HK1024400A - Normothermic heater wound covering - Google Patents

Description

Normal body temperature heater band-aid

Technical Field

The present invention relates to a wound covering for the treatment of wounds, and in particular to a wound covering in which a substantial portion of the wound covering is not in contact with the wound and is capable of transferring heat to the wound. The wound covering provides good control of the ambient temperature, humidity and other conditions at the wound site.

Technical Field

As used herein, a wound is typically a laceration in the intact skin of a patient. Wounds may arise by different mechanisms. One of these mechanisms is through mechanical wound devices, such as cuts, tears and abrasions. There are many mechanical wound-inducing instruments, including kitchen bread knives, cullet, street stones, or surgeons' scalpels. When heat alone is not sufficient to produce a full-face burn, the different mechanisms cause mechanical wounds due to a combination of varying heat and pressure. The common consequences of these wounds are pressure sores (pressure sores), ulcers or pressure sores (bedsores), and the resulting mechanical damage over a longer period of time.

Another mechanism that causes wounds is the blood vessels at the wound site, including arterial or venous blood vessels. Blood flow through the injured area is significantly altered causing a second weakening of the final ruptured tissue, forming a wound. For reasons caused by arterial blood vessels, the main difficulty in treating wounds is the aerobic blood flow to the injured area. For venous vascular causes, the main difficulty is that fluid accumulates in the obstructed wound area, reducing the flow of aerobic blood. These vascular lesions are also chronic and form ulcerated matrix wounds, as these wounds represent skin phenomena of other underlying chronic disease processes, such as atherosclerotic vascular disease, congestive heart failure and diabetes.

Conventional wound protection layers (e.g., bandages) are used in mechanical packing to help heal wounds. These bandages generally pack the wound in direct contact with the wound. This form is suitable for acute, non-infectious traumatic wounds, but it must be borne in mind that bandages in direct contact with the wound may interfere with the healing process of the wound. This interference is particularly prevalent in chronic ulcer wounds because of repeated mechanical impact and the interaction of the bandage with delicate, pressure sensitive tissue within the wound.

Advantages (and documented advantages) known for treating wounds with heat include: accelerating blood flow through the skin and subcutaneous tissue, increasing oxygen partial pressure at the wound site, and enhancing immune system function (humoral and cellular transport, including migration of white blood cells and fibroblasts to the wound site).

However, it has been difficult to achieve treatment of wounds (including infected or clean) with heat therapy in practice. For example, heat lamps have been used, but this method results in dry wounds, in some cases even charring of the tissue due to high heat. Because of these and other difficulties, and because most sharp wounds often take a long time to heal, physicians no longer consider applying heat to wounds as part of the treatment process. It is widely accepted by medical practitioners that any disturbance in the natural process must be minimized before the natural process can fail. In addition, the effectiveness of antibiotics on infected wounds has been superior to other therapies for treating chronic wounds and localized infections.

French patent 1,527,887 to Veihan published on 29.4.1968 discloses a protective sheet with a rigid oval dome whose edge rests directly on the skin of the patient. One aspect of the Veihan wound protector is a single oval shaped heating element resting against the outer surface of the rigid dome and positioned at the periphery of the rigid dome. Veihan does not discuss the heating aspect except to indicate that this is an assembly.

The advantages of controlling other environmental parameters around the wound site are not well known. The advantages of controlling moisture at the wound site and isolating the wound have not been widely studied and documented.

While the benefits of heat application to wounds are generally recognized, it is not known what type of heating should be used or applied. Historically, heat was supplied at higher temperatures for the purpose of raising the body temperature of wounds. These higher temperatures often result in increased tissue damage in addition to the intended wound treatment and healing objectives. Thus, there is a need in the art for a wound treatment regimen that incorporates a safe and reasonably priced heating regimen that is beneficial for wound healing.

