System for coupling to a respiratory appliance

Abstract

The invention relates to a system (1) to be connected to an air inlet (3) of a respiratory appliance (2) in order to allow, for example for pre-hospital therapy for carbon monoxide poisoning, maximisation of alveolar ventilation while retaining normocapnic ratios at maximum oxygen concentration. For this purpose, according to the invention, CO2 from a gas source (14) is provided in a reservoir volume (19) at the air inlet (3) instead of air, so that the respiratory appliance (2), in conjunction with an O2 source, can produce a mixture of CO2 and O2 and the patient can be ventilated therewith.

Description

[0001] Description

[0002] System for coupling with a ventilator.

[0003] The invention relates to a system for coupling to a ventilator having the features of claim 1 and to the combination of the system with a ventilator having the features of claim 11.

[0004] 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 during artificial respiration. Ventilation is therefore performed at a high frequency and with large volumes, while the ventilation gas is adjusted by adding CO2 so that the CO2 content (CO2 = carbon dioxide) and the blood pH remain within the normal range. This is based on the concept of creating the maximum possible CO2 concentration gradient (CO = carbon monoxide) at the alveolar membrane between the blood side and the air side, thus accelerating the exhalation of the poison.

[0005] Thornhill Research's ClearMate product is a system specifically designed for manual ventilation. The system features a dosing unit that delivers a mixture of CO2 and O2 (O2 = oxygen), which is manually administered to the patient via a resuscitation bag and breathing mask. The operator controls the frequency and volume applied.

[0006] 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.

[0007] 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 CO2, NO or H2) to the aspirated ambient air 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 context of a fulminant pulmonary embolism, the gas to be admixed is NO (NO = nitric oxide). To date, even for such treatment with defined concentrations of NO for pre-clinical use, only systems are known that are intended for use with a manual resuscitation bag. 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 context of cardiac arrest, H2 (H2= hydrogen) or noble gases.

[0008] In the following, a “ventilator” always means an automatic ventilator, in particular an automatic emergency ventilator.

[0009] 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.

[0010] The system according to the invention can be coupled to a ventilator. This allows the entire technology of ventilators already widely used in pre-hospital emergency medicine to be utilized, 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 drawn in for the ventilator's gas path without the system. The air inlet is therefore not an inlet for air to cool the device, but for drawing in air to deliver the breathing gas to the patient.

[0011] The system comprises a gas source, in particular a gas container such as a gas cylinder, with which a gas is provided.

[0012] The system also includes a connection element for fluidic connection to the air inlet. The connection element is, in particular, a solid body with a device nozzle geometrically matched to one or more ventilators and a circular connecting nozzle. However, a flexible, tube- and / or film-like element is also conceivable, which is clamped or fixed with adhesive strips to the ventilator in such a way that the air inlet is enclosed. A fluidic connection for the gas connects the gas source to the connection element.

[0013] With the ventilator, the system according to the invention can provide a mixture of the gas from the gas source, in particular CO2, NO, or H2, and another gas, in particular O2, in a desired mixing ratio. Ventilators are equipped with an O2 inlet as standard, and the O2 can be mixed with air drawn in through the air inlet in a desired mixing ratio. Furthermore, the ventilation frequency and ventilation volume can be adjusted. With the system according to the invention, the air is replaced by the gas from the gas source, allowing targeted ventilation, for example, with a mixture of 95 vol.% O2 and 5% CO2.

[0014] The fluidic connection and the connection element preferably have a reservoir volume of 5 ml to 1,500 ml, in particular of 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 any gas flowing in from the gas source. The reservoir volume is systematically filled with gas from the gas source, 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, which could result in the gas mixture delivered to the patient containing too much gas, in particular too much CO2, NO or H2.

[0015] 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 engineering effort, as well as an interface to the ventilator and / or a sensor to measure the resulting gas concentrations in the ventilation circuit.

[0016] To ensure as simply as possible that the desired amount of gas is sucked in by the ventilator, the invention proposes that the system have 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 the same as during operation without the system according to the invention, namely approximately ambient pressure prevails. 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 guaranteed if, regardless of the gas flow from the gas source, the flow resistance for the ventilator's intake approximately corresponds to that of the otherwise conventional filter at the air inlet.

[0017] The pressure equalization system preferably has a negative pressure limiting element, particularly in the form of a valve. A valve, in particular, allows ambient air to flow in should the pressure in the reservoir volume fall below a predetermined limit. Should the ventilator mistakenly draw very large quantities of gas from the reservoir volume, for example because an operator has not connected O2 or has set an O2 concentration that is too low and thus excessive gas is drawn in through the inlet, this ensures, on the one hand, that no negative pressure that could potentially damage the ventilator's function is created and, on the other hand, that ambient air is drawn in after the reservoir volume has been drained. This helps prevent too much CO2 from reaching the patient.

