FR3112691A1 - Actuating device for medical mechanical ventilation system - Google Patents

Abstract

Title Actuating device for medical mechanical ventilation system The invention relates to the field of medical mechanical ventilation systems. It relates more particularly to an actuation device (3) for a medical mechanical ventilation system (1) comprising: An enclosure (31) configured to house therein a balloon (21) of a manual resuscitator (2), and An actuator ( 32) configured to deform the ball The enclosure comprises a shell (311) having an interior volume and shape conforming to the volume and shape of the ball at rest and a first opening (312). The actuator includes a piston (321) arranged in conjunction with the shell (311) to deform the balloon as it moves through the first opening (312). The actuation device thus makes it possible both to deform the balloon and to stiffen it so that the insufflator can be used in an automated manner with reliability, particularly in terms of the volume of air insufflated. Figure for abstract: Fig.4

Description

Actuating device for medical mechanical ventilation system

The present invention relates to the field of medical mechanical ventilation systems. It finds a particularly advantageous application in the automated insufflation and ventilation of a patient's lungs in the event of respiratory failure or arrest.

STATE OF THE ART

Manual resuscitators are medical or paramedical instruments designed to supplement the breathing of a patient who has stopped or has difficulty breathing. They adhere to strict medical standards. In particular, each manual resuscitator includes a balloon whose characteristics, and in particular the volume, are intended to ensure the insufflation of a volume of air respecting the standard.

• depuis une configuration dite au repos, dans laquelle le ballon présente un volume maximal et une forme déterminés,
• vers une configuration déformée dans laquelle le ballon présente un volume inférieur à son volume maximal.

The balloon of a manual resuscitator is designed to be deformed by a user's hand. More specifically, the balloon is designed to deform:

• from a so-called resting configuration, in which the balloon has a determined maximum volume and shape,
• towards a deformed configuration in which the balloon has a volume less than its maximum volume.

Thus, the balloon is configured to be able to be crushed by the hand of the user and to deform so as to inject a controlled volume of air into the respiratory system of a patient. When the user releases the constraint exerted by his hand on the deformed ball, the ball automatically recovers, due to its intrinsic characteristics, and in particular its elastic characteristics, its shape and its volume at rest.

Each ventilator also includes a system of one-way valves to provide ventilation without the supply of compressed gas. More specifically, two one-way valves are mounted on the balloon to respectively allow air to be admitted into the balloon when it returns to rest and to let air out from the balloon to the patient's respiratory system when the balloon is deformed by the user's hand.

Each manual resuscitator can also be connected to a mask or to an endo-tracheal intubation tube. It can still be connected to a source of medical oxygen.

It is therefore understood that the use of a manual resuscitator makes it possible to comply with the standards in force, but requires manual actuation, which it may be desirable to automate in certain circumstances.

In order to automate the actuation of a manual resuscitator, the OxVent group offers a solution based on pneumatic actuation.

More specifically, the manual resuscitator is, according to this solution, enclosed in a hermetic enclosure connected to an external pneumatic pressure source configured to pressurize the interior volume of the box, up to a pressure substantially equal to 6 bar. At this pressure, the balloon of the manual resuscitator is crushed so as to supplement the patient's breathing.

It is understood that the pressurization of the enclosure makes it possible to apply a deformation force equally distributed in any portion of the balloon. In this way, this pneumatic actuation solution allows the insufflation of a controlled volume of air regardless of the state of rigidity, or flexibility, of the patient's lungs.

In other words, the pneumatic actuation solution proposed by the OxVent group has the advantage of delivering an invariable, or slightly variable, air volume depending on the air outlet pressure from the balloon to the lungs of the patient, said output pressure being defined as the pressure necessary to insufflate air into the patient's lungs, this pressure depending on the rigidity of the patient's lungs.

• elle est relativement coûteuse,
• elle est relativement encombrante, et donc peu portable,
• elle nécessite un entretien régulier,
• son usage doit être sécurisé en permanence, au moins au vu des fortes pressions impliquées, et
• elle nécessite une infrastructure pneumatique fournissant de l'air filtré pour le médical.

However, this actuation solution also has a number of drawbacks. In particular, because it is based on pneumatics:

• it is relatively expensive,
• it is relatively bulky, and therefore not very portable,
• it requires regular maintenance,
• its use must be permanently safe, at least in view of the high pressures involved, and
• it requires a pneumatic infrastructure supplying filtered air for the medical sector.

