WO2001074437A1

WO2001074437A1 - Surgical prep solution dispenser and method

Info

Publication number: WO2001074437A1
Application number: PCT/US2001/007635
Authority: WO
Inventors: Nicholas R. Baumann; Matthew T. Scholz; Donald L. Pochardt
Original assignee: 3M Innovative Properties Company
Priority date: 2000-04-03
Filing date: 2001-03-09
Publication date: 2001-10-11
Also published as: AU2001245571A1

Abstract

A dispenser for a surgical prep having a dispensing pad with a means for quickly and releasably gripping the pad. Conveniently, this means is a readily attachable handle. Most conveniently, the handle can be presented to the used in a sterile condition and that handle will easily attach the dispensing pad with the pad having to be touched directly. Using the handle, the pad is used to paint the prep solution onto the patient. The pad includes a metering layer having microreplicated pores so that substantially drip-free application can be accomplished.

Description

SURGICAL PREP SOLUTION DISPENSER AND METHOD

Technical Field This invention relates to liquid applicators having particular utility in the field of antiseptic skin preparation prior to surgery. More particularly, this invention relates to articles useful in applying pre-operative surgical scrubs or paints to skin.

Background of the Invention

Antiseptic preparation of patients for surgery conventionally includes a 3-10 minute scrubbing of the affected area with a soap solution followed by the application of a water-soluble antiseptic paint solution. These solutions are generally applied with saturated sponges that are attached to a blade or held with forceps. These sponges are often saturated by soaking them in open pans of solution. Sometimes sponges with attached handles are provided in a plastic pouch containing enough liquid to saturate the sponges. While inexpensive, these techniques are messy and offer little control over inadvertent dripping of the solution into areas where it is undesired. Since many of the available solutions contain active ingredients such as alcohol and iodine, which can be very irritating if allowed to pool on the skin, good control over the application has long been desirable. Over the years, devices have been developed in an attempt to prevent the dripping of solution associated with these early techniques, and to reduce the time required for application of the antiseptic solution. In particular, the Duraprep™ products commercially available from 3M Company of St. Paul, MN have enjoyed commercial success by providing substantially drip-free, convenient application. Coassigned U.S. Pat. No. 4,925,327, which is hereby incorporated by reference, describes a liquid applicator that incorporates a rigid, porous metering insert to regulate the flow rate of liquid disposed between the applicator handle and a foam sponge covering a major orifice of the handle.

The liquid to be dispensed is contained in a rupturable reservoir removably affixed at the other major orifice of the handle. Coassigned U.S. Patent 5,658,084, which is also hereby incorporated by reference, further discloses a liquid applicator where the liquid is contained in a frangible ampoule inside the body of the applicator. This ampoule is supported and protected by a deformable element that prevents unintentional breakage of the ampoule from impacts during storage and handling before use. The applicator is actuated by pushing at least a portion of the frangible ampoule through an aperture in the deformable element and into contact with a means for breaking the ampoule.

While these products have provided a considerable advance, they are complex to manufacture, placing them beyond the means of some health care consumers. The art could still benefit from an applicator that could provide convenient, substantially drip-free dispensing of surgical preps at a lower cost.

Other Background Art U.S. Pat. Nos. 4,415,288; 4,507,11 1; and 4,498,796 describe surgical scrub devices that include a liquid-containing, rupturable, cylindrical cartridge which is slidable within a tubular handle having one or two longitudinally oriented hollow spikes that communicate to recesses in the interior of a sponge. Sliding the cartridge in the tubular handle causes the spikes to rupture one end of the cartridge. Liquid from the cartridge flows through the lumen of the spikes to the sponge. To prevent rupture of the cartridge by the spikes from impact during, for example, shipping, an embodiment of the device incorporates an inwardly projecting shoulder in the tubular handle that may interfere with the sliding of the cartridge. Ease of actuation is also a potential problem with an applicator that requires puncturing a plastic cartridge.

