WO2021191408A1

WO2021191408A1 - A ventilator

Info

Publication number: WO2021191408A1
Application number: PCT/EP2021/057879
Authority: WO
Inventors: Philippe CAERS; Dirk Ernest Rosalia WENMAKERS
Original assignee: No2covid BV
Current assignee: No2covid BV
Priority date: 2020-03-27
Filing date: 2021-03-26
Publication date: 2021-09-30
Anticipated expiration: 2022-09-27
Also published as: BE1028164A1; EP4126144A1; BE1028164B1

Abstract

A simple pressure-controlled ventilator comprising a pneumatic drive mechanism is described which does not require any power source other than the pressurized respiratory air which is given to the patient.

Description

A VENTILATOR

TECHNICAL FIELD

The technical field relates to ventilators, more specifically ventilators for artificial respiration apparatus.

PRIOR ART

The Covid-19 pandemic has caused a worldwide shortage of ventilators. There is a need to increase the capacity of ventilators during such crisis situations.

SUMMARY

With the aim of increasing the worldwide capacity of ventilators, a simple pressure-controlled ventilator with a pneumatic drive mechanism was developed which does not require any other power source than the pressurized respiratory air which is used to supply the patient and/or any other suitable source of pressurized air, as defined in the claims below. In this case, the respiratory air preferably comprises any suitable mixture of air and/or a gas mixture with an oxygen percentage required for that patient.

According to a first aspect there is provided a ventilator for an artificial respiration apparatus comprising a pneumatic drive mechanism which is configured to generate a breathing cycle when it is only coupled to a pressurized source of artificial respiration air and/or a pressurized source of air.

According to a preferred embodiment, there is provided a ventilator, wherein the pneumatic drive mechanism comprises the following components:

• an adjustable pneumatic timer valve configured to control the inspiratory period;

• an adjustable pneumatic timer reset valve which controls the expiratory period; and

• a switching valve for switching the ventilator from an inspiratory cycle on an inspiratory line to an expiratory cycle on an expiratory line. According to a preferred embodiment, there is provided a ventilator, wherein the switching valve comprises one of the following elements:

- a 5/2 valve;

- a combination of a 3/2 valve on the inspiratory line and another 3/2 valve on the expiratory line.

According to a preferred embodiment, there is provided a ventilator, wherein the switching valve is configured and/or controlled in such a way that an inspiratory line and an expiratory line of the ventilator are never open at the same time for a stream of artificial respiration air.

According to a preferred embodiment, there is provided a ventilator, wherein the adjustable pneumatic timer valves are sequentially coupled in such a way that the end of the timer cycle of the adjustable pneumatic timer valve initiates the start of the timer cycle of the adjustable pneumatic timer reset valve and vice versa.

According to a preferred embodiment, there is provided a ventilator, wherein the ventilator furthermore comprises a variable pressure regulator which is configured to lower the pressure of the supplied respiratory air to the required respiratory air peak pressure.

According to a preferred embodiment, there is provided a ventilator, wherein the variable pressure regulator comprises a control range from 0 mbar up to 80 mbar.

According to a preferred embodiment, there is provided a ventilator, wherein the ventilator comprises at least one of the following manometers:

- a manometer coupled between the pressure regulator and the switching valve which is configured to display the required respiratory air peak pressure during both the inspiratory and the expiratory portion of the artificial respiration cycle;

- a manometer coupled after the switching valve in the artificial respiration air circuit on the patient side.

According to a preferred embodiment, there is provided a ventilator, wherein the ventilator furthermore comprises an adjustable blow-off valve which is coupled to the outlet of the expiratory line, behind the switching valve, and which is configured so as to never allow the pressure in the respiratory air cycle of the patient to drop below the set blow-off pressure.

According to a preferred embodiment, there is provided a ventilator, wherein the ventilator furthermore comprises one or more of the following safety systems:

- an excess pressure/cough valve on the patient side of the circuit;

- an underpressure valve on the patient side of the circuit, configured to ensure that inspiration originating from the patient is given priority;

- one or more filters on the patient side.

