DE102023001116A1 - System for coupling with a ventilator - Google Patents

Abstract

The invention relates to a system (1) for connection to an air inlet (3) of a ventilator (2) in order to enable maximization of alveolar ventilation while maintaining normocapnic conditions at maximum oxygen concentration, for example for the preclinical treatment of carbon monoxide poisoning. To this end, the invention proposes providing CO ₂ from a gas source (14) in a reservoir volume (19) at the air inlet (3) instead of air, so that the ventilator (2) in conjunction with an O ₂ source can produce a mixture of CO ₂ and O ₂ and ventilate the patient with it.

Description

The invention relates to a system for coupling to a ventilator having the features of claim 1 and the combination of the system with a ventilator having the features of claim 11.

For the treatment of conditions such as carbon monoxide poisoning, maximizing alveolar ventilation while maintaining normocapnic conditions at maximum oxygen concentration may be therapeutically desirable as part of artificial ventilation. Ventilation is therefore carried out at a high frequency and with large volumes, and the ventilation gas is adjusted by adding CO ₂ so that the CO ₂ content (CO ₂ = carbon dioxide) and the pH value of the blood remain within the normal range. The concept behind this is to create the maximum possible CO concentration gradient (CO = carbon monoxide) between the blood side and the air side at the alveolar membrane, thus accelerating the exhalation of the poison.

The ClearMate product from Thornhill Research is a system that offers a manual ventilation option specifically for this purpose. The system has a dosing unit that provides a mixture of CO ₂ and O ₂ (O ₂ = oxygen), which is administered manually to the patient via a ventilation bag and a breathing mask. The frequency and volume applied are controlled by the operator.

Commercially available automatic emergency ventilators usually do not have an option for such therapy, as they are only designed to administer mixtures of the ventilation gases oxygen, room air or compressed air.

The invention is therefore based on the object of creating a system, particularly for pre-clinical use, in which a defined admixture of a gas (for example CO ₂ , NO or H ₂ ) to the ambient air drawn in is possible using an automatic emergency ventilator. In addition to the treatment of carbon monoxide poisoning described above, this can also be used to treat various other clinical pictures. For the treatment of acute right heart strain, for example in the case of a fulminant pulmonary embolism, the gas to be added is NO (NO = nitrogen monoxide). To date, even for such treatment with defined concentrations of NO for pre-clinical use, only systems that are intended for use with the manual resuscitation bag are known. Other gases are also intended for the treatment of other clinical pictures (e.g. for the treatment of ischemia-related damage, for example in the case of cardiac arrest, H ₂ (H ₂ = hydrogen) or noble gases.

In the following, a “ventilator” always means an automatic ventilator, in particular an automatic emergency ventilator.

This object is achieved according to the invention by the system having the features of claim 1 and the combination of such a system with a ventilator according to claim 11.

The system according to the invention can be coupled to a ventilator. This means that the entire technology of the ventilators that are already widely used in preclinical emergency medicine can be used, including the built-in pumps, dosing units, control electronics and user interfaces. According to the invention, the system can be connected to an air inlet of the ventilator, through which ambient air can be sucked in for the gas path of the ventilator without the system. The air inlet is therefore not an inlet for air to cool the device, but for sucking in air to provide the breathing gas to the patient.

The system comprises a gas source, in particular a gas container such as a gas cylinder, with which a gas is provided.

The system also has a connection element for fluid connection to the air inlet. The connection element is in particular a solid body with a device nozzle that is geometrically matched to one or more ventilators and a circular connecting nozzle. However, a flexible, hose-like and/or film-like element that is clamped to the ventilator or fixed with adhesive strips in such a way that the air inlet is enclosed is also conceivable.

A fluidic connection for the gas connects the gas source with the connection element.

With the ventilator, a mixture of the gas from the gas source, in particular CO ₂ , NO or H ₂ , and another gas, in particular O ₂ , can be made available in a desired mixing ratio by means of the system according to the invention. Ventilators have an inlet for O ₂ as standard and the O ₂ can be mixed in a desired mixing ratio with air that is sucked in through the air inlet. In addition, the ventilation frequency and the ventilation volume can be adjusted. With the In the system according to the invention, the air is replaced by the gas from the gas source and it is thus possible, for example, to specifically ventilate with a mixture of 95 vol.% O ₂ and 5% CO ₂ .

The fluidic connection and the connection element preferably have a reservoir volume of 5 ml to 1,500 ml, in particular 50 ml to 100 ml. The reservoir volume is the volume that can theoretically be sucked out by the ventilator via the air inlet without taking into account gas flowing in from the gas source. The reservoir volume is filled with gas from the gas source in a planned manner, in particular continuously, and the ventilator sucks the gas out of the reservoir volume, in particular with a cyclically changing volume flow. A lower limit of the reservoir volume ensures that sufficient gas is available, while an upper limit can ensure that not too much gas is available, as a result of which the gas mixture added to the patient could contain too much gas, in particular too much CO ₂ , NO or H ₂ .

