VENTILATOR WITH BREATHING VALVE ASSEMBLY
FIELD OF THE DISCLOSURE
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 positive pressure from a source of pressure to be applied to a user's airway, and to allow for lead- ing an ingress of breathing gas into a user's airway during inha- lation and egress of expired tidal volume of gases from the us- er's respiratory system to be exited during exhalation, while al- lowing control of positive end-expiratory pressure (PEEP). Many of such known systems are mechanically complex and may e.g. not be able to properly prevent rebreathina of expired gases.
BRIEF DESCRIPTION
The arrangements according to this disclosure and embodiments discussed herein relate to e.g. addressing a problem of rebreath- ing of expired gas as well as complexity of a breathing circuit of the system. The arrangement and embodiments thereof of this disclosure include features of the valve assembly being designed . to allow for venting gases only during an exhalation cycle while
N also e.g. providing protection against high lung pressures and,
N on the other hand, a basically resistance-free breathing valve in 2 30 case of ventilator failure. oO z DESCRIPTION OF FIGURES a &
S The disclosure below will be referring to the attached Figures,
N 35 out of which
N
Fig. 1 shows, as an example, an overview of an arrangement com- prising a ventilator and a valve assembly,
Fig. 2 shows one example of a construction of a valve assembly according to this disclosure,
Figs. 3 and 3a show, as an example, a frame defining a valve space,
Fig. 4 shows, as an example, a pouch-like deformable object de- signed to be placed within a frame defining a valve space,
Figs. 5a-5c show, as an example, a few different operational sta- tuses 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,
Figs. 7 is a flow chart showing an example of operation of a sys- tem to control an arrangement according to this disclosure,
Fig. 8 shows, as an example, an overview of an arrangement com- prising a ventilator and a valve assembly used in connection with an anaesthesia system.
N DETAILED DESCRIPTION OF THE FIGURES
N
& 0 Fig. 1 shows one embodiment comprising a ventilator and a valve = assembly. The arrangement includes a control system which con- > 30 trols a flow of breathing gas to the valve assembly. The valve
E assembly is configured to enable providing of breathing gas to a = patient, exchange of gases between the valve assembly and the pa- tient as well as to allow for flowing of gases from the valve as- sembly to atmosphere (ambient).
Fig. 2a shows, as an example, a construction of one valve assem- bly according to this disclosure. The valve assembly (10) of Fig. 2 comprises a valve space (20) comprising a ventilator port (11) for re- ceiving breathing gas from the ventilator, a patient port (12) for ex- changing gases with a patient and an exhalation port (13) in connection to ambient. Within the valve space (20) is arranged a pouch-like de- formable valve member (14) such that it is in contact with struc- tures defining the valve space (20) in an area between the venti- lator 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) 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 com- pletely open and close a flow connection from the second subspace (202) to the exhalation port (13), and wherein the pouch-like de- formable valve member (14) comprises an opening structure (15) providing, as dependent on an operational status of the valve as- sembly, a unidirectional flow connection from the first subspace (201) to the second subspace (202).
N In the context of Fig. 2 the opening structure (15) is a lid which opens
N towards the second subspace (202) but not towards the first subspace 3 30 (201) . In another embodiment not shown in the Figs. the opening structure 2 (15) may be a mere opening arranged in the pouch-like deformable valve
I member (14) at such location that when the pouch-like deformable 5 valve member (14) is in an operational stage as shown in Fig. 2a,
S the opening provides a passage between the first and second sub-
N 35 spaces but when collapsed, as will be discussed further below,
N the opening gets pressed against the wall of the valve space and thus prevents flow of gases between the first and second sub- space.
In reference to Figs. 3, 3a, 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 exhala- tion 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 sub- space (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 con- nection 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 sub- space (202) when pressure in the first subspace (201) is lower than pressure in the second subspace (202).
The arrangement of the Figs. comprises a frame structure (21) comprising inner walls which delimit 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
N direction of the patient port (12) and concerning the pouch-like
N deformable valve member (14) as not deformed by any external 3 30 force acting on it, the pouch-like deformable valve member (14) 2 comprises a section with larger diameter than the diameter of the
I inner wall of the valve space (20) within that section. s
S Further, the arrangement of the Figs. comprises a frame structure
N 35 (21) comprising inner walls which delimit the valve space (20)
N and, concerning a sub-volume within the valve space (20) which extends from said area where the pouch-like deformable valve mem- ber (14) is in contact with the structures defining the valve space (20) to an end of the pouch-like deformable valve member 5 (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 to- wards 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 diameter than the diameter 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 de- formable 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 diameter than the diameter 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. And 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 thus be presented such that the pouch-
N like deformable valve member (14), when not assembled within the
N valve space (20) and when no external forces act on it which 3 30 would squeeze it, has a section of larger diameter than that of 2 inner walls of the valve space (20) along a corresponding section = of the valve space whereto said section of the pouch-like deform- 5 able valve member (14) gets positioned when assembled, such sec-
S tion starting at the end or from a proximity of the end of the
N 35 pouch-like deformable valve member (14) which when assembled
N 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), op- tionally beyond location of the exhalation port (13).