[0018] Furthermore, the pressure equalization system preferably comprises an overpressure limiting element, in particular in the form of a valve. A valve allows, in particular, the gas to flow out when the reservoir volume is completely filled with gas and the pressure rises above a predetermined limit. This enables particularly simple refilling of the reservoir volume, for example, with a continuous gas flow, whereby excess gas can always escape through the valve due to the resulting overpressure.

[0019] When combining positive and negative pressure relief devices, it is also possible that some ambient air may enter the reservoir volume during each phase of the ventilator's suction and be flushed out again by the gas when suction stops. Therefore, the negative pressure relief valve should be positioned closer to the gas source, and the positive pressure relief valve closer to the connection element.

[0020] Preferably, an actuator for metering the gas, in particular a throttle valve, is arranged fluidically between the gas source and the reservoir volume. "Metering" means controlling or regulating a volumetric or mass flow. A throttle valve enables the simple control of a volumetric flow and, depending on the design, also the regulation of a volumetric flow.

[0021] 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.

[0022] 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 equalization system. However, it is also conceivable to provide one additionally. Instead of a pressure relief valve or in addition to it, an opening can be provided in the region of the flexible wall in particular 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 a different location in the reservoir volume.

[0023] The system preferably includes a filter. The filter can be used to filter the gas from the gas source. However, it is preferably used to filter any ambient air flowing in through a valve of the pressure equalization system. The volume of the filter forms part of the reservoir volume.

[0024] The invention proposes the combination of the described system with a ventilator. The ventilator preferably has a connecting device to which a filter element can be connected to the air inlet. For the combination with the system, the filter of the ventilator is removed, and instead, the connecting element is connected to the ventilator via the connecting device.

[0025] The invention is explained below using two exemplary embodiments. They show:

[0026] Figure 1 is a schematic representation of the system according to the invention with a ventilator;

[0027] Figure 2 is a schematic representation of an alternative system according to the invention; Figure 3 is a partial perspective view of a ventilator with the filter removed;

[0028] Figure 4 shows the same ventilator with a connection element according to the invention in a perspective partial view; and

[0029] Figure 5 shows the same connection element in perspective.

[0030] Figure 1 shows 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 O2 source 5 in the form of an oxygen cylinder is connected. Lines lead from the air inlet 3 and the further inlet 4 to a module 6, with which the incoming gas streams 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 further elements of the ventilator 2 are not important in the context of the invention, which is why they are not shown.

[0031] A first T-piece 8 is connected to the air inlet 3 via a connection element 7 of the system 1. Also connected to the first T-piece 8 is a first valve 9 as an overpressure relief element 10 and a bellows-like pipe section 11. The first valve 9 is designed, for example, as a disk pressure relief valve with a flexible elastomer plate. The valve 9 is connected in such a way that when the pressure in the first T-piece 8 exceeds 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. At its two other ends, this second T-piece 12 is connected to a filter 13 on the one hand and, via a line, to a gas source 14 in the form of a gas container 15 on the other. The gas here is CO2, but could also be NO or H2, for example, and the gas container 15 is a CO2 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, allowing air to flow into the filter 13. A gas throttle valve 18 is arranged between the gas source 14 and the second T-piece 12, with which a continuous gas flow from the gas source 14 to the second T-piece 12 can be adjusted, thus serving as an actuator 22 for dosing the gas.

[0032] The interior of the area between the throttle valve 18, the two valves 9, 16 and the connecting 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 connecting 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.

[0033] To treat carbon monoxide poisoning, settings of the ventilator 2 can be selected that are actually used for ventilation with a mixture of O2 and air, for example, 95% O2 and 5% air. To do this, the module 6 draws in a gas stream via the air inlet 3; 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, CO2 is drawn from the reservoir volume 19 instead of air. The pressure equalization system 21 ensures that there is no significant overpressure or underpressure compared to the ambient air, so that the set mixture ratio is not disturbed. For example, in the event of a significant overpressure, more than the 5% CO2 mentioned as an example could reach the patient. The suction takes place in particular cyclically with a variable volume flow according to the ventilation cycle for the patient.The continuous flow of CO2 into the reservoir volume 19 ensures that a sufficient supply of CO2 is always available. At the same time, the reservoir volume 19 also limits the maximum amount of CO2 that can be sucked in per breath, so that in the event of an incorrect adjustment by the operator, too much CO2 cannot reach the patient. The bellows-like tube section 11 allows the reservoir volume 19 to be adapted to different therapy situations. Instead of 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 is sucking in air.On the other hand, so much CO2 should not flow into the reservoir volume 19 that, due to the resulting overpressure, larger quantities of CO2 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.