Alternatively, the reservoir volume could be kept very small and the gas flow from the gas source could be continuously adjusted to the amount required by the ventilator using a control system. However, this requires considerable control effort as well as an interface to the ventilator and/or a sensor to measure the resulting gas concentrations in the ventilation tube system.

In order to ensure in the simplest possible way that the desired amount of gas is sucked in by the ventilator, the invention proposes that the system has a pressure equalization system such that the pressure in the reservoir volume essentially corresponds to the ambient pressure. As a result, the pressure situation at the inlet of the ventilator is exactly the same as when operating without the system according to the invention, namely the pressure is approximately ambient. This ensures that the mixing unit of the ventilator creates the desired mixing ratio with the gas from the gas source in the same way as it would otherwise with ambient air. This is particularly ensured if, regardless of the gas flow from the gas source, the flow resistance for the suction of the ventilator corresponds approximately to that of the otherwise usual filter at the air inlet.

The pressure equalization system preferably has a negative pressure limiting element, in particular in the form of a valve. A valve in particular allows ambient air to flow in if the pressure in the reservoir volume falls below a predetermined limit. If the ventilator incorrectly sucks very large quantities of gas from the reservoir volume, for example because an operator has not connected O ₂ or has set an O ₂ concentration that is too low and thus more gas is sucked in through the inlet, this ensures on the one hand that no negative pressure is created that could potentially damage the ventilator and on the other hand that ambient air is sucked in after the reservoir volume has been drained. This helps to prevent too much CO ₂ from reaching the patient.

Furthermore, the pressure equalization system preferably has an overpressure limiting element, in particular in the form of a valve. A valve allows the gas to flow out when the reservoir volume is completely filled with gas and the pressure rises above a predetermined limit. This enables the reservoir volume to be filled particularly easily, for example with a continuous gas flow, whereby excess gas can always escape through the valve due to the resulting overpressure.

When using a combination of overpressure and negative pressure limiting elements, it is also possible that some ambient air enters the reservoir volume during each phase of suction by the ventilator and is flushed out again by the gas when suction stops. In this respect, the negative pressure valve should be located closer to the gas source and the overpressure valve closer to the connection element.

Preferably, an actuator for dosing the gas, in particular a throttle valve, is arranged fluidically between the gas source and the reservoir volume. "Dosing" means controlling or regulating a volume or mass flow. A throttle valve enables a volume flow to be controlled in a simple manner and, depending on the design, also the regulation of a volume flow.

The invention proposes that the reservoir volume is adjustable so that the amount of gas available for the ventilator can be adapted to the respective therapy situation.

In one embodiment, the fluidic connection has a region with a flexible wall such that the reservoir volume changes with different internal and external pressure. In particular, a bag forms part of the fluidic connection and the reservoir volume. This may make it possible to dispense with a pressure compensation system. However, it is also conceivable to provide one in addition. Instead of a pressure relief valve or in addition to it In particular, an opening can be provided in the area of the flexible wall in order to counteract excess pressure or to ensure in a simple manner with a continuous excess of gas that there is always sufficient gas in the reservoir volume at ambient pressure. Alternatively, the opening can also be provided at another point in the reservoir volume.

The system preferably has a filter. The filter can be used to filter the gas from the gas source. Preferably, however, it is used to filter any ambient air that may flow in through a valve of the pressure equalization system. The volume of the filter forms part of the reservoir volume.

The invention proposes the combination of the described system with a ventilator. The ventilator preferably has a connecting device with which a filter element can be connected to the air inlet. To combine it with the system, the filter of the ventilator is removed and instead the connection element is connected to the ventilator by means of the connecting device.

• 1 eine schematische Darstellung des erfindungsgemäßen Systems mit einem Beatmungsgerät;
• 2 eine schematische Darstellung eines alternativen erfindungsgemäßen Systems;
• 3 eine perspektivische Teildarstellung eines Beatmungsgeräts mit entnommenem Filter;
• 4 dasselbe Beatmungsgerät mit einem erfindungsgemäßen Anschlusselement in perspektivischer Teildarstellung; und
• 5 dasselbe Anschlusselement in perspektivischer Darstellung.

The invention is explained below using two exemplary embodiments. They show:

• 1 a schematic representation of the system according to the invention with a ventilator;
• 2 a schematic representation of an alternative system according to the invention;
• 3 a partial perspective view of a ventilator with the filter removed;
• 4 the same ventilator with a connection element according to the invention in a perspective partial view; and
• 5 the same connection element in perspective view.