An object of the present invention is to provide an automated actuation solution for a manual resuscitator which makes it possible to overcome one or more of the aforementioned drawbacks, while guaranteeing invariability, or at least low variability, as a function of the pressure of output as defined above.

The other objects, features and advantages of the present invention will become apparent from a review of the following description and the accompanying drawings. It is understood that other benefits may be incorporated.

SUMMARY

• Une enceinte configurée pour y loger un ballon d’un insufflateur manuel, et
• Un actionneur configuré pour déformer le ballon.

To achieve this objective, according to a first aspect of the invention, there is provided an actuation device for a medical mechanical ventilation system comprising:

• An enclosure configured to accommodate a balloon of a manual resuscitator, and
• An actuator configured to deform the balloon.

• L’enceinte comprend une coque présentant un volume et une forme conformes au volume et à la forme du ballon au repos et une première ouverture, et
• L’actionneur comprend un piston agencé conjointement avec la coque pour déformer le ballon en se déplaçant à travers la première ouverture.

The device is essentially as follows:

• The enclosure comprises a shell having a volume and a shape conforming to the volume and shape of the ball at rest and a first opening, and
• The actuator includes a piston arranged together with the shell to deform the balloon as it moves through the first opening.

Thus, the actuation device makes it possible both to deform the balloon and to stiffen it so that the insufflator can be used in an automated manner with reliability, particularly in terms of the volume of air insufflated. Since the proposed solution consists of an essentially mechanical actuation, its cost is advantageously reduced and does not require significant maintenance. Furthermore, the proposed solution does not induce any particular risk either for the operator or for the patient, with respect to manual actuation. In addition, it should be noted that the actuation device as introduced above can be said to be passive, in the sense that it does not necessarily imply an actuation control feedback based on measurement data that would come from one or more sensors.

A second aspect concerns a medical mechanical ventilation system comprising a manual ventilator and an actuation device according to the first aspect of the invention.

The ventilation system as introduced above is advantageously set up and implemented greatly simplified compared to the existing one. Space-saving, it can equip mobile medical units, such as ambulances.

BRIEF DESCRIPTION OF FIGURES

The aims, objects, as well as the characteristics and advantages of the invention will emerge better from the detailed description of an embodiment of the latter which is illustrated by the following accompanying drawings in which:

Figure 1 shows a side view of the ventilation system according to an embodiment of the second aspect of the invention comprising a ventilation device according to an embodiment of the first aspect of the invention and a manual resuscitator.

FIG. 2 represents the view of FIG. 1 in which the manual insufflator has been removed so as to reveal, partly by transparency, the piston of the actuator.

FIG. 3 represents a perspective view of the enclosure of the ventilation device according to an embodiment of the first aspect of the invention, the manual insufflator, and more particularly its balloon, being housed in the enclosure.

Figure 4 shows an exploded view of the various elements illustrated in the view of Figure 3.

The drawings are given by way of examples and do not limit the invention. They are intended to facilitate understanding of the invention.

DETAILED DESCRIPTION

Before starting a detailed review of embodiments of the invention, optional characteristics are set out below which may possibly be used in combination or alternatively:

According to one example, the shell has two additional openings, one accommodating a one-way air intake valve in the ball, the other accommodating a one-way air exhaust valve from the ball. For example, the two additional openings are located opposite each other relative to a transverse plane of symmetry of the shell;

For example, the device further comprises a piston guide fixed to the shell and extending from the first opening so as to guide the piston in its movements through the first opening. For example, the first opening and the piston guide have the same axis of symmetry of revolution perpendicular to an axis of symmetry of revolution of the shell;

• disposer un insufflateur manuel, et plus particulièrement son ballon, dans une des parties de la coque avant d’assembler ses parties entre elles, et
• retirer un insufflateur manuel depuis la coque en séparant ses différentes parties pour libérer l’insufflateur manuel, et plus particulièrement son ballon. Pour le dispositif ainsi conçu, l’insufflateur manuel est avantageusement rendu consommable, interchangeable, voire réutilisable après nettoyage.

