WO2014178730A2

WO2014178730A2 - Anaesthetic machine

Info

Publication number: WO2014178730A2
Application number: PCT/NZ2014/000072
Authority: WO
Inventors: John Edward FOY
Original assignee: Iac Ip Limited
Priority date: 2013-04-30
Filing date: 2014-04-23
Publication date: 2014-11-06
Also published as: WO2014178730A3

Abstract

The invention provides an anaesthetic machine which includes a housing and a plurality of user controls. A plurality of supply line connectors are located on a side of the housing, and at least one low friction conveyor is located on the underside of the housing. In preferred embodiments the housing defines a fully enclosed space locating the functional components of the anaesthetic machine.

Description

Anaesthetic Machine

Technical Field This invention provides an anaesthetic machine with a compact and efficient form.

Background art An application which places performance demands on the arrangement of a work area is the role performed by an anaesthetist.

An anaesthetist needs to closely monitor display screens showing the performance of their equipment and the condition of their patient. Ready access to treatment drugs and other equipment is also required by the anaesthetist, who may need to lay their hands on particular materials under urgency. The anaesthetist uses a relatively large and bulky anaesthetic machine which incorporates gas supply and collection lines in addition to associated monitoring equipment. All of these tools and materials need to be accommodated within an operating theatre as close as possible to a patient without impeding the actions of the surgical team.

The work areas currently used by anaesthetists are generally of an ad hoc nature and provided by an assembly of tables and a chair mounted on wheels or castors. The various equipment and materials used by the anaesthetist are deployed on these tables and arranged as close as possible to the patient without impeding access for the surgical team. However, due to the ad hoc nature of how the work area is assembled it is difficult for all the equipment used to be kept in a confined area while still being easily accessible to the anaesthetist.

Furthermore, to gain access to all of the equipment requirement an anaesthetist needs to divert their attention from their patient - potentially moving their body away from facing the patient and towards the

equipment they desire. In most cases the displays screens of an

anaesthetic machine need to be positioned to one side of a patient, forcing an anaesthetist to face at 90 degrees to their patient and compromising their ability to monitor them closely, reducing situational awareness. Existing anaesthetic machines are also large pieces of equipment. They generally mandate a seperate table or desk, in addition to a number of seperate cabinets and receptacles for equipment. Due to the spatial layout of this assembly, it is difficult to interface with the machine, supplies, and the patient simultaneously.

Existing anaesthetic machines can also be formed with a left handed or right handed configuration, relating to which side a set of carbon dioxide absorbing canisters and the patient gas tubing is on as the anaesthetist stands facing the machine. Most machines are left handed, with the above apparatus on the anaesthetists left hand side as they stand-in front of, and look at the machine. This is a real limitation if the roof gas services of an operating theatre don't match the handedness of the machine available, and results in dysfunctional arrangements of the patient life support tubing, and increased distraction to the Anaesthetist.

It would therefore be of advantage to have an anaesthetic machine which addressed any or all of the above issues or at least provided an alternative choice over the prior art.

Disclosure of Invention

According to one aspect of the invention there is provided an anaesthetic machine which includes

a housing, and

a plurality of user controls, and

a plurality of supply line connectors located on a side of the housing, and at least one low friction conveyor located on the underside of the housing. According to a second aspect of the invention there is provided an anaesthetic machine which includes

a housing with a form defining an underside surface, top surface and at least one side surface, the housing defining a volume locating the functional components of the anaesthetic machine, and

a plurality of user controls mounted in a substantially horizontal plane on the top surface of the housing, and

a plurality of supply line connectors, and

at least one low friction conveyor mounted on the underside of the housing. This invention is arranged to provide a compact anaesthesia machine. Preferably the anaesthesia machine is one modular component of an anaesthesia workstation. Various arrangement and configurations of anaesthetic machines are known from the prior art and can include functional components such as patient ventilators, suction units and also patient monitoring sensors. An anaesthetic machine requires the supply of a number of types of gases such as oxygen or nitrous oxide which it combines with anaesthetic vapour delivered to a patient in fixed

concentrations and at controlled flow rates. In some instances an anaesthetic machine may include functional components such as a carbon dioxide absorber or scrubber system and may implement a close circuit for gas flows. These arrangements of anaesthetic machines control the amounts of anaesthetic vapour delivered to a patient, with any

anaesthetic not absorbed initially in the patient's lungs being recycled and redelivered.

Anaesthetic machines are complicated pieces of equipment which require the supply of pressurised carrier gases and anaesthetic, in addition to a power supply which preferably cannot be interrupted. These machines also provide the anaesthetist with a large amount of real time information relating to both the performance and operation of the machine and the vital signs of their patient. The anaesthetist must pay close attention to the feedback provided by the anaesthetic machine to perform their role effectively.

The present invention provides a housing which locates substantially all of the operative or functional components expected within an existing anaesthetic machine. Those skilled in the art will appreciate that the term functional component as referenced throughout this specification will include any form of component or element of existing anaesthetic machine technology which can deliver or extract gas to or from a patient, and or which can monitor a patient.

The present invention provides a housing which encloses the operative components of the anaesthetic machine, with the housing having an underside, top and side surface or surfaces. Preferably this housing in use extends from the floor of an operating theatre to approximately the height of a desk, or table. Preferably the housing provided by the invention defines a fully enclosed volume locating these functional components within a compact form. Reference in general throughout this specification will also be made to the housing fully enclosing and encapsulating the volume of space used to locate the machine's functional components. However those skilled in the art will appreciate that in other embodiments a housing provided by the invention may only partially enclose this volume if required.