According to a preferred embodiment, there is provided a ventilator, wherein the ventilator is configured to operate in a plurality of operating modes, wherein:

- during one of said operating modes the switching valve is configured and/or controlled in such a way that an inspiratory line and an expiratory line of the ventilator are open at the same time for a stream of artificial respiration air; and

- during another one of these operating modes the switching valve is configured and/or controlled in such a way that an inspiratory line and an expiratory line of the ventilator are never open at the same time for a stream of artificial respiration air

According to a preferred embodiment, there is provided a ventilator, wherein the switching valve comprises a combination of a 3/2 valve on the inspiratory line and another 3/2 valve on the expiratory line.

DESCRIPTION

A few exemplary embodiments will be explained by way of example by means of the following figures, in which:

Fig. 1 diagrammatically shows a ventilation cycle;

Figs. 2A and 2B show a front view of an embodiment of a ventilator, with and without a housing, respectively;

Fig. 3 shows a rear view of the embodiment from Figs. 2A and 2B; and Fig. 4 shows an embodiment similar as shown in Figs. 2A, 2B and 3. A ventilation cycle of the breathing from the perspective of pressure versus time is diagrammatically illustrated in Fig. 1.

In this connection, it is important to control four parameters in order to achieve a good pressure-based breathing cycle as illustrated in Fig. 1, i.e.:

• Ppip: peak inspiratory pressure

• Ppeep: positive end-expiratory pressure

• Tin: inspiratory period (in seconds)

• Tout: expiratory period (in seconds)

As is illustrated in Fig. 2A, the ventilator comprises a pressure inlet location 1, also referred to as a pressure line, which is configured to receive a pressurized respiratory air mixture, for example a premixed pressurized gas mixture of air and/or oxygen, in accordance with the needs of the patient.

As is illustrated in Fig. 2A, this pressure line 1 is divided in two by means of a T-splitter 2. A first branch 2a of the divided line is used for the pneumatic drive mechanism. The other branch 2b is used for respiratory air to apply artificial respiration to the patient.

Figs. 2A and 2B further illustrate an embodiment of the pneumatic drive mechanism. The illustrated embodiment of the pneumatic drive mechanism comprises the following 3 components:

• an adjustable pneumatic timer valve 4 which controls the inspiratory period [Tin]

• an adjustable pneumatic timer reset valve 3 which controls the expiratory period [Tout]

• a 5/2 valve 5 for switching the ventilator from the inspiratory cycle and the inspiratory line 6 to the expiratory cycle and the expiratory line 7.

The two pneumatic timers are connected in succession, as is indicated by reference numeral 34 in Fig. 3, so that the end of one of the timer cycles initiates the start of the next timer cycle, which eventually results in an endless loop, in which the inspiratory and the expiratory cycle alternate. The adjustable pneumatic timer valve controls the inspiratory period, as is diagrammatically illustrated in Fig. 3 by reference numeral 31, and also drives the 5/2 valve via line 32, as is diagrammatically illustrated in Fig. 3 by reference numeral 33.

This results in a time period of a gas supply flowing to the patient via the inspiratory line 6 when the valve opens and the expiratory line 7 is simultaneously closed, as a result of which a closed loop on the patient side is maintained.

The 5/2 valve ensures that neither the inspiratory streams nor the expiratory streams are open simultaneously under any circumstances, since this is controlled by one and the same valve, each separately in one of both positions of the valve.

It will be clear that alternative embodiments for such a switching valve 5 which fulfil a similar function as the 5/2 valve are possible. According to an alternative embodiment, it is possible, for example, for the switching valve to comprise a combination of a 3/2 valve on the inspiratory line 6 and another 3/2 valve on the expiratory line 7. In this case, the expiratory timer controls the 3/2 valve which controls the expiratory line of the patient, and the inspiratory timer controls the 3/2 valve which controls the inspiratory line of the patient. It will be clear that the timers in this case are still switched as described above in order to ensure the continuous cycle.

Flow of the respiratory air

According to the illustrated exemplary embodiment, the pressure of the supplied respiratory air is lowered from a line pressure to the required respiratory air peak pressure, Ppip, by means of a variable pressure regulator 8, for example having a control range varying from 0 mbar up to 80 mbar. Such pressure regulators are readily commercially available for this control range and are used, for example, as variable pressure regulators for propane gas bottles.

