GB1582899A

GB1582899A - Pneumatically controlled breathing apparatus

Info

Publication number: GB1582899A
Application number: GB53002/77A
Authority: GB
Original assignee: Kombinat Medizin und Labortechnik Leipzig VEB
Current assignee: Kombinat Medizin und Labortechnik Leipzig VEB
Priority date: 1976-12-22
Filing date: 1977-12-20
Publication date: 1981-01-14
Also published as: DE2739954A1; DD130309A1; DD130309B1; DE2739954C2; SU950405A1; CS211460B1

Description

(54) A PNEUMATICALLY CONTROLLED BREATHING APPARATUS (71) We, VEB KOMBINAT MEDI ZIN-UND LABORTECHNIK LEIPZIG, of Franz-Flemming-Strasse 43-45 7035 Leipzig, German Democratic Republic, a German body corporate, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the follow ing statement The invention relates to a pneumatically controlled breathing apparatus in which its control has a calibrated setting for the breathing frequency and the inspiration/ expiration time ratio and, in instead of a single setting for control of the inspiration time and the expiration time, the various magnitudes used to provide the breathing rhythm can be set independently of each other.

Automatically controlled breathing apparatuses are known, the technical means of which are fluid logic elements and associ ated peripheral elements which comprise assemblies of individual or connected parts of prefabricated parts known in digital technology and with which the flow and pressure of the breathing gas are automatic ally controlled during inspiration and ex piration. With controlled or assisted IPP (intermittent positive pressure) respiration, the functioning of these controlled systems depends on fixed and predetermined input magnitudes and depends on whether a gas is supplied to the patient up to a certain pressure or up to a quanitity of breathing gas which is volumetrically measured. In many cases, respiration systems controlled volumetrically have the shortcoming that there is no reaction or only a relatively late compensating reaction to a changing func tioning of the lungs.

Other respiration systems avoid this dis advantage but are designed exclusively for use in a hospital. Their extensive and routine use requires standardised and compatible construction of the breathing apparatus. This has quite a good functional efficiency but, for various reasons, this is ensured by. relatively complicated and expensive technical means.

It has been attempted to solve the outstanding problems by providing the device automatically controlling the flow and pressure of the breathing gas with several underlying automatic control systems. One of these automatic control systems contains a circuit for controlling breathing gas during inspiration and expiration. A flow and pressure measuring device is located near to the connection to the patient, and between this and the gas output and source there is a valve arrangement for control of flow and pressure of the breathing gas. With this known system, flow control is carried out during inspiration and pressure control is carried out during expiration. Here it seems necessary to comment that, with these control devices, the limit of the maximum flow of breathing gas can be reached event before the inspiration phase has been terminated and, as result of reaching this maximum, switchover to pressure control would take place compulsorily. In this case the set volume per minute of the breathing gas to be delivered will not be achieved.

In another known system automatic control can be operated as desired by either air or oxygen. These gases are introduced by: means of connections, which are protected by unindirectional valves to enable exchange of cylinders while the apparatus is in use. Both gases are passed through valves which are controlled by a separate control unit .by way of a pressure-reducing valve connection being made with the patient by means of a subsequently arranged and controlled circuit.

The injector is so arranged in the circuit that it can suck in fresh air from the atmosphere as well as oxygen from a breathing bag. The patient also has the opportunity, in the case of coughing, of taking in additional air from the atmosphere which has been filtered by means of a pressurelimiting valve.

The lines conducting gas in the injector circuit are in direct or indirect connection with the valves which are actuated by the separate control in the rhythm of the breathing frequency and of the breathing time ratio. The choice of the type of respiration takes place by means of a further valve which acts directly on the control.

The respiraton apparatus is, in addition, suitable for assisted respiration with final assisted expiration. It permits alternating pressure respiration and allows preprogrammed deep breathing to be introduced. It warns of any conditions dangerous to life such as exceeding or falling below the preselected respiration pressure, respiration frequency or the control pressure. Apart from the further possibility of switching to a mixed control, the device control has suitable technical means which control the respiration process in accordance with a selection of characteristic respiratory curves, the selection having been made from medical indications. Thus time-controlled, pressure-controlled, flow-controlled and volume-controlled processes of known types of respiration device are carried out in only one respiration apparatus yet amongst other things this is intended for prolonged respiration and is used preferably therefore in intensive care.