Disclosure of the invention

The present invention discloses a method of treating a wound with heat based on physiological understanding. For purposes of this disclosure, the normal core temperature of a human is defined as 37 ℃. + -. 1 ℃ (36 ℃ -38 ℃), which represents the normal core temperature range of a human. For purposes of the discussion and disclosure of the present invention, the normal core temperature is the same as normal body temperature. Skin temperatures are typically between about 32 c and about 37 c, depending on ambient temperature, the insulating garment, and the body part. From a physiological point of view, a skin temperature at the distal end of a healthy leg of 32 ℃ is moderate hypothermia. The skin temperature at the distal end of a patient's leg with vascular defects may normally be only 25 c, which is a severe hypothermia.

One fundamental physiological premise is that at normal body core temperatures, cellular physiological functions, biochemical and enzymatic reactions are optimized in the human body. The importance of this premise can be seen from how tightly the core temperature is regulated. When the core temperature varies by only + -0.1 deg.C, a normal tempering response will occur. However, as mentioned above, skin is often hypothermic and changes temperature. For example, the skin of the torso is often only slightly hypothermic, while the skin of the lower parts of the legs is always hypothermic. Therefore, wounds and ulcers of the skin are often hypothermic, regardless of the body site. Hypothermia in the skin reduces cellular function and biochemical reactions, preventing wound healing.

The effects of hypothermia on healing are well known. Some regulatory systems in the human body, such as the immune system and coagulation, have effects of platelet function and coagulation (cascade) receptor hypothermia. Patients with hypothermic wounds experience more infections that are more difficult to treat, prolonged bleeding time, and more blood transfusions. All of these complications add to the cost of disease and patient treatment and, to a lesser extent, increase the likelihood of death.

It is an object of the present invention to raise the temperature of wound tissue and/or tissue surrounding the wound to normal body temperature to achieve a better healing environment. The present invention is not "heat therapy" per se, which means heating tissue above normal body temperature to high temperatures. And the present invention refers to elevating the wound tissue and tissue surrounding the wound to normal body temperature without exceeding normal body temperature.

Normothermic heating has historically not been considered a treatment by the medical community. Many physicians consider hypothermia to be protective and therefore desirable. The present study shows that the commonly held notion that hypothermia is at least beneficial to health or may be beneficial for wound healing is incorrect.

The present invention is a wound covering for use with a selected treatment area (e.g., including at least a portion of the selected treatment area, the selected wound area) of a patient's body. The selected treatment area may also include a portion of the area closest to the wound, referred to as the periwound area. The wound covering includes a heater adapted to provide heat to a selected treatment area; a connector for connecting the heater in a non-contact position over the selected treatment area; and a heater controller connected to the heater and further comprising a heater energy source to control the temperature of the heater in a temperature range from ambient temperature to about 38 ℃. The ambient temperature is the ambient temperature immediately surrounding the selected treatment area, i.e. the temperature of the bed, the air in the room, the patient's clothing, etc., and not the temperature of some part of the patient's body.

The heater may be selected from several types of heat sources, such as a direct hot gas over the selected treatment area and a bank of electric heaters placed in close proximity to the selected treatment area. The electric heater group is suitable for being constructed into thin layers of different sizes and geometries or into point sources. The present invention contemplates that several different sizes and geometries of heaters can be provided. The present invention is flexible to provide both uniform heating over the entire selected treatment area and non-uniform distributed heating over selected portions of the selected treatment area. Alternative heat source embodiments may include hot water pads, heat generating chemical heating pads, phase change salt pads, or other heat source materials.

The present invention contemplates that the controller can control both the temperature and the duration of heating. The control can be manually controlled or fully automatically controlled. Manual control contemplates that the controller maintains the operator selected temperature at all times as long as the operator turns on the heater. The more automated mode allows the operator to enter a duty cycle, set an operating temperature, and determine a treatment cycle and treatment sequence. As used herein, a duty cycle is a period measured from the beginning of the period to the end of the period when the heater is heating. The heater cycle is a single full on/off cycle measured from the beginning of one duty cycle to the beginning of the next. Thus, a duty cycle may also be expressed as a percentage or ratio of on time to off time. Multiple heater cycles are used to maintain the heater temperature at the set point within a selectable temperature range during the treatment cycle. The treatment cycle is defined as an "on" period consisting of multiple heater cycles and an "off" period equal to the heater remaining off for an extended period of time. The treatment sequence as used herein is often a longer period of time comprising a plurality of treatment cycles, which is longer than an extended period of time, most notably up to one day. The present invention contemplates any time period as a treatment sequence, including one treatment cycle or more than one treatment cycle.