U.S. Pat. No. 4,183,684 describes a fluid dispenser that includes a liquid- containing ampoule in a flexible housing. A porous pad element is disposed over the bottom opening. The liquid is released to the porous pad by crushing the ampoule through the flexible housing walls.

U.S. Pat. No. 4,957,385 describes a dispensing applicator having a wedge used for breaking a frangible ampoule.

U.S. Pat. No. 4,528,268 to Andersen et al. discloses an apparatus for testing the sufficiency of sterilization. It includes an ampoule containing a sterile liquid culture medium which is broken by the user when a plunger pushes the ampoule against an opening wedge.

U.S. Patent Nos. 4,415,288; 4,507, 1 1 1 ; and 4,498,796 describe a device that includes a liquid-containing rupturable cylindrical cartridge which is slidable within a tubular handle.

The device described in U.S. Pat. No. 3,847,151 includes a sponge mounted on a nozzle extending from a hollow handle which contains an antiseptic solution. The solution is dispensed into the sponge when a rupturable joint in the nozzle is broken and external pressure is applied to the flexible handle. The problems associated with the design of this device include the unreliability of the rupturable joint and the lack of control of the fluid delivery into the sponge. Inherent mass production variability makes the fabrication of a reliable rupturable joint based on stress concentration difficult. After the nozzle is opened, it is very difficult, in practice, to deliver precisely the correct volume of fluid to saturate the sponge without dripping. In addition, as the sponge is wetted by the fluid, its ability to entrain air is diminished.

U.S. Pat. No. 4,148,318 describes a device that includes an antiseptic solution contained in an integral reservoir with a frangible cover. Spikes affixed to a recess in the sponge pierce the cover to release the solution. The disadvantage of this device and other devices that include liquid-containing ampoules, such as those described in U.S. Pat. Nos. 3,891,331 and 4,183,684, is the absence of a means to control the delivery of fluid to the sponge. The absence of a means to control the fluid flow rate to the sponge limits the volume of solution that can be delivered without dripping.

U.S. Pat. No. 4,342,522 describes a roll-on dispenser which includes a porous open-cell foam membrane deformable by an applicator ball to regulate the dispensation of controlled amounts of powders. The amount of material dispensed is dependent upon the porosity of the membrane and the porosity of the membrane is dependent upon the degree of its deformation by the ball upon operation of the dispenser.

Summary of the Invention The present invention provides a dispenser for a surgical prep having a dispensing pad with a means for quickly and releasably gripping the pad. Conveniently, this means is a readily attachable handle. Most conveniently, the handle can be presented to the user in a sterile condition and that handle will easily attach the dispensing pad without the pad having to be touched directly. Using the handle, the pad is used to paint the prep solution onto the patient. The pad includes a metering layer having pores so that substantially drip- free application can be accomplished. The metering layer is preferably a pattern replicated porous material. Membranes may also be used as the metering layer material.

The dispenser includes a handle and a pad. such that the handle is adapted to be removably attached to the pad. There are a number of mechanical expedients that can be employed, but a hook and loop mechanical bonding system is presently considered preferred. In particular, a hook and loop mechanical bonding system can engage at low contact pressures and can engage even if the pad is already moistened with e.g. a liquid surgical prep solution.

The pad includes a core having absorbent or reservoir ability, a metering film covering at least a portion of the core, and a backing that supports the means for attaching the handle. Most conveniently, this will be the loop structure of a hook and loop mechanical bonding system. The metering film is preferably macroporous pores having a three dimensional structure.

Brief Description of the Drawings Fig. lis a perspective view of the dispenser according to the present invention;

Fig. 2 is a perspective view of the dispenser of Fig. 1, separated into major elements;

Fig. 3 is a plan view of a kit conveniently storing the dispenser along with the solution to be dispensed; Fig. 4 is a perspective view of an alternate embodiment of the pad of the invention;

Fig. 5 is a perspective view of an additional alternate embodiment of the pad; and Fig. 6 is a cross section view of the pad of Fig. 1.