The invention seeks to enable the possibility of using a movable respiration apparatus which, despite its small mass and dimensions ensures the basic functions of a controlled and assisted respiration such as IPP at the same time as having the most economical gas consumption.

The invention therefore seeks to develop a respiration apparatus designed for rapid medical aid, which, in analogy to the last above-mentioned device control, has a closed control circuit which is separate from the breathing gas circuit and which, despite the smaller number of its parts facilitates a flow of breathing gas with gradual variation of the proportion of oxygen. As a result of the invention, the degree of utilization of control elements present is to be increased, these ensuring the control process of those setting facilities described in this field of application.

According to the invention, there is provided a pneumatically controlled respiration apparatus comprising a control unit controlling an inspiration valve and an expiration valve, a compressed air connection and a compressed oxygen connection connectable to the input of the inspiration valve and to the control unit an injector with a suction imput in an inspiration line connected to the output of the inspiration valve and a bypass arrangement for by-passing the injector comprising a by-pass line and a manually operable control valve controlling both a pneumatic control valve in the by-pass line and a suction control valve for controlling inlet to the suction imput of the injector, and a variable throttle being connected in the by-pass after the pneumatic control valve.

Preferably a pressure reducer is provided between the compressed air and compressed oxygen connections and the control unit.

The manually operable control valve may be connected at one side to the line between a pressure reducer and the control unit and at the side into a line between the pneumatic control valve and an OR-element connected to the suction control valve. The inspiration line may be connected to a threshold value switch connected to the control unit and to a valve controlling a breathing pressure meter.

As a result of a preferred embodiment of the invention, the basic functions which could be achieved previously with relatively expensive means or with a compact control are controlled by a relatively small number of operating elements. In addition, the control technology pneumatically facilitating calibrated setting of the frequency and the breathing time ratio, particularly the bypass control or its associated control circuits permits selective freshening-up of the breathing gas flow. Preferably there is a gradual variation of the proportions of oxygen from 21% to approximately 50% and 100%. Apart from a safe breathing pressure and deep breathing volume control, the volume of gas which is most suitable for the patient can be enriched or moistened with medicaments.

Administering a medicament or moistened breathing gas can be achieved in accordance with a further development of the invention; that the line directly connecting the control unit with the inspiration valve may also be connected to an amplifier which comprises two logically connected double-membrane relays and which may be linked via a signal line to a connection piece for connection of an atomizer or a humectant device.

The linking with the logically connected control is occupied by a signal so that during inspiration via the pneumatically controlled valve an L-signal is present at the expiration valve and an O-signal is present at the OR-element, on the other hand during expiration, reverse signalling takes place i.e.

the valve and the expiration valve have a O-signal and the OR-element has an Lsignal.

The invention will now be described in greater detail, by way of example, with reference to the drawing, the single figure of which is a plan of a device in accordance with the invention, which uses elements of the fluid control sytems which are fundamentally known.

The respiration apparatus shown schematically serves above all for rapid medical aid, this being ensured particularly by its supply system which is independent of fixed devices, its small mass and small dimensions.

By utilizing pneumatic logic elements for control purposes for the control of circuit elements such as a gas control valve 1, suction control valve 2, expiration valve 3 or threshold value switch 4 forming a pressure converter and as they are arranged in the complex of the circuit in a rational manner, the basic functions of the controlled and assisted respiration as well as other important respiration processes can be controlled.