The present invention also contemplates a number of modes of program control including peak heater temperature for a duty cycle and/or treatment cycle, average heater temperature for a duty cycle and/or treatment cycle, minimum heater temperature for a duty cycle and/or treatment cycle, duty cycle ratio, treatment cycle length, number of duty cycles in a treatment cycle, and number of treatment cycles in a treatment sequence. Different duty cycles within a treatment cycle may be programmed to have different peak heater temperatures throughout the treatment cycle and/or the heater cycle may have an average heater temperature. Different treatment cycles within a treatment sequence may be programmed to have different peak heater temperatures and/or average heater temperatures within each treatment cycle. The wound covering control is operator programmable or may have a preprogrammed duty cycle, treatment cycle, and treatment sequence selected by the operator.

The preferred form of wound covering includes an attachment member which acts as a peripheral sealing ring and which completely surrounds the wound and the area surrounding the wound, i.e. the selected treatment area. The upper surface of the peripheral sealing ring is spanned by a continuous layer which is preferably transparent and substantially impermeable, although the invention also foresees the use of gas permeable layers in some cases. Once positioned, the sealing ring and the thin layer define a wound treatment space surrounding the wound. In addition, a thin layer spanning the peripheral sealing ring may seal the periphery of the sealing ring and act as a barrier over the wound treatment space. Alternatively, the heater may be incorporated into the barrier layer, or the barrier layer may be incorporated into the heater. An adhesive and release-compatible liner is applied to the lower surface of the peripheral seal ring to facilitate application of the wound covering to the patient's skin.

The barrier layer may comprise a pouch suitable for housing an active heater. Another form of the invention is to deliver heated gas from a remote heat source to a wound treatment space. In active heater embodiments, a constant thermal controller and/or pressure sensitive switches may be used to control the heating effect of the heater. Passive heating embodiments are also contemplated by the present invention. These passive forms of devices include thermal shields that act to maintain body heat within the treatment space. These reflectors or spacers may be placed in pockets formed in the barrier layer. Each of these embodiments of heating promotes wound healing by maintaining a generally high temperature at the wound site and controlling the temperature.

In general, the peripheral seal is made of an absorbent material that can act as a reservoir to hold and/or disperse moisture within the treatment space, increasing the moisture content at the wound site. The reservoir may also contain and deliver drugs or the like to promote wound healing.

The present invention contemplates raising the hypothermic skin temperature and the temperature of the subcutaneous tissue of a selected treatment area to a temperature near normal body temperature. The purpose of the device is to create a more normal physiological condition, in particular a condition closer to normal body temperature, for better wound healing, in the wound tissue and the tissue surrounding the wound in the selected treatment area. The present invention proposes the use of an active heater, but the function of the heater can be described as more appropriate to "protect", i.e. to prevent heat loss by providing a heat source to counteract the effect of heat loss.

The concept of a protective heater is straightforward. The protective heater is heated to approximately the same temperature as the adjacent heated body. Because the heat must flow to the low of the temperature gradient, it can only be lost to the cooler body surface. The temperature of the protective heater is no lower than the temperature of the adjacent body and thus does not receive heat from the adjacent body. The normal temperature gradient of the tissue is from about 37 ℃ deep in the core of the body down to about 32 ℃ at the surface of the skin. With the protective heater, the heat loss directly from the wound and the tissue surface surrounding the wound is significantly reduced. This reduction in localized heat loss causes the 37 ℃ core temperature zone to migrate outward toward the skin, and the core temperature to surface temperature gradient is reduced because the core temperature zone temperature is close to the surface temperature of the protective heater zone. The protective heater acts much like a perfect insulator, providing an environment suitable for wound insulation in the way heat flows out of the core. The protective heater of the present invention has an additional advantage over near perfect passive isolation, which requires the use of bulky isolation materials that are several inches thick. Such a cumbersome covering of the wound is not practical for proper wound treatment.

