WO2008049149A1

WO2008049149A1 - Air flow device to create a more sterile environment

Info

Publication number: WO2008049149A1
Application number: PCT/AU2007/001513
Authority: WO
Inventors: Sinclair Park
Original assignee: Animotion Australia Pty Ltd
Priority date: 2006-10-24
Filing date: 2007-10-05
Publication date: 2008-05-02

Abstract

A system (20) for creating a relatively more sterile environment at or about a site. The system comprises a mat (22) positionable adjacent or about said site and comprising a first layer (24) and at least a second layer (26), the first layer and the at least second layer defining an internal space for receiving a fluid, such as air. A fluid supply (10) can supply the fluid to the internal space of the mat (22) at a relatively elevated pressure. At least a portion of the first layer (24) of the mat (22) is fluid permeable such that fluid can flow therethrough and away therefrom to create a fluid flow region adjacent at least said portion of said first layer.

Description

AIR FLOW DEVICE TO CREATE A MORE STERILE ENVIRONMENT

Cross-Reference to Related Applications

The present application claims priority from Australian Provisional Patent

Application No 2006905917 Filed on 24 October 2006, the content of which is incorporated herein by reference.

Field of the Invention

The present invention relates generally to a method and device for creating a sterile environment at or about a specific site, and in particular to a method and apparatus for creating a sterile environment at or about a specific site that is portable and readily adapted to a variety of applications.

Background Art

A variety of situations require the creation and maintenance of a sterile environment in which to perform a specific task. Typically, such situations require a dedicated and sterilized space where the task is performed, and great care and expense is required to maintain the space in such a condition.

Such a sterilized space may be in the form of a room or workstation for assembling a precision device, such as an electronic device which may be effected by dust particles or the like, or an implantable medical device, such as a cochlear implant and the like, whereby foreign particles present on or in the device may be introduced in to the human body. In such instances, the space is controlled and regulated through filtering and controlling the quality of the air introduced into the space, as well as ensuring that individuals entering the space are appropriately attired and clean.

For this purpose, laboratory work chambers or hoods have been developed. The chamber typically defines an enclosed work space in which work can be performed, such as assembling the device. In order to keep particulate matter out of the work space, the chamber is operated at a positive pressure relative to the outside and is provided with a filter to remove the particles from the air being pumped into the chamber. A variety of chambers employ laminar flow techniques to direct the flow of filtered air past the work space thereby excluding particulate matter present in the air from entering the work space.

Another space which requires finite control and sterilisation is an operating room of a hospital or clinic, where surgical procedures are performed on a regular basis. Such operating rooms are created with much care, and at great expense, to ensure that maximum sterile integrity is maintained and that the various procedures to be performed therein are performed in the safest environment possible.

In creating such an operating room, it is known to arrange the room to define a laminar flow of filtered air, usually from the ceiling to the operating table. Typically, it is necessary to produce a clean air flow directed across the surgical area in a manner to isolate the area and to prevent contamination from the ambient conditions. By providing a protective air flow "blanket" over the surgical area travelling at a velocity higher than any contaminating particles that could penetrate the "blanket" (such as bacteria laden particles that may be exhaled from one or members of the surgical team adjacent the surgical site or bacteria carrying skin flakes which can be shed at a rate of about 1000 particles/minute for every person present in the room), ,the contaminating particles are able to be at least substantially or wholly prevented from entering the surgical site. In this regard, it has been shown that there is a direct relationship between rates of post-operative infection and the incidence of airborne particles. One problem associated with creating such a laminar flow environment in an operating room is that the flow is vulnerable to turbulence or other disruption that may be caused by surgical lighting or equipment which has the potential to compromise the sterile environment.

In each of the above described instances, relatively large and often chilled airflows are required, and the laminar flow environment is dependent upon being installed into the structural members of the chamber or the operating room. Hence, such arrangements are not readily portable and require significant capital expenditure, and relatively high running and maintenance costs.