Reference throughout this specification will also be made to the invention providing an anaesthetic machine. Those skilled in the art will appreciate that anaesthetic machines are well known in the art and therefore will not be described in detail throughout this specification. Furthermore, someone skilled in the art will also appreciate that there is some

variability available in terms of the components included in various anaesthetic machines. In a preferred embodiment a housing may define a substantially

rectangular form defining an underside, top and side surfaces, with the housing extending in use from the floor of an operating theatre to approximately the height of a desk or table. However in other embodiments the invention may not necessarily employ a substantially rectangular form housing. For example in one alternative embodiment a cylindrical form housing may be provided which provides one single side wall surface only. In yet another embodiment a triangular formed housings may be employed if required. Those skilled in the art will appreciate that references to the provision of rectangular form housings throughout this specification should in no way be seen as limiting.

The underside of the housing is used to mount at least one low friction conveyor. This form of conveyor allows the anaesthetic machine to be pushed along or over a surface easily. In a preferred embodiment a low friction conveyor may be implemented by a wheel or castor mounted to the underside of the machines housing.

In one aspect of the invention an anaesthetic machine is provided which includes a plurality of supply line connectors on the side or sides of the housing.

A supply line connector can be used to deliver a consumable resource to the machine, to remove waste from the machine or to provide a source of vacuum pressure. For example, in a variety of embodiments any combination of one or more of the following may be provided in association with a supply line connector:

• A supply of vacuum pressure · A connection to an Active Gas

Scavenging System (AGSS)

• Medical Oxygen · Medical Air

• Nitrous Oxide · Desflurane Gas

• Halothane Gas · Enflurane Gas

• Isoflurane Gas · Sevoflurane Gas

• Electrical Energy, either by

alternating or direct current

Those skilled in the art will appreciate that various permutations and combinations of different forms of supply line connectors may be provided in accordance with the invention. In some embodiments multiple

instances of the same form of supply line connector may also be provided, For example in one instance duplicate sets of electrical energy supply line connectors may also be provided in combination with gas or vacuum supply line connectors.

In a preferred embodiment the housing provides all the supply line connectors in a clustered or localise region on one side wall only. This arrangement of the housing and supply connectors allows the invention to engage with a supply of the resources at one connection site.

In a preferred embodiment a supply line connector integrated into a side of the housing may be formed from a self sealing, push lock or snap lock connection system. In such embodiments the connector system used allows the housing to be pushed up against and into engagement with a complimentary supply line connector provided within an operating theatre. For example, in one embodiment a set of complementary supply line connectors may be provided by an anaesthetist's workstation. This workstation can include a number of duplicate supply connectors at various locations around the perimeter of the workstation, allowing the relative position of the anaesthetic machine to the workstation to be adjusted depending on the needs of an anaesthetist.

In yet another embodiment the plurality of supply line connectors can be engaged with a set of complementary supply line connectors installed in the wall and/or floor of an operating theatre. The compact and self- contained nature of the anaesthetic machine provided by the invention allows it to be used and a variety of different forms of operating theatres. As indicated above, in some instances resources may be delivered through a set of complementary supply line connectors mounted on the wall of an operating theatre, or on the floor of an operating theatre. In yet other instances the anaesthetic machine provided may be engaged with supply line connectors installed on the walls or floor of a vehicle acting as a mobile operating theatre. Those skilled in the art will appreciate that the compact and flexible nature of the anaesthetic machine provided by the invention allows it to be used and a range of roles and applications.

According to another aspect of the invention there is provided a modular anaesthetic machine which comprises

a housing, and

a plurality of user controls, and

a plurality of supply line connectors located on one side of the housing that determine the orientation of the anaesthetic machine within and about an anaesthetic workstation, and

at least one low friction conveyor located on the underside of the housing.

This aspect of the invention allows it to accommodate both left-hand and right-handed preferences of anaesthetists using the workstation.

Preferably the anaesthetic machine provided by the invention is

ambidextrous in the sense that a single embodiment can be seamlessly connected to a workstation at several different places to accommodate both left-hand and right-handed orientations. It is understood that this handedness orientation reference made is not being made to the anaesthetists being left or right handed, but rather to the relative orientation of the components relative to the position of a patient i.e. to the left or right of the patient. Prior art anaesthetic machines can also be referred to by their manufacturers with a handed orientation depending on where carbon dioxide absorbing soda lime canisters sit on the anaesthesiologists left side as they stand facing the machine, or on their right side, as they stand facing the machine.

It is envisioned that a variety a different forms of complementary supply line connectors may be employed in conjunction with the present invention. Various connectors - be they male or female in arrangement - can be used to provide a push lock self-sealing connection system for the delivery of pressurised gas, or to provide electrical current for example. In a preferred embodiment a supply line connector employed by the invention may be implemented by the Staubli SCB 316 non-spill gas connector code SCB04 manufactured by Staubli and described at

www.staubli.com. Those skilled in the art will however appreciate that other forms of connectors may also be used in conjunction with the invention.