For example, the use of the "protective" heaters of the present invention on a wound in the lower part of the knee, which may be starved, raises the temperature of the wound from ambient to 38 ℃ (including within normal body temperature). It is clear that due to the hot mass of the leg, blood flow through the leg and congenital lack of heat transfer, the result is that the wound and tissue surrounding the wound are often at a temperature below the operating temperature of the "protective" heater and possibly below the core temperature of the patient.

In contrast, general topical hyperthermia (e.g. thermos, hot pad, chemical heater, infrared lamp) delivers temperatures above 46 ℃ to the skin. Conventional hyperthermia aims at heating the tissue above normal temperature to a high temperature.

The invention differs from infrared lamps in two ways. First, the present invention comprises a dome over the wound that is relatively impermeable to the transmission of water vapor. After the bandage is applied, the moisture evaporates from the skin or wound and the air in the cover quickly reaches 100% relative humidity. Now the inside of the dome of the invention is warm and humid. For example, a 2.5 square inch piece of bandage requires only 0.0014g of water to saturate at 28 ℃. When the air is saturated, no further evaporation occurs and, therefore, no drying of the wound occurs. This equilibrium state will be maintained as long as the bandage is applied to the patient.

When heating is provided by the preferred embodiment of the present invention, the absolute amount of water required to reach 100% relative humidity is slightly increased due to the greater ability of hot air to retain moisture. However, the air in the bandage dome also quickly reaches a water vapor saturation state, and thus no further evaporation occurs. For example, a 2.5 square inch bandage of the present invention requires only 0.0024g of water to reach saturation at 38 ℃. Excess water is absorbed by the foam loops but remains in the bandage. The closed dome is designed to maintain 100% humidity above the wound, which also prevents evaporation due to heat generation. As long as the moisture in the bandage is retained, heat therapy can theoretically continue indefinitely without the wound drying out. In contrast, when infrared lamps are used, the wound is cracked open and exposed to the environment, with the result that the wound is excessively dry, increasing tissue damage.

Secondly, the invention operates at low temperatures (from ambient to 38 ℃). This produces minimal heat to the skin. In contrast, infrared lamps are operated at temperatures in excess of 200 ℃. The high temperatures to which these lamps heat the wound can cause thermal damage to the wound tissue.

At the low (normothermic) operating temperatures of the present invention, minimal heat is transferred to the skin. The low wattage heater provides insufficient heat transfer to the tissue, thermal mass of the tissue, and blood flow (albeit significantly reduced), all of which prevent the wound temperature from reaching the heater temperature. The hypothermic wound tissue heats up due to the "migration" of the temperature of the core temperature zone of the body to the local wound area.

The following data record the tissue temperature generated by the heater heating at 38 ℃ in accordance with the present invention:

	mean value of	Highest value
			Normal full of human skin	36℃	36℃
Foot ulcer of arterial/diabetic patients	32℃	35℃
			Leg/foot ulcers in silent/arterial patients	33℃	35℃
Non-full person mode	35℃	35℃

The wound on the underfilled leg reached a stable average temperature of 32-33 ℃ when heated with a 38 ℃ heater. Instead, the skin was normally filled to 36 ℃. Special attention is paid to these data in contradiction to the assumption that less filled tissue can reach higher temperatures than normally filled tissue. This result demonstrates the physiological finding that core temperature migration into the local wound area, and that a reduction in the core temperature to surface temperature gradient is responsible for a significant increase in wound temperature. The regulation of the core temperature is mainly dependent on the degree of filling, and thus the migration of the core temperature zone is also mainly dependent on the degree of filling. Underfilled tissue does not reach normal body temperature. The unfilled leg is cooler than the normally filled leg, and therefore, the unfilled leg effectively constitutes a deeper hot pocket.

