WO1997001367A1

WO1997001367A1 - Bag in pressure chamber arrangement for use in anaesthesia and resuscitation apparatus

Info

Publication number: WO1997001367A1
Application number: PCT/AU1996/000388
Authority: WO
Inventors: David Komesaroff; Rodney Westhorpe
Original assignee: Techbase Pty. Ltd.; The Royal Childrens Hospital
Priority date: 1995-06-26
Filing date: 1996-06-26
Publication date: 1997-01-16
Also published as: AUPN381195A0

Abstract

The invention relates to a bag in bottle breathing unit (10) for use in anaesthetic or resuscitation equipment for a patient, the bag in bottle unit including a breathing bag (30b) mounted within a chamber (11), the chamber being adapted to be connected (61a) to an external gas source, and the bag interior being adapted to be connected to the breathing circuit of a patient (21a, 21b), the arrangement being such that variation of pressure in the chamber will cause the patient to inhale or exhale according to whether the pressure is increased or reduced respectively, wherein the bag is easily separably connected in the breathing circuit (22), thereby facilitating enabling sterilisation or disposal of the parts after each patient treatment. The breathing unit is moveable between two operating locations diametrically opposed when the bag is suspended from the integral, or projects vertically upwards thereform. The bag may be a bellows (30a) or a smooth bag type (30b) in the same breathing unit. The unit is easily dismantled and assembled without the need for tools.

Description

BAG IN PRESSURE CHAMBER ARRANGEMENT FOR USE IN ANAESTHESIA AND RESUSCITATION APPARATUS

The present invention relates to bag in bottle arrangements for use as part of a ventilator breathing system for anaesthesia and resuscitation apparatus and in particular, bag in bottle arrangements that can be sterilised or have a single use application. Additionally, the present invention is in relation to components used in bag in bottle arrangements which are in contact with the patient and the ability to be able to use different types of bags and in particular either a concertina type bag or a smooth type bag. BACKGROUND OFTHE INVENTION

There are considerable concerns at the moment for the need to be able to completely sterilise medical equipment to prevent the spread of serious diseases such as Tuberculosis, Hepatitis B, Hepatitis C and HIV. In particular to date, it has been extremely difficult to adequately sterilise ventilator equipment. Ventilators are more common place within anaesthetic circuits as opposed to resuscitation circuits and for convenience, we will discuss the use of ventilators during anaesthesia.

During many anaesthesia operations, where the patient's breathing is controlled artificially, the patient is delivered a gas mixture which contains oxygen and a mixture of anaesthetic gases and vapours. The patient receives the gas mixture via a breathing system or circuit. To ensure that the gas circulates in and out of the patient, ventilators are often used. Ventilators enable automatic intermittent inflation of the patient's lungs with the gas by adding pressure to the circuit. Ventilators generally are used in association with a gas tight chamber enclosing either a concertina type bag or a smooth type bag (either of these are known as "the bag"). This arrangement is hereinafter for convenience, called the "bag in bottle". Additionally, for convenience the concertina bag will be referred to as the "bellows", the chamber will be referred to as the "bottle", the conventional commonly used smooth rebreathing bag, which may or may not be textured, will be referred to as the "smooth bag". The bottle is connected to a ventilator used to provide an external gas source and the interior of the bag is in direct contact with the patient breathing circuit. To inflate the patients lungs, the pressure within the bottle (and outside the bag or bellows) is increased expelling some or all of the gas in the bag into the patient circuit. To allow the patient to exhale, the pressure in the bottle is reduced and the bellows or bag within the bottle expands by means of the elastic recoil of the patient's lungs.

The problem with the bag in bottle arrangement commonly used with conventional ventilators is that they can not easily be completely sterilised since they either cannot be readily dismantled or because some of the portions in contact with the patient are inaccessible. For example the manifold or pipe connecting the bellows or bag arrangement to the patient circuit is often inextricably linked with the control mechanism of the ventilator means which controls the time for inspiration, the time for expiration and the flow rate of gas into the bottle. In this case the gas, which is in contact with the patient, flows through the control mechanism to the bag. Because the control mechanism is either too bulky to sterilise or contains components which cannot be autoclaved due to the high temperatures achieved in the autoclaving process, the portions in contact with the patient are not sterilised in between uses which greatly increases the chances of disease transmission. In fact there may be long delays between sterilisation procedures. Some attempts have been made to develop an anaesthesia ventilator in which the patient circuit can be sterilised, however, to date these ventilators are complex and costly due to the material used to construct the components. There is also extreme difficulty in assembling and disassembling the ventilator which makes regular sterilisation difficult and sometimes impossible between patient treatments.