In a preferred embodiment the present invention also includes at least one alignment prong which extends from a side of the housing adjacent to one or more supply connectors. In such embodiments an alignment prong can be used to correctly align complimentary supply line connectors when moved into engagement with each other. This alignment is completed as the prong slides into a complimentary cavity in the surface mounting supply line connectors. However, in an alternative embodiment a side of the housing may form an alignment recess adjacent to one or more supply connectors which is arranged to receive an alignment prong substantially as described above. In such embodiments the housing may define a recesses which receives an alignment prong to assist in the alignment of supply line connectors as they are brought together.

In a preferred embodiment the anaesthetic machine provided may also include one or potential a plurality of electrical supply outlet ports. These ports may be used to distribute the energy supplied or available to the anaesthetic machine to further peripheral devices connected to these ports.

In a further preferred embodiment the invention may provide two different banks of electrical supply ports on opposite sides of the housing. This arrangement of banks of power ports gives the invention flexibility in terms of how other peripheral devices requiring electrical energy can be physically arranged. In such embodiments is envisioned that both these banks of electrical supply ports can be located adjacent to the side of the housing which deploys a cluster of supply line connectors. In a preferred embodiment the housing may also form or deploy a partially enclosed equipment bay arranged to receive various forms of additional equipment or patient monitoring devices. In a further preferred embodiment this bay may be formed with an entry aperture defined in a side wall or surface of the housing opposite to the side wall which provides the invention's supply connectors. This configuration of an equipment bay can therefore face the entry point of bay towards a patient.

In a further preferred embodiment an internal wall or surface of an equipment bay can mount one or more electrical supply ports. These electrical supply ports can be used to deliver energy to power equipment located within the bay.

In a preferred embodiment the anaesthetic machine may include or provide a number of gas supply terminals or sensor connection terminals on one side of the housing. In a further preferred embodiment the housing may deploy a cluster of supply line connectors on one of its sides, and a collection of gas supply or electrical connector terminals on its opposite side. This arrangement of the invention allows one side of the housing to be connected to a variety of supply line connectors, and the other side of the housing to extend out the gas supply lines and electrical connectors required to engage the anaesthetic machine with a patient.

In a preferred embodiment the invention may include at least one gas reservoir located within the housing. In a further preferred embodiment the invention may provide a plurality of gas reservoirs located within the housing. Those skilled in the art will appreciate that such reservoirs may have a compact form and therefore the ability to supply a limited volume of gas.

In such embodiments the invention's gas reservoir or reservoirs can provide an emergency backup supply of the gas consumed by the machine in case of failure of the supply received through the supply line connectors. Furthermore the provision of a gas reservoir within the invention's housing also allow an anaesthetist to continue to care for their patients if the patient needs to be moved during a surgical procedure. For example, emergency situations may require operating theatres to be evacuated during surgical procedures. A gas reservoir or reservoirs provided within the housing allows the patient to be moved on the theatre table in combination with the compact anaesthetic machine provided by the invention. Once the patient reaches safety the anaesthetic machine can then be reattached to an alternative set of supply connectors.

In a preferred embodiment the invention may include or provide at least one uninterruptible power supply. This power supply may include energy storage elements such as batteries, fuel cells or similar components capable of providing a source of electrical engine energy when mains power utility connections are not available.

This feature of the invention can provide an emergency backup supply electrical energy to devices or equipment powered by the anaesthetic machine, and provides invention a portable character - allowing for the supply of energy by the invention even if disconnected from a set of supply line connectors. In one aspect of the invention an anaesthetic machine is provided with a plurality of user controls mounted in a substantially horizontal plane on the top surface of the housing . This aspect of the invention provides significant usability and patient safety advantages, positioning user controls which modify the functional or operational behaviour of the anaesthetic machine immediately in the line of sight of an anaesthetist attending to their patient.

Reference in general will be made throughout this specification to the invention including a number of user controls mounted on the top surface of the housing, and in particular these controls being mounted in substantially the same horizontal plane. However those skilled in the art will appreciate that the scope of the invention encompasses a degree of variability in the angling or limited elevation of the various user controls relative to each other.

Preferably user controls are capable of actuation by a user to trigger the performance of control actions related to the operation of the functional elements of the anaesthetic machine. An anaesthetist can therefore actuate the various user controls to ensure that the anaesthetic machine functions as required during a surgical procedure. The control actions available to a user will depend on the form and functional elements used to implement the anaesthetic machine as should be appreciated by those skilled in the art.

Those skilled in the art will appreciate that a range of parameters may be adjusted through these top mounted user controls. For example in a variety of embodiments these controls may also:

• Regulate the tidal volume of gas per breath of the patient.

• Identify and enqueue the delivery of a selected volatile anaesthetic gas.

• Adjust anaesthetic gas concentration

• Regulate ventilator pressure settings, such as breathing rate and/or setting how much pressure to apply to a patients lungs.

• Regulate post end expiration pressure applied to the patient's lungs by the ventilator.

• Apply vacuum to clear patient airways

• Trigger an emergency oxygen flush procedure

• Implement a malfunction warning light if gas flows go outside

predefined acceptable parameters.

In a preferred embodiment user controls may be provided by physically actuated elements. For example, in some embodiments user controls may be formed by one or more buttons, switches or dials which are manually actuated by an anaesthetist to control the functional components of the anaesthetic machine.

However, in other alternative embodiments a set of virtual controls may be provided in conjunction with a display screen, where various user interactions made by the anaesthetist can control the operation of the functional components of the anaesthetic machine.