Wound healing trials are currently being conducted to study patients with chronic arterial and/or venous ulcers in the lower leg. These patients have suffered from these ulcers for many months or even years, despite their invasive drug and surgical treatment. Of the 29 patients enrolled, 24 had completed the study protocol or were still under treatment. Of these 24 patients, 29% healed completely and 38% reduced wound size significantly within 2-5 weeks of treatment with the present invention.

It is known that the effect of tissue normothermia is to induce some degree of vasodilation, which increases local blood flow. This view has been demonstrated by preliminary data collected during the trial of the present invention, i.e., the present study of the effects of normal subjects and wound healing. An additional effect is to increase the oxygen partial pressure (P) of the subcutaneous tissue_sqO₂) The oxygen partial pressure is an indirect indicator of the tissue state. P_sqO₂The higher the value, the greater the likelihood that the tissue will benefit and promote the healing process. Some of the results of these studies are listed in tables 1-4.

In conducting the studies represented in tables 1-4, the wound patch of the present invention was placed over the skin. The temperature of the subcutaneous tissue is then measured over time. From-60 minutes to 0 minutes mark, the heater is turned off to obtain a baseline temperature. At the 0 minute mark, the heater was turned on and its temperature was held constant for 120 minutes while the heater was turned off. Temperature measurements were recorded during this 120 minutes and 180 minutes after the heater was turned off. As shown in table 1, as the heater was turned on to 38 ℃, the temperature of the subcutaneous tissue rapidly increased from about 34.3 ℃ to about 36 ℃ after the first 30 minutes. After the next 90 minutes, the temperature of the subcutaneous tissue continued to rise slowly to about 36.7 ℃. After turning off the heater, the subcutaneous tissue temperature was reduced to 35.9 ℃ and maintained fairly uniformly at that temperature for at least 120 minutes.

Table 2 lists the skin temperature data collected in the wound coverings of the present invention over the same time periods as table 1. The overall curve shape is similar to the subcutaneous tissue temperature curve. The baseline temperature marked at 0 minutes was about 33.5 ℃. After turning on the heater to 38℃, the skin temperature rose rapidly to about 35.8C in the first 30 minutes, and slowly to 36.2C until heating was stopped for 120 minutes. After turning off the heater, the skin temperature was reduced to about 35 ℃ and maintained at that temperature for at least 2 hours.

Table 3 lists laser Doppler (Doppler) data collected from tissue during the experiment, which correlates with blood flow through the local area treated with heat. The baseline flow was approximately 80ml/100g/min, peaking at about 200ml/100g/min during the first half of the heating period. During the second half of the heating time, the flow "normalized" returned to the baseline and remained around the baseline for the remainder of the measurement period.

P_sqO₂The changes in (A) are shown in Table 4. Baseline P when heating begins_sqO₂About 75, steadily rising during heating, to about 130 when heating is complete. Although the heating was stopped for 180 minutes, P was present for the remaining period of time during the measurement_sqO₂And remain at this level. By heating P_sqO₂The added benefit of the boost continues until some time after the active heating ceases. After the heating ceases, the wound will continue to benefit from the heating effect for a considerable period of time. The conclusion of this study of the present invention is that constant heating is not required, as long as one or several cycles of heater treatment are delivered, which may or may not be part of a larger treatment sequence.

Our initial human clinical data indicate that heat is applied to blood flow and P_sqO₂Is at least 1 hour longer than the actual duration of heating. In addition, we have noted that periodic heating appears to be more effective for wound healing than continuous heating. Thus, it is recommended that the heater cycle (e.g., 1 hour "on", 1 hour "off") be on for a total heating time of 2-8 hours per day for a treatment cycle as a treatment sequence.

The 29 patients treated with the combined cycle have shown to date no signs of skin damage due to heat at 38 ℃. In addition, none of these wounds exceeded 35 ℃ tissue temperature, with an average wound temperature of 32-33 ℃. The present invention raises the temperature of the wound to near normal body temperature, but on the underfilled legs, the tissue does not reach normal body temperature.

