Bacteriostatic drawsheet

106-18»34

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SR

3?308»488

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March 14, 1967

Filed May 3, 1965

R, J. SCHOONMAN

3,308,488

BACTERIOSTATIC DRAWSHEET

Sheets-Sheet i

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FIG. 2

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ATTORNEY

March 14, 1967 r, j. schoonman 3,308,488

BACTERIOSTATIC DRAWSHEET Filed May 3, 1965 2 Sheets-Sheet 2

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FIG. 5

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FIG. 6

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FIG. 7

INVENTOR

RICHARD J. SCHOONMAN

BY

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ATTORNEY

3,308,483

Patented Mar. 14, 1967

United States Patent Office

2

3,308,488

BACTERIOSTATIC DRAWSHEET

Richard J. Schoonman, 1020 E. Wendover Ave., Greensboro, N.C. 27405

Filed May 3,1965, Ser. No. 452,765

Claims. (Cl. 5—335)

This invention relates to bedcoverings and, more particularly, to an improved bacteriostatic or bacteria fighting drawsheet suited for use on hospital and other beds.

It has long been the practice for hospitals to utilize water-impervious rubber or plastic sheeting to protect the mattresses of their beds from the deleterious effects of water, urine, blood, etc. These protective sheets are conventionally arranged to present a smooth, flat top surface upon which the patient reclines and are quite uncomfortable to lie upon for extended periods of time, for the impervious sheeting blocks ventilation beneath the patient and tends to uncomfortably cling to the body of the patient. It, therefore, has become the practice to utilize the impervious drawsheet in combination with an overlying cotton or other pervious moisture-absorbent sheet interposed between the patient and the protective sheet in order to promote the comfort of the patient.

Unfortunately, the overlying fabric or cotton sheet tends to increase the danger of disease through reinfection or cross-contamination by serving as a breeding place for harmful bacteria such as Staphylococcus, Streptococcus, and other related gram-positive pathogens. The cotton sheet tends to become moist from the perspiration and other wastes excreted by the patient and the body heat of the patient keeps the moist fabric warm, thereby providing highly favorable conditions for the proliferation and growth of harmful bacteria. The bacteria are amply supplied with nutrients from the body wastes of the patient, but much of the body waste is acidic, and those bacteria which prefer more neutral conditions tend to migrate through the cotton sheet toward and onto the impervious drawsheet where less acidic conditions of moisture and warmth prevail.

The rapid and continued growth of colonies of bacteria on the impervious drawsheet and the cotton sheet is dangerous not only to the patient lying on the drawsheet but also to the hospital personnel and other patients. The patient immediately involved and the hospital personnel handling the contaminated drawsheets are endangered through direct infection while other patients and personnel are endangered through cross-infection. It is the practice in many hospitals to change the overlying cotton sheet periodically without changing or sterilizing the impervious drawsheet. Unfortunately, colonies of bacteria frequently remain on the impervious drawsheet despite efforts to remove them and continue to multiply and flourish when returned to the favorable conditions of warmth and moisture.

It has been previously proposed to combat the growth of bacteria by incorporating in an impervious drawsheet a bacteriostatic agent which tends to kill or inhibit the growth of harmful bacteria. United States Letters Patent No. 2,272,397 to Becher et al. discloses a smooth rubber drawsheet which has been permeated with the vapor of oxyquinoline and, when so treated, is said to inhibit the growth of Staphylococcus aureus and other organisms. The disclosure, however, teaches that the treated rubber sheeting is to be brought into direct contact with the skin of the patient in order to obtain the beneficial effects of the bacteriostatic agent. The disclosure is obviously impractical because of the extreme discomfort encountered in lying on a smooth rubber sheet, particularly while feverish. Also, the rubber itself tends, in use, to become brittle and crack thereby impairing the water imperviousness of the sheet in addition to become more uncom fortable. The beneficial effects of the sheeting continually lessen in use in that the oxyquinoline tends to evaporate or sublimate from the sheeting.

According to the disclosure in United States Letters 5 Patent No. 2,919,200 to Dubin et al., which disclosure is incorporated herein in its entirety by reference, it has been found that bacteriostatic compounds including Aptamer^ sold toy Monsanto Chemical Company, and hexacffloroC^phene, such as compound “G-ll,” manufactured by~S’TF~ jO dar Corporation of New York are compatible with polyolefins or plastics such as polyethylene and may be used to make bacteriostatic plastics which effectively kill bacterial outright or inhibit their growth.