Such a pressure regulator ensures a control range which is comparable to the control range of known commercial ventilators comprising readily available components.

According to the illustrated exemplary embodiment in Fig. 2, the Ppip pressure is displayed to the operator by means of a manometer 9. This manometer is placed behind the regulator and in front of the 5/2 valve in order to ensure that adjustment is possible during both the inspiratory cycle and the expiratory cycle. According to the illustrated exemplary embodiment in Fig. 2, a second manometer 10 is placed behind the 5/2 valve in the respiratory air circuit of the patient in order to ensure correct monitoring during the entire breathing cycle.

According to the illustrated exemplary embodiment in Fig. 2, an adjustable blow-off valve 11 is placed at the outlet of the expiratory line, behind the 5/2 valve, in order to set the Ppeep. This blow-off valve 11 ensures that the pressure in the respiratory air cycle of the patient never drops below the set blow-off pressure Ppeep.

Safety measures

According to the illustrated exemplary embodiment, two safety valves are included in order to ensure the safety of the operations.

According to the illustrated embodiment in Figs. 2A and 2B, an adjustable or fixed excess pressure/cough valve 12 is added, preferably on the patient side of the circuit, which protects the patient against excess pressure in the mechanism, for example due to coughing or excess pressure caused by a malfunction in the system.

According to the illustrated embodiment in Figs. 2A and 2B, an adjustable or fixed pressure/underpressure valve 13 is added, preferably on the patient side, in order to ensure that inspiration originating from the patient is given priority over the system or, in other words, suppresses the system, as a result of which air supply to the patient side of the circuit is possible in this position, irrespective of the position of the 5/2 valve.

Optionally, two filters may be placed on the patient side of the hose, as is illustrated in Figs. 2A and 2B. For example, one filter 14 to protect the patient against inhaling dirt from the system or non-conditioned air from the inlet and a second filter in the expiration line 15 in order to protect the environment against the expiration of biologically hazardous air from the lungs of the patient. This filter preferably protects against bacteria and viruses.

Figure 4 shows an embodiment similar as described with reference to Figures 2A, 2B and 3. Similar elements are indicated by means of similar reference signs and function in a similar way as described above.

According to the embodiment illustrated in Fig. 4, the ventilator comprises a pressure inlet location 1, also referred to as a pressure line, which is configured to receive a pressurized respiratory air mixture, for example a premixed pressurized gas mixture of air and/or oxygen, in accordance with the needs of the patient. Alternatively, but similar to the embodiments shown above, instead of making use of a T-splitter 2, according to this embodiment, the first branch 2a with a line that is used for the pneumatic drive mechanism, is provided by pressurized air from a different pressure inlet location 17, then the pressure inlet location for the other branch 2b that is used for respiratory air to apply artificial respiration to the patient. The inlet location 1 could for example comprise a source of mixed oxygen/air gas is provided from the accessory blender to the ventilator 1. The other inlet location 17 could for example comprise a source of a separate pressurized medical air supply. However, it is clear, that alternative embodiments are possible in which use is made of single source of pressurized respiratory air and in which for example a splitter 2 is used to split the gas provided at the inlet into the two branches 2a, 2b.

Figure 4 further illustrates an embodiment of the pneumatic drive mechanism. The illustrated embodiment of the pneumatic drive mechanism comprises the following components:

• a further valve 34 configured to cycle the pneumatic timer valve 4 and timer reset valve 3, in a continuous cycle, one after the other. In other words, the further valve 34, which is part of the pneumatic timing circuit, connects the two pneumatic timers are connected in succession, and in this way realizes a similar function as is indicated by reference numeral 34 in Fig. 3, so that the end of one of the timer cycles initiates the start of the next timer cycle, which eventually results in an endless loop, in which the inspiratory and the expiratory cycle alternate.

• a 3/2 valve 5b on the inspiratory line 6 and another 3/2 valve 5a on the expiratory line 7. In this case, the expiratory timer valve 3 controls the 3/2 valve 5b which controls the expiratory line 7 of the patient, and the inspiratory timer valve 4 controls the 3/2 valve 5b which controls the inspiratory line of the patient.