Additionally, it is observed that the medical professionals which use the bag in bottle devices are generally divided as to which type of bag arrangement they prefer. That is, they either prefer the bellows or alternatively, the smooth bag. Existing ventilator bag in bottle devices generally only allow the fitting of one type of bag since the positional operations of the two types of bags are different to each other.

In particular, popular but expensive bellows in bottle arrangements have been generally designed such that the bellows must be inflated in the upward direction. However, the requirements for the operation of the traditional and cheaper smooth bags are different as they are not self-supporting and of necessity are held within the bottle by the neck and hang in a downward direction so as to ensure that inflation of the bag is not restricted. Thus as indicated above because of these differences in the method of functioning of the two types of bags, existing ventilators only allow for one or other type of bag/bellows. Further none provide for either upward or downward operation of the bag or bellows in the one unit. Thus the current arrangements do not provide the required flexibility to meet the varied needs of the professionals that use anaesthesia equipment.

It is an object of the present invention to provide a bag in bottle arrangement for use with a ventilator system which enables both bellows and smooth bags to be used without losing any effectiveness in the function of the ventilator. Additionally, it is an object of the present invention to provide a bag in bottle arrangement for use with a ventilator system which can also be easily dismantled for sterilisation or altematively, be a single use system and thus easily replaceable. SUMMARY OF THE INVENTION The invention therefore provides in one aspect an integral unit for use in a bag in bottle arrangement of a ventilator system including an inlet/outlet means which in use, is connected with the patient's breathing circuit, a means to retain the bag in a gas tight manner and a means to seal the bottle or chamber in a gas tight manner. In a further aspect there is provided according to the invention, a ventilator breathing unit for use in anaesthetic or resuscitation equipment for a patient, the ventilator unit including a breathing bag mounted within a chamber , the chamber being adapted to be connected to an external gas source, and the bag interior being adapted to be connected to the breathing circuit of a patient, the arrangement being such that variation of pressure in the chamber will cause the patient to inhale or exhale according to whether the pressure is increased or reduced respectively, wherein the bag is easily separably connected or disconnected in disposal of the breathing circuit, thereby enabling sterilisation or disposal of the parts after each patient treatment. Preferably the means to retain the bag includes a bellows retaining disc to ensure that the shape of the bellows is maintained and preferably, the means for retaining the bag may also be a portion of the inlet/outlet means.

In this latter case a smooth bag can be attached to the inlet/outlet means, thus advantageously enabling the use of either the bellows or smooth type bag. Additionally, this leads to a significant reduction in the costs associated with maintaining the ventilator in a sterile manner, since the smooth bags are significantly cheaper than the bellows and can thus be used as a single use item. Furthermore as a result of the present invention, maintaining the part of the bag and chamber combination in contact with the patient breathing circuit in a sterile manner is made significantly easier and cheaper because of the options available. In particular, these options include, after each patient use, autoclaving the bellows bag and integral unit, autoclaving the smooth bag and integral unit, autoclaving the integral unit and replacing the smooth bag or bellows, or discarding a disposable integral unit fitted with a disposable bag or bellows.

Another aspect of the invention provides a retaining means for the chamber means which comprises an attachment means releasably attached to the chamber means and connects to a pivot means which may be pivotably supported. If a smooth bag is used it is essential to turn the bag in bottle arrangement upside down to ensure that the smooth bag will hang upside down and inflate unrestricted as required. Alternatively some professionals may prefer to use the bellows bag in this downward orientation. Additionally, this downward orientation of the invention advantageously enables easier access to the integral unit and thus the bag for removal and disposal and/or sterilisation.