It is an object of this invention to provide an improved 15 impervious drawsheet formed from a polyolefin plastic and treated with a bacteriostatic agent in accordance with said Patent No. 2,919,200, and having textured surface characteristics which improve the effectiveness of the bacteriostatic agent while contributing to the flexibility of the 20 impervious drawsheet and to the comfort of the patient.

It is a further object of the invention to provide a drawsheet of the type described which may be used in combination with a cotton sheet in the conventional manner and which will effectively retard the growth of bac25 teria and maintain the bacterial concentration at satisfactorily low levels.

It is a further object of the invention to provide a drawsheet of the type described which will retain its bacteriostatic qualities through several changes of the cotton 30 sheets.

A still further object of the invention is to provide a drawsheet of the type described which may be produced with sufficient economies to permit it to be economically destroyed after use by a patient. The disposable nature 35 of the improved drawsheet makes it possible to effect economies in the storage and handling of conventional impervious drawsheets.

Having set forth some of the objects of this invention, other objects and a fuller understanding of the inven40 tion may be had by referring to the claims and the following description in connection with the drawings wherein—

FIGURE 1 is a perspective view of a mattress having positioned thereon a protective, bacteriostatic drawsheet 45 according to the invention;

FIGURE 2 is an enlarged plan view of a portion of one side of the improved drawsheet;

FIGURE 3 is a sectional view taken substantially along the line 3—3 in FIGURE 2;

FIGURE 4 is a sectional view taken substantially along the line 4—4 in FIGURE 2;

FIGURE 5 is a plan view of the other side of the sheet from that shown in FIGURE 2;

FIGURE 6 is a sectional view taken substantially 55 along the line 6—6 in FIGURE 5;

FIGURE 7 is a sectional view taken substantially along the line 7—7 in FIGURE 5.

As shown in FIGURE 1, an impervious drawsheet, textured and treated according to the invention, is posi00 tioned across the mid-portion of a sheet covered mattress 12, and held in place by tucking its ends under the mattress in the usual way. The drawsheet 10 is preferably used in combination with an overlying cotton or other air-pervious and absorbent drawsheet 14, corre05 spending end portions of which are tucked under the mattress. The bedcoverings may also include a blanket 16 and top sheet 18.

The textured bacteriostatic drawsheet 10 is preferably made from a water-impervious film of a polyolefin such 70 as polyethylene which has incorporated or dispersed therein a compatible antibacterial or bacteriostatic agent such as hexachlorophene or Actamer in the manner

3,308,488 taught by United States Patent No. 2,919,200. More (Particularly, the bacteriostatic agent in dry particulated iform is preferably admixed in the range of 0.01% to 0.05% with powdered polyethylene. The mixture may be polymerized and extruded as a thin film, or alternatively, as a rod which is subsequently particulated and reextruded as a thin film in a manner well known in the plastic art. Having been extruded and calendered to any desired thickness (a 3 mil film being suggested as an example) the film may be fed, preferably while still warm, through a pair of embossing rolls which impart to the bacteriostatic plastic film the desired irregular or textured surfaces. The embossed bacteriostatic film may be cut as desired into conveniently sized drawsheets of 36 or 45 inches by 70 inches, as shown in FIGURE 1. If desired, the embossed bacteriostatic sheet may be of a size sufficient to cover the entire mattress.

Referring to FIGURES 2 through 7, greatly enlarged portions of respective sides of a drawsheet 10 textured according to the invention are shown to clearly illustrate the intaglio pattern embossed thereon. The obverse side 17 of the said drawsheet which is desirably positioned to be the upper or bacteria contacting surface is characterized by hollow protrusions 20 optionally of diamondshaped configuration which appear in relief and are spaced from each other by a network of communicating channels 22 defined on the surface 17 by walls 28 of the protrusions 20. The other surface 17' of the sheet 10 (FIGURES 5-7) is the converse of the side 17, the said side 17' being characterized by interconnected upstanding ribs 22' defined by walls 28' of spaced-apart depressions 20' which are the reverse of the hollow protrusions 20 rising from the obverse side 17.