Reference in general throughout this specification will also be made to the present invention supplying or providing a set of physically actuated or physically implemented user controls. Those skilled in the art will also appreciate that in other embodiments virtual user controls may also be employed in conjunction with the present invention if required.

In a preferred embodiment a set of user controls may be provided by a set of buttons located on the top of the housing. Placing user control buttons on the top of the housing puts these buttons in easy reach of the anaesthetist, and these buttons can also be seen easily by an anaesthetist without looking away from a patient.

For example, a button press may trigger the flow of medical oxygen at a predefined flow rate, or may alternatively trigger the release of a flow of medical nitrous oxide or air. Button presses (or other forms of user control actuations) may also highlight an anaesthetist's interest in a particular operational parameter with further elements - such as rotary dials for example - allowing adjustment of the value of the parameter up or down.

In a preferred embodiment a user control may also include one or more activation acknowledgement elements. Activation acknowledgement elements can signal to an anaesthetist the activation of one of the user controls.

In a preferred embodiment an activation acknowledgement element may include a light source deployed underneath a user control, where actuation of the user control triggers the activation of the light source. Preferably, a subsequent activation of the same control (or a different control) can deactivate this light source.

In one further preferred embodiment a coloured light source may be provided underneath each user control, with activation of the control triggering the emission of light of a specific colour. Preferably the particular colour of light emitted may be associated with the user control and the control action or actions which can be triggered by this control.

In yet other embodiments an activation acknowledgement element may include an audio signal generator to provide an audio signal to a user. In a yet further embodiment the invention may include a vibration

generation element vibrate a control gently to provide an

acknowledgement. For example, in some instances a confirmation chime may be generated by a speaker at the same time as a user control is vibrated gently. In other embodiments vocal recordings may be played to generate a voice announcing the name of the last selected control.

In further preferred embodiments a series of sequential activations of the same user control may cycle through the selection of number of possible control actions capable of user selection. Preferably the availability of each of these control actions may be indicated by the colour of light emitted by a light generation element mounted underneath a user control. In such embodiments the colour of light emitted by the control indicates to the user which option is currently capable of selection or which is in effect. For example, the colour of light emitted may be coded to the same colour associated to particular gases delivered by an anaesthetic machine.

In a preferred embodiment a physical user control can define at least one contact surface which is touched by a user to actuate the control. In a further preferred embodiment a contact surface of a user control can define at least one projecting marking. In such embodiments user controls may bear a distinctive projecting surface pattern or relief markings. These distinctive markings can be identified by anaesthetists as belonging to certain user controls by touch alone.

Preferably the anaesthetic machine includes a presentation system being arranged to provide information to an anaesthetist from one or more patient monitoring sensors and/or one or more anaesthetic machine monitoring sensors. As indicated above anaesthetic machines are capable of providing a significant amount of important real-time information relating to the machines performance and the vital signs of a patient. The presentation system provided by the invention may provide an

anaesthetist with easy access to this information without them having to divert their attention or gaze from the patient.

In a further preferred embodiment an information presentation system may be implemented by one or more display screens positioned on the top of the anaesthetic machine. This arrangement of display screens present the information they supply automatically within the view of the anaesthetist when they are attending to their patient.

In a further preferred embodiment of the information presentation system may also implement a user interface system, allowing commands to be received from an anaesthetist. For example, in one preferred embodiment where the presentation system is provided by one or more displays, these displays may be touch sensitive to allow an anaesthetist to interact with the presentation system without diverting their gaze from a patient. In a variety of embodiments this touch sensitive user interface may also be used to receive command from an anaesthetist to operate the functional components of the anaesthetic machine. The present invention may provide many potential advantages over the prior art.

The invention provides for an anaesthetic machine with a compact form. This machine need not integrate reservoirs of consumable resources such as the gas canisters normally employed by existing anaesthetic machines. All the requirements of a machine provided by the invention can be met through supply line connectors, allowing the overall volume occupied by the machine to be minimised. The smaller size of the anaesthetic machine allows it to be part of a modular anaesthetic workstation and seamlessly connect to an anaesthetic workstation that incorporates the anaesthetic machine provided herein. The modular placement of the anaesthetic machine within and about an anaesthetic workstation allows the workstation to accommodate different orientations that may affect it's ease of use by a particular anaesthesiologist or operator.

In preferred embodiments the anaesthetic machine provided includes a number of quick coupling connection systems for the various supply lines it requires. These connectors allow the compact form of the machine to be deployed anywhere a set of mating supply connectors are available within an operating theatre. An improved anaesthetist workstation may also be provided with a number of duplicate sets of complementary supply line connectors. This arrangement can allow the workstation and connected anaesthetic machine to be quickly configured to suit the preferences of an anaesthetist and the physical layout of a particular operating theatre.

The invention also includes a number of user controls, were in preferred embodiments these controls can be implemented through physically actuated elements mounted to the top of the housing. These physically actuated controls can be placed almost directly in the line of sight of an anaesthetist and can be easily reached and quickly actuated in emergency situations. In various embodiments these controls can also implement a number for feedback mechanisms, giving an anaesthetist confirmation of the current configuration of the machine and the gases it is delivering.

