspaces (201, 202) . The ventilator may be used to control pressures or flows in the valve assembly so as to control a degree of opening of the exhalation port (13) e . g. when approaching an end of an exhalation mode .

In reference to Fig. 6a, concerning a situation where there is overpressure on the patient side of the valve assembly (10) , the pouch-like deformable valve member - which can be e . g . a membrane made of silicone - collapses so as to allow for a leak out of gases form the exhalation port (13) . The higher the over pressure, the more the membrane will collapse . In addition, the ventilator controller may be configured to decrease the pressure on the ventilator side to actively help reducing the overpressure .

In reference to Fig. 6b, in case of such complete ventilator failure that the pressure from the ventilator disappears, a patient will still be able to breathe spontaneously with very low resistance from the arrangement . During inhalation, in case resistance through ventilator is too high, a lower pressure on the patient end of the valve assembly will first open the opening structure ( 15 ) which will equal the pressure within the valve space (20) , after which when pressure in the valve space (20) will be smaller than ambient pressure, the pouch-like deformable valve member ( 14 ) will collapse, which then allows for the air to be drawn via the exhalation port (13) .

In an embodiment, as shown in Fig. 7, a separate collector casing (30) with an outlet port is arranged on top of the valve assembly, to cover and encircle any number of exhalation ports (13) the valve assembly may comprise . The collector casing (30) may be arranged as releasably connectable to the assembly. The connection may also be arranged to allow for e . g. rotation of the collector casing (30) in relation to the valve assembly and thus orienting the outlet port in a desired direction . By such arrangement, one will be able to collect exhalation gases of e . g. an infected patient exiting the valve assembly, and forward the gases to proper processing, like to be filtered.

In embodiments , the arrangement comprises in connection with the second subspace ( 202 ) a measuring sensor ( 16 ) which is arranged in functional connection with the control system, wherein the control system is configured to control providing of the breathing gas as a response to a signal received from the measuring sensor ( 16 ) .

In embodrments , the control system rs confrgured to provrde breathing gas to the ventilator port ( 11 ) when a signal value received from the measuring sensor ( 16 ) is higher than a given set target signal value and decrease or cease providing breathing gas to the ventilator port ( 11 ) when a signal value received from the measuring sensor ( 16 ) is higher than a given set target signal value . In embodiments, the measuring sensor (16) is a pressure sensor.

As one particular aspect, the arrangement may be arranged devoid of a non-return valve between the ventilator port (11) and the ventilator. This enables flowing of gases towards the ventilator in case pressure in the valve assembly (10) gets too high. Besides there being no non-return valve, the arrangement may be arranged to be devoid of any structure that could as such prevent the ventilator port (11) to be in connection via the ventilator with ambient.

In embodiments, the control system comprises an inspiration mode wherein the first target signal value is a first target pressure higher than ambient pressure and wherein the control system is configured to control the providing of the breathing gas so as to, when reaching the first target pressure, maintain the pressure in the second subspace at said first target pressure, whereby during the inspiration mode the pouch-like deformable valve member (14) is pressed against the exhalation port (13) and thus prevents flow from the second subspace (202) to the exhalation port (13) while the opening structure (15) does provide the unidirectional flow connection from the first subspace (201) to the second subspace (202) , and an exhalation mode wherein the second target signal value is a second target pressure lower than the first target pressure and wherein the control system is configured to control the providing of the breathing gas so as to allow for the pressure in the second subspace (202) to be higher than pressure in the first subspace (201) , whereby the pouch-like deformable valve member (14) collapses from the side of the second subspace (202) and thereby opens the exhalation port (13) and allows for flow from the second subspace (202) to the exhalation port (13) and whereby the opening structure (15) providing the unidirectional flow connection from the first subspace (201) to the second subspace (202) closes and prevents flow from the second subspace (202) to the first subspace (101) . One possible circuit to implement controlling of the arrangement is shown in Fig. 8. There, Goal is set by user or by algorithms to define the target for the system, i . e . Set value . Set value is given to Controller, which is an algorithm that compares Set value and Feedback value (s) from

Sensor (s) and decides appropriate System Input . System herein comprises of the whole physical system including ventilator electronics, mechanics, pneumatics, actuators, patient breathing circuit, actual patient and all related noise . With a System Input the System has a specific Output based on its systemic transfer function. The Output is measured with the Sensor within its accuracy, noise and sampling rate (its transfer function) . The measurement is given to the Controller as Feedback signal .

Fig. 9 shows an overview of an arrangement comprising a ventilator and a valve assembly as discussed herein, which can be used e .g. as an actuator operating bellows included in an anaesthesia system .

