FR2727023A1 - APPARATUS FOR AIDING BREATHING - Google Patents

Abstract

The apparatus comprises on the one hand means for supplying pressurized air to a patient, and comprising in particular a venturi (7) where a jet of compressed air sucks in atmospheric air, and on the other hand means for supplying oxygen comprising in particular a concentrator (40) with molecular sieve, supplied with compressed air. A compressor (30) with two cylinders arranged in parallel can supply the venturi on the one hand, and the concentrator on the other hand, with compressed air in variable proportions according to requirements. The device can be used for home care.

Description

The present invention relates to an apparatus

help with breathing.

  Current techniques of breathing assistance are

  multiple, and vary according to the needs of the patient.

  In some cases, the patient is breathing normally, and only needs to breathe oxygen enriched air. The apparatus may then comprise "breathing goggles", that is to say a device formed of a spectacle frame on which small tubes are fixed which open into the nostrils and are connected to a source of Oxygen flow continuously. This oxygen mixes with the air inspired in the nostril. It is a simple and inexpensive apparatus, relatively easy

to wear.

  In other cases, assistance should be given to the muscular system that controls respiration. The apparatus may then comprise a mask connected to an air source under a relative pressure of the order of 25 mbar maximum, this source being equipped with a valve which controls the delivery of pressurized air into the system. patient's lung during the inspiration phase. During the expiration phase, another valve connects the pulmonary system to the atmosphere, the pressurized air valve being closed. If the muscular system, while insufficient, is however active, sensors detect the phases of inspiration and expiration and control the valves accordingly. If the muscular system is momentarily or permanently inert, a control organ will actuate the valves to a

rate set by the doctor.

  If the muscular insufficiency is added to a lack of oxygenation, it will be possible to provide a device for mixing oxygen with compressed air for at least

  part of the inspiration phase.

  Sometimes, during a breathing aid process, it is necessary to maintain, even during the exhalation phase, a certain excess pressure inside the pulmonary system to maintain the pulmonary alveoli in a state of more great opening. The air exiting from the patient's lungs during expiration will then, for example, have to be sent to an enclosure maintained under said overpressure, called positive expiratory pressure, abbreviated

P.E.P.

  For many years, there has been a tendency to prefer home care to inpatient treatment where possible, and many respiratory deficiencies can be treated in this way. There is therefore a growing need for self-contained, lightweight and space-saving apparatus for supplying oxygen and / or compressed air to the patient suffering from insufficiency.

  Respiratory and treated at home.

  With regard to pressurized air, one could think of using a simple fan delivering air at suitable conditions, for example 170 liters / minute under

a relative pressure of 200 mbar.

  Experience shows that such fans have such inertia that they are not suitable for satisfactorily supplying a pulsed flow rate at a frequency corresponding to a respiratory cycle. It is preferable to use the arrangement developed for hospitals, in which air, supplied at a pressure of the order of 3.5 bar, passes through a solenoid valve controlled at a respiratory rate and is sent into a venturi. o It causes the desired flow of atmospheric air to

  the user, at the proper pressure.

  To adapt this provision to use in the home or in a hospital service that does not have a compressed air system, it is sufficient to provide a

  compressor capable of delivering air at about 3.5 bar.

  Such compressors are commercially available.

  As regards oxygen, in the absence of an oxygen distribution network, the use of compressed gas cylinders proves to be impractical, but in recent years there have been "concentrators". In such devices, air under a pressure of at least 2 bar is sent into a column filled with a material called "molecular sieve" which fixes the nitrogen and passes oxygen with a low nitrogen content, which is supplied under a pressure of the order of 300 to 400 mbar maximum. The nitrogen-loaded molecular sieve releases it when it is brought back to atmospheric pressure, which regenerates it for a new use. The concentrators therefore comprise at least two molecular sieve columns, one of which is in operation and another in regeneration. The permutation of the columns takes place after 15 to

seconds in general.

  To avoid the complication of having two separate compressors, in a home care facility, one might think of using a single compressor

  under about 3.5 bars, to power both devices.

  Experience has shown that satisfactory results can not be obtained in this way: the pressure network of 3.5 bar undergoes two types of disturbances: the ones resulting from the pulsed emission of pressurized air at a variable respiratory rate, of the order of 7 to 12 times per minute, the others resulting from commutations of the columns of the concentrator, at a frequency which is, for example, four commutations per minute. The interferences between these two types of disturbances are such that it is impossible to obtain a suitable stability of the pressure

  pressurized air, unless reservoirs are

  tampons with unacceptable bulk.

  Pressure changes in pressurized air are very uncomfortable and can be dangerous. On the other hand, variations in the feed pressure of the concentrator have little effect on

  the output flow and do not have unfortunate consequences.