Detailed Description Referring now to Fig. 1, a perspective view of the dispenser 10 according to the present invention is illustrated. The dispenser 10 includes a handle 12 and a pad 14. A backing 16, conveniently having the loop structure of a hook and loop mechanical bonding system, helps provide attachment of the pad 14 to the handle 12. A metering film 18 is provided on the opposite side of the pad 14. As shown in Fig. 1, pad 14 preferably, but not necessarily, is larger than the base of handle 12. This arrangement allows for soft edges and also facilitates prepping between digits since both surfaces 16 and 18 are available to prep.

Referring now to Fig. 2, the dispenser 10 seen in Fig. 1 has had the handle 12 separated from the pad 14 so that the hook structure 20 of a hook and loop mechanical bonding system can be seen on the pad contacting surface of the handle. While shown as a circle, pad 14 may be of any shape that makes prep application convenient. Shapes such as squares, ellipses, rectangles, ovals, etc., are contemplated.

Referring now to Fig. 3, a plan view of a kit 30 for conveniently storing the dispenser along with the solution to be dispensed is illustrated. The kit 30 includes a pouch 32, which conveniently has a conventional construction including a transparent upper layer 34 preferably heat-bonded around the periphery to a gas permeable lower layer 36.

Conveniently, the lower layer 36 is made from TYNEK spunbonded polyolefin. Such pouches are well known in the art, and permit the contents to be terminally sterilized by e.g. ethylene oxide gas. Pouch 32 may have alternative constructions but preferably has at least one gas permeable panel to allow sterilization. The handle 12 is stored in the pouch 32, along with at least one pad 14. Also within the kit 30 is a dish 38 and a container 40 holding surgical prepping solution. It requires about 13 ml of surgical prepping solution to paint the torso of a typical adult patient from chin to navel. Since some overage is needed to account for the fluid that will remain within the pad after the painting, the container conveniently holds about 26 ml of fluid. One example of the use of kit 30 follows: The circulating nurse opens the pouch

32, conveniently at the peel grip 42, and a scrub nurse removes the contents within the sterile area of the operating suite. The scrub nurse then opens the container 40 and dispenses surgical prepping solution into the dish 38, soaking the pad 14. The handle 12 is then attached to backing 16, and the now soaked but substantially drip-free pad 14 is then used to paint the surgical prepping solution onto a patient. Referring now to Fig. 4, a perspective view of an alternate embodiment of the pad 14a of the invention is illustrated. The pad 14a has a layer of metering film 18a as previously discussed, and backing 16a is also similar. In this embodiment, an additional partial layer 44a is present, bonded to the pad 14a along part of the outer periphery, but leaving an open edge 46a forming a pocket arrangement. To use this alternate means of releasably gripping the pad 14. the nurse seizes the open edge 46a with e.g. long handled surgical forceps, and uses the forceps in the manner of a handle to paint surgical prepping solution onto the patient.

Referring now to Fig. 5, a perspective view of an additional alternate embodiment of the pad 14b is illustrated. The pad 14b has a layer of metering film 18b as previously discussed, and backing 16b is also similar. In this embodiment a tab 48b, conveniently provided by adhering a folded strip of material to the backing 16b, is provided as an alternate means of releasably gripping the pad 14. Analogous to the embodiment of Fig. 4, the nurse seizes the upraised tab 48b with e.g. long handled surgical forceps, and uses the forceps in the manner of a handle to paint surgical prepping solution onto the patient.

A metering film 18 suitable for use with the present invention has a macroporous structure, preferably a replicated patterned structure. A polyethylene macroporous film that has a repeating frusto-conical three-dimensional structure, resembling an ordered array of funnels oriented with all of the funnels aligned in the same direction, is considered particularly suitable. A film of this type is commercially available from Tredegar

Corporation of Richmond, Virginia as Nispore brand film, product number S-6010025. This film has a structure resembling funnels having one side with large openings and the other side with smaller openings, and the orientation of these openings are uniformly structured. Other membranes may also be suitable for the film 18. The material described in U.S. Patent No. 3,929,135 (the entire contents of which are herein incorporated by reference) is believed to be suitable.

