MASQUE
TECHNICAL FIELD The present invention relates to a masque that provides cooling therapy to an area of body surface and notably may be used for patients recuperating from facial trauma such as surgery or injury.
BACKGROUND ART
It is well known in the medical profession that cooling of bodily tissues immediately after physical trauma or injury is necessary to reduce swelling of such tissues. A variety of ice packs and related devices are commercially available to provide such therapy. Therapy of facial trauma, however, involves unique considerations .
Human beings are much more sensitive in the areas of the face and head than in other areas of the body. An application of direct pressure to the face, particularly after surgery, can cause a patient to suffer additional discomfort beyond that incurred by the surgery. Traditional ice packs possess many characteristics that are disadvantageous when applied to patients who have suffered facial trauma.
Traditional water-filled packs are heavy. The weight of the pack increases the patient's discomfort during recuperation.
Traditional water-filled cooling packs often are frozen solid when applied to a patient's face. As such, the ice pack does not mold to the patient's features. The solid nature of the ice pack causes discomfort until the ice pack has warmed to the point where the frozen water inside the ice pack has melted. The solid icepack also may fail to provide cooling therapy uniformly because the frozen ice pack may not contact the patient's face in the absence of undue pressure.
A water-filled cooling pack which is not frozen solid before use generally does not remain cold for prolonged periods of time. The ability of a substance to store energy is termed specific heat. It can be advantageous to use liquid water because it has high specific heat, but it would be desirable to maintain water in a mobile rather than rigid state below 0°C. While it is known to mix water with sodium chloride (NaCl) or ethylene glycol (an additive commonly used in automobile anti-freezes) , the resultant mixtures obtained often are heavy. They, too, would cause increased discomfort to a patient who has suffered facial trauma. Although the solutions affect the specific heat of the water, the solutions may freeze sufficiently that rigidity is a disadvantage. For example, an NaCl solution progressively freezes during cooling as the temperature of the solution approaches -21°C. Thus, the known solutions do not fully address the concerns raised when one tries to provide therapeutic cooling to the face of a patient.
The disadvantages of known ice packs are so great that medical practitioners have suggested alternatives to conventional ice packs, such as advising patients to place bags of frozen vegetables on their faces to achieve the cooling therapy effect.
Accordingly, the present invention aims to provide a cooling pack that allows prolonged cooling therapy compared with conventional ice packs, and/or has reduced weight, and/or remains malleable at sub-zero temperatures.
SUMMARY OF THE INVENTION The present invention provides a masque comprising first and second layers which are fixed together to form a closed interior space, the interior space being occupied by a coolant comprising water, a polyhydric alcohol, and a water-soluble (or possibly a water-swellable) polymer.
A therapeutic masque may be designed to cover the entire, or
majority of the, face, or may be designed to only cool a certain part of the face, such as areas surrounding the eyes. The present invention also relates to masques that comprise two separate component masques, for example, one for most of the face and another, separate masque to cover the recesses of the patient's eyes.
The two layers which define the masque are preferably made from nylon or another plastics material, such as vinyl plastisols or polyurethane. It is most preferred that the material which forms the layers is itself such as to remain pliable at -20°C (e.g. a low-temperature plastics).
Furthermore, the masque may be provided with a cloth sheath separating the layers which form the interior space from the patient's face. Such a sheath may be removably attached to the rest of the masque, and may be disposable.
The masque may be formed so as to have a single interior space into which the coolant is placed, or the interior space may be divided by segmenting seals into a number of cells; these cells may be completely sealed in respect to one another or coolant may be allowed to flow from one cell to another.
The masque may further be provided with straps for securing the masque to the patients head. The straps may be made from elastic Velcro, or may be integral with the layers which form the interior space.
Preferably at least one of the layers is formed from a sheet material which has been shaped - notably by vacuum forming - so that it is no longer planar. This can enable the masque to have a more uniform thickness, greater than would be achieved with two planar layers joined together and distended by the coolant contained therein.
The water-soluble polymer is preferably organic, and the polyhydric alcohol preferably has at least three hydroxy groups (trihydric alcohol) , or has a carbon chain length of three or greater.
It is preferred that the amount of water soluble polymer in the coolant is 20% or less, more preferably 5% or less, and most preferably 2% or less. The weight of water preferably is equal to, or greater than, the weight of polyhydric alcohol, more preferably is in a ratio of 2:1 or greater, and most preferably 3:1 or greater.
Suitable water-soluble or water-swellable polymers include: hydroxyethyl cellulose, dextran, polyvinyl pyrrolidone, polyacrylamide, ficoll (a polymer of sucrose cross linked with ethylene chlorohydrin) , polyethyleneimine, polyethylene glycol and polypropylene glycol. The polymers may well contain saccharide residues, as in starch or chemically modified starch or in a cellulose or chemically modified cellulose.
The polymer should desirably serve to increase the viscosity, i.e. thicken, the mixture of water and polyhydric alcohol compared to viscosity at the same temperature without polymer.
Of the listed polymers, hydroxyethyl cellulose and dextran are preferred because they contribute to superior flexibility of the cooling medium at low sub-zero temperatures.
