GB2104394A

GB2104394A - An anaesthesia respirator

Info

Publication number: GB2104394A
Application number: GB8224644A
Authority: GB
Inventors: Lucien Romanat
Original assignee: LEJEUNE SEITZ AMELINE LAB
Current assignee: LEJEUNE SEITZ AMELINE LAB
Priority date: 1981-08-28
Filing date: 1982-08-27
Publication date: 1983-03-09
Also published as: DE8224154U1; GB2104394B; FR2511874B1; FR2511874A1

Abstract

The invention concerns an anaesthesia respirator comprising an indeformable container (1), an elastically deformable envelope (2) defining between it and the container cushions of air (4 and 5) which store energy (as well as the envelope when the source 6 supplies and inflates the envelope). A valve (7) puts the said respirator in intermittent communication with the patient through a variable flow limiting device (8). <IMAGE>

Description

SPECIFICATION An anaesthesia respirator Modern anaesthesia has given rise to the creation of breathing apparatus for administering to the patient a gaseous mixture in addition to a volatile anaesthetic. These apparatuses also permit the provision of a breathing assistance to the patient.

In order to ensure a forced ventilation or an assisted ventilation for a patient it is desirable to apply energy to the gas to be driven in the direction of the patient. The movement imparted to the breathed gas may be of mechanical origin from an electric or pneumatic source of energy. It may be of a purely pneumatic origin, the gas than being breathed directly by the sick person or through an elastic device which restores it in a progressive and controllable manner.

Numerous apparatuses exist today for carrying into effect the different principles disclosed above. Devices will be recalled operating a bellows or a piston actuated mechanically in accordance with a predetermined- rhythm over an equally selected stroke. In other devices, the pressure in a control chamber is caused to vary cyclically and in which a flexible wall has been located delimiting a reservoir of gas to be breathed subjected to variations in pressure from the said closed chamber which causes it "to breathe" The flexible wall of the reservoir may be a sack, a diaphragm or a bellows loaded or not.Alternatively, the chamber is supplied with a compressed gas either by means of a piston compressor or by means of a source of compressed gas and purged by that gas, or by expansion during the return stroke of the piston, or by escape to atmosphere, the deformable wall then being either elastic, or loaded so as to provide the reservoir with its initial volume.

These earlier devices have the disadvantage of being consumers of compressed fluid and of some of them necessitating the installation of a motor unit which is not always desirable in an operating theatre.

In the case where the gas to be breathed comes directly from a source of compressed gas, the installation consists essentially of an expansion valve and a control valve for opening the conduit towards the patient during the period necessary for the insufflation. This device requires a delicate control of the expander and of the control for the valve and besides is badly suited to the insufflation of a mixture which is not delivered at high pressure.

Finally, if the gas to be breathed leaves through an elastic device forming an accumulator reservoir for the gas when the valve is closed and a mechanical insufflation generator when the valve is open which adds directly to the supply, the said elastic device requires a mechanical rearming after each insufflation produced by any means particularly by rams.

The present invention proposes a respirator in which the above disadvantages are overcome. Hence it permits dispensing with a mechanical source of energy for the installation in an operating theatre, using the energy in the gas to be breathed to ventilate the sick person in a constant manner even if the gas is delivered under a very low pressure and finally being simple and occupying little space.

Thus, to this end, the subject of the invention is an anaesthesia respirator constituted by a rigid indeformable container equipped internally with a deformable pocket forming an accumulator connected to a source of anaesthetizing fluid under pressure and by intermittence to a patient by means of an electro valve.

According to one of the characteristics of the invention, the said pocket is constituted by an elastic envelope the lateral walls of which follow strictly the lateral walls of the rigid container over a portion of their length and the end walls of which delimit together with the end of the lateral walls and the ends of the container, elastically compressible volumes.