Optimal metering of a surgical prep containing an alcohol solvent, with minimum dripping of the surgical prep, was achieved when two layers of Nispore film were used and when these two layers were oriented such that the small diameter opening of one side of the film was directed towards the reservoir containing the prep solution and that the small diameter of the funnels of the second film were directed outward, towards the patient. That is to say, two layers of the same film were used, and these layers were ordered back-to- back such that the outward portion of the funnels presented the small diameter of the funnels. When the two layers of the Nispore film is ordered as described, the result is that the two films are able to support a pressure head of a low viscosity liquid, such as a surgical prep formed of an alcohol/water solution 70% isopropyl alcohol by volume, of one inch.

It should also be noted that the two film system as described will meter the solution through the pores controllably due to capillary action. Additionally, this construction creates a uniformly painted film because the fine structure of the funnels act as paint brush bristles act to create locally high regions of shear thus delivering smooth coatings.

Furthermore, when the painting motion is ceased and the pressure used to paint the solution onto the patient is relieved, the metering of the surgical solution stops and no liquid drips through the metering film due presumably to the capillary forces acting in the porous film(s). If the surgical solution used is a film forming solution such as DURAPREP brand, and should that solution dry onto the pores and block the pores, a gentle application of pressure onto the pad works to drive additional solution into the funnels of the pores. It is observed that the solvent in the prepping solution dissolves the film occluding the pores and opens the metering pores allowing a resumption of the painting of the prep. In this manner, the fine openings of the pores can be self-clearing. In summary, it has been discovered a structured film that supports a pressure head of a low viscosity, low surface tension liquid, and meters this liquid through the pores on demand. Because of this, the metering film, as described, controls liquid flow out of the prep solution absorbent core and onto the patient. Furthermore, this preferred embodiment impedes the dripping of the solution through the pores, aides in the painting/ film forming of the prep, is self-clearing should the pores become blocked with prepping solution, and provides a non-linting surface.

Referring now to Fig. 6, a cross section view of the pad 14 of Fig. 1 is illustrated. In this view it can be observed that metering film 18 is advantageously formed from two layers of macroporous, pattern replicated film, with layer 50 presenting the narrower ends of its frusto-conical projections towards the patient, and with layer 52 presenting the narrower ends of its frusto-conical projections towards absorbent core 54. In this view it can more readily be seen that the illustrated backing 16 has the loop structure of a hook and loop mechanical bonding system.

The absorbent core 54 is conveniently a nonwoven composite web. In particular, a nonwoven composite commercially available from 3M Company and sold as Thinsulate CS 150, a single scrim Thinsulate insulation having a basis weight of 150 g/πT, is considered suitable. Also considered suitable would a simple blown microfiber web having a basis weight of about 150 g/m^", a fiber diameter of less than 40 micrometers, preferably less than 20 micrometers. It is considered preferable that the web have a thickness of greater than 0.25 cm, preferably greater than 0.5 cm, more preferably greater than 1.0 cm. For best results, the solidity of the nonwoven web should be low. Solidity is calculated by comparing the nonwoven web's physical density to the density of the polymer used to make the web. The lower the solidity, the loftier, or thicker, the nonwoven web. Best results should be obtained when the solidity is less than 10% preferably less than 5%, more preferably less than 3%. For the CS 150 Thinsulate the basis weight is 150 g/m², the thickness is 0.8 cm and the polymer density is about 0.91 g/cc. The calculated solidity is 2%.