There is a need to provide a more effective and more affordable method and apparatus for creating a sterile environment at or about a specific site that can be readily adapted to suit a variety of applications and which contribute to the exclusion of airborne particles from the site, and, in the application to surgical rooms, greatly reduces the rates of post-operative infection.

Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application.

Summary of the Invention

Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

According to a first aspect, the present invention is a system for creating a relatively more sterile environment at or about a site comprising: a mat positionable adjacent or about said site and comprising a first layer and at least a second layer, the first layer and the at least second layer defining an internal space for receiving a fluid; and a fluid supply for supplying a fluid to the internal space of the mat at a relatively elevated pressure; wherein at least a portion of said first layer of said mat is fluid permeable such that fluid is flowable therethrough and away therefrom to create a fluid flow region adjacent at least said portion of said first layer.

According to a second aspect, the present invention is directed to a method of creating a relatively more sterile environment at or about a site comprising: a) providing a system according to the first aspect of the invention; b) positioning the mat of said system adjacent or about the site; and c) supplying the fluid to the internal space of the mat at a relatively elevated pressure; and d) allowing the fluid to flow through and away from at least a portion of the first layer to create a fluid flow region adjacent to at least said portion of the said first layer.

According to a third aspect, the present invention is directed to a method of creating a relatively more sterile environment at or about a site comprising: a) providing a mat having:

(i) a first layer having at least a portion that is fluid permeable; (ii) at least a second layer, wherein the first layer and the at least second layer define an internal space for receiving a fluid, and

(iii) one or more inlets for receiving a fluid into the internal space; b) positioning the mat adjacent or about the site; and c) supplying the fluid at a relatively elevated pressure to the internal space of the mat through said one or more inlets; and d) allowing the fluid to flow through and away from said fluid permeable portion of the first layer to create a fluid flow region adjacent to at least said portion of said first layer.

The present invention is directed to a system and method that at least assists in creating a sterile environment at or about a site. The phrase "at or about a site" will be understood to mean the immediate area surrounding a specific position, place or location and includes but is not limited to a surgical site on an animal or human such as an open incision, a place where surgical instruments are stored such as a tray or shelf, a worktop where implant devices are prepared, and any other site where a sterile environment is desired or required.

By creating a fluid flow region, the system and method serves to create a region into which surrounding air is at least partially prevented from entering.

In one embodiment, the mat can comprise a sandwich of at least three layers, the first layer and the second layer, and an intermediate layer. The entire mat is preferably sufficiently flexible and/or foldable for ease of use. The mat is also relatively thin to ensure it can be used in a surgical or other required environment.

At least a portion and preferably all of the first layer is fluid permeable. The first layer can act as a filter layer. Some or all of the second layer can be substantially or wholly impervious to fluid flow. In another embodiment, the second layer can be at least partially fluid permeable. If desired, the second layer can in use be brought into contact with a substantially impervious surface.

It will be appreciated that the mat may be of any size, shape or form and will depend on the nature of the site.

In one embodiment, the mat is sterilisable and is a single use disposable product. In another embodiment, the mat can be sterilisable and/or reusable.

In one embodiment, part or all of the first layer can be comprised of the filter layer. The fluid permeability of the first layer can be provided by forming the first layer at least in part or entirely from a relatively high efficiency particulate absorbing (HEPA) grade filter material. In one embodiment, the filter material can be a Spun/Melt/Melt/Spun (SMMS) four layer material. For example, the SMMS material can comprise a polypropylene and comprise a 30gsm Spunbond layer, two inner layers of 30gsm Meltblown material and a 15gsm Spunbond layer. The filter layer can be capable of removing 99.97% of all particles in the fluid having a size over about 0.3 μm. Other standards of HEPA filter can be utilised and envisaged. In one embodiment, the filter material can serve to sterilise the fluid exiting the mat. In another embodiment, the filter material assists in sterilisation of the fluid exiting the mat and being delivered to the site. Still further, the first layer can be relatively low linting. Some or all of the first layer material can be resiliently flexible.