It will be clear that the timers in this case are still switched as described above in order to ensure the continuous cycle by means of valve 34. It is also

The adjustable pneumatic timer valve 4 controls the inspiratory period, and also drives the 3/2 valve 5a via line 32a, as is diagrammatically illustrated in Fig. 4. The adjustable pneumatic timer valve 3 controls the inspiratory period, and also drives the 3/2 valve 5b via line 32b, as is diagrammatically illustrated in Fig. 4.

The valves 3, 4 and 34 of the timing circuit ensure that neither the inspiratory streams nor the expiratory streams are open simultaneously under any circumstances, or in other words that when valve 5a is activated, then valve 5b is deactivated and/or vice versa.

It is clear, that all above mentioned valves are controlled by means of pressurized gas in the pneumatic circuit. It is further clear that in the illustrated embodiments, preferably none of the valves described above are electrically controlled.

As further illustrated in the embodiment of Figure 4, the mixed oxygen/air gas is for example provided from an accessory blender to the ventilator via for example a suitable connector 1. As further shown, the pressure of this oxygen/air gas mixture is for example reduced to the peak inspiratory pressure (PIP) through the pressure regulator valve 8 set by the PIP knob 16 on the valve. The set maximum pressure is for example displayed on a manometer 10 when the ventilator is in the expiratory phase or when switched off. The pressure of the supply gas can be seen on manometer 9.

According to the embodiment shown, optionally the ventilator can be switched on or off by a suitable switch 22 or other suitable input element, which for example operates to keep both valves 5a, 5b in an inoperative state, as for example shown in Figure 4. This is preferably realized by means of suitable pneumatic control of the pneumatic timer circuit 40 comprising the pneumatic timer valves 3, 4, for example by halting the cyclic operation and keeping them in a predefined state.

According to the embodiment shown, there are provided a plurality of different operating modes from which the user can select by means of a suitable input element 23, such as for example a knob or switch 23. According to the embodiment shown, two different modes can be selected, which are for example labelled CPAP and PCV. Similarly, as explained above, this input element 23 is for example configured control the pneumatic operation of the pneumatic timer circuit. According to one example of an operating mode, when in PCV mode, setting of the inspiratory and expiratory timings is done by the timer valves 3, 4 of the pneumatic timer circuit 40 by means of for example suitable input elements such as for example knobs that control the timing of the operation of these valves 10 and knobs. Input element 24 is for example configured to control the timing of the inspiratory timer valve 4. Input element 25 is for example configured to control the timing of the expiratory timer valve 3. It is clear, that all these control functions are preferably configured to be performed by mechanical and/or pneumatic adjustments that influence the control of the operation of the pneumatic timer valves 3, 4. In other words, preferably without making use of any need for electronic control.

According to another example of an operating mode, when in CPAP operating mode, the pneumatic timer circuit 40 is controlled such that both valves 5a and 5b are continuously in an opened state. This operating mode allows for Continuous positive airway pressure or CPAP, which is a form of positive airway pressure or PAP ventilation, in which a constant level of pressure greater than atmospheric pressure is continuously applied to the respiratory system of a patient, in other words, the upper respiratory tract of a person. The application of positive pressure may be intended to prevent upper airway collapse, as occurs in obstructive sleep apnea, or to reduce the work of breathing in conditions such as for example acute decompensated heart failure. According to this operating mode, when for example the pressure regulator valve 8 is set to a desired pressure that is larger than that of PEEP valve 11 or blow-off valve, then there will be a continuous flow of artificial air via the inspiratory line 6 and the expiratory line 7, of which the pressure is regulated by the blow-off valve or PEEP valve 11. For example, when the pressure regulator valve 8 is set to 12mbar and the PEEP valve 11 is set to lOmbar, while in the CPAP operating mode both valves 5a, 5b remain opened, the patient during a breathing cycle the pressure in both the inspiratory line and the expiratory will not drop below lOmbar, or in other words the pressure in the respiratory air cycle of the patient to drop below the set blow-off pressure. It is clear, that alternative embodiments are possible with different pressure values. It is further clear that this CPAP operating mode can be implemented with the embodiment of Figure 4, or any other suitable embodiment of a switching valve in which during such an operating mode, the switching valve 5 is configured and/or controlled in such a way that an inspiratory line and an expiratory line of the ventilator are open at the same time for a stream of artificial respiration air. In other words preferably, as in the embodiment of Figure 4, the ventilator is able to operate in a plurality of operating modes, during one of these operating modes for example the switching valve 5 is configured and/or controlled in such a way that an inspiratory line and an expiratory line of the ventilator are open at the same time for a stream of artificial respiration air; and during another one of these operating modes the switching valve 5 is configured and/or controlled in such a way that an inspiratory line and an expiratory line of the ventilator are never open at the same time for a stream of artificial respiration air.