The frame structure (21) comprises inner walls which delimit the valve space (20), wherein the inner walls may comprise a protrud- ing sub-area at and next to a location of the exhalation port (13), as shown in Fig. 3a which shows a (part of a) profile of a cross-sectional cut of the valve space from where exhalation ports (13) are located. Such protruding sub-area optionally ex- tends 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 struc- ture may ease collapsing of the pouch-like deformable valve mem- ber (14), i.e. separation of the pouch-like deformable valve mem- ber (14) from the frame (21) when pressure increases within the second subspace (202).
In an embodiment, there are three exhalation ports (13) each lo- cating at the same distance from both the ventilator port (11) and the patient port (12) and locating at even distances from each other, as like partially shown in Fig. 3.
As one particular safety 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 venti-
N lator in case pressure in the valve assembly (10) gets too high.
N Besides there being no non-return valve, the arrangement may be 3 30 arranged to be devoid of any structure that could as such prevent 2 the ventilation port (12) to be in connection via the ventilator
I with ambient a
Xx
S The valve space (20) may be delimited as for its cross-section by
N 35 a rotationally symmetrical or elliptic frame (21) having a virtu-
N al central axis and wherein the ventilator port (11) and the pa- tient 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 radi- us 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 embodiments, the pouch-like deformable valve member (14) is as for its general overall shape a rotationally symmetrical or el- liptic object having a virtual central axis and has an area of smaller outer radius at a location in the direction where the pa- tient port (12) is located than at a location where the exhala- tion port or ports (13) is/are located.
In view of what has presented above, Fig. ba shows an operational status of the valve assembly (10) where 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 s trough the exhalation port (13). Fig. 5c shows a status of the
N valve assembly (10) when there is equal pressure in the subspaces
N (201, 202). The ventilator may be used to control pressures in the valve
S 30 assembly so as to control a degree of opening of the exhalation port (13) 2 e.g. near an end of the arrangement being in an exhalation mode. x 5 In reference to Fig. 6a, concerning a situation where there is over-
S pressure on the patient side of the valve assembly (10), the pouch-like
N 35 deformable valve member - which can be e.g. a membrane made of
N silicone - collapses so as to allow for a leak out of gases form the ex- halation port (13). The higher the over pressure, the more the membrane will collapse. In addition, the ventilator controller may be configured to decreases the pressure on the ventilator side to actively help reduc- ing 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 collapses which then allows for the air to be drawn via the exhalation port (13).
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 breath- ing gas as a response to a signal received from the measuring sensor (16).
In embodiments, the control system is configured to provide breathing gas to the ventilator port (11) when a signal value re- ; ceived from the measuring sensor (16) is higher than a given set
N
N target signal value and decrease or cease providing breathing gas
N to the ventilator port (11) when a signal value received from the
O
? 30 measuring sensor (16) is higher than a given set target signal oO — value.
I
Ao a < In embodiments, the measuring sensor (16) is a pressure sensor.
O oS
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N
O
N
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 pres- sure in the second subspace at said first target pressure, where- by 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 uni- directional 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 config- ured 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 de- formable valve member (14) collapses from the side of the second subspace (202) and thereby opens the exhalation port (13) and al- lows 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 sec- ond subspace (202) to the first subspace (101).
One possible circuit to implement controlling of the arrangement is shown : in Fig. 7. There, Goal is set by user or by algorithms to define the tar-
N get for the system, i.e. Set value. Set value is given to Controller,
N which is an algorithm that compares Set value and Feedback value(s) from
ST 30 Sensor(s) and decides appropriate System Input. System herein comprises 2 of the whole physical system including ventilator electronics, mechanics, z pneumatics, actuators, patient breathing circuit, actual patient and all > related noise. With a System Input the System has a specific Output based
S on its systemic transfer function. The Output is measured with the Sensor
S within its accuracy, noise and sampling rate (its transfer function). The measurement is given to the Controller as Feedback signal.
Fig. 8 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.
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Ao a + oO o
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