In the respiration apparatus underlying the invention, control takes place as desired by means of air or oxygen and these control gases are used at the same time as a breathing gas and are controlled initially by a manually operated valve 5. Unindirectional valves 6; 7 designed for compressed oxygen and oil-free compressed air supply connections respectively, are connected via filters 8 to the valve 1 and to a pressure reducer 9 respectively. This pressure reducer ensures feed of a constant gas pressure of 1.4 kp/cm2 into a control unit 26 to which it is connected. Its output pressure line is connected to a valve 13 which moreover is connected to a valve 12 and an OR-element 25. The OR-element 25 is connected by its second input to the control unit 26 so that the control path formed by the valve -13 represents a control bypass for the control unlit 26. Two further control paths are controlled by the valve 1 which in turn is controlled by the control unit 26. These paths open into an inspiration line 27 via the valve 12 and a variable throttle 11a and into an injector 15 by way of a variable throttle, 10. The injector 15 has a lateral connection to the suction control valve 2, which has a membrane chamber connected to the output of the OR-element 25 and a spring chamber connected to a pressure-reducing valve 17 and to an inlet filter 16.

The pressure reducing valve 17 and an overpressure limiting valve 18 are connected to the inspiration line 27 which is connected to the output end of the injector 15, this line in turn having a control connection to a threshold value switch 4 forming a negative low pressure converter linked to the control unit 26 and to a valve 20 which is to be manually actuated and which has a breathing pressure meter 21 connected thereto.

The expired gas is passed via an expiration non-return valve 23 which is in connection with the control unit 26 through volumeter 22 for measuring the exhaled breath and through the expiration valve 3 connected thereto. In the case of assisted IPPB, an optical indicator 24 providing a digitical display for assisted IPPB by the control 26.

It is also possible to check each controlled breath by means of binary optical display 28. The bypass control facilitates gradual changing of the proportions of oxygen in the flow of breathing gas as is used in emergencies eg from 21% to approximately 50% and 100%. The provision of 21% oxygen is achieved by the oil-free compressed air which is introduced via unindirectional valve 7. The valve 5 is actuated manually to the "open" position and thus triggers a barrier (not shown) to the flow of oxygen or connection of oxygen. The valve 12 is in the condition "not open" and the OR-element has a O-signal in the case of inspiration.

If approximately a 50% proportion of oxygen-is reqired in the breathing gas, then the valve 5 is moved into the "closed" position. The supply of oxygen is introduced via the non-return valve 6 in this switching position but is not used for the control elements. Thus the compressed air still flowing serves for this latter purpose. With the same position of the valve 12 and with a O-signal of the OR-element 25 in the case of inspiration, the mixture of compressed air and oxygen is achieved in accordance with the mass flow ratio of the injector 15.

With a breathing gas comprising 100% oxygen, the injector 15 should be taken out of operation. The suction provided by the injector 15 is prevented by the L-signal at the OR-element 25 during inspiration. Since this would necessarily result in a considerable reduction of the volume of inspired gas, this loss is compensated for by the bypass control which provides for a flow of oxygen via the throttle 11a as a result of the "open" position of the valve 12. Any connection in the volume of inspired gas, which is necessary in some circumstances, can be carried out by variation of the throttle 11a.

This bypass control with its three control paths has great advantages, particularly with a reversing operation i.e. when reducing the oxygen ratio in the breathing gas; particularly if there is a change back to a gas mixture from 100% oxygen. Without the bypass control it is not possible to eliminate endangering the patient and special training would be required for the operators if they were to cope with the conditions requiring rapid medical aid to avoid this catastrophe.

If the breathing gas is 100% oxygen, then, when there is compressed air present, this should be used for control purposes. In this case, the valve 5 remains in the "closed" position. If the compressed air for the control process is missing, then oxygen may also be used for this. In this case the valve 5 is to be moved into the "open" position.

The diagrammatic circuit shown in the drawings alsp contains an amplifier indicated by the reference numeral 14, which amplifier is linked to the control line from the control unit 26 to the valve 1. It comprises two logically connected doublemembrane relays and is connected to a connection piece 19. An atomizer (not shown) may be connected thereto, preferably operating on the venturi principle.

In the embodiment shown, individual switching groups may also be provided for volumetric control and for binary display for assisted or controlled respiration. These features are already known and will not be described here.

This is not the case however with the following measure to form a locking mechanism which is designed for making the connection of oxygen and/or compressed air. This is switched in relation to the position of the valve 5 in that, with compressed air operation at 21%O2 and with the "open" position, the supply of oxygen from the directional valve 6 is blocked and, with the "closed" position, the supply of oxygen as well as the supply of compressed air takes place by means of the in directional valves 6; 7.

