WO2008140871A1

WO2008140871A1 - Device for treating inhaled air having an antimicrobial sheet

Info

Publication number: WO2008140871A1
Application number: PCT/US2008/058975
Authority: WO
Inventors: Steve Sotendahl; Eric J.C. Kroon; Reed Walsh
Original assignee: Meadwestvaco Corporation
Priority date: 2007-04-03
Filing date: 2008-04-01
Publication date: 2008-11-20
Also published as: WO2008140871A9; WO2008140871A8

Abstract

Antimicrobial papers are described for use in medical heat and moisture exchanger (HME) devices.

Description

DEVICE FOR TREATING INHALED AIR HAVING AN ANTIMICROBIAL SHEET

BACKGROUND

[0001] This invention deals with medical heat and moisture exchanger (HME) devices used to assist patients on respirators or persons breathing through tracheostomies. A variation on such a device is alieat and moisture exchanging filter (HMEF).

[0002] During use of a respirator, air is inhaled through an endotrachial (or endotracheal) tube that bypasses the nose, mouth and upper respirator}' tract. Air directly inhaled this way is not heated or humidified in the normal fashion before it Teaches the lungs. The air is dry and cool, and may damage the lungs. Therefore steps are taken to heat and humidify respiratory gases before inhalation.

[0003] Persons breathing through a tracheostomy (stoma) inhale air directly into their trachea, so it does not -pass through pass through the nose and sinuses, and therefore lacks the -normal humidification and heating benefits gained by air inhaled through these cavities. There, persons with tracheostomies may also benefit from having air heated, humidified, or filtered before it is inhaled. [0004] Two types of devices are commonly used for heating and humidifying inhaled air in these situations. One is a powered mechanical device or "active humidifier" that actively heats and humidifies air. Such a device provides good levels of heat and moisture, but can be expensive, has a higher risk of failure, and has some operating problems.

[0005] The second type of device is a passive HME that absorbs heat and moisture from exhaled breath and transfers it to inhaled air. An HME is usually made out of a hydrophilic media (paper or sponge) placed in a plastic housing

[0006] Many HMEs also include media of various types that act as a barrier to bacteria and viruses, using various mechanical (filtration) and other separation means. Since most of these antimicrobial barriers act via filtration, they usually increase the resistance to air flow in the HME which can make breathing more difficult and require adjustments on the respirator. An HME media with antimicrobial properties could eliminate the need for an extra antimicrobial barrier, thus reducing air flow resistance. Additionally, if a separate microbial filter were not needed, it would make the HME simpler to manufacture. This would reduce manufacturing costs.

[0007] Some HMEs are used for multiple days. During that time the HME media could become contaminated with microorganisms. These organisms could multiply in the warm, moist HME media and be detrimental to the health of the patient. A media with antimicrobial properties would prevent this occurrence. SUMMARY

[0008] In one embodiment, a device is disclosed for treating inhaled air. The device includes a housing. Within the housing are one or more packing layers comprising a sheet material. The sheet material has antibacterial or antiviral properties.

[0009] In certain embodiments, the sheet material includes a cellulosic material. In certain embodiments, the sheet material includes fibers treated with copper oxide. In certain embodiments, the sheet material includes N-halamine siloxane. In certain embodiments, the sheet material includes organosilanes containing quaternary salts.

BRIEF DESCRIPTION OF FIGURES

[0010] FIG. 1 illustrates an exemplary method of making fibrous web including antimicrobial or antiviral properties in an embodiment according to the invention;

[0011] FIG.2 illustrates another exemplary method of making fibrous we^"b including antimicrobial or antiviral properties in an embodiment according to the invention; and

[0012] FIG. 3 is an isometric view of a heat and mass transfer device ^"having antimicrobial or antiviral properties.

DETAILED DESCRIPTION

[0013] There are several methods to impart antimicrobial properties to an HME media. It would be advantageous to provide ^"both antibacterial and antiviral iunctionality [0014] In one embodiment, the media comprises copper oxide treated cellulose fibers. These fibers are pretreated by a multistep, electrodeless, chemical plating process that deposits nodules of copper oxide onto the cellulose fibers. This process is commercially available under the CUPRON™ name from Cupron, Inc. The treated fibers with the permanently attached copper are added to a furnish of untreated fibers so that the treated fibers comprise from 0.1% to 20% of the total fiber furnish. The use of copper oxide treated fibers in this way provide cellulose-based finished media with antibacterial and antiviral properties.

[0015] PIG. 1 illustrates an exemplary method for making the antimicrobial HME material using apaper machine. A forming wire 410 in the form of an endless belt passes over a breast toll 415 that xotates proximate to a headbox or primary headbox 420. The headbox provides a fiber slurry in water with a fairly low consistency (for example, about 0.5% solids) that passes onto the moving forming wire 410. During a first distance 430 water drains from the slurry and through the forming wire 410, forming a web 140 of wet fibers. The slurry during distance -430 may yet have a wet appearance as there is free water on its surface. At some point as drainage continues the free water may or may not disappear from the surface, and over distance 431, water may continue to drain although the surface appears free from water. Eventually the well is carried (for example by transfer felt or press felt, not shown) through one or more pressing devices such as press rolls 421 that help to further dewatering the web, usually with the application of pressure, vacuum, and sometimes heat. After pressing, the web is dried. Typically one or more [0016] As an example, copper oxide treated fibers maybe added to the slurry in an earlier stage of the slurry preparation, or before or in the headbox 420, or shortly after leaving the headbox. Addition at these locations provides good mixing throughout the slurry. Standard papermaking practice is to try to achieve uniform distribution of solids in the slurry, leading to good "formation" of the paper product. If the antimicrobial or antiviral fibers have different physical or chemical properties from the usual paper fibers, additives maybe used to achieve desired results, such as keeping all materials uniformly in suspension. The point at which fibers are added may influence their orientation in the web.