Claims

1. Arrangement comprising a ventilator and a valve assembly, wherein the ventilator is arranged to provide breathing gas to the valve assembly, wherein the valve assembly (10) comprises a valve space (20) comprising a ventilator port (11) for receiving breathing gas from the ventilator, a patient port (12) for exchanging gases with a patient and an exhalation port (13) in connection to ambient, c h a r a c t e r i z e d i n t h a t within said valve space (20) is arranged a pouch-like deformable valve member (14) such that it is in contact with structures defining the valve space (20) in an area between the ventilator port (11) and the exhalation port (13) such that the pouch-like deformable valve member (14) divides the valve space (20) into a first subspace (201) and a second subspace (202) such that the first subspace (201) is in connection with the ventilator port (11) and the second subspace (202) with the patient port (12) , and wherein the pouch-like deformable valve member (14) extends from said area between the ventilator port (11) and the exhalation port (13) where it is in contact with structures defining the valve space (20) towards the patient port (12) and is deformable in the valve space (20) such that the pouch-like deformable valve member (14) is able to, via its deforming and as dependent on an operational status of the valve assembly (10) , partially or completely open and close a flow connection from the second subspace (202) to the exhalation port (13) , and wherein the pouch-like deformable valve member (14) comprises an opening structure (15) providing, as dependent on an operational status of the valve assembly, a unidirectional flow connection from the first subspace (201) to the second subspace (202) .

2. Arrangement according to claim 1, c h a r a c t e r i z e d i n t h a t the pouch-like deformable valve member (14) is configured to partially or completely close a flow connection from the second subspace (202) to the exhalation port (13) when pressure in the second subspace (202) is not higher than pressure in the first subspace (201) , and partially or completely open the flow connection from the second subspace (202) to the exhalation port (13) when pressure in the first subspace (201) is lower than pressure in the second subspace (202) , and wherein the pouch-like deformable valve member (14) with said opening structure (15) providing the unidirectional flow connection from the first subspace (201) to the second subspace (202) is configured to provide said unidirectional flow connection when pressure in the first subspace (201) is higher than pressure in the second subspace (202) and not to provide flow connection between the first subspace (201) and the second subspace (202) when pressure in the first subspace (201) is lower than pressure in the second subspace (202) .

3. Arrangement according to claim 1 or 2, c h a r a c t e r i z e d i n t h a t the arrangement comprises a frame structure (21) comprising an inner wall which delimits the valve space (20) and, concerning a sub-volume within the valve space (20) which extends from said area where the pouch-like deformable valve member (14) is in contact with the structures defining the valve space (20) to an end of the pouch-like deformable valve member (14) in the direction of the patient port (12) , and concerning the pouch-like deformable valve member (14) as not deformed by any external force acting on it, the pouch-like deformable valve member (14) comprises a section with larger radius than the radius of the inner wall of the valve space (20) within that section.

4. Arrangement according to any of the claims 1 - 3, c h a r a c t e r i z e d i n t h a t the arrangement comprises a frame structure (21) comprising an inner wall which delimits the valve space (20) and, concerning a sub-volume within the valve space (20) which extends from said area where the pouch-like deformable valve member (14) is in contact with the structures defining the valve space (20) to an end of the pouch-like deformable valve member (14) in the direction of the patient port (12) , and concerning the pouch-like deformable valve member (14) as not deformed by any external force acting on it, concerning a section extending towards the end of the pouch-like deformable valve member (14) in the direction of the patient port (12) from where the exhalation port (13) is located, the pouch-like deformable valve member (14) comprises a section with larger radius than the radius of the inner wall of the valve space (20) within that section.

5. Arrangement according to claims 1 or 2, c h a r a c t e r i z e d i n t h a t the pouch-like deformable valve member (14) , when not assembled within the valve space (20) and when no external forces act on it which would squeeze it, has a section of larger radius than that of an inner wall of the valve space (20) along a corresponding section of the valve space whereto said section of the pouch-like deformable valve member (14) gets positioned when assembled, such section starting at the end or from a proximity of the end of the pouch-like deformable valve member (14) which when assembled within the valve space (20) gets positioned beyond a location of the exhalation port (13) in the direction of the ventilator port (11) and continuing therefrom towards the patient port (12) , optionally beyond location of the exhalation port (13) .

6. Arrangement according to any of the claims 1 - 5, c h a r a c t e r i z e d i n t h a t the pouch-like deformable valve member (14) comprises reinforcement stripes extending axially on its inner surface, wherein the stripes are optionally protrusions of the same material as of which the pouch-like deformable valve member (14) itself is made.

7. Arrangement according to any of the claims 1 - 6, c h a r a c t e r i z e d i n t h a t the arrangement comprises a frame structure (21) comprising an inner wall which delimits the valve space (20) , the inner wall comprising a protruding sub-area at and next to a location of the exhalation port (13) , which protruding subarea optionally extends a distance towards the patient port (12) .

8. Arrangement according to any of the claims 1 - 7, c h a r a c t e r i z e d i n t h a t the valve space (20) comprises three exhalation ports (13) locating at even distances from each other.

9. Arrangement according to any of the claims 1 - 8, c h a r a c t e r i z e d i n t h a t the opening structure (15) comprises an openable disc (31) and a seat structure (32) to support the disc in a closed operation mode of the opening structure (15) , the seat structure (32) comprising more than one hole to provide the unidirectional flow connection from the first subspace (201) to the second subspace (202) .