The invention also provides a ventilator system for use in anaesthetic and resuscitation circuits comprising a ventilator control means, at least one bag in bottle arrangement wherein the bag in bottle arrangement has an integral unit comprising an inlet/outlet means which in use, is connected with the patient's breathing circuit, a means to retain the bag in a gas tight manner with the inlet/outlet means and a means to seal the bottle in a gas tight manner. The invention further provides a bottle and bag arrangement for use in a ventilator system comprising at least one bottle and bag wherein the bottle and bag arrangement has an integral unit comprising an outlet means which in use, is connected with the patient's breathing circuit, a means to retain the bag in a gas tight manner with the inlet/outlet means and a means to seal the bottle in a gas tight manner.

Advantageously, the present invention provides a ventilator system, a bag in bottle arrangement and an integral unit for use in a bag in bottle arrangement of a ventilator which is very easy to dismantle and thus is conductive to sterilisation or disposal after each patient treatment to prevent the transmission of serious diseases. Thus, the invention provides an integral unit and a bag in bottle arrangement that can be readily adapted for single use. DETAILED DESCRIPTION OFTHE INVENTION

The invention will be better understood with reference to the accompanying illustration of a preferred embodiment of the invention.

Figure 1 is a cross-sectional view of a preferred embodiment of the bag in bottle arrangement of the present invention wherein the bag in bottle arrangement is in the "upward" direction.

Figure 2 is a cross-sectional view of a preferred embodiment of the bag in bottle arrangement wherein the bag in bottle is in the "downward" direction.

Figure 3 is a cross-sectional view of a preferred embodiment of the integral unit of the present invention.

Figure 4 is a partial cross-sectional view of a preferred embodiment of the bag and bottle arrangement in the upward direction with an adjustable limiting means.

Figure 5 is an exploded view showing removal of the locking unit, integral unit and connected bag.

The bag in bottle arrangement designated 10, comprises the bottle portion 11 , and the bellows portion 30a or bag portion 30b. Preferably the bottle portion 11 , is made of transparent material so that the bellow portion 30a or bag portion 30b can be viewed. The bottle portion 11 , does not come in contact with gas from the patient breathing circuit and can be made of a non-sterilisable material. With reference to the bottle portion 11 , it can be seen that guiding means 12 may be fixed to the inside wall of the bottle portion 11. Such guide means 12, can run along the entire length of the bottle thus ensuring that the bellows bag 30a evenly inflates in the upwards or downwards direction. Preferably the guide means 12, are strips or rods. Additionally, there are preferably more than three strips or rods positioned along the length of the bottle portion 11.

In order to assist the bellows type bag to inflate evenly in an upward direction, a disc means 31 may be affixed to the top of the bellows as illustrated, also an inner ring means 31a may be inserted inside the bellows, as illustrated, to further assist even inflation of the bellows. The, integral unit 20, comprises an inlet/outlet means, with an external portion 21a, and an internal portion 21b. The integral unit 20, further comprises a bellow retaining means 22, and sealing means 23. Both the bellow retaining means 22, and the sealing means 23, are preferably, disc shaped. More preferably, bellows retaining means 22, is a disc of smaller diameter than the disc of sealing means. Bellows retaining means, 22, allows the fitment of bellows portion 30a in a gastight manner. Internal inlet/outlet means, 21b allows the fitment of a smooth bag portion 30b in a gastight manner. The external portion of inlet/outlet means 21a is connected to the patient breathing circuit. The integral unit 20 may preferably include a valve means 25 for the venting of excess pressure from the patient circuit, thereby controlling pressure build up in the patient circuit as a result of constant gas flow.

The valve means 25 is adjustable between about 1cm to 5 cm H₂O and acts to release excess gas from the patient circuit if the circuit pressure is above the set pressure at the end of expiration.

Unlike prior art arrangements the integral unit 20 enables all portions in contact with the patient breathing circuit to be easily and quickly removed and sterilised or disposed of so that changeover between patient treatment is feasible and in fact easily achieved. if the integral gas inlet/outlet unit 20, is intended for repeated use then preferably the integral unit 20, is made from heat resistant material which can be repeatedly autoclaved such as heat resistant polycarbonate, steel, aluminium or other heat resistant material. Alternatively, if the unit 20, is for single use the unit can be made from plastics such as polystyrene or styreneacrylonitrile (SAN). Also, the integral unit 20, can be made in a number of pieces (as illustrated in Figures 1 and 2) or a single piece (as illustrated in Figure 3).