The polyhydric alcohol may be selected from the group of: glycerol, sorbitol, ribitol, xylitol, propylene glycol and butane diol. Of the polyhydric alcohols, glycerol is preferred. Glycerol is liquid yet viscous at room temperatures, and facilitates manufacture of the cooling medium as external heat does not have to be supplied in order to mix the components. Additionally, because glycerol resists crystallization at any temperature, glycerol contributes to improve flexibility at low
temperatures .
Masques according to the present invention may contain further ingredients in the coolants, such as biocides and colorants. An alternative to the use of biocides is to ensure that all the components of the coolant are sterilized before use - a convenient way of doing this is by boiling the coolant before filling the mask.
In general, the masque is lighter than conventional water-filled ice packs which provide the same cooling effect and is malleable even when cooled to, or below, freezing temperatures associated with water. Further, a masque according to the invention usually provides improved cooling therapy because it can be cooled to lower temperatures and remains cold for longer periods of time relative to water-filled ice packs of the same weight.
BRIEF DESCRIPTION OF DRAWINGS
Embodiments of the invention will now be described by way of example with reference to the drawings in which:
Figure 1 is a frontal plan view of a face masque of the present invention;
Figure 2 is a sectional view of the masque of Figure 1 without segmenting seals taken along the line II-II;
Figure 3 is a sectional view of the masque of Figure 1 with segmenting seals taken along the line III-III; Figure 4 is a frontal plan view of a first embodiment of an eye masque of the present invention;
Figure 5 is a sectional view of the eye masque of Figure 4 taken along the line V-V;
Figure 6 is a perspective view of a second embodiment of an eye masque of the present invention;
Figure 7 is a sectional view of the eye masque of Figure 6 taken
along the line VII-VII;
Figure 8 is a plan view of an alternative structural embodiment of a face masque of the present invention.
DETAILED DESCRIPTION
Turning now to FIGS. 1 and 2, there is shown a face masque 10 constructed in accordance with the present invention. Masque 10 is formed of a first and a second layer 12 and 14 each of which possesses an elliptical shape having dimensions sufficient for the masque 10 to cover a human face. The first layer and second layer 12 and 14 form a closed interior space 16 there between. The layers 12 and 14 may be sealed together around the periphery of the masque using techniques known in the art. Alternatively, the layers 12 and 14 may be formed as a continuous envelope structure. The masque 10 forms cutouts for eyes 20, nose 22 and mouth 24. The first and second layers 12 and 14 are fixed to each other along the edges of such cutouts to maintain the interior space 16 a closed one. A coolant is provided within the interior space 16.
In one embodiment, the first layer 12 is vacuum formed and so is non-planar with a greater width (as measured across the masque) than that of the second layer 14, the difference in widths forming a natural pocket structure. The interior space 16 defined thereby is larger than that of a masque formed from two sheets of the same dimensions and permits a greater volume of coolant to be provided therein. The degree to which the widths of the two layers differ is one factor in determining the volume defined thereby.
In addition, the difference in width between the two layers 12, 14 also permits the masque 10 to mold to facial features of a patient more readily. Viewed from above, a patient's face is generally semi-circular. In use, the second layer 14 of the masque 10 is placed on the patient's face. When the masque 10
conforms to the semi-circular features of a patient, the greater width of the first layer 12 permits the first layer 12 to take a greater circumference than the second layer 14 without requiring external exertion of pressure. For this use, the masque 10 has a front and a back; the first layer 12 is the front of the masque 10 and the second layer 14 is the back of the masque 10 to be placed on the patient.
The first and second layers 12 and 14 may be made of light, flexible materials. For example, in an embodiment, the layers 12 and 14 may be formed of twelve thousandth gauge vinyl. Accordingly, the layers 12 and 14 possess sufficient flexibility to mold to a patient's facial features without requiring external pressure to be applied. Such flexibility permits the masque 10 to cool traumatized tissues without imposing additional trauma thereon. In a preferred embodiment the layers 12 and 14 may be formed of polyurethane, preferably with a gauge of between 10 and 20. It is preferred that if the first layer 12 is vacuum formed it is made from 20 gauge polyurethane, whereas the second layer is preferably made from 10 gauge polyurethane.
Preferably, the first and second layers 12 and 14 may be provided with interior segmenting seals 30 over the surface of the masque 10. Segmenting seals 30 join the first and second layers 12 and 14 together by glued or welded bonds. The segmenting seals 30 divide the closed interior space 16 into a plurality of "cells" 32 (as shown in Figure 3) , interior chambers that inhibit migration of the coolant within the masque 10. The cells 32 may be closed entirely from each other.
Alternatively, the cells 32 may be closed only partially to permit a slow migration of the coolant there between. The arrangement of the cells 32 and the segmenting seals 30 may be such that the masque more easily conforms to the shape of the patient's face.