In another embodiment, the first layer can be bonded or otherwise connected to the second layer and if present, the intermediate layer, in a manner that still allows formation of the internal space. For example, the perimeter of the first layer can be joined to the second layer and, if present, the intermediate layer. The join can be provided by heat or high frequency welding and/or by a suitable adhesive. Joins can also be provided at locations other than at the perimeter. For example, a plurality of joins can be provided across the dimension of the mat. The joins can be spot joins or longitudinal joins or a combination of both. The joins can be equally or non-equally distributed.

Whether or not some or all of the first layer is resiliently flexible, some or all of the second layer can be formed from a resiliently flexible material. The combination of the first and second layers and the nature of the materials can be such so as to create a cellular matrix construction when fluid is provided at the relatively elevated pressure to the internal space.

The second layer can be adapted, in use, to be a lower or inner layer. The second layer can be made of a relatively thin and relatively strong plastic film. Some or all of the second layer can have an adhesive outer surface to facilitate adhesion to a surface, such as the patient or work surface. In a further embodiment, some or all of the second layer can be treated with a continuous broad-spectrum antimicrobial agent.

As described, the mat can have an intermediate layer. The intermediate layer can be made of a relatively thin and perforated plastic film. The intermediate layer can be joined to the first and/or second layers around its edge or edges. It can also be joined to the first and/or second layers at other locations.

In a further embodiment, a fluid flow passage can extend about some or all of the perimeter of the mat. The passage can be in fluid communication with one or more inlets that can receive relatively elevated pressurized fluid. The passage preferably serves to assist in ensuring the fluid is initially distributed about said perimeter, or said portion thereof, of the mat due to the relatively lower resistance to air flow within the passage in comparison with the filter material of the first layer. Once the fluid flows within the passage, the fluid may then be evenly distributed throughout the mat via the cellular matrix. Relatively even pressure distribution can be achieved by varying the size and/or spacing of the perforations provided in the intermediate layer in relation to their distance from the inlet port or ports.

A recess can be located in the mat. In one embodiment, the recess can be centrally located. The recess serves to define to users a sterile site around which the sterile environment is to be created. The recess can be substantially oval in shape or take a variety of shapes.

In one embodiment, the recess may be positioned about a site of an incision in a patient's body in a manner such that access to the incision and body is possible through the recess. The recess may be covered in a sterile, flexible and adhesive material that is incisable (for example, a material that can be used in incisable surgical drapes), thereby further increasing asepsis of the surgical field. In one embodiment, the second layer as defined herein can extend across the recess.

In a further embodiment, the fluid supply can supply a quantity of fluid under pressure by way of a connector, for example one or more tubes, pipes or hoses, to the mat. The tubes, pipes or hoses can be resiliently flexible. A valve/regulator member can be provided between the fluid supply and the connector to control and regulate the pressure of the fluid being supplied to the mat.

The fluid supply can comprise a supply of air. The air is preferably relatively clean and also relatively dry. The fluid supply is also preferably provided at a pressure sufficient to create a relatively slow flow of sterile air emanating outwards from the first layer of the mat. The rate of flow can be between about 0.01 to 0.5m/s adjacent the first layer. The actual pressure of the air supply and the capacity of the air supply will be dependent upon the area of the sterile zone to be created by the system and the degree of permeability of the first layer of the mat.

As an example, for a sterile zone having an area of about 300mm x 400mm, the air may be supplied at about 0.5 to 1 Cubic Feet per Minute (CFM). Typically, the supply air pressure will also depend on the environmental conditions in which the system is being used. For example, if the system is being used in a makeshift tent field hospital in a disaster area the conditions will have higher turbulence and the like; therefore a higher air supply pressure is likely to be required. In this regard, the valve/regulator member may be used to regulate the air supply pressure as desired.