As further shown, according to the embodiment of Figure 4, optionally there can be provided a further input element, such as for example a push button 21, configured to hold a manual inspiration to perform an alveolar recovery manoeuvre. When for example this pushbutton 21 is pushed during the inspiratory cycle, this will influence the operation of the timer circuit in such a way that an alveolar recovery manoeuvre can be performed.

It is thus clear that according to the embodiment shown in Figure 4, valves 5a and 5b are cycled by the pneumatic timer valves 3, 4 of the pneumatic timer circuit 40 or optionally by adjusting the operation of the pneumatic timer circuit 40 by means of for example suitable input elements configured for selecting the operating mode 23, the on/off switch 22, etc. . According to the embodiment shown, the pneumatic timer circuit 40 and valves 5a, 5b are configured to operate on a suitable source of pressurized gas, such as for example a medical air supply provided at connector 17. It is clear, that preferably the pneumatic timer circuit 40 and the valves 5a, 5b only require such a source of pressurized gas for their operation and control, and preferably have are configured to operate and/or continue their operation without the need for any electric control or a source of electric power.

Further optional elements of the embodiment shown in Figure 4 are described below. Optional valve 45 is for example an operator adjustable pressure limiting valve that is for example configured to be set and tested before usage on patients, to allow for safety and which could for example function as an excess pressure/cough valve on the patient side of the circuit as described above. Optional emergency air valve 46, also arranged on the patient side of the inspiratory line 6, is configured to provide a means of spontaneous breathing during ventilator malfunctioning by allow influx of air when the inspiratory line 6 is not pressured and is exposed to a pressure lower than the atmospheric pressure, as a consequence of spontaneous breathing of the patient. Optionally, a further manometer 47 is mounted at the patient side of the valve 5a on the inspiratory line 6. This manometer 47 is configured to monitor the airway pressure or Paw downstream of valve 5a in the inspiratory line. Preferably, but optionally, there is made use of suitable external respiratory connectors configured to connect suitable respiratory tubes to the ventilator. According to the embodiment shown, there is provided an inspiratory connector 48 that is coupled via suitable respiratory tubes to the respiratory system of the patient and further an expiratory connector 49, which is also coupled by suitable via suitable respiratory tubes to the respiratory system of the patient. Further, according to this particular embodiment, there is further provided a operator adjustable pressure limiting valve 11, at the downstream end of valve 5b on the expiratory line 7. This valve could for example be referred to as an external PEEP valve 11, and is for example configured to control the positive end-expiratory pressure. It is thus clear that this PEEP valve 11 functions in a similar way as the adjustable blow- off valve which is coupled to the outlet of the expiratory line, behind the switching valve 5, and which is configured so as to never allow the pressure in the respiratory air cycle of the patient to drop below the set blow-off pressure.

It is clear, that the embodiment of Figure 4 can also be realized by making use of an alternative switching valve 5, such as for example described above, with respect to Figures 2A, 2B and 3, and that alternative embodiments of the pneumatic timer circuit 40 are possible, configured to suitable control the one or more switching valves 5, 5a, 5b.