Optionally, the masque 10 possesses a cloth sheath 18 (shown in Figure 2) that separates a plastic layer 14 of the masque from the face of the patient. From the patient's perspective, the cloth sheath 18 diffuses the effect of the cold masque while permitting the masque to cool the patient's face. The cloth sheath 18 possesses cutouts for the eyes, nose and mouth corresponding to the cutouts of the two layers 12 and 14. The cloth sheath 18 preferably is removably attached to the layer 14 to properly orient the eye cutouts of the sheath 18 with those of the layers. The cloth sheath 18 should be made from a material that may be washed by typical domestic laundry process. In a preferred embodiment, the cloth sheath 18 is made of a light cotton material. In use, the cloth sheath 18 may be disposable to be replaced by other cloth sheaths.
The face masque 10 may be provided with a plurality of straps 40 to mount the masque 10 on a patient's face. The straps 40 may be made of elastic Velcro (Trade Mark) to facilitate mounting and removal of the masque 10 from the patient.
The interior space 16, 32 is filled with a coolant that absorbs heat during use. The coolant contains water, a polyhydric alcohol and a water-soluble or water-swellable polymer. The components are usually provided in such proportions that the coolant possesses the following characteristics: The coolant does not completely solidify at temperatures down to temperatures conventional to domestic freezers (-20°C) and below, i.e. it remains malleable, the components are completely miscible between -10 to 40°C, and the coolant possesses improved energy storage capacity over ice weight for weight basis.
A further structural embodiment of the face mask 10 is shown in figure 8, in which the interior space 16 is divided by segmenting seals 30, although completely enclosed cells are not formed. The segmenting seals slow the flow of the coolant within the interior space. The straps 40' are integral with the
first and second layers 12 and 14, and may carry Velcro pads 42 for ease of attachment of the masque 10 to the patient.
In a first embodiment of the cooling medium, it comprises a homogeneous mixture of 20% dextran, 40% water, and 40% glycerol. To test this mixture, it was enclosed in a vinyl bag so as to form a 5 mm thick flexible sheet weighing 120 grams, then cooled to -10°C. At such temperature, the sheet remained flexible. When exposed to air at 20°C, the sheet took longer than an hour to reach air temperature. The sheet was cooled to -20 °C and exposed to air at body temperature (37 °C) . Again, the sheet remained flexible. After about two hours, the sheet had reached a temperature of about 20°C.
In a second embodiment, the cooling medium comprises a solution of 80 parts per volume (ppv) water, 20 ppv glycerol and 1 parts per weight (ppw) hydroxyethyl cellulose. In order to assess this mixture, twelve ounces of the coolant was enclosed so as to form a sheet having a generally 6.4 mm (1/4 inch) thickness and cooled to a temperature of -26°C (-15°F) . At such a temperature, the coolant remained plastic, soft and ductile. To simulate the use of the coolant on a patient, an ordinary towel was placed on a hot plate set to 38°C (100°F) , a temperature that simulates inflamed facial tissues. The cooled prototype was removed from the freezer and placed on top of the hot plate and towel as a continuous mass. After four hours of exposure to the hot plate, the center of mass of the coolant had reached 18°C (65°F) . At 18°C (65°F), a face masque would provide a cooling effect to a patient' s face .
A masque containing the 80/20/1^ solution of the prototype coolant subject to the above test weighs 14 to 16 ounces. This is considered a light-weight masque. Thus, the present invention provides a light-weight face masque that remains soft and pliable at temperatures of less than -26°C (-15°F) and possess prolonged cooling effect.
Other combinations of the water, glycerol and hydroxyethyl cellulose were tested. A coolant made of 75 ppv water, 25 ppv glycerin and 1 ppw hydroxyethyl cellulose subjected to the same test above demonstrated similar benefits in that it remained pliable and soft at -26°C (-15°F) . When exposed to the 38°C
(100°F) hot plate as described above, the coolant's center of mass reaches 18°C (65°F) after three hours fifteen minutes.
The masque 10 may be adapted to receive optional eye masques 50 to ensure that cooling therapy is applied in the area of the patients eyes. An eye masque 50 is a pack placed over the patients eyes before the face masque 10 is applied. The surface of the .eye masque 50 may be a flat disk as shown in Figure 4 or may be donut shaped with an unobscured center area 58 as shown in Figure 6. The flat disk 50' obscures the patient's vision whereas the donut-shaped eye masque 50" does not.
As with the face masque 10, either eye masque 50 possesses first and second layers 52 and 54 defining a closed interior space 56. The first and second layers 52 and 54 may be continuously formed or may be bonded or welded together. The coolant occupies the interior space 56. The eye masque 50 may be enclosed by a cloth sheath 60 in a manner similar to the face masque 10 (shown in Figure 5) . For the donut shaped eye masque 50", the cloth sheath 60 possesses a cutout to permit the patient to see through the eye masque (not shown)
The present invention provides cooling therapy for persons who have experienced facial injuries and for cooling therapy following laser, plastic, oral or dental surgery. The face masque provides a cold compress to reduce swelling following such trauma. Additionally, the face masque may be used for treating headaches, aches or pains and can be used additionally for cosmetic therapies. The masque may be formed into a number of different shapes as the therapy dictates, such as flexible, cooled bandage and elastic stockings. The masque may be formed
as a partial masque to conform to a portion of a patient's face, Additionally, the invention may be formed as a general purpose cooling pack to provide therapy to other body parts.