We have dispensed with graphic representation of the locking mechanism since the opportunities for coupling it to the valve 5 can be carried out in many ways by means of known switching linkages.

WHAT WE CLAIM IS: 1. A pneumatically controlled respiration apparatus comprising a control unit controlling an inspiration valve and an expiration valve, a compressed air connection and a compressed oxygen connection connectable to the input of the inspiration valve and to the control unit an injector with a suction imput in an inspiration line connected to the output of the inspiration valve and a by-pass arrangement for by-passing the injector comprising a by-pass line and a manually operable control valve controlling both a pneumatic control valve in the by-pass line and a suction control valve for controlling inlet to the suction input of the injector, a variable throttle being connected in the by-pass after the pneumatic control valve.

2. Apparatus according to Claim 1, wherein a pressure reduce is provided between the compressed air and compressed oxygen connections and the control unit.

3. Apparatus according to Claim 2, wherein the manually operable control valve is connected at one side to the line between the pressure reducer and the control unit and at the other side into a line between the pneumatic control and an OR-element connected to the suction control valve.

4. Apparatus according to Claim 1, 2 or 3, wherein the inspiration line is connected to a threshold value switch connected to the control unit and to a valve controlling a breathing pressure meter.

5. Apparatus according to any one of Claims 1 to 4 wherein the line connecting the control unit with the inspiration valve is also connected to an amplifier which comprises logically connected doublemembrane relays and which is linked by a line to a connection piece for connection of auxiliary apparatus.

6. Apparatus according to claims 4 or 5 when appendent to claim 4, wherein, during inspiration a logic L-signal is present at the inspiration valve and at the expiration valve and an O-signal is present at the ORelement while during expiration, the logic signals are reversed.

7. Apparatus according to claim 4 or 5 when appendent to claim 4, wherein, where 100% oxygen is required, the suction connection connecting the injector to atmosphere is cut off by the suction control valve by the presence of an L signal at the OR-element: 8. A pneumatically controlled respiration apparatus substantially as described herein with reference to the drawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. control process is missing, then oxygen may also be used for this. In this case the valve 5 is to be moved into the "open" position. The diagrammatic circuit shown in the drawings alsp contains an amplifier indicated by the reference numeral 14, which amplifier is linked to the control line from the control unit 26 to the valve 1. It comprises two logically connected doublemembrane relays and is connected to a connection piece 19. An atomizer (not shown) may be connected thereto, preferably operating on the venturi principle. In the embodiment shown, individual switching groups may also be provided for volumetric control and for binary display for assisted or controlled respiration. These features are already known and will not be described here. This is not the case however with the following measure to form a locking mechanism which is designed for making the connection of oxygen and/or compressed air. This is switched in relation to the position of the valve 5 in that, with compressed air operation at 21%O2 and with the "open" position, the supply of oxygen from the directional valve 6 is blocked and, with the "closed" position, the supply of oxygen as well as the supply of compressed air takes place by means of the in directional valves 6; 7. We have dispensed with graphic representation of the locking mechanism since the opportunities for coupling it to the valve 5 can be carried out in many ways by means of known switching linkages. WHAT WE CLAIM IS:

1. A pneumatically controlled respiration apparatus comprising a control unit controlling an inspiration valve and an expiration valve, a compressed air connection and a compressed oxygen connection connectable to the input of the inspiration valve and to the control unit an injector with a suction imput in an inspiration line connected to the output of the inspiration valve and a by-pass arrangement for by-passing the injector comprising a by-pass line and a manually operable control valve controlling both a pneumatic control valve in the by-pass line and a suction control valve for controlling inlet to the suction input of the injector, a variable throttle being connected in the by-pass after the pneumatic control valve.

7. Apparatus according to claim 4 or 5 when appendent to claim 4, wherein, where 100% oxygen is required, the suction connection connecting the injector to atmosphere is cut off by the suction control valve by the presence of an L signal at the OR-element:

8. A pneumatically controlled respiration apparatus substantially as described herein with reference to the drawing.