The shell can be composed of a plurality of removable and/or jointed parts. More particularly, the shell may be composed of a rear part taking the form of a half-shell in which the first opening is formed and of a front part also taking the form of a half-shell, the front parts and rear being assembled with each other to form the hull. The front and rear parts can more particularly be articulated together by a pivot connection, for example a hinge. Preferably, the front and rear parts are further lockable in position with respect to each other when assembled with each other to form the shell. It is thus advantageously possible to separate the different parts of the hull from each other to alternately:

• place a manual insufflator, and more particularly its balloon, in one of the parts of the shell before assembling its parts together, and
• remove a manual resuscitator from the shell by separating its different parts to release the manual resuscitator, and more particularly its balloon. For the device thus designed, the manual insufflator is advantageously made consumable, interchangeable, or even reusable after cleaning.

For example, the actuator further includes a motor configured to control movement of the piston through the first aperture. The motor may be a rotary motor. In which case, the actuator may further comprise a screw-nut system arranged mechanically between the motor and the piston to transform the rotary movement of the motor into a translational movement of the piston.

At least the end of the piston intended to press on the balloon to deform it is of a dimension substantially equal to, or even greater than, the transverse extent of the balloon. In this way, we ensure that a single piston can deform the ball in a comparable way to the front of a user.

The present invention originated from a study carried out to develop a mechanical emergency respirator system based on the operating principle of a pneumatic cylinder operated by a motor. This study led to the production of a model comprising a mechanical respirator, the operation of which is as follows.

In order that the chamber of the cylinder, from which, according to the principle of the study, the air is sent into the patient's lungs, respects the medical standards in force, a manual insufflator, for example the insufflator known under the name commercial “Ambu® Mark IV”, was used. The balloon of the manual resuscitator is thus related to the body of the pneumatic cylinder according to the principle of the study. Note that the manual resuscitator used has the advantage of being a standard product widely distributed in the medical community.

Still within the framework of the aforementioned study, the actuation of the cylinder is ensured, according to the principle of the study, by a pneumatic cylinder piston. Its actuation allows air to escape from the bag of the insufflator; the piston thus aims to replace the action of the hand of a user of the manual resuscitator, so as to automate its use. More specifically, the piston as implemented in the context of the aforementioned study consisted of an articulated arm deforming the ball by a rotational movement by pressing it against a stop located opposite the articulated arm relative to the ball.

The model of the mechanical respirator thus designed was then evaluated with a calibration system, such as for example the calibration system known under the trade name ASL 5000™. It was then observed that, for the same cylinder stroke, the volume of air blown depended on the output pressure of the corresponding cylinder, according to the principle of the study at the output pressure as defined above. More particularly, the more the outlet pressure increased, the more the volume of air blown in decreased, and this including for low pressures not involving the compressibility of the air, typically pressures of the order of 3000 Pa or 30 mbar, i.e. pressures roughly equal to the average pressure in the lungs of a human being. This observation led to an experiment consisting in blocking the outlet of the model cylinder which led to the observation that, under these conditions, the stroke of the cylinder was not zero, and this always while remaining at so-called low pressures.

An interpretation of these experimental results then made it possible to identify, as the probable cause of this phenomenon of dependence of the volume of air insufflated on the outlet pressure, an excessive mechanical compliance (or flexibility, or even flexibility) of the insufflator. manual, resulting in an error between the position of the piston rod and the volume of air sent out of the cylinder. In other words, the cylinder, materialized in the model by the balloon of the manual insufflator, is too soft and therefore changes shape depending on the outlet pressure. Consequently, for too high a pressure at the outlet, corresponding for example to an abnormally high state of rigidity of the patient's lungs, the manual insufflator conforms to the geometry of the piston according to the principle of the study. The practitioner adjusts the volume of air to be sent into the patient's lungs by observing the temporal monitoring of the pressure values. It increases or decreases the volume of air delivered in order to reach the desired equilibrium pressure in the patient's lungs. A dependency between the volume of air sent by the machine and the pressure at the outlet thereof would make it very difficult to adjust, or even impossible to adjust, for the needs of the patient.

In order to take into account, or even eliminate, the excessive compliance of the insufflator, a new model has been developed which solves the problem of the dependence of the volume of air insufflated relative to the outlet pressure, and maintains a level of appreciable simplicity of installation and implementation, in particular compared to the aforementioned solution proposed by the OxVent group.