Furthermore, in a number of embodiments the invention can integrate an information presentation system, allowing an anaesthetist to easily view all information presented in this component without diverging their attention or gaze from a patient. A number of embodiments of the invention can also confer this

anaesthetic machine with a limited degree of portability and the ability to continue functioning when cut off from its supply of resources. In some embodiments small reservoirs of gas may be integrated within the inventions housing, as may be an uninterruptible power supply. Combined with the small physical footprint of the anaesthetic machine, these features allows it to be moved with a patient in emergency situations while still continuing to provide service to this patient. Furthermore in additional embodiments the invention may also provide a further equipment bay which can continue to supply patient modern equipment with electrical energy during transportation and in emergency situations

Brief description of the drawings Example embodiments of the invention are now discussed with reference to the drawings in which :

• Figures la shows a rear perspective view of an anaesthetic machine as provided in accordance with a preferred embodiment, and

• Figures lb shows a front perspective view of an anaesthetic

machine as provided in accordance with a preferred embodiment, and · Figures lc shows a rear view of an anaesthetic machine as provided in accordance with a preferred embodiment, and

• Figures Id shows a front view of an anaesthetic machine as

provided in accordance with a preferred embodiment, and

• Figure 2a, 2b show a perspective and end view of an anaesthetist workstation prior to connection to the anaesthetic machine shown with respect figure 1, and · Figure 2c shows a perspective view of the anaesthetist workstation of figures 2a, 2b when connected to the anaesthetic machine shown with respect to figure 1, and

• Figure 2d, 2e show a perspective and side view of a wall mounted supply manifold prior to connection to the anaesthetic machine shown with respect figure 1, and Figure 2f shows a perspective view of the wall mounted supply manifold of figures 2d, 2e when connected to the anaesthetic machine shown with respect to figure 1, and

Figures 3a and 3b show an array of different configurations of supply line connectors used in conjunction the embodiment shown in figure 1, and

Figure 4 shows a perspective view of the supply connectors of figure 3a as deployed in the side wall of the anaesthetic machine

illustrated with respect to figures la-Id, and

Figure 5 shows a number of user controls on the top of the anaesthetic machine illustrated with respect to figures la-Id, and

Figures 6a, 6b show top and perspective views of a selection of the user controls provided in the anaesthetic machine illustrated with respect to figures la-Id, and

Figure 7 shows an alternative embodiment of the invention which deploys a variation on the user controls illustrated in the

embodiment of figures 1-6, and

Figures 8a, 8b, 8c show comparative test results obtained from clinical trials completed using a prior art anaesthetic workstation and machine and the workstation of the embodiment shown in figures 1-6, and

Figures 9a, 9b and 9c show perspective and side view of the anaesthetic machine of figures la-Id when used with an alternative "L" form anaesthetist workstation

Figure 9d shows comparative test results obtained from clinical trials completed with using a prior art anaesthetic workstation and the embodiment of the invention shown in figure 1 when used with the workstations shown in figures 2a-c and figures 9a-c. Best modes for carrying out the Invention

As can be seen from figures la-Id the present invention provides an anaesthetic machine 1. The functional components of the machine are enclosed within a substantially rectangular housing 2. This housing defines a top surface, four sides and a rear or underside surface.

The underside surface is used to mount a series of wheels 3 providing a low friction conveyance system for the machine. The top surface of the housing terminates at approximately the height of a desk or table normally used by an anaesthetist.

One side wall of the housing 2 mounts a cluster of supply line connectors 4. The supply line connectors are used to provide services to or deliver a number of resources to the machine 1.

These supply line connectors 4 are also shown in further detail in figures 3a, 3b. The machine 1 also includes an information presentation system, illustrated in this embodiment by a pair of flat screen displays 5. These displays are arranged to present information sourced from patient monitoring sensors (not shown) within the field of view of an anaesthetist as they tend to their patient.

A number of user controls 6 are mounted to the top of the housing, these controls being located in a substantially horizontal common plane. These used controls are shown further detail respect figures 5. The opposite side of the housing to the supply line connectors implements an equipment bay 7, where the rear interior face of the bay provides a number of electrical supply ports 8. This bay is used house and also power various forms of patient monitoring devices (not shown). Projecting from the same front side of the housing are a set of patient gas service ports 9 used to deliver or retrieve gas to from a patient.

Figures 2a-c illustrate how a complimentary set of female supply line connectors - as illustrated with respect to figure 3b - are deployed in two redundant locations within an anaesthetist's workstation 10. Figure 2a, 2b show a perspective and end view of an anaesthetist workstation prior to connection to the anaesthetic machine shown with respect figure 1. Figure 2c shows a perspective view of the anaesthetist workstation of figures 2a, 2b when connected to the anaesthetic machine shown with respect to figure 1.

These figures illustrate the use of self-sealing push to lock supply line connectors 4. The wheels 3 deployed in the underside of the housing 2 allow the anaesthetic machine 1 to be wheeled up to either of redundant set of supply line connectors 4 provided at the ends of either side of the workstation 10.

This aspect of the invention allows it to accommodate both left-hand and right-handed preferences of anaesthetists using the workstation 10.

Preferably each anaesthetic machine 1 is ambidextrous in the sense that a single embodiment can be seamlessly connected to a workstation 10 at different places to accommodate both left-hand and right-handed orientation preferences of anaesthetists. Thus the anaesthetic machine 1 may also dictate the handedness of a workstation 10, for example by the placement of an anaesthetic machine 1 within a substantially U-shaped workstation 10. It is understood that by handedness reference is not being made to the anaesthetists being left or right handed, but rather to the relative orientation of the components. The small and compact form of the housing 2 allows it to be positioned close in to a patient, with the anaesthetist resident in the workstation 10 having both the machine and their patient in the same common field of view.