The type of fluid provided in the fluid supply may also vary. The fluid may be a clean, dry and oil free supply of air, as is typically used in a surgical environment. The source of this air may be the "in-house" air supply of the hospital or other entity, bottles of compressed air, or other source of pressurised air. It is also possible that other gasses such as carbon dioxide may be added to the air supply to further improve asepsis. The air may pass through a filter prior to delivery to the connector and mat to remove relatively gross particulate matter therefrom prior to reaching the mat. It will be appreciated that in remote areas where a clean supply of compressed air may not be readily available, the system of the present invention may also be employed using a conventional source of compressed air. The air delivered to the mat may be relatively chilled. It will be appreciated that the compressed air will cool in any event as it moves from a compressed state to a less compressed state in the mat. The relatively cooler air can be understood as producing a

"blanket" of sterile air about the surgical area that is relatively denser that the surrounding air.

In some instances, it may be appropriate that the air is relatively warmed or heated prior to delivery such that the pressurized air delivered from the mat is at least a few degrees warmer than the room temperature of the surgical room. Such an arrangement may also be used to encourage the creation of a generally upward flow of air from the mat, further increasing the achievable level of asepsis.

In one embodiment, the fluid supply may be in the form of a pump or blower which delivers the air under pressure to the mat. Where the system is being used in an operating room, the pump or blower may be provided external to the operating room such that the hose is merely connected to an outlet in the room, as is conventional in most hospital settings. However, if the system is used in a remote location and the fluid supply is located near to where the sterile zone is required, the pump or blower employed can be selected to operate in a relatively quiet manner which is oil and moisture free.

In one embodiment, the connector can be suitable to undergo autoclave cleaning or can be a single-use disposable product. An adaptor may be provided at an end of the connector to facilitate connection of the end of the connector to an inlet of the mat. The adaptor may also be removable from the connector and/or inlet for autoclave cleaning or disposal after single use. A further adaptor may also be provided at the other end of the connector for facilitating connection of the connector to the valve/regulator of the fluid supply. The diameter of the connector (e.g. hose) can vary in accordance with the required airflow of the system to achieve the desired the sterile zone and to cater for acceptable line loss. In this regard, a plurality of different sized hoses may be supplied with the system to meet the variable needs of the user.

In one embodiment, the mat and/or connector and/or adaptor can be supplied in a sealed sterile package which is opened prior to use such that it is in a sterile state. Following use, the mat may then be disposed. The system as defined herein and its use can preferably create a sterile zone immediately above or around a surgical or other site. The sterile zone is created by forming a relatively slight pressure differential adjacent the first layer relative to the air outside the sterile zone, with the air in this region having a higher pressure than the surrounding air, thereby serving to at least partially, and preferably wholly, exclude any possible airborne contaminants from entering the work area, such as a surgical field work area.

According to a fourth aspect, the present invention is a mat for use in the system or method as defined herein.

According to a fifth aspect, the present invention is a mat positionable adjacent or about a site and comprising: a first layer; and at least a second layer; the first layer and the at least second layer defining an internal space for receiving a fluid; wherein at least a portion of said first layer of said mat is fluid permeable such that fluid is flowable therethrough and away therefrom to create a fluid flow region adjacent at least said portion of said first layer.

In one embodiment of the fourth and fifth aspects, the mat can have one, more or all of the features of the mat defined herein.

Brief Description of the Drawings

By way of example only, preferred embodiments of the invention are now described with reference to the accompanying drawings, in which:

FIG. 1 depicts a sterile zone system incorporating a fluid dispersal mat and fluid supply in accordance with an embodiment of the present invention;

FIG. 2 shows the dispersal mat of FIG. 1 in use in a surgical application;

FIG. 3 shows the sterile zone created by the system of FIG. 1; FIGS. 4a and 4b depict alternative embodiments of the mat; and

FIGS. 5 and 5a depict a still further embodiment of the mat comprised of a first layer, a second layer and an intermediate layer.

Detailed Description of an Exemplary Embodiment of the Present Invention

The device and method of the present invention will be described below in relation to its application at a surgical site, such as an open incision in a surgical procedure being performed on a human or animal. However, it will be appreciated that the present invention could be equally employed in a variety of situations where a sterile environment is required to be created at or about a work site.