This new model is the subject of the present invention which, according to one of its aspects, therefore relates to a medical mechanical ventilation system 1 comprising a manual ventilator 2 and an actuation device 3, as illustrated for the example on Figures 1 and 2.

• Une enceinte 31 configurée pour y loger un ballon 21 d’un insufflateur manuel 2, et
• Un actionneur 32 configuré pour déformer le ballon 21.

More particularly, the actuation device 3 according to the first aspect of the invention comprises, like the solution proposed by the OxVent group:

• An enclosure 31 configured to accommodate therein a balloon 21 of a manual insufflator 2, and
• An actuator 32 configured to deform the balloon 21.

• L’enceinte 31 comprend une coque 311 présentant un volume et une forme intérieures conformes au volume et à la forme du ballon 21 au repos et une première ouverture 312, et
• L’actionneur 32 comprend un piston 321 agencé conjointement avec la coque 311 pour déformer le ballon 21 en se déplaçant à travers la première ouverture 312.

The actuation device 3 according to the first aspect of the invention, in accordance with this preamble, differs from the solution proposed by the OxVent group, in that:

• The enclosure 31 comprises a shell 311 having an internal volume and shape conforming to the volume and shape of the ball 21 at rest and a first opening 312, and
• Actuator 32 includes piston 321 arranged in conjunction with shell 311 to deform balloon 21 as it moves through first opening 312.

Thus, the shell 311 having an internal shape corresponding to the geometry of the balloon at rest, rigidly constrains the balloon 21, when it is placed around the latter, so as to compensate for its mechanical compliance, throughout the stroke of the piston. 321. The actuation is thus essentially mechanical, and not pneumatic, thus overcoming one or more drawbacks of the aforementioned existing solution.

It should be noted that a result comparable to that which makes it possible to obtain the present invention could also have been obtained with a so-called active system, since comprising and implementing a set of sensors according to the feedback from which the movement of the articulated arm of the model initially considered would have been subject. Compared to this solution, the present invention has the advantage of constituting a passive system (as opposed to the so-called active system mentioned above) guaranteeing that the volume of air blown in does not depend on the outlet pressure.

Note that in the figures, and in particular in Figures 3 and 4, the balloon 21 appears to have an ovoid shape, consistent with that of the balloon of the manual resuscitator used in each of the two aforementioned models. However, the invention according to its various aspects is not limited to a particular shape of the balloon of the manual insufflator. In other words, the internal shape of the shell 311 can be adapted to different shapes of balloon 21, and in particular to the different shapes of existing or future manual resuscitator balloons.

As illustrated in Figures 3 and 4, the shell 311 also has two additional openings 313, 314, relative to the first opening 312. A first 313 of these two additional openings is configured to accommodate a one-way air intake valve 22 in the balloon 21. The other 314 of these two additional openings is configured to accommodate a one-way air evacuation valve 23 from the balloon 21. It should be noted here that the one-way valves 22, 23 of the manual resuscitator 2 are rigid relative to the balloon 21 of the manual resuscitator 2. It is therefore not necessary for the shell 311 to encapsulate the one-way valves 22, 23 of the manual resuscitator 2 to play its role of stiffening four o'clock of the balloon 21 of the manual resuscitator 2. It may even be preferable that the shell 311 does not encapsulate the one-way valves 22, 23 of the manual resuscitator 2, so as to ensure that their functionalities are not p as hindered by the shell 311. Symmetrically to these last considerations, it may not be necessary, even if it may be considered preferable, that the shell 311 entirely encapsulates the balloon 21 of the manual insufflator 2, provided that the shell 311 satisfactorily stiffens ball 21, particularly in view of the intended application. Thus, the shell 311 could only encapsulate a part, for example central, of the balloon 21, leaving one or more other parts, for example distal in the longitudinal extent of the balloon 21, unencapsulated.