It is further clear that the embodiment of the ventilator, more specifically ventilators for artificial respiration apparatus, according to the embodiments shown is an open ventilator configured to let the outbreath received from the patient exit via the expiratory line 7 and via valve 5 and via an outlet to the outside atmosphere, for example during the expiratory period. In other words, the ventilator is configured as an open ventilator for artificial ventilation or artificial respiration. Although alternative embodiments are possible, such as for example a ventilator configured for closed artificial ventilation, the embodiments described above in which the ventilator for the inspiratory air cycle feeds artificial respiration air to a patient via an inspiratory line 6 from pressurized source of artificial respiration air, and lets expiratory air exit via an expiratory line 7 during the expiratory period from the ventilator, in other words back into the atmosphere. It is clear, that still further embodiments of the ventilator for an artificial respiration apparatus comprising a pneumatic drive mechanism which is configured to generate a breathing cycle when it is only coupled to a pressurized source of artificial respiration air and/or a pressurized source of air are possible. It is clear, that only one or more suitable sources of pressurized air are required for the operation of the ventilator, and preferable the operation of the ventilator can be continued without the need for any electrical power and/or control.

It will be clear that numerous combinations and variant embodiments are possible, such as for example defined in the dependent claims, without departing from the scope of protection as defined in the claims.

Claims

1. Ventilator for an artificial respiration apparatus comprising a pneumatic drive mechanism which is configured to generate a breathing cycle when it is only coupled to a pressurized source of artificial respiration air and/or a pressurized source of air.

2. Ventilator according to Claim 1, wherein the pneumatic drive mechanism comprises the following components:

• an adjustable pneumatic timer valve (4) configured to control the inspiratory period;

• an adjustable pneumatic timer reset valve (3) which controls the expiratory period; and

• a switching valve (5) for switching the ventilator from an inspiratory cycle on an inspiratory line (6) to an expiratory cycle on an expiratory line (7).

3. Ventilator according to Claim 2, wherein the switching valve comprises one of the following elements:

- a 5/2 valve;

- a combination of a 3/2 valve on the inspiratory line (6) and another 3/2 valve on the expiratory line (7).

4. Ventilator according to Claim 2 or 3, wherein the switching valve (5) is configured and/or controlled in such a way that an inspiratory line and an expiratory line of the ventilator are never open at the same time for a stream of artificial respiration air.

5. Ventilator according to one or more of Claims 2 to 4, wherein the adjustable pneumatic timer valves (4, 3) are sequentially coupled in such a way that the end of the timer cycle of the adjustable pneumatic timer valve (4) initiates the start of the timer cycle of the adjustable pneumatic timer reset valve (3) and vice versa.

6. Ventilator according to one or more of the preceding claims, wherein the ventilator furthermore comprises a variable pressure regulator (8) which is configured to lower the pressure of the supplied respiratory air to the required respiratory air peak pressure.

7. Ventilator according to Claim 6, wherein the variable pressure regulator (8) comprises a control range from 0 mbar up to 80 mbar.

8. Ventilator according to Claim 6 or 7, wherein the ventilator comprises at least one of the following manometers:

- a manometer (9) coupled between the pressure regulator (8) and the switching valve (5) which is configured to display the required respiratory air peak pressure during both the inspiratory and the expiratory portion of the artificial respiration cycle;

- a manometer (10) coupled after the switching valve (5) in the artificial respiration air circuit on the patient side.

9. Ventilator according to one or more of the preceding claims, wherein the ventilator furthermore comprises an adjustable blow-off valve (11) which is coupled to the outlet of the expiratory line, behind the switching valve (5), and which is configured so as to never allow the pressure in the respiratory air cycle of the patient to drop below the set blow-off pressure.

10. Ventilator according to one or more of the preceding claims, wherein the ventilator furthermore comprises one or more of the following safety systems:

- an excess pressure/cough valve (12) on the patient side of the circuit;

- an underpressure valve (13) on the patient side of the circuit, configured to ensure that inspiration originating from the patient is given priority;

- one or more filters (14, 15) on the patient side.

11. Ventilator according to one or more of the preceding claims, wherein the ventilator is configured to operate in a plurality of operating modes, wherein:

- during one of said operating modes the switching valve (5) is configured and/or controlled in such a way that an inspiratory line and an expiratory line of the ventilator are open at the same time for a stream of artificial respiration air; and

- during another one of these operating modes the switching valve (5) is configured and/or controlled in such a way that an inspiratory line and an expiratory line of the ventilator are never open at the same time for a stream of artificial respiration air.

12. Ventilator according to Claim 11, wherein the switching valve (5) comprises a combination of a 3/2 valve on the inspiratory line (6) and another 3/2 valve on the expiratory line (7).