  The object of the present invention is to solve this problem and to provide a breathing aid apparatus which is autonomous and easy to use, and which makes it possible to feed, in variable proportions at will, a patient with pressurized air and oxygen. , while ensuring acceptable stability of the pressure of the pressurized air. To obtain this result, the invention provides a breathing aid apparatus comprising: a) means for supplying pressurized air to a patient, and comprising: a venturi which can be supplied with air under high pressure for entrain air at atmospheric pressure in a first duct connected to the pulmonary system of the patient, - a first valve placed on the supply of the venturi to interrupt the supply of said venturi during the expiration periods, - a second valve to connect the system

  pulmonary to the atmosphere during expiration periods.

  b) means for supplying oxygen to the patient, and comprising: - a concentrator, which can be supplied with air under high pressure to produce oxygen, this concentrator comprising at least two molecular sieve columns operate alternately, one absorbing nitrogen while the other is regenerating, - a second conduit, connecting an outlet of the concentrator to said first conduit, and equipped with a valve preventing the passage of oxygen to the patient for at least periods of time. 'expiry; and a compressor capable of supplying oxygen at high pressure to the venturi and / or the concentrator, this apparatus having the particularity that the compressor is of the type with at least two cylinders provided with pistons and operating in parallel, the outputs of the two cylinders being independent of one another and connected to a set of pipes which comprise a first pipe which makes it possible to connect the outlet of a first cylinder to the venturi, a second pipe which makes it possible to connect the outlet of a second cylinder to the concentrator, and means for interconnecting the first and second pipes, and further non-return valves are arranged on said means to prevent an overpressure in the second pipe to reach the first pipe. In this way, the necessary independence of the circuits

  can be ensured for any distribution.

  By "high pressure" is meant here a pressure

relative of at least 2 bars.

  In a particularly simple and economical embodiment, the second pipe is permanently connected to the concentrator, and there is provided, on the first pipe, a three-way valve which makes it possible to send the compressed air produced in the first cylinder

  either to the venturi or to the concentrator.

  In this case, the apparatus comprises, in addition to the first and second pipes, a connecting pipe, and a three-way valve on the first pipe, and it can operate in two modes: - breathing assistance with pressurized air and oxygenated,

  - Respiratory support by oxygenated air only.

  In the first mode, you can always switch off the concentrator if the oxygen is not

necessary.

  According to a slightly more sophisticated embodiment, there is provided, on the first pipe, between said valve and the venturi, a weir which allows to divert a part of the compressed air sent to the venturi to direct it.

to the concentrator.

  This realization makes it possible to modulate at will the

pressurized air / oxygen ratio.

  In any case, it is possible to further improve the constancy of the flow rates and pressure of the pressurized air by providing that a buffer tank, of low volume, is

  connected to the first pipe.

  In an interesting embodiment, the concentrator comprises an output that makes it possible to connect it to a device

  breathing aid operating without pressurized air.

  The advantage of this arrangement is to allow, in case of need, a very fast passage of a "natural" breathing

  in super-oxygenated air, with forced air assisted breathing.

  The invention will now be described with the aid of a practical example, illustrated with the help of the single figure which is a diagram of a respiratory assistance apparatus

according to the invention.

  The apparatus described by way of example comprises, on the one hand, a "respirator" 1, which is derived from a similar device intended for hospital use, and marketed by the applicant under the name "ARM 25" , and a power module 2, which has the features

specific features of the invention.

  The respirator 1 comprises two parts, the first of which is intended for the blowing of pulsed air into the respiratory system of the patient P. This first part comprises an inlet A, connected to the source of compressed air which will be described later. A pressure switch 3 makes it possible to control the inlet pressure and a regulator 4 makes it possible to stabilize it at a value of approximately 3 bars. An inspiratory aid valve 5 makes it possible to lower the pressure established by the regulator 4 to an adjustable value chosen according to the needs. A solenoid valve 6 can interrupt and restore the flow at will, so as to constitute a pulsed regime. A venturi 7 comprises an axial nozzle 8, supplied with compressed air from the solenoid valve 6, and a filtered secondary air inlet 9, which is driven by the air leaving the nozzle 8, when the latter is fed. The venturi 7 is extended by a conduit 10 provided with a valve

  11, and a heating wire flow sensor 12.

  There is shown at 13 and 14 a manometer and a pressure sensor, connected to the conduit 10, downstream of the non-return valve 11. The conduit 10 opens into the body of a mask in permanent communication with the system

respiratory i patient.

  The mask body has an expiratory orifice 15, connected to the open air, and provided with a valve 16, arranged to interrupt its communication with the valve body outside expiratory periods. All the elements of this first part of the respirator, from the solenoid valve 6 to the valve 16, are described

  in the previous patent US-A-5.000.173.

  The second, much simpler, part of the respirator is intended to introduce additional oxygen (which may be another treatment gas) into the patient's respiratory system 1. I1 comprises an inlet B, connected to an oxygen source of the apparatus which will be described below, and a valve 21 for dosing oxygen as needed. A solenoid valve 22 is interposed on a conduit 23 which connects the valve 21 to the conduit 10, where it joins the mask body, so as to send

  oxygen in the respiratory system 1 of the patient.