It will be noted that the opening 312 as shown takes the form of a disk or a cylinder passing through the thickness of the shell 311. The geometry of the opening 312 is not however limited to the shape illustrated on the drawings. The opening 312 could for example be square, rectangle, oval, triangular, etc. It will also be noted that, according to the geometry of the opening 312 as illustrated in the figures, the diametral extent of the opening 312 is relatively significant, and more particularly relatively close although less significant, relative to the transverse extent of the balloon 21. Thus, the piston 321 preferably configured to slide narrowly through the opening 312 has the same relative proportions, at least by its end intended to press on the balloon 21. These proportions are intended to allow deformation of the balloon 21 by the piston 321 comparable to the deformation that a hand of a user would allow the latter to apply to the balloon 21. It will be noted here that the different possible shapes of the opening 312 can accommodate preferential proportions between the piston 321 and the balloon 21 mentioned above.

The piston 321 as illustrated has a substantially cylindrical shape configured to slide tightly through the opening 312. It has more particularly, at its end intended to press on the balloon 21, the shape of a half-sphere with a radius of curvature oriented towards the other end of the piston 321. This prevents the piston 321 from injuring the balloon 21 by deforming it; any risk of the balloon 21 puncturing due to the actuation of the piston 321 is thereby reduced. aforementioned of opening 312.

With reference to each of the appended figures, the actuating device 3 according to the first aspect of the invention may further comprise a piston guide 315. The latter may be fixed to the shell 311. It may further extend from the first opening 312. It is configured so as to guide, preferably narrowly, the piston 321 in its movements through the first opening 312. The piston guide 315 thus makes it possible to release the mechanical stresses on the mechanical elements allowing the drive in movement of the piston 321, these mechanical elements being described in more detail below, after having described some remarkable characteristics of the shell 311.

The shell 311 may in particular be composed of a plurality of parts 311a, 311b that are removable and/or hinged together. It is indeed particularly advantageous to be able to consider the manual insufflator 2 as a consumable that will be changed from one patient to be treated to another, over time for the same patient. That the shell 311 is made up of several removable and/or jointed parts contributes to this, and this in particular according to the specific features described below.

More particularly, and as illustrated in FIG. 4, the shell 311 can be composed of a rear part 311a taking the form of a half-shell and a front part 311b also taking the form of a half-shell. The first opening 312 can be formed in the rear part 311a. The front 311b and rear 311a parts can be assembled together to form the shell 311, as shown in Figure 3. As shown in Figures 1 and 2, one of the parts of the shell 311, and in particular its rear part 311a, can be fixed to a support structure, or frame, of the actuating device 3; the front part 311b is for its part fixed to the rear part 311a.

The front 311b and rear 311a parts of the shell 311 can also be articulated together by a pivot connection 316, for example by a hinge. Furthermore, the front 311b and rear 311a parts of the shell 311 can be locked in position with respect to each other, by a lock 317, when assembled with each other to form the shell 311. Thus, the installation of the manual insufflator 2 in the actuation device 3 is very simple. It consists in unlocking between them the front 311b and rear 311a parts of the shell 311 by manipulating the lock 317, in pivoting the front part 311b of the shell 311 so as to open the shell 311, in placing the manual insufflator 2, and in particular its ball 21, in one of the front 311b and rear 311a parts of the shell 311, then to close the front part 311b of the shell 311 by pivoting it, to finally close the lock 317 holding the front 311b and rear parts 311a of the hull 311 in position.

The actuation device 3 as illustrated in particular in FIG. 2 advantageously provides for being able to automate the movement of the piston 321 so as to ventilate a patient without the need for manipulation of the insufflator by a practitioner.

To this end, the actuator 32 further comprises a motor 322 configured to control the displacements of the piston 321 through the first opening 312.

Motor 322 may be a rotary motor. In which case, the actuator 32 may further comprise a screw-nut system 323 mechanically arranged between the motor 322 and the piston 321 to transform the rotary movement of the motor 322 into a translational movement of the piston 321.

More particularly, the actuation of the piston 321 by the actuator 32 as illustrated in FIGS. 1 and 2, and such that the motor 322 fixed on a first axis pivot with the frame of the system, actuates in rotation a screw of the screw-nut system 323. The nut of the screw-nut system 323 transforms the rotation of the screw into translation along the axis of the screw.

The piston 321 could be directly connected to the screw. However, a mechanical configuration as described below is preferable because it allows in particular to play on the amplitude of displacement in translation of the piston 321, in order possibly to be able to adjust it differently according to the cases encountered.