10. Arrangement according to claim 9, c h a r a c t e r i z e d i n t h a t the disc (31) is a piece partially cut off from the tip of the pouch-like deformable valve member (14) .

11. Arrangement according to claim 9, c h a r a c t e r i z e d i n t h a t a tip area of the pouch-like deformable valve member (14) comprises a thicker layer of material than the rest of the pouchlike deformable valve member (14) and such tip is so formed as to function as the seat (32) for the disc (31) .

12. Arrangement according to any of the claims 1 - 11, c h a r a c t e r i z e d i n t h a t the valve space (20) is elongated and at least a section of its cross-sections is formed by rotationally symmetrical or elliptic or multi-curved inner wall of the frame (21) .

13. Arrangement according to claim 12, c h a r a c t e r i z e d i n t h a t said cross-sections are triangular circles.

14. Arrangement according to claim 11, c h a r a c t e r i z e d i n t h a t the arrangement comprises a frame structure (21) comprising an inner wall and a cross-section of the inner wall of the frame is multi-curved such that as to form a triangular circle, wherein optionally three exhalation ports (13) are arranged each within a section of the frame structure (21) where the curvature of the inner wall is lower.

15. Arrangement according to any of the claims 1 - 14, c h a r a c t e r i z e d i n t h a t the valve space (20) has a virtual central axis and wherein the ventilator port (11) and the patient port (12) are located on the virtual central axis at the ends of the frame (21) and at least one exhalation port (13) on the frame (21) at a location or locations between the ventilator port (11) and the patient port (12) .

16. Arrangement according to any of the claims 1 - 15, c h a r a c t e r i z e d i n t h a t the frame (21) has an area of smaller inner radius at a location in the direction where the patient port (12) is located than at a location where the exhalation port or ports (13) is/are located.

17. Arrangement according to any of the claims 1 - 16, c h a r a c t e r i z e d i n t h a t the valve space (20) and the pouch-like deformable valve member (14) are elongated and the ventilator port (11) is located at the first end of the elongated valve space (20) and the patient port (12) is located at the second end of the elongated valve space (20) .

18. Arrangement according to any of the claims 1 - 17, c h a r a c t e r i z e d i n t h a t the arrangement comprises a collector casing (30) with an outlet port arranged on top of the valve assembly, to cover and encircle any number of exhalation ports (13) the valve assembly may comprise.

19. Arrangement according to any of the claims 1 - 18, c h a r a c t e r i z e d i n t h a t the arrangement is devoid of a nonreturn valve between the ventilator port (11) and the ventilator (10) , and of any structure that could as such prevent the ventilation port (12) to be in connection via the ventilator with ambient .

20. Arrangement according to any of the claims 1 - 19, c h a r a c t e r i z e d i n t h a t the pouch-like deformable valve member (14) is as for its general overall shape a rotationally symmetrical or elliptic object having a virtual central axis and has an area of smaller outer radius at a location in the direction where the patient port (12) is located than at a location where the exhalation port or ports (13) is/are located.

21. Arrangement according to any of the claims 1 - 20, c h a r a c t e r i z e d i n t h a t the arrangement comprises in connection with the second subspace (202) a measuring sensor (16) which is arranged in functional connection with the control system, wherein the control system is configured to control providing of the breathing gas as a response to a signal received from the measuring sensor (16) .

22. Arrangement according to claim 21, c h a r a c t e r i z e d i n t h a t the control system is configured to provide breathing gas to the ventilator port (11) when a signal value received from the measuring sensor (16) is higher than a given set target signal value and decrease or cease providing breathing gas to the ventilator port (11) when a signal value received from the measuring sensor (16) is higher than a given set target signal value.

23. Arrangement according to claim 22, c h a r a c t e r i z e d i n t h a t the control system comprises an inspiration mode wherein a first target signal value is a first target pressure higher than ambient pressure and wherein the control system is configured to control the providing of the breathing gas so as to, when reaching the first target pressure, maintain the pressure in the second subspace at said first target pressure, whereby during the inspiration mode the pouch-like deformable valve member (14) is pressed against the exhalation port (13) and thus prevents flow from the second subspace (202) to the exhalation port (13) while the opening structure (15) does provide the unidirectional flow connection from the first subspace (201) to the second subspace (202) , and an exhalation mode wherein the second target signal value is a second target pressure lower than the first target pressure and wherein the control system is configured to control the providing of the breathing gas so as to allow for the pressure in the second subspace (202) to be higher than pressure in the first subspace (201) , whereby the pouch-like deformable valve member (14) collapses from the side of the second subspace (202) and thereby opens the exhalation port (13) and allows for flow from the second subspace (202) to the exhalation port (13) and whereby the opening structure (15) providing the unidirectional flow connection from the first subspace (201) to the second subspace (202) closes and prevents flow from the second subspace (202) to the first subspace (101) .