  The solenoid valve 22 makes it possible to synchronize the shipments

  of oxygen and the pressurized air shipments.

  The lower part of the attached figure is occupied by the feed module 2, which will now be described

in more detail.

  The motor element of the module 2 is a compressor 30, comprising two cylinders provided with pistons and operating in parallel. The compressor thus has two separate outputs 31, 32. The first outlet 31 is connected, via a duct 32, to a three-way valve 33. One of the outputs of the valve 33 is connected to a duct 34, itself connected to a "discharger" 35, the operation of which will be explained further, and an output of which is connected by a pipe 36 to the output "compressed air" of the module, which is coincident with the inlet A of the first part of the respirator. The pressure at the first outlet 31 of the compressor is about 3.5 bar, it is kept almost completely until the outlet A. The second outlet 32 of the compressor is arranged to send compressed air, at a pressure of approximately 3.5 bar substantially equal to that prevailing at the first outlet 31, in a concentrator 40, of the type comprising two molecular sieve columns operating alternately. A nonreturn valve 41 is interposed between the outlet 32 and the concentrator 40, so as to prevent a backflow of air from the concentrator to the

  compressor, especially when changing the column.

  The three-way valve 33 has a second output, which is also connected to the input of the concentrator 40. This second output also includes a non-return valve 42, which also protects the outlet 31 of the compressor. against the return of pressurized air coming from the concentrator 40, when the three-way valve 33 is in the position where the outlet 31 is connected to this concentrator. The inlet of the concentrator 40 is also connected to another outlet of the discharger 35, through which it is possible to send to the outlet A only a portion of the air which has passed through the three-way valve 33 and the duct 34. The excess air is then sent to the concentrator 40. The discharger 35 is also protected by a non-return valve 43, arranged in the same way as the flaps

anti-return 41 and 42.

  A small buffer capacity 44, connected to the pipe 36, provides additional stabilization to the pressure at the outlet A. The concentrator 40 has an outlet B, which coincides with the inlet of the second part of the ventilator 1. It comprises a third output C, which is not in use when the respirator is running, but which can be used for respiratory assistance not involving

the use of pulsed air.

  As an indication, the compressor is supplied by the Thomas Company. Outlets 31 and 32 each issue 18

  Nlitres per minute, at 3.5 bar (350 kPa).

  The invention therefore makes it possible to have a virtually autonomous device, that is to say one that does not need to be connected to networks of compressed air or oxygen. It suffices to connect to a suitable energy source for the compressor motor, for example an electrical network. The device has a great flexibility, since it allows, by simple switching of the valve 33 in particular, to proceed either to respiratory assistance with pulsed compressed air, this compressed air can contain adjustable proportions of oxygen, or a assistance respiratory less, by simple addition

  of oxygen, naturally inspired air.

  The equipment is compact and easy to handle.

Claims (5)

  Breathing aid apparatus comprising: a) means for supplying pressurized air to a patient, and comprising: - a venturi (7) which can be supplied with air under high pressure to entrain air at atmospheric pressure in a first conduit (10) connected to the pulmonary system of the patient, - a first valve (6) placed on the supply of the venturi to interrupt the supply of said venturi during the expiration periods, - a second valve ( 16) to connect the system   pulmonary to the atmosphere during expiration periods.   b) means for supplying oxygen to the patient, and comprising: - a concentrator (40), which can be supplied with air under high pressure to produce oxygen, this concentrator comprising at least two molecular sieve columns operate alternately, one absorbing nitrogen while the other is regenerating, - a second conduit (23), connecting an outlet of the concentrator to said first conduit (10), and equipped with a valve (22) preventing the passage oxygen to the patient for at least the expiration periods; and a compressor (30) capable of supplying oxygen at high pressure to the venturi and / or the concentrator, characterized in that: the compressor (30) is of the type with at least two cylinders provided with pistons and operating in parallel, the outlets (31, 32) of the two cylinders being independent of one another and connected to a set of pipes which comprise a first pipe (34) which makes it possible to connect the outlet (31) of a first cylinder at the venturi, a second pipe which makes it possible to connect the outlet (32) of a second cylinder to the concentrator, and means (33) for connecting the first and second pipes together, and in that non-return valves (41, 42, 43) are disposed on said means to prevent overpressure in the second pipe to reach the first pipe. 2. Apparatus according to claim 1, characterized in that the second pipe is permanently connected to the concentrator, and in that there is provided on the first pipe, a three-way valve (33) which allows to send the compressed air produced in the first cylinder   either to the venturi or to the concentrator.   3. Apparatus according to claim 2, characterized in that there is provided on the first pipe, between said valve and the venturi, a discharger (35) which allows to divert a portion of the compressed air sent to the venturi   to direct it to the concentrator.   4. Apparatus according to one of claims 1 to 3,   characterized in that a buffer tank (44) is provided   connected to the first pipe.   5. Apparatus according to one of claims 1 to 4,   characterized in that the concentrator has an outlet (6) for connecting it to a device for assisting the   breathing functioning without pressurized air.