As indicated above, bellows retaining means, 22, allows the fitment of bellows portion 30a in a gastight manner and similarly the internal inlet/outlet means, 21a allows the fitment of smooth bag portion 30b in a gastight manner. Thus the present invention allows the interchangeable use of either the bellows or the alternative smooth type bag.

By comparison at present most bag in bottle arrangements utilise a non disposable autoclavable bellows or non disposable autoclavable smooth bag which are expensive to purchase and therefore it is not economical to dispose of them after each patient use. The present invention provides the option of a fully disposable system by allowing the use of a disposable bellows or a disposable smooth bag which is readily available and significantly cheaper. With further reference to Figures 1 and 2, sealing plate, 23, ensures that when the bottle 11 , is under pressure and the locking means, which is preferably a plate, 14, is secured, the bottle maintains that pressure and does not leak. An O-ring seal 45 may be provided on the flange 45 or plate 23, fixed in place to ensure a good seal. Integral unit, 20 is held into place on the bottle 11, by locking member 14, which includes locking pins 14b adapted to secure in locking collar 42 preferably in a bayonet type fixture or partial thread fitting which enables a tightening of the connection to ensure sealing but easy connection and disconnection of the components. The external portion of the inlet/outlet means, 21a is preferably a male/female taper fitting which is preferably straight but may also be elbow shaped (not shown). The fitting 21a as illustrated in Figure 1 preferably includes a nipple protrusion, 24, for attachment of a hose line to connect to a respiratory pressure manometer (not shown) or can form a coaxial line which unit 61a is described in greater detail later. The integral unit 20, may be rotated to a desired position by loosening the locking means 14 and then retightening. This is advantageous when the shape of the external portion of the inlet/outlet means, 21a, is elbow shaped. With reference to both Figures 1 and 2, another important feature of the invention is a retaining means 40, which comprises an attachment means 41, connected to locking collar 44, a pivot means 42 and support means 43. The retaining means 40, allows the bag in bottle arrangement 10, to be rotated about the pivot means 42, to a downward orientation which firstly, allows easier access to the integral unit, 20 and secondly allows the smooth bag, 30b, to hang freely thus ensuring that inflation is unrestricted. Alternatively, a bellows bag may be fitted in this downward orientation.

Figure 1 illustrates the bag in bottle arrangement in the upward position. As can be seen from Figure 1 , either the smooth bag 30b portion or preferably the bellows 30a can be used in this upward position if required. Figure 2 illustrates the bag in bottle arrangement in the downward position. As can be seen from Figure 2, either the bellows 30a or more preferably the smooth bag 30b portion can be used in this downward position if required. These aspects of the invention assist in easily allowing the use of either the bellows 30a or smooth bag 30b interchangeably without any loss of effectiveness or reliability of the ventilator system.

Another feature of the bag in bottle arrangement is that it may include the limiting means generally indicated 54, which as the name suggests, limits the extent to which the bellows type bag 30a can extend in the vertical direction. The limiting means, is preferably rod-shaped and is in contact directly or indirectly with the bellows 30a. With reference to Figure 4, the adjustable limiting means 50, may also comprise a stopping means 51 , which is preferably disc-shaped and is in contact directly or indirectly via disc 31 attached to the bellows 30a, which is attached to a means which allows the fixing and adjustment of the position of the stopping means 51, in this case, spindle 52, passes through a locking means 53. Locking means 53, can be unlocked or loosened to allow spindle 52 to move freely and once the desired height of the linking means 51 , is obtained then the locking means 53 can be locked or screwed. This adjustable limiting mechanism allows the volume of the bellows 30a to be easily varied depending upon the size of the patient to which the ventilator is attached.

In use the bag in bottle arrangement 10, is attached to a ventilator control means (not shown), which can be any ventilator control means such as the Clare Ventilator, which in turn is connected to a gas source. With reference to Figures 1 and 2, the inlet marked "driving gas inlet" is preferably connected by a co-axial hose 61a with a non-standard taper fitting control means (not shown).