Referring to FIG. 1, the sterile zone creation system 20 according to one embodiment of the present invention is shown. The system 20 comprises a fluid supply

10 which supplies a quantity of fluid under pressure by way of a flexible tube or hose

15 to a dispersal mat 22. A valve/regulator member 12 is provided between the hose 15 and the fluid supply 10 to control and regulate the pressure of the fluid being supplied to the dispersal mat 22, in accordance with specific requirements. It will be appreciated that the system 20 could use the alternative embodiments of the mat described herein.

The fluid supply 10 is in the form of a supply of relatively clean and dry air. In the depicted embodiment, the fluid supply is provided at a pressure sufficient to create a relatively slow flow of sterile air emanating outwards from an upper or first layer of the mat 22. In this embodiment, the rate of flow can be between about 0.01 to 0.5m/s adjacent the first layer but other flow rates are encompassed by the present invention. The actual pressure of the air supply and the capacity of the air supply will be dependent upon the area of the sterile zone to be created by the system 20 and the degree of permeability of the first layer of the mat 22. The material of the first layer and its ability to act as a filter is described in more detail below.

As an example, for a sterile zone having an area of around 300mm x 400mm, the air may be supplied at around 0.5 to 1 Cubic Feet per Minute (CFM). Typically, the supply air pressure will also depend on the environmental conditions in which the system 20 is being used. For example, if the system is being used in a makeshift tent field hospital in a disaster area the conditions will have higher turbulence and the like; therefore a higher air supply pressure is likely to be required. In this regard, the valve/regulator member 12 may be used to regulate the air supply pressure as desired.

The type of fluid provided in the fluid supply 10 may also vary. The fluid may be a clean, dry and oil free supply of air, as is typically used in a surgical environment.

The source of this air may be the "in-house" air supply of the hospital or other entity, bottles of compressed air, or other source of pressurised air. It is also possible that other gasses such as carbon dioxide may be added to the air supply to further improve asepsis. The air may pass through a filter prior to delivery to the hose 15 and dispersal mat 22 to remove relatively gross particulate matter therefrom prior to reaching the mat. It will be appreciated that in remote areas where a clean supply of compressed air may not be readily available, the system 20 of the present invention may also be employed using a conventional source of compressed air.

In some instances, it may be appropriate that the air is relatively chilled in order to produce a "blanket" of sterile air about the surgical area that is relatively denser that the surrounding air. Alternatively, the air can be relatively warmed or heated prior to delivery such that the pressurized air delivered from the dispersal mat 22 is at least a few degrees warmer than the room temperature of the surgical room.

It will be appreciated that the fluid supply 10 may be in the form of a pump or blower which delivers the air under pressure to the dispersal mat 22. The pump or blower may be provided external to the operating room such that the hose 15 is merely connected to an outlet in the room, as is conventional in most hospital settings. However, if the system 20 is used in a remote location and the fluid supply 10 is located near to where the sterile zone is required, the pump or blower employed can be selected to operate in a quiet manner which is oil and moisture free.

In the embodiment depicted in FIG. 1, the hose 15 is made from a resiliently flexible tube. The tube can be suitable to undergo autoclave cleaning or can be a single-use disposable product. An adaptor 16 may be provided at an end of the hose 15 to facilitate mating of the hose 15 to an inlet 21 of the dispersal mat 22. The adaptor 16 may also be removable from the hose 15 and inlet 21 for autoclave cleaning or disposal after single use. A further adaptor may be provided at the other end of the hose 15 for facilitating mating of the hose 15 to the valve 12 of the fluid supply 10. As will be appreciated, the diameter of the hose 15 is selected in accordance with the required airflow of the system 20 to achieve the desired sterile zone and to cater for acceptable line loss. In this regard, a plurality of different sized hoses 15 may be supplied with the system 20 to meet the variable needs of the user.

Referring to FIG. 3, the depicted dispersal mat 22 is a sterile, single use disposable product. The first upper layer 24 is made from a resiliently flexible and relatively high efficiency particulate absorbing (HEPA) grade filter material layer. In this embodiment, the filter material is a Spun/Melt/Melt/Spun (SMMS) four layer polypropylene material and is capable of removing 99.97% of all particles having a size over about 0.3 μm.