In 1 is a schematic overview of a system 1 according to the invention, connected to a commercially available ventilator 2. The ventilator 2 is an automatic emergency ventilator. The ventilator 2 has an air inlet 3 and a further inlet 4, to which an O ₂ source 5 in the form of an oxygen bottle is connected. Lines lead from the air inlet 3 and the further inlet 4 to a module 6, with which the incoming gas flows are mixed and conveyed in a ratio predetermined by a controller (not shown). Another line leads from the module 6 to a patient-side outlet of the patient. These other elements of the ventilator 2 are not important in connection with the invention, which is why they are not shown.

A first T-piece 8 is connected to the air inlet 3 via a connection element 7 of the system 1. A first valve 9 as an overpressure limitation element 10 and a bellows-like pipe section 11 are also connected to the first T-piece 8. The first valve 9 is designed, for example, as a plate pressure relief valve with a flexible elastomer plate. The valve 9 is connected in such a way that if there is an overpressure in the first T-piece 8 compared to the ambient pressure, it opens so that the gas can escape into the environment. Opposite the first T-piece 8, on the pipe section 11, a second T-piece 12 is connected, which is connected at its two other ends on the one hand to a filter 13 and on the other hand via a line to a gas source 14 in the form of a gas container 15. The gas here is CO ₂ , but could also be NO or H ₂ , for example, and the gas container 15 is a CO ₂ bottle. Opposite the second T-piece 12, a second valve 16 is connected to the filter 13 as a vacuum limiting element 17. The second valve 16 is connected in such a way that it opens when the ambient pressure is above the filter 13, so that air can flow into the filter 13. Between the gas source 14 and the second T-piece 12, a gas throttle valve 18 is arranged, with which a continuous gas flow from the gas source 14 to the second T-piece 12 can be set, which is therefore an actuator 22 for dosing the gas.

The interior of the area between the throttle valve 18, the two valves 9, 16 and the connection element 7 forms a reservoir volume 19. In addition, these elements form a fluidic connection 20 for the gas between the gas source 14 and the connection element 7. The two valves 9, 16 form a pressure equalization system 21 for the reservoir volume 19 such that essentially ambient pressure prevails in the reservoir volume 19.

To treat carbon monoxide poisoning, settings of the ventilator 2 can be selected that are actually used for ventilation with a mixture of O ₂ and air, for example 95% O ₂ and 5% air. To do this, the module 6 draws in a gas flow via the air inlet 3, whereby without the system 1, ambient air would be drawn in for the gas path of the ventilator 2. By connecting the system 1 according to the invention, CO ₂ is drawn out of the reservoir volume 19 instead of air. The pressure compensation system 21 ensures that there is no significant overpressure or underpressure compared to the environment, so that the set mixing ratio is not disturbed. For example, in the case of a significant overpressure, more than the exemplary at least 5% of CO ₂ reaches the patient. In particular, suction takes place cyclically with a variable volume flow according to the ventilation cycle for the patient. The continuous flow of CO ₂ into the reservoir volume 19 ensures that sufficient CO ₂ is always made available. At the same time, the reservoir volume 19 also limits the maximum amount of CO _{2 that} can be sucked in per breath, so that in the event of incorrect adjustment by the operator, not too much CO ₂ can reach the patient. The bellows-like pipe section 11 allows the reservoir volume 19 to be adapted to different therapy situations. Instead of using a bellows-like structure, the reservoir volume 19 could also be changed using a telescope, a piston or the like. The throttle valve 18 is to be adjusted in particular so that the reservoir volume 19 is always well filled and not too much air flows in through the negative pressure limiting element 17 when the ventilator 2 sucks in. On the other hand, not so much CO ₂ should flow into the reservoir volume 19 that, due to the resulting overpressure, larger quantities of CO ₂ are permanently released into the environment via the overpressure limiting element 10, because this could accelerate the emptying of the gas source and have a negative effect on the people present in enclosed spaces.

In 2 an alternative system 1 according to the invention is shown schematically, but without a ventilator. In the following, only the differences will be discussed to avoid repetition. Corresponding elements are designated with the same reference numbers. Instead of via a pipe section 11, in the alternative system 1 the filter 13 is connected directly to the first T-piece 8. The filter 13 also has a filter inlet 23 on the side of the first T-piece 8, to which the gas source 14 is connected with the actuator 22. On the side of the filter 13 facing away from the first T-piece 8, a second valve 16 is connected. The first valve 9, however, does not exist; instead, a bag 24 with a small opening 25 is connected to the first T-piece 8 opposite the filter 13. The bag 24 is part of the reservoir volume 19 and forms an area with a flexible wall 26.