The co-axial hose may be finished with a straight or elbow fitting. The intemal hose 24a preferably exits the outer hose proximal to both ends and connects to the respiratory pressure manometer (not shown), and the nipple protrusion 24. The intemal hose 24a may also be a separate external hose which connects to the respiratory pressure manometer (not shown) and the nipple protrusion 24. Inlet/outlet means 21a and 21b, is connected to the patient breathing circuit and is in contact with the patient's expired gases. On inspiration, the driving gas from the ventilator control means is delivered into the bottle 11 , which pressurises the chamber causing compression of the bellows portion 30a or smooth bag portion 30b, which pushes the gas out of the bellows portion 30a or smooth bag portion 30b via inlet/outlet 21a and 21b, to the patient. On expiration, the gas from the patient flows back through inlet/outlet

21a and 21b, and reinf lates the bellows portion 30a or smooth bag portion 30b.

Once the ventilator and bag in bottle are no longer required, the bag in bottle arrangement 10, (if not already in a downward orientation) can be rotated such that the locking plate 14 can be removed. Once the locking plate means 14 is removed the integral unit 20 can be removed along with the bellows portion 30a or smooth bag portion 30b attached thereto within seconds. The locking plate is easily removed simply by gripping slots 14a and turning through a part circle to release the locking pins 14b. The entire assembly of the integral unit 20 and bag or bellows can be removed for sterilisation or disposal in a matter of seconds without the need for any tools. The integral unit, 20 can then either be sterilised along with the bellows portion 30a or the smooth bag portion 30b, or disposed of, if it is a single-use component. As can be seen from both Figure 1 and 2 where a bellows portion 30a is used the bag in bottle arrangement 10 can be in the upward position (Figure 1) or downward position (Figure 2). If a smooth bag, 30b, is used the preferable position is with the bag in bottle arrangement in a downward orientation as illustrated in Figure 2.

Thus the present invention provides a bag in bottle arrangement which incorporates an integral unit offering the ability to use a bellows or a smooth bag. The present invention provides a bag in bottle arrangement for use in an anaesthetic or resuscitation patient breathing circuit. Additionally, and advantageously the integral unit and the retained bellows or smooth bag can be easily and rapidly removed from the bag in bottle arrangement thus allowing regular sterilising or replacement with sterile disposable single use units, between patient treatments. The risks of cross infection with the proposed invention will be greatly reduced and the costs associated with ensuring that the apparatus is sterile are also reduced significantly. Also the invention enables the different types of bellows or smooth bags to be used in the most appropriate orientation whether this be upwards or downwards without losing any effectiveness in the function of the ventilator.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A bag in bottle breathing unit for use in anaesthetic or resuscitation equipment for a patient, the ventilator unit including a breathing bag mounted within a chamber, the chamber being adapted to be connected to an extemal gas source, and the bag interior being adapted to be connected to the breathing circuit of a patient, the arrangement being such that variation of pressure in the chamber will cause the patient to inhale or exhale according to whether the pressure is increased or reduced respectively, wherein the bag is easily separably connected in the breathing circuit, thereby enabling sterilisation or disposal of the parts after each patient treatment.

2. A bag in bottle unit as claimed in claim 1, wherein the bag is easily separably connected into the breathing circuit via an integral unit easily separably connected to the bag and the chamber.

3. A bag in bottle unit as claimed in claim 1 or claim 2, wherein the breathing bag and integral unit are either autoclavable or disposable or both.

4. A bag in bottle unit as claimed in any preceding claim where the unit is moveable between two operating locations which are diametrically opposed where the bag is suspended from the integral unit or projects vertically upwards therefrom.

5. A bag in bottle unit as claimed in any preceding claim wherein the bag may be of a bellows or smooth bag type within the same treatment unit.

6. A bag in bottle unit as claimed in any preceding claim wherein the bag and associated integral unit are retained by locking means quickly releasably connectable to the chamber.

7. A bag in bottle unit as claimed in any proceeding claim wherein the integral unit includes a sealing member quickly engagable with the chamber acting to seal the chamber.

8. A bag in bottle unit as claimed in claim 7, when read through claim 6, wherein the locking means is a bayonet type or limited thread connection allowing progressive pressure to be applied to the sealing member.