Brief description of the drawings

The objects, advantages and features of the present invention will be more readily understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

fig. 1A is an exploded view of a wound covering of the present invention;

FIG. 1B shows an assembled view of the wound covering of FIG. 1A;

FIG. 2A is another wound covering;

FIG. 2B is a view of the alternative wound covering of FIG. 2A with a passive heating element inserted therein;

fig. 3A is an exploded view of another wound covering;

FIG. 3B is an assembled view of the wound covering of FIG. 3A;

fig. 4 is a side view of a wound covering;

fig. 5 is an enlarged top plan view of the wound covering;

FIG. 6 is an enlarged cross-sectional view taken along line 6-6 of FIG. 5;

FIG. 7 is a bottom view of the wound covering of FIG. 4;

fig. 8A is an exploded view of another wound covering;

FIG. 8B is an assembled view showing air flowing through the wound covering;

fig. 9A is a perspective view of another wound covering;

FIG. 9B is a side view of the wound covering of FIG. 9A;

FIG. 10 is a perspective view of another wound covering;

fig. 11A is a perspective view of another wound covering;

FIG. 11B is a side view of the wound covering of FIG. 11A;

FIG. 11C is a view of the wound covering of FIG. 11A;

fig. 12 is a perspective view of another attachment arrangement for a wound covering;

FIG. 13A is another attachment assembly for a wound covering;

FIG. 13B is a side cross-sectional view of the wound covering of FIG. 13A;

FIG. 14 is a diagram of a rigid attachment member attached to a wound covering;

FIG. 15 is another fluid inflow tube of the wound covering;

FIG. 16A is a view of a two-layer barrier wound covering;

fig. 16B is a side view of the wound covering of fig. 16A;

FIG. 17 is another wound covering;

FIG. 18A is another wound covering;

fig. 18B is a side view of the wound covering of fig. 18A;

fig. 19 is a side view of another wound covering;

FIG. 20 is a schematic diagram of an embodiment of the present invention;

FIG. 21A is a block diagram of an alternative embodiment of the heater arrangement shown in FIG. 20;

FIG. 21B is a block diagram of an alternative embodiment of the heater arrangement shown in FIGS. 20 and 21A;

FIG. 21C is a block diagram of an alternative embodiment of the heater arrangement shown in FIGS. 20, 21A and 21B;

FIG. 21D is a block diagram of an alternative embodiment of the heater arrangement shown in FIGS. 20, 21A, 21B and 21C;

FIG. 22 is a sample graphical representation of the operational flow of an embodiment of the present invention, such as the embodiment shown in FIG. 20;

FIG. 23 is a sample graphical representation of another operational procedure of an embodiment of the present invention, such as the embodiment illustrated in FIG. 20 of the procedure depicted in FIG. 22; and

FIG. 24 is a sample graphical representation of another operational procedure of an embodiment of the present invention, such as the embodiment shown in FIG. 20 using the procedures depicted in FIGS. 22 and 23.

Best mode for carrying out the invention

The present invention is directed to a non-contact wound covering for controlling the local environment of a wound site of a patient. Wound sites include those areas of the patient's skin that are apparently referred to as the wound and the area around the wound immediately adjacent to the wound (e.g., the selected treatment area of the wound site). The wound plaster prevents the wound from being polluted by external environment substances, and also prevents the wound part from being interfered by pollutants in the surrounding environment (namely hospital ward) of a patient. The treatment volume formed proximate the wound site may be controlled to create an optimal environment for wound healing. The term "wound" as used herein generally refers to a surgical incision, ulcer, or other scar or breach in the skin.

First, a substantially vertical wall is provided to surround a selected treatment area on the surface of the patient's skin. The vertical wall provides an upper surface to support the lamina across the wall from above the wound surface; and a lower surface adapted to be attached to the skin of a patient. This structure is commonly referred to as a connector or perimeter seal. Together, these elements form a wound treatment space between the thin layer and the surface of the selected treatment area. The thin layer does not contact the wound itself and mechanical stress on the skin tissue is minimized, thus promoting healing. The lower surface adapted for attachment to the skin may include an adhesive, releasable liner assembly to facilitate attachment of the wound covering to the skin of a patient. The invention proposes the use of a heater whereby the sheet may comprise a heater in the form of a sheet formed from, or comprise a heater in the form of a sheet in some part of the sheet. The thin layer also includes the function of completely surrounding the wound treatment space as a barrier.