The first filter layer 24 is bonded to a second lower layer 26 in such a fashion as to create a cellular matrix 25 arrangement. This depicted second layer 26 is at least substantially fluid impervious and also has an adhesive outer surface to facilitate adhesion to a surface, such as the patient or work surface.

In FIG. 1, an open passage 28 extends about the perimeter of the mat 22 which is in direct communication with the inlet 21 for receiving the relatively pressurized air. The open passage 28 allows the air to be initially distributed about the perimeter of the mat 22 due to the lower resistance to air flow within the passage 28 in comparison with the filter material 24. Once the air flows within the open passage 28, the air may then be relatively evenly distributed throughout the mat 22 via the cellular matrix 25.

FIGS. 4a and 4b depict alternative arrangements of bonding the first, intermediate and second layers. In both FIG. 4a and 4b, the mat 22 is sealed about its perimeter. In the case of FIG. 4a, a plurality of spot joins 51 between the layers is provided whereas in FIG. 4b, a plurality of longitudinal joins 52 are provided. The joins between the layers provides a distribution path for the air but also serve to prevent any significant inflation of the mat 22.

As shown in the drawings, a recess 30 is centrally located in the mat 22 to define a sterile site around which the sterile environment is to be created. It will be appreciated that the recess 30 can take a variety of forms and positions. Also, the mat can have no such recess. One embodiment of how the recess 30 may be positioned about a site to create a sterile environment is shown in FIG. 2. In this embodiment, the cross-section of a patient's body is generally represented as 40, and an incision 35 is created to provide internal access into the body 40. The mat 22 is positioned on the body 40 such that the recess 30 extends about the incision 35 and access to the incision and body is possible through the recess 30 of the mat 22. The recess 30 may be covered in a sterile, flexible and adhesive material that is incisable (for example, the material used in incisable surgical drapes), thereby further increasing asepsis of the surgical field. In another embodiment, the first layer can extend across the recess and be incisable. Whilst not shown, it will be appreciated that one or more surgical drapes could be readily employed with the mat 22 to substantially enclose the body 40 during the procedure.

The first filter layer 24 of the dispersal mat 22 is substantially air permeable such that air passing through the mat 22 is able to disperse from the upper surface of the first filter layer 24 in the manner as shown in FIG. 3. This is achievable through the application of the fluid impervious second lower layer 26 which prevents pressurized air from flowing therethrough such that air is directed in a relatively upward direction through the first layer 24.

Due to the application of the above described embodiment of the invention to a surgical environment, it will be appreciated that the mat 22 may be supplied in a sealed sterile package which is opened just prior to use such that it is in a sterile state. Following use, the mat 22 may then be disposed of appropriately.

An alternative embodiment of the mat is depicted generally as 60 in FIGS. 5 and

5a. Here, the mat 60 is comprised of a first upper layer 61, again made from a resiliently flexible and relatively high efficiency particulate absorbing (HEPA) grade filter material layer. As described above, the filter material is again a Spun/Melt/Melt/Spun (SMMS) four layer polypropylene material and is capable of removing 99.97% of all particles having a size over about 0.3 μm.

The first filter layer 61 is bonded to a perforated intermediate layer 62 of resiliently flexible and relatively thin plastic film, and a second lower layer 63 in such a fashion as to create a cellular matrix arrangement. The depicted second layer 63 is again at least substantially fluid impervious and also has an adhesive outer surface to facilitate adhesion to a surface, such as the patient or work surface. In FIG. 5, an open passage 64 extends about the perimeter of the mat 60. The passage 64 is in fluid communication with an inlet for receiving the relatively pressurized air. The open passage 64 allows the air to be initially distributed about the perimeter of the mat 60 due to the lower resistance to air flow within the passage 64 in comparison with the filter material 61. Once the air flows within the open passage 64, the air may then be relatively evenly distributed throughout the mat 60 via the cellular matrix.