In use, the protrusions and depressions tend to be flattened toward a common plane and it is desirable that they be of relatively small dimensions. A satisfactory size for the diamond-shaped protrusions 20 is that which includes walls having a length of about one-sixteenth of an inch, and a satisfactory width for the channels 22 is about one thirty-second of an inch. The depressions 20' and ribs 22' are correspondingly dimensioned. The overall thickness of the 3 mil film after embossing may be about 10 mils.

Thus textured, the amount of bacteriostatic agent which is dispersed in the polyethylene from which the walls 28, 28' are made is effectively added to that present in the protrusions 20 and depressions 20' and in the channels 22 and ribs 22', thereby greatly increasing the surface area of the bacteriostatic sheet regardless of whether the sheet is positioned top side up or bottom side up. Consequently, a larger quantity of the bacteriostatic agent is exposed than in the case of a smooth surface.

In use, the bacteriostatic agent applied according to Patent No. 2,919,200 tends to leach to both the top and the bottom surfaces of the drawsheet 10 to contact any bacteria adjacent thereto and either kill outright or greatly inhibit their growth. Further, any bacteria-containing moisture which may collect in the channels 22 (or in the depressions 22' if the sheet be inverted) so positions the bacteria that the bacteriostatic agent in the walls 28 and in the channels 22 may more quickly reach and effectively kill or inhibit the growth of the bacteria.

Therefore, it is seen that the bacteria tending to migrate away from the acidic conditions present adjacent the patient and toward the more neutral conditions on or adjacent the protective sheet 10 are killed or growth-inhibited by the bacteriostatic agent rather than being allowed to propagate, grow and spread back toward the patient through the fabric sheet 14. Thereby, the danger of the overall concentration of bacteria in the fabric sheet 14 increasing above the dangerous infection levels is reduced. Consequently, by the textured arrangement of the prospective bacteria contacting surface of the draw4 sheet 10, a much more effective and improved bacteriostatic drawsheet has been provided.

The textured sheet has a further beneficial effect in that such arrangement reduces the discomfort previously experienced in lying on a smooth water-impervious sheeting. This benefit is thought to arise from the fact that small pockets of air are disposed between the patient and the protective drawsheet.

While it is only necessary that one prospective bacteria contacting surface be textured with the pluralities of protrusions and depressions, certain beneficial side effects are noted when both the top surface and the bottom surface of the sheet 10 are textured.

First, where the sheet is textured on both sides, one need not worry about making sure that the sheet be positioned with the top side up, for either the top or the bottom side may serve as the bacteria contacting surface.

Also, it is much easier to impart the textured bacteria contacting surface to the plastic film as by embossing if both the top and the bottom sides may be textured or made irregular. Further, a thin film which has been embossed with corresponding patterns on both sides is more flexible, and, therefore, more comfortable than a thicker film embossed only on one side with correspondingly deep depressions so as to present the same total area of bacteria-contacting surface.

Moreover, a sheet is thereby provided which has both a top and a bottom frictional surface attributable to the pluralities of protrusions and depressions whereby the sheet is prevented from slipping from position on the mattress and from becoming untucked. Further, the overlying fabric drawsheet is prevented from becoming untucked by the irregular top surface.

Also, it has been found that comfort in lying upon the sheet is increased when the bottom surface is also irregular in that air is thought to become trapped under the protective sheet and, thereby, add to the resiliency of the protective sheet as positioned on the mattress.

While the sheet disclosed may be so positioned on the mattress that either side becomes the bacteria contacting surface, it is preferred that the bacteria contacting surface be characterized by protrusions spaced apart by communicating depressions, for it has been found that some air is allowed to pass between the protective sheet and the overlying fabric sheet as the patient lying thereon redistributes his weight thereby allowing some ventilation to the underside of the patient and increasing the comfort experienced in lying thereon.

Moreover, the positioning of the collapsible relief pattern toward the patient is advantageous in that it increases the effective bacteriostatic surface area presented to combat harmful bacteria.

There is thus provided an improved textured and bacteriostatic impervious drawsheet adapted for single-patient use which is capable of greatly reducing the danger of infection in hospitals.

In the drawings and specification there have been set forth preferred embodiments of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being defined in the claims.