When suction is taken from the reservoir volume 19, the bag 24 can contract and a substantially constant pressure is maintained without air having to flow in via the second valve 16. If the volume flow sucked in decreases during the ventilation cycle, the bag 24 can be refilled with the gas flowing in from the gas source 14 and the bag 24 can expand again. Only when it has reached a certain degree of filling does the gas flow out of the bag 24 through the opening 25. The opening 25 therefore fulfills a similar function to the first valve 9 of the first embodiment and could therefore also be regarded as an overpressure limiting element 10.

3 shows a perspective section of one side of the ventilator 2 as it is in the 1 and 2 is only shown schematically. Compared to the operating state without the system 1 according to the invention, a cover plate (not shown) has been removed and a filter element 27 underneath has been taken out. The 3 shows a hand 28 removing the filter element 27. The filter element 27 was previously located in a pocket-shaped recess 29, at one end of which the air inlet 3 is located. The filter element 27 was held in the recess 29 with a pivoting bracket 30. To remove the filter element 27, the bracket 30 was pivoted to the right in the figure so that the filter element 27 was released.

4 shows a perspective section of the ventilator 2, whereby the connection element 7 is connected to the air inlet 3 instead of the filter element 27. The bracket 30 is opposite the 3 pivoted to the left so that it engages behind the connection element 7 and holds it in the position shown. The bracket 30 thus forms a connecting device 31 for connecting the connection element 7 to the ventilator 2.

The connection element 7 is also individually mounted from the side facing the air inlet 3 in 5 shown. On this side, the connection element 7 has a rectangular device nozzle 32, which protrudes from a base body 33 of the connection element 7. The device nozzle 32 corresponds in shape to the air inlet 3. Offset from the device nozzle 32, on the opposite side, a circular connecting nozzle 34 protrudes for connection to the first T-piece 8. The two nozzles 32, 34 are fluidically connected via the interior of the base body 33. The base body 33 corresponds to the geometry of the recess 29 and has, in addition to the connecting nozzle 34, a slope 35 and a notch 36 (concealed) for pivoting and locking the bracket 30 (see 4 ).

List of reference symbols

1

system

2

Ventilator

3

Air intake

4

further admission

5

O ₂ source

6

module

7

Connection element

8

first T-piece

9

first valve

10

Overpressure limiting element

11

Pipe section

12

second T-piece

13

filter

14

Gas source

15

Gas tank

16

second valve

17

Vacuum limiting element

18

Throttle valve

19

Reservoir volume

20

fluidic connection

21

Pressure equalization system

22

Actuator

23

Filter input

24

bag

25

opening

26

flexible wall

27

Filter element

28

hand

29

Recess

30

Ironing

31

Connecting device

32

Device socket

33

Base body of the connecting element 7

34

Connecting piece

35

Slope

36

score

Claims (12)

System (1) for connection to an air inlet (3) of an automatic ventilator (2), wherein ambient air for the gas path of the ventilator (2) can be sucked in through the air inlet (3) without the system, with a gas source (14), in particular a gas container (15), with which a gas, in particular CO ₂ , NO or H ₂ , is provided, with a connection element (7) for fluidic connection to the air inlet (3) and with a fluidic connection (20) for the gas between the gas source (14) and the connection element (7). System (1) according to Claim 1 , characterized in that the fluidic connection (20) and the connection element (7) have a reservoir volume (19) of 5 ml to 1500 ml, in particular of 5 ml to 100 ml. System (1) according to Claim 2 , characterized in that the system (1) has a pressure equalization system (21) such that the pressure in the reservoir volume (19) substantially corresponds to the ambient pressure. System (1) according to Claim 3 , characterized in that the pressure compensation system (21) has a negative pressure limiting element (17), in particular in the form of a valve (16). System (1) according to Claim 3 or 4 , characterized in that the pressure compensation system (21) has an overpressure limiting element (10), in particular in the form of a valve (9). System (1) according to one of the Claims 2 until 5 , characterized in that an actuator (22) for metering the gas, in particular a throttle valve (18), is arranged fluidically between the gas source (14) and the reservoir volume (19). System (1) according to one of the Claims 2 until 6 , characterized in that the reservoir volume (19) is adjustable. System (1) according to one of the Claims 2 until 6 , characterized in that the fluidic connection (19) has a region with a flexible wall (26) such that the reservoir volume (19) changes at different internal and external pressure, in particular a bag (24). System (1) according to Claim 8 , characterized in that the reservoir volume (19) has an opening (25) in the region of the flexible wall (26). System (1) according to one of the Claims 2 until 9 , characterized in that the system (1) comprises a filter (13). Combination of a system (1) according to one of the preceding claims with an automatic ventilator (2). Combination according to Claim 11 , characterized in that the connection element (7) is connected to the ventilator (2) by means of a connecting device (31), and wherein the connecting device (31) alternatively to the connection element (7) a filter element (27) can be connected to the air inlet (3).

Images