Many other absorbent cores may be possible, including non-woven carded webs, open cell foams, knit pads, such as gauze, woven pads, and the like. These pads can be made from synthetic or natural polymers. The backing material of the pad was chosen to have the loop structure and to be a liquid barrier so as to impede the flow of the surgical prep solution out of the back side of the pad when painting the prep onto the patient. A loop fabric/film extrusion bonded laminate combination is considered suitable. Other attachment means such as those described in U.S. Patent No. 5,364,367 (the entire contents of which are hereby incorporated by reference) may also be used.

It is also contemplated in the present invention that an additional layer of a fabric may be placed over the metering film 18. Such additional fabrics do not function as reservoirs but may aid in coating uniformity and drag reduction.

The handle is any molded plastic piece about 10-20 cm, preferably about 15 cm in length having an attachment means for the pad at the base, preferably a hook and loop attachment means, where the hook portion is found on the base of the handle. The base portion of the handle is at an angle of 45 degrees to the axis of the handle to most beneficially align the pad/base with the healthcare workers' hand/arm so as to ergonomically assist in holding and painting with the handle and pad system. A hook system, commercially available from the 3M Company as XMH-99235, is considered suitable .

With regard to the kit 30 within its sterilization pouch 32, it is important that the container 40 be gas tight; toxic byproducts may be formed if some surgical prepping solutions are exposed to ethylene oxide gas during gas sterilization. A polymer/metal film/polymer laminate tube made by Expac of Montvale, NJ has been found to be an exceptional barrier to penetration of ethylene oxide into the tube and is also an excellent barrier to evaporation of isopropyl alcohol and water out of the tube. Other polymer aluminum foil laminates, structures (e.g., polyethylene/aluminum foil laminates) may also be used.

Example 1 A dispensing pad was made by layering two layers of Tredegar Nispore film

(product number S-6010025) to one 0.8 cm thick layer of Thinsulate CS 150 and one layer of 3M extrusion bonded loop having the film backing. These four layers were then ultrasonically welded by delivering energy from a Dukane sonic welder set for 3.1 milli- inch peak-to-peak amplitude, with 750 watts power at peak and 90 psig between the aluminum anvil and aluminum horn.

This dispensing pad was attached to a handle having a circular base having a hook element commercially available as XMH-99235 from the 3M Company, the hook element on the handle engaging the loop element on the pad. Using the handle, the pad was dipped into a shallow dish containing Duraprep brand surgical prepping solution commercially available from 3M Company. At least 26 ml of solution was taken up. Using the handle, the pad was used to dispense the surgical prepping solution onto a human torso. A smooth, even application was achieved over the entire back of the patient from neck to waistline.

Example 2 The ability of a potential metering film to support a surgical prepping solution within the dispensing pad without dripping was assessed using a Prep Drip Test. A low- surface tension challenge liquid used to simulate typical surgical prepping solutions was prepared by mixing 70% isopropyl alcohol with 30% distilled water by volume. The test apparatus was a vented, hollow glass column. That is, the column of liquid had a free surface that was open to atmospheric pressure. The porous material to be evaluated was stretched over the downward end of the vented glass tube and held in place by rubber binders. A quantified height of the challenge liquid was brought into contact with the porous material, and the height or head is maintained for at least 15 seconds. If no drips were observed within 15 seconds, the quantified height was recorded. This challenge was repeated at greater column heights of liquid, using unchallenged porous films that are not pre-wetted with the challenge liquid, until dripping is observed.

The greatest height at which no dripping is observed for 15 seconds was recorded as the Prepping Solution Support Value of the porous material.

Example 3 A single layer of Nispore S-6010025 film was assessed using the test method of

Example 2. One series of tests was made with the narrow openings of its frusto-conical structure pointing away from the challenge liquid within the tube. These tests resulted in a Prepping Solution Support Nalue of 0.25 inch (6.35 mm). A second series of tests was made with the narrow openings of its frusto-conical structure pointing towards the challenge liquid within the tube. These tests resulted in a Prepping Solution Support Nalue of 0.50 inch (12.7 mm).