As a result of the arrangements described herein, and as is clearly shown in

FIGS. 3 and 5, air flows from the mat in the direction of arrows A to create a sterile zone 45 immediately above the mat and around the sterile site. The sterile zone 45 is created in essentially two ways. Firstly, through the creation of a slight pressure differential in the air around the sterile zone 45, with the air in this region having a higher pressure than the surrounding air, thereby at least partially and preferably wholly excluding any possible airborne contaminants from entering the surgical field work area. Secondly, through the creation of laminar air flow emanating out from the zone 45 which acts to minimize the effect of any locally created turbulence. It will be appreciated that there may be instances where an uneven distribution of airflow is required. In such instances, this can be readily achieved through variation of the cellular structure of the matrix and/or through variation of filter resistance of the first filter layer material.

It will be appreciated that whilst the invention has been described above in the form of a surgical mat 22,60 configured to be placed about a surgical site of a subject during a surgical procedure; the invention could take a variety of different forms. In this regard, the mat 22,60 may be in the form of a liner for a surgical instrument tray or any other area that could benefit from being surrounded by sterile air, including a liner for a cabinet or bench in a laboratory.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

CLAIMS:

1. A system for creating a relatively more sterile environment at or about a site comprising: a mat positionable adjacent or about said site and comprising a first layer and at least a second layer, the first layer and the at least second layer defining an internal space for receiving a fluid; and a fluid supply for supplying a fluid to the internal space of the mat at a relatively elevated pressure; wherein at least a portion of said first layer of said mat is fluid permeable such that fluid is flowable therethrough and away therefrom to create a fluid flow region adjacent at least said portion of said first layer.

2. The system of claim 1 wherein the mat comprises a sandwich of at least three layers, the first layer and the second layer, and an intermediate layer.

3. The system of claim 1 wherein at least a portion or all of the first layer is fluid permeable.

4. The system of claim 1 wherein the first layer is comprised of a filter layer.

5. The system of claim 1 wherein some or all of the second layer is substantially or wholly impervious to fluid flow.

6. The system of claim 1 wherein the mat is sterilisable and is a single use disposable product.

7. The system of claim 4 wherein the filter layer is formed from a relatively high efficiency particulate absorbing (HEPA) grade filter material.

8. The system of claim 2 wherein the first layer is bonded or otherwise connected to the second layer and the intermediate layer in a manner that still allows formation of the internal space.

9. The system of claim 8 wherein the perimeter of the first layer is joined to the second layer and the intermediate layer.

10. The system of claim 9 wherein a plurality of joins are provided across the dimension of the mat.

11. The system of claim 10 wherein the j oins are spot j oins or longitudinal j oins or a combination of both.

12. The system of claim 1 wherein some or all of the second layer has an adhesive outer surface to facilitate adhesion to a surface, such as the patient or work surface.

13. The system of claim 1 wherein the mat has a recess that defines to users a sterile site around which the sterile environment is to be created.

14. The system of claim 13 wherein the second layer extends across the recess.

15. The system of claim 1 wherein the fluid supply supplies a quantity of fluid under pressure by way of a connector.

16. The system of claim 1 wherein the fluid supply delivers a supply of relatively clean and also relatively dry air.

17. The system of claim 16 wherein the air delivered to the mat is relatively chilled.

18. The system of claim 1 wherein the fluid supply is a pump or blower which delivers the air under pressure to the mat.

19. A method of creating a relatively more sterile environment at or about a site comprising: a) providing a system according to claim 1 ; b) positioning the mat of said system adjacent or about the site; and c) supplying the fluid to the internal space of the mat at a relatively elevated pressure; and d) allowing the fluid to flow through and away from at least a portion of the first layer to create a fluid flow region adjacent to at least said portion of the said first layer.

20. A method of creating a relatively more sterile environment at or about a site comprising: a) providing a mat having:

21. A mat positionable adjacent or about a site and comprising: a first layer; and at least a second layer; the first layer and the at least second layer defining an internal space for receiving a fluid; wherein at least a portion of said first layer of said mat is fluid permeable such that fluid is flowable therethrough and away therefrom to create a fluid flow region adjacent at least said portion of said first layer.