Figures 2d-f illustrate how a complimentary set of female supply line connectors 14 - as illustrated with respect to figure 3b - are deployed in a wall mounted configuration. Figure 2d, 2e show a perspective and side view of the anaesthetic machine shown with respect figure 1 prior to connection to the wall mounted supply line connectors 14. Figure 2f shows a perspective view of the anaesthetic machine shown with respect to figure 1 when connected to the wall mounted supply line connectors. Again as indicated above with respect to the arrangement of figures 2a-c, the wheels of the machine allow it to be wheeled up to and be pushed into contact with the supply line connectors, with the compact form of the housing minimising the floor area required by the machine.

Figures 3a, 3b show two different forms of supply line connector clusters as provided in accordance with various embodiments of the invention. In the embodiment shown with respect to figure 3a number of male push fit connectors 4 are provided to supply an anaesthetic machine with a supply of vacuum pressure (4a), anaesthetic gas (4b), medical air (4c) and medical oxygen (4d).

A further set of male electrical current delivery connectors (4e) are also provided in this embodiment. In other embodiments a single electrical current delivery connector may be vertically separated from the

flammable gas supplies while still being located on the same side of the workstation and in approximately the same horizontal plane as the other anaesthetic machine connectors.

A pair of alignment prongs 11 are also shown with respect to figure 3a positioned to either side of the anaesthetic machine connectors when mounted on a side wall of the workstation. In the embodiment show the left hand prong also serves as an anaesthetic machine connector by providing a further connection to an Active Gas Scavenging System

(AGSS). The embodiment shown with respect to figure 3b is implemented with a number of female push fit connectors 14 which again supply an

anaesthetic machine with medical oxygen (14a), medical air (14b), anaesthetic gas (14c) and a supply of vacuum pressure (14d). A further set of female electrical current delivery connectors (14e) are also provided. As indicated above with respect to the embodiment illustrated in figure 3a, in other embodiments a single electrical current delivery connector may be vertically separated from the flammable gas supplies. Again in this configuration the electrical connector can still be located on the same side of the workstation and in approximately the same horizontal plane as the other anaesthetic machine connectors.

A pair of alignment recesses 12 are also shown with respect to figure 3b positioned to either side of the anaesthetic machine connectors when mounted on a side wall of the workstation. In the embodiment shown the right hand recess also serves as an anaesthetic machine connector by providing a further connection to an Active Gas Scavenging System

(AGSS). Figure 4 also provides a perspective view of the male supply connectors of figure 3a as deployed in the side wall of the anaesthetic machine illustrated with respect to figures la-Id. As can be seen from figure 4, the anaesthetic machine can be initially wheeled into alignment with a complementary set of connectors provided by a workstation - or in the floor or wall of an operating theatre. The machine can then be urged against these complementary connectors with the alignment prongs ensuring correct alignment of the push fit connectors provided .

Figure 5 shows a number of user controls on the top of the anaesthetic machine illustrated with respect to figures la-Id. As can be seen from this figure a number of physically actuated buttons and control dials are provided on the top surface of an anaesthetic machine in easy reach of an anaesthetist. As can be seen from figure 5 all the user controls provides are located in substantially the same horizontal plane on the top of the housing 2.

Control dial 6a applies vacuum to clear patient airways, while control dial 6b triggers an emergency oxygen flush procedure. Control switch 6c provides a ventilator on/off selector dial, and control dial 6d provides an adjustable pressure limiting valve control used to modify the amount of gas leaving a patient.

Figures 6a and 6b show top and perspective views of a selection of the button user controls illustrated with respect to figure 5. These user controls perform the following actions in relation to the anaesthetic machine :

Vtidal Regulate the tidal volume of gas per breath of the patient.

EtVol Identify and queue up the delivery of a selected volatile anaesthetic

RR Regulate ventilator breathing rate

Pinsp Sets how much pressure to apply to a patients lungs.

PEEP Regulates post end expiration pressure applied to the patient's lungs by the ventilator.

Air Trigger the delivery of medical air

N₂0 Trigger the delivery of Nitrous oxide

O2 Trigger the delivery of medical oxygen

The center dial shown provides an adjustment dial turned clockwise or anticlockwise to raise or lower a value assumed with the last selected control. The volatile control button can be pressed many times to cycle through a range of possible selections of anaesthetic volatiles. In the embodiment shown a number of different coloured light sources (not shown) are deployed under the button as activation acknowledgement elements. The colour of light emitted from underneath the button will identify the current volatile gas available for delivery to a patient.

In the embodiment shown the invention also implements further

activation acknowledgement elements in the form of an audio signalling system. In this embodiment the anaesthetist's activation of a particular control will result in the generation of local audio signal which announces the name of the last control selected and the value of an operational parameter associated with this control. In addition to the audio signal system, each button shown vibrates gently each time depressed, confirming for an anaesthetist that the button has been properly

depressed.