Moreover, the envelope referred to above issues outside the rigid container for connection to the source referred to above and to the patient by means of a conduit passing through an end wall of the said container and comprising a first branch permanently connected to the source referred to above and a second branch connected to the patient by means of the electro valve mentioned above.

Finally, the second branch comprises an adjustable flow limiting device upstream of the electro valve.

The invention will be better understood during the course of the description given hereafter purely by way of a non-limiting example which will permit the advantages and the secondary characteristics to be disclosed.

Reference will be made to the accompanying drawing in which the single Figure is a diagram of the respirator according to the invention.

Referring to this Figure, a rigid, indeformable container 1 can be seen constituted for example by a cylinder 1 a closed in a fluidtight manner at each of its ends by ends 1 b and 1c. An elastic envelope 2 - for example of rubber - is situated inside the reservoir 1 and has the form of a substantially cylindrical balloon the lateral walls 2a of which follow strictly the inner surface of the central cylinderical portion 1 a of the container. This envelope 2 issues outside the container through the end 1 c (passing through in a fluid-tight manner) into a conduit 3. The relative dimensions of the envelope 2 and of the container 1 are such that there exists between the envelope and the container end spaces 4 and 5 delim ited in a fluid-tight manner with respect to the outside of the container and the inside of the envelope.

The conduit 3 is permanently connected by a first branch 3a to a source of anaesthetic mixture under pressure 6 and by a second branch 3b to the patient (not shown). This branch comprises an electro valve 7 the open ing of which is controlled at the desired instant and during the period of insufflation.

Between the valve 7 and the branch 3a; the branch 3b comprises an adjustable flow limit ing device 8 permitting delivery either of a constant flow or of a decreasing flow according to its degree of opening.

The operation of the respirator according to the invention is as follows. The valve 7 being closed, the gas coming from the source 6 fills the envelope 2. The energy is stored by the envelope itself due to its resistance to deformation with which it opposes the pressure of the gas and by the compression of the volumes 4 and 5 which form cushions of air.

When the valve 7 is opened, the pressure in the cushions of air 4 and 5 and the compliance of the balloon 2 restore the energy stored in the respirator, this energy expelling the gas in the branch 3b towards the patient through the flow limiting device 8 which thus regulates the flow. It will be noted that at the same time the mixture admitted by the branch 3a is also directed towards the patient during the insufflation. By way of example the pressure prevailing in the branch 3a is of the order of 0.2 Kg/cm2, the pressure delivered at the outlet from the valve 7 not being greater than 0.08 Kg/cm2 It will be seen that this respirator takes up little space and functions without any energy other than the pressure of the gas delivered by the source 6. Its operation is very reliable and silent and without any movable external parts which confers upon it qualities for its use in an operating theatre requiring severe sterile conditions.

The invention is not limited to the description which has just been given but, on the contrary, covers all variants which could be applied to it without departing from its scope or its concept.

It is of interesting application within the filed of apparatus for medical use.

Claims

1. An anaesthesia respirator constituted by a deformable rigid container (1) equipped internally with a deformable pocket (2) forming an accumulator connected to a source of anaesthetizing fluid (6) under pressure and by intermittence to a patient by means of an electro valve (7), characterised in that, the said pocket (2) is constituted by an elastic envelope the lateral walls (21 a) of which follow strictly the lateral walls (lea) of the rigid container (1) over a portion of their length and the ends of which together with the end of the lateral walls and the ends (1 b, 1 c) of the container, delimit elastically compressible volumes (4, 5).

2. A respirator according to claim 1, characterised in that, the envelope (2) referred to above issues in the interior of the rigid container for connection to the source (6) referred to above and to the patient by means of a conduit (3) passing through an end wall (1c) of the said container (1) and comprising a first branch (3a) permanently connected to the source (6) referred to above and a second branch (3b) connected to the patient by means of an electro valve (7) referred to above.

3. A respirator according to claim 2, characterized in that, the said second branch (3b) comprises an adjustable flow limiting device (8) upstream of the electro valve.