Example 4 A double layer of Nispore S-6010025 film was assessed using the test method of Example 2. In this series of tests, the narrow openings of the frusto-conical structure of each layer faced outward with respect to the other layer. To put it another way, the narrow openings of the layer closest to the challenge solution faced the challenge solution, and the narrow openings of the layer farthest from the challenge solution faced away from the challenge solution. These tests resulted in a Prepping Solution Support Nalue of 1.0 inch (25.4 mm). Example 5 A dispensing pad was made by layering two layers of Tredegar Nispore film X 6582 to a 390 g m² blown microfiber web made of Exxon 3505 polypropylene having a solidity of about 2 percent and one layer of Reemay Typar polypropylene spunbonded nonwoven having a basis weight of 54 g/m"^". The four layers were then ultrasonically welded by delivering energy from a Dukane sonic welder set for 3.1 milli-inch peak-to- peak amplitude, with 1700 watts power at peak and 90 psig (400-600 pounds force) between the titanium anvil and steel horn, immediately prior to the sonic welding cycle, and during the sonic welding cycle, a vacuum was applied to the anvil portion to form a pillow shape of the four layers prior to completing the welded edge. The vacuum assist to the anvil allows for a more pronounced pillow shape in the pad.

The weld is assisted by using a thermal barrier film such as PET (polyester) on the anvil side of the product. It is also possible to weld without the anvil thermal insulation layer by using a heated anvil (below the melt temperature of the polyethylene). This dispensing pad was attached to a handle using hot melt adhesive.

Using the handle with the pad glued in place, the pad was dipped into a shallow dish containing DuraPrep brand surgical prepping solution commercially available from 3M Company. At least 26 ml of the solution was taken up. Using the handle, the pad was used to dispense the surgical prepping solution onto a human back. A smooth even application was achieved.

Claims

What is claimed is:

1. An applicator for delivering surgical prepping solution onto mammalian tissue comprising: a pad having an exterior, the pad comprising an absorbent core having the capacity to receive the surgical prepping solution; a metering film having pores, said metering film being situated to afford fluid flow from the core toward the exterior of the pad and toward the mammalian tissue, the applicator being adapted to spread the surgical prepping solution.

2. An applicator according to claim 1 wherein the applicator further comprises a means for releasably gripping the pad.

3. The applicator according to claim 1 further comprising a handle, and a gripping means, wherein the handle comprises one element of a hook and loop fastening system, and wherein the gripping means is the complementary element of a hook and loop fastening system.

4. An applicator according to claim 1 further comprising a handle having a major surface that is capable of delivering surgical prepping solution to a patient at at least an outer portion thereof.

5. An applicator according to claim 1 wherein the metering film affords fluid flow in a direction from the core toward the exterior of the pad at a delivery direction fluid flow rate and the metering film affords fluid flow from a position external of said applicator toward said core at a pad loading fluid flow rate.

6. An applicator according to claim 1 wherein the applicator is a substantially drip free applicator.

7. A kit for prepping a patient for surgery, the kit comprising: a bottle for storing a predetermined amount of a surgical prepping solution, said bottle being constructed from a material capable of preventing almost any access of ethylene oxide to the surgical prepping solution during an ethylene oxide sterilization procedure; and an applicator comprising a pad having an exterior, the pad comprising an absorbent core having the capacity to receive a surgical prepping solution, a metering film affording fluid flow from the core to the exterior of the pad to spread the surgical prepping solution onto mammalian skin; and a manually graspable handle.

8. The kit according to claim 7 further comprising a dish for holding the surgical prep solution for absorption into the pad.

9. A method of prepping a patient for surgery, comprising the steps of:

(a) providing an applicator for surgical prep solution comprising a pad comprising an absorbent core; a metering film having pores for conducting fluid from the core to the exterior of the pad, the metering film adapted to spread the surgical prep solution onto mammalian skin;

(b) causing the pad to absorb surgical prepping solution; and

(c) contacting the skin of the patient with the metering film so as to dispense surgical prep solution onto the skin.