This is how the nut of the screw-nut system 323 is preferably linked to a rocker by a second axis pivot and that the rocker is linked in turn to the piston 315 by a third axis pivot . The rocker is thus arranged to transmit the translation generated by the nut of the screw-nut system 323 to the piston 321 thanks to the third axis pivot . The piston 321 is guided thanks to the piston guide 315. The piston 315 actuated in translation by a rotation, for example clockwise, of the motor 322 comes to crush the balloon 21 of the manual insufflator 2 sending a volume of air into the system; then the direction of rotation of the motor 322 is reversed to allow the withdrawal of the piston 321 and the return of the balloon 21 to its configuration at rest; the balloon 21 is thus filled with air through the one-way air intake valve 22, before being again deformed by the piston 321 driven by the motor rotating again in the clockwise direction.

Tests were carried out on the new model, by varying the outlet pressure of the jack according to the principle stated above, and for a constant jack stroke. No variation in the volume of blown air was observed. By remaining in a range of low pressures, going all the same up to a pressure substantially equal to 8000 Pa (i.e. 80 mBar) at the blocked output of the cylinder, the latter is stopped. This validates the capacity of the actuation device 3 according to the first aspect of the invention to allow both the deformation of the balloon 21 and the stiffening thereof so that the insufflator 2 can be used in an automated manner with reliability, in particular in terms of volume of blown air.

It should be noted that the invention also finds application in the medical field of resuscitation and in that of pneumology.

The invention is not limited to the embodiments described above and extends to all the embodiments covered by the claims.

For example, the shell of the actuation device according to the first aspect of the invention does not necessarily have a solid surface. It can be traversed by orifices, or even consist of a mesh, provided that the ball does not deform through said orifices, or even through the meshes of the mesh, when the piston deforms the balloon. In other words, the shell can be pierced, or even mostly hollowed out, if it continues to fulfill its function of stiffening the ball during its deformation by the piston.

For example, the shell 311 and/or the piston guide 315 and/or the piston 321 can be made from plastic, or any other suitable material; the frame and/or the screw of the screw-nut system 323 and/or the nut of the screw-nut system 323 and/or the lever can be made from a metal, or from any other suitable material.

Claims (10)

Actuation device (3) for a medical mechanical ventilation system (1) comprising:

• An enclosure (31) configured to house therein a balloon (21) of a manual resuscitator (2), and
• An actuator (32) configured to deform the balloon (21),

Characterized in that:

• The enclosure (31) comprises a shell (311) having an interior volume and shape conforming to the volume and shape of the ball (21) at rest and a first opening (312), and
• The actuator (32) includes a piston (321) arranged together with the shell (311) to deform the balloon (21) as it moves through the first opening (312).

Device (3) according to the preceding claim, in which the shell (311) has two additional openings (313, 314), one accommodating a one-way air intake valve (22) in the balloon (21), the the other accommodating a one-way valve for venting air (23) from the balloon (21). Device (3) according to one of the preceding claims, further comprising a piston guide (315) fixed to the shell (311) and extending from the first opening (312) so as to guide the piston (321) in its movements through the first opening (312). Device (3) according to any one of the preceding claims, in which the shell (311) is composed of a plurality of parts (311a, 311b) that are removable and/or hinged together. Device (3) according to the preceding claim, in which the shell (311) is composed of a rear part (311a) taking the form of a half-shell in which the first opening (312) is formed and a front part ( 311b) also taking the form of a half-shell, the front and rear parts (311b, 311a) being assembled together to form the shell (311). Device (3) according to the preceding claim, in which the front and rear parts (311b, 311a) of the shell (311) are articulated to one another by a pivot connection (316), for example by a hinge. Device (3) according to any one of the two preceding claims, in which the front and rear parts (311b, 311a) of the shell (311) are lockable in position with respect to each other, by a latch ( 317), when assembled together to form the shell (311). A device (3) according to any preceding claim, wherein the actuator (32) further comprises a motor (322) configured to control movement of the piston (321) through the first aperture (312). Device (3) according to the preceding claim, in which the motor (322) is a rotary motor and in which the actuator (32) further comprises a screw-nut system (323) mechanically arranged between the motor (322) and the piston (321) to transform the rotary movement of the motor (322) into a translational movement of the piston (321). Medical mechanical ventilation system (1) comprising a manual ventilator (2) and an actuating device (3) according to any of the preceding claims.