[0034] Figure 2 schematically illustrates an alternative system 1 according to the invention, but without a ventilator. To avoid repetition, only the differences will be discussed below. Corresponding elements are designated by the same reference numerals. Instead of being connected 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 to the actuator 22. A second valve 16 is connected on the side of the filter 13 facing away from the first T-piece 8. However, the first valve 9 is omitted; 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.

[0035] When drawn from the reservoir volume 19, the bag 24 can contract, maintaining a substantially constant pressure without the need for additional air to flow through the second valve 16. If the drawn-in volume flow decreases during the ventilation cycle, the bag 24 can be refilled by 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 thus fulfills a similar function to the first valve 9 of the first embodiment and could therefore also be considered an overpressure limiting element 10.

[0036] Figure 3 shows a perspective section of one side of the ventilator 2, as shown only schematically in Figures 1 and 2. Compared to the operational state without the system 1 according to the invention, a cover plate (not shown) has been removed and an underlying filter element 27 has been taken out. Figure 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 by 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. Figure 4 again shows a perspective section of the ventilator 2, wherein the connection element 7 is connected to the air inlet 3 instead of the filter element 27.The bracket 30 is pivoted to the left relative to Figure 3, so that it engages behind the connecting element 7 and holds it in the position shown. The bracket 30 thus forms a connecting device 31 for connecting the connecting element 7 to the ventilator 2.

[0037] The connecting element 7 is also shown individually in Figure 5 from the side facing the air inlet 3. On this side, the connecting element 7 has a rectangular device nozzle 32 that protrudes from a base body 33 of the connecting element 7. The shape of the device nozzle 32 corresponds 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, in addition to the connecting nozzle 34, has a bevel 35 and a notch 36 (concealed) for pivoting and locking the bracket 30 (see Figure 4).

[0038] List of reference symbols

[0039] 1 system

[0040] 2 ventilators

[0041] 3 Air intake

[0042] 4 additional entrance

[0043] 5 Ch source

[0044] 6 Module

[0045] 7 Connection element

[0046] 8 first T-piece

[0047] 9 first valve

[0048] 10 Overpressure relief element

[0049] 11 Pipe section

[0050] 12 second T-piece

[0051] 13 filters

[0052] 14 Gas source

[0053] 15 gas tanks

[0054] 16 second valve

[0055] 17 Vacuum limiting element

[0056] 18 throttle valve

[0057] 19 Reservoir volume

[0058] 20 fluidic connection

[0059] 21 Pressure equalization system

[0060] 22 Actuator

[0061] 23 Filter input

[0062] 24 bags

[0063] 25 Opening

[0064] 26 flexible wall

[0065] 27 Filter element

[0066] 28 hands

[0067] 29 recess

[0068] 30 hangers

[0069] 31 Connecting device 32 Device nozzle

[0070] 33 Base body of the connecting element 7

[0071] 34 connecting pieces

[0072] 35 slopes

[0073] 36 notch

Claims

Claims 1. 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 CO2, NO or H2, 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).

2. System (1) according to claim 1, characterized in that the fluidic connection (20) and the connecting element (7) have a reservoir volume (19) of 5 ml to 1500 ml, in particular of 5 ml to 100 ml.

3. 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.

4. System (1) according to claim 3, characterized in that the pressure equalization system (21) has a negative pressure limiting element (17), in particular in the form of a valve (16).

5. System (1) according to claim 3 or 4, characterized in that the pressure equalization system (21) has an overpressure limiting element (10), in particular in the form of a valve (9).

6. System (1) according to one of claims 2 to 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).

7. System (1) according to one of claims 2 to 6, characterized in that the reservoir volume (19) is adjustable.

8. System (1) according to one of claims 2 to 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).

9. 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).

10. System (1) according to one of claims 2 to 9, characterized in that the system (1) comprises a filter (13).

11. Combination of a system (1) according to one of the preceding claims with an automatic ventilator (2).

12. Combination according to claim 11, characterized in that the connecting element (7) is connected to the ventilator (2) by means of a connecting device (31), and wherein a filter element (27) at the air inlet (3) can be connected to the connecting device (31) as an alternative to the connecting element (7).

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