Figure 7 shows an alternative embodiment of the invention which deploys a variation on the user controls illustrated in the embodiment of figures 1- 6. In the embodiment shown with respect to figure 7 a relatively simple array of control buttons, switches and dials are mounted in the same horizontal plane on the top of the anaesthetic machine shown. These controls perform the following actions in this embodiment:

A - Patient suction control dial

B - Nitrous oxide glass flow control dial

C - Ventilator on/off selector switch

D - Volatile anaesthetic concentration control dial

E - Emergency oxygen flush button

F - Ridged side wall oxygen gas flow control dial

G - Adjustable pressure limiting valve

H - Medical air gas flow control dial Figures 8a, 8b, 8c show comparative test results obtained from clinical trials completed using a prior art anaesthetic workstation and machine and the workstation of the embodiment shown in figures 1-6.

Two separate simulation activities were undertaken at the Auckland University Tamaki Campus, Patient Safety Simulation Centre, New

Zealand. The basis for the activities was IEC Standard 62366, Medical devices - Application of usability engineering to medical devices.

(General) Date of Standard : 2007.

The embodiment of the invention shown with respect to figures 1-6 was used to simulate anaesthesia delivery for routine use, emergency use and extreme use. These procedures were :

• Routine general anaesthesia for an entire low risk surgical care

episode.

• Emergency use with a cardiac arrest requiring advanced life support including external cardiac massage, and defibrillation, during a trauma laparotomy that had required advanced airway

instrumentation prior to induction.

• Extreme use with a drape fire and intra-operative conflagration

during an otherwise routine surgical care episode, requiring extreme and immediate response from all staff present.

Results captured in relation to this embodiment are shown in figures 8a, 8b and 8c as reference 21. Comparison simulations were also completed using a conventional prior art Boyles table workstation utilising the same scenarios. Results captured in relation to this prior art workstation are shown in figures 8a, 8b and 8c as reference 20.

Video footage from 4 locations in the room, of all activities, was recorded to quantify exactly when the anaesthetist had their back fully to the patient. As can be seen from figure 8a, using the Boyle table the anaesthetist spent 28% of their time with their back to the patient, compared with only 2.5% with the use of the invention. The 'back to patient' measurements were calculated by scoring off the simulation's video footage, to ensure it was only scored when the anaesthetist was fully turned 180 degrees away from the patient. This was scored in seconds for accuracy.

The anaesthetist's response to a simulated on-table drape fire was 3 seconds for the invention compared to 10 seconds for the prior art Boyle table.

During those simulations, the Auckland University of Technology RFID team mapped the movements of the anaesthetist and the anaesthesia assistant with radio frequency identifiers. This measurement technique allowed quantitative measurements to be undertaken of the distance travelled by those persons, the distances between those 2 person, and anaesthetist hand excursion. Hand excursion measurements referenced relate to the cumulative vertical and horizontal distance travelled by the anaesthetist's hands interfacing with the control points on the respective machines used. The movement measurements referenced relate to the horizontal cumulative distance walked by the anaesthetist and assistant as they interface with their machine, and /or any other drawers, storage receptacles, trolleys, and the patient.

Figure 8b shows a comparison of the movements undertaken by the anaesthetist and their assistant when the prior art equipment (20) or the invention (21) was used. As can be seen from this figure the users of the invention only walked 56% of the distances walked by users of the prior art workstation. Figure 8b shows a comparison of the movement excursions undertaken by the anaesthetist when the prior art equipment (20) or the invention (21) was used. This figure illustrates that the hands of the user of the invention only moved 44% of that required by the user of the prior art workstation.

Further clinical testing of the embodiment of the invention shown with respect to figure 1 was also undertaken with two different forms of anaesthetist's workstation. Figure 9d shows the results obtained from this investigation where the time spent by an Anesthesiologist with their backs to a patient was considered in similar clinical scenarios to those discussed above with respect to figures 8a-c.

In this set of tests the implementation of the invention shown with respect to figure 1 was again combined with an enclosed workstation as shown with respect to figures 2a-c. This same anaesthetic machine was also tested in combination with an alternative "L" form workstation which lacked one of the side walls of the enclosed workstation of figures 2a-c. Figures 9a and 9b show perspective views of this L form workstation when combined with the embodiment of the invention shown by figure 1, while figure 9c shows a plan view of the combined workstation and anaesthetic machine. A comparative assessment was also completed using a prior art Boyle table.

The results of these test are shown as figure 9d, which illustrate that the Anesthesiologist spent 28% of their time with their back to the patient Anesthesiologist using the conventional Boyle table. The enclosing workstation identified by the iAC reference had the Anesthesiologist with their back to the patient only 2.8% of the time, while the L form

workstation identified by the LiAC reference had the Anesthesiologist turning their back on the patient only 1 % of the time.

It is to be understood that the present invention is not limited to the embodiments described herein and further and additional embodiments within the spirit and scope of the invention will be apparent to the skilled reader from the examples illustrated with reference to the drawings. In particular, the invention may reside in any combination of features described herein, or may reside in alternative embodiments or

combinations of these features with known equivalents to given features. Modifications and variations of the example embodiments of the invention discussed above will be apparent to those skilled in the art and may be made without departure of the scope of the invention. It is also

understood that the term 'includes' as used herein has the same meaning as 'comprises'.

Claims

What we claim is:

1. An anaesthetic machine which includes

a housing, and

a plurality of user controls, and

a plurality of supply line connectors located on a side of the housing, and

at least one low friction conveyor located on the underside of the housing.

2. An anaesthetic machine as claimed in claim 1 wherein the housing defines a fully enclosed space locating the functional components of the anaesthetic machine.

3. An anaesthetic machine as claimed in claim 1 wherein the housing provides a rectangular form defining an underside, top and side surfaces, the housing extending in use from the floor of an operating theatre to approximately the height of a desk or table.