[0017] Copper oxide treated fibers maybe added when the web being formed has just left the headbox, and is fairly fluid, for example in the first distance 430. Material added at this point, whether liquid or solid, may be less likely to distribute evenly because the slurry of fibers is becoming set. Therefore migration of the copper oxide treated fibers across the web or into the web may be somewhat limited.

[0018] Copper oxide treated fibers may be added when the web being formed is "further away from the headbox, and less fluid, for example in the second distance 431. Materials added at this point may be expected to remain closer to the surface of the web. Besides addition in or before the headbox 420, possible application methods for copper oxide treated fibers include, for example, a curtain coater440, or a spray coater450, or a secondary headbox (not shown). [0019] In another embodiment, cellulose fibers are treated with N-halamine siloxane. An N-halamine siloxane system is commercially available as HALOSHIELD® from HaloSource, Inc., and provides both antibacterial and some antiviral action.

[0020] The fibers may be -treated with up to 5% of N-halamine siloxane in several ways. In the one embodiment shown in FIG. 2, N-halamine maybe applied in an aqueous or dilute alcohol based solution after the wet end of the paper machine with an applicator 471. The application may be a spray coater, size press, roll coater, rod coater, blade coater, or any other typical coating device. Subsequent drying of the paper, for example with dryer 463, completes the attachment of the siloxane portion of the N-halamine on the fiber.

[0021] In another embodiment the N-halamine may be added to the fiber in the wet end of a fourdrinier paper machine. The N-halamine may be added to the fiber furnish at the thick stock or thin stock, or elsewhere before headbox 420, or may be sprayed onto the web further down the machine, for example using an applicator such as a curtain coater 440 or spray applicator 450.

[0022] Attachment of the N-halamine may be made permanent during the subsequent drying process 461, 462, 463. Chlorine in various forms, most commonly sodium or calcium hypochlorite (bleach), may be added to the wet end system as well. The chlorine atoms attach to the N-halamine and are stabilized for an extended period of time. The chlorine then provides antimicrobial action. amounts may be the same as the N-halamine siloxane above, and as shown in FIG. 2. Application may be in the wet end, for example in or before headbox 420, or on the fourdrinier area, for example with a curtain coater 440 or spray 450. Application may also be after some drying has occurred, for example with an application device 471, provided that additional drying occurs after the application, for example with dryer 463. Antimicrobial organosilanes with quaternary functionality are available as MICROBE SHIELD® from Aegis Environments.

[0024] FIG. 3 is an isometric view of a heat and mass transfer device 100. The HME has a first port 102 and second port 104 through which air may pass bidirectionally through the HME (for example repeatedly and alternately flowing in through first port 102 and out through second port 104, then in through second port 104 and out through first port 102). HME 100 has a housing 106 containing a media 108 for accomplishing heat and mass transfer. For example, as shown in FIG. 3 for a rectangular shaped HME 100, the media 108 may be a stack of corrugated paper treated with antimicrobial and or antiviral agents according to one of the embodiments described above. For low air flow resistance, the flutes (corrugations) in the media 108 are preferably aligned in the air flow direction, so that the air will flow through the open area of the flutes. Jn order to prevent the flutes or corrugations from "nesting" or collapsing upon one another, flatpaper layers may be used between the corrugated layers. The geometry of the HME may vary and may be rectangular, cylindrical, or any other form suitable for an HME. In all cases, the media 108 may be provided with antimicrobial and /or antiviral properties as disclosed herein. [0025] The invention disclosed here is not limited to paper based HMEs. hi principle, any sheet material may be used to make the HME.

[0026] In any embodiment, a humectant (substance to help retain moisture) may be added to the sheet material.

[0027] Whilst the above embodiments describe an exchanger for use in respiratory applications, it should be understood that the invention applies to the use of such a deviceor other applications in which heat and mass transfer are also useful.

Claims

CLAIMSWhat is claimed is:

1. A device for treating inhaled air, comprising:

a housing;

within the housing one or more packing layers comprising a sheet material, wherein the sheet material is provided with at least one of an antibacterial and an antiviral property.

2. The device of claim 1, wherein trie sheet material includes a cellulosic material.

3. The device of claim 1 , wherein the sheet material includes fibers treated with copper oxide.

4. The device of claim 3 , wherein the fibers treated with copper oxide comprise from 0.1% to 20% of the total fiber weight.

5. The device of claim 1, wherein the sheet material includes N-halamine siloxane.

6. The device of claim 5, wherein the sheet material includes up to 5w% of N- halamine siloxane.

7. The device of claim 1, wherein the sheet material includes organosilanes containing quaternary salts.

8. The device of claim 7, wherein the sheet material includes up to 5w% organosilanes containing quaternary salts.

9. The device of claim 1, wherein said packing layers are treated with a humectant.