According to the invention, the climate in the wound treatment space can be controlled. Temperature, humidity and gas composition are typically controlled (e.g., to increase oxygen, nitric oxide or ozone). Also aerosolized drug or compound may enter the space. The above list is an example of climate control that may promote wound healing and is not meant to limit the scope of the present invention. Those skilled in the art will appreciate that various other climatic factors may be controlled within the treatment space of the present wound covering system without departing from the scope of the invention.

Fig. 1A shows an exploded view of wound covering 50. In this embodiment, the peripheral seal ring 52 is generally square in shape. The peripheral seal 52 is intended to be attached to the intact skin surrounding the selected treatment area by adhesive 56. In this embodiment, the adhesive 56 is a layer of adhesive hydrogel. In addition, the peripheral seal 52 is preferably constructed of an open-celled hydrophilic foam having a sealed outer surface 58 that isolates the wound from the environment. The peripheral seal ring is made of a material that can conform to the curved surface of the patient's body. The inner surface 60 of the sealing ring 52 is preferably porous or absorbent so as to form a container to contain and release moisture or water vapor into the air in the treatment area 62 to create a high moisture environment if desired. In addition, the hydrophilic absorbent properties of the peripheral seal 52 absorb fluids and blood secreted from the wound.

The layer 64 is preferably attached as a barrier to the upper surface 66 of the peripheral sealing ring 52 to seal the treatment area 62. The sheet 64 is preferably formed of a flexible synthetic polymer film such as polyethylene, polyvinyl chloride, polyurethane or polypropylene. In addition, other natural and semi-synthetic polymeric films suitable for medical applications, such as cellulose and cellulose acetate, may also be used. A wound tracking grid 68, also constructed of a substantially transparent flexible material, may optionally be used as sheet 64, or attached to sheet 64 to facilitate wound therapy management, so that the physician can outline the wound to help track the wound healing process. The wound tracking grid preferably contains a marking field 70 to identify the patient, the date when the wound is tracked, and other medical data.

Those skilled in the art will appreciate that the spacing of the peripheral seal 52 will depend on the structural strength of the support material and the amount of fluid desired to be absorbed. The overall area of the peripheral seal 52 is also dependent upon the size of the wound size. For example, a larger wound and a more flexible protective layer would require a thicker seal so that the central portion of the protective layer does not contact the wound.

The upper surface 66 of the peripheral sealing ring 52 is preferably sealed by a barrier layer 64 that extends over the entire area of the upper surface 66 (see fig. 1A and 1B). The adhesive 56 that bonds the peripheral seal 52 to the intact skin surrounding the selected treatment area 54 may be of any form, however, it is preferred that the adhesive be a two-sided hydrogel that bonds to the lower surface 72 of the peripheral seal 52. Such adhesive 56 can adhere the peripheral seal 52 to the skin of the patient. Finally, the peripheral seal 52 may serve as a reservoir to hold moisture or medication within the treatment volume 62 so as to maintain a high humidity of the air within the volume. Water may be added to the peripheral seal 52 at any time during the treatment period.

Those skilled in the art will appreciate that the outer ring seal 52 can be used in different shapes and sizes to fit different wounds. The shape may include a circle, a square, or a rectangle. Although it is preferred to formulate the wound covering as a single component, it will be apparent that the individual pieces of peripheral sealing ring material may be assembled in any shape necessary to form a periphery around the wound area. Likewise, the barrier layer 64 and wound tracking grid 68 may be formed as a large sheet that can be cut to the desired size and attached to the peripheral sealing ring.

Fig. 1B is an assembled view of the wound covering 50 of fig. 1A. To prepare the assembled product, release liner 74 of FIG. 1B is attached to adhesive 56 of FIG. 1A. The releasable liner 74 may span the entire lower surface of the protective layer to maintain the sterility of the treatment volume 62. Release liner 74 preferably has gripping tabs 76 to facilitate removal of release liner 74 from wound covering 50 prior to application of wound covering 