4. An anaesthetic machine as claimed in claim 3 wherein the underside of the housing mounts a plurality of wheels.

5. An anaesthetic machine as claimed in claim 1 wherein a supply line connector is used to supply any one of the following : a supply of vacuum pressure, A connection to an active gas scavenging system (AGSS), medical oxygen nitrous oxide, halothane gas, isoflurane gas, medical air, desflurane gas, enflurane gas , enflurane gas.

6. An anaesthetic machine as claimed in claim 1 wherein the housing provides all the supply line connectors in a localised region on one side wall only.

7. An anaesthetic machine as claimed in claim 1 wherein a supply line connector integrated into a side of the housing is formed from a self sealing, push lock connection system.

8. An anaesthetic machine as claimed in claim 1 wherein the plurality of supply line connectors are arranged to engage with a set of complementary supply line connectors provided by an anaesthetist's workstation.

9. An anaesthetic machine as claimed in claim 1 wherein the plurality of supply line connectors are arranged to engage with a set of complementary supply line connectors installed in the wall and/or floor of an operating theatre.

10. An anaesthetic machine as claimed in claim 1 which includes at least one alignment prong adjacent to one or more supply

connectors.

11. An anaesthetic machine as claimed in claim 1 which includes at least one alignment recess adjacent to one or more supply connectors.

12. An anaesthetic machine as claimed in claim 1 which includes at least one electrical supply outlet port.

13. An anaesthetic machine as claimed in claim 12 which includes at least one electrical supply port mounted on one side of the housing and at least one additional electrical supply port mounted on the opposite side of the housing.

14. An anaesthetic machine as claimed in claim 13 wherein each

electrical supply port is mounted on a side of the housing adjacent to a side of the housing which deploys a cluster of supply line connectors.

15. An anaesthetic machine as claimed in claim 1 which includes a

plurality of gas supply terminals and/or sensor connection terminals on one side of the housing.

16. An anaesthetic machine as claimed in claim 15 wherein said gas supply and/or electrical connector terminals are mounted on the opposite side of the housing to a plurality of supply line connectors.

17. An anaesthetist workstation as claimed in claim 1 which includes at least one gas reservoir located within the housing.

18. An anaesthetist workstation as claimed in claim 1 which includes a plurality of gas reservoirs located within the housing.

19. An anaesthetist workstation as claimed in claim 1 which includes at least one uninterruptible power supply.

20. An anaesthetic machine as claimed in claim 1 which includes an information presentation system arranged to provide information to an anaesthetist from one or more patient monitoring sensors and/or one or more anaesthetic machine monitoring sensors.

21. An anaesthetic machine as claimed in claim 20 wherein the

information presentation system includes one or more display screens positioned on the top of the anaesthetic machine.

22. An anaesthetic machine which includes

a housing with a form defining an underside surface, top surface and at least one side surface, the housing defining a volume locating the functional components of the anaesthetic machine, and a plurality of user controls mounted in a substantially horizontal plane on the top surface of the housing, and

a plurality of supply line connectors, and

at least one low friction conveyor mounted on the underside of the housing.

23. An anaesthetic machine as claimed in claim 22 wherein user

controls are capable of actuation by a user to trigger the

performance of control actions related to the operation of the functional elements of the anaesthetic machine.

24. An anaesthetic machine as claimed in claim 22 wherein user

controls are provided by physically actuated elements.

25. An anaesthetic machine as claimed in claim 24 wherein a plurality of user controls are provided by buttons located on the top of the housing.

26. An anaesthetic machine as claimed in claim 24 wherein a contact surface of a user control defines at least one projecting marking.

27. An anaesthetic machine as claimed in claim 22 wherein a user

control is adapted to control any one or combination of the following : regulate the tidal volume of gas per breath of the patient, identify and enqueue a selected volatile anaesthetic gas for delivery, adjust anaesthetic gas concentration, regulate ventilator pressure settings, regulate post end expiration pressure, apply vacuum to clear patient airways, and/or trigger an emergency oxygen flush procedure

28. An anaesthetic machine as claimed in claim 22 which includes one or more activation acknowledgement elements.

29. An anaesthetic machine as claimed in claim 28 wherein an

activation acknowledgement element includes a light source deployed underneath a user control, where actuation of the user control triggers the activation of the light source.

30. An anaesthetic machine as claimed in claim 29 wherein a

subsequent actuation of a user control deactivates the light source.

31. An anaesthetic machine as claimed in claim 29 wherein the light source emits light of a particular colour associated with a particular user control.

32. An anaesthetic machine as claimed in claim 28 wherein an

activation acknowledgement element includes an audio signal generator

33. An anaesthetic machine as claimed in claim 28 wherein an

activation acknowledgement element includes a vibration

generation element.

34. An anaesthetic machine as claimed in claim 22 wherein a series of sequential activations of a user control cycles through the selection of number of possible control actions capable of user selection.

35. An anaesthetic machine as claimed in claim 34 wherein the

availability of a control action is indicated by the colour of light emitted by a light generation element mounted underneath a user control.

36. An anaesthetic machine as claimed in claim 22 which includes an information presentation system arranged to provide information to an anaesthetist from one or more patient monitoring sensors and/or one or more anaesthetic machine monitoring sensors.

37. An anaesthetic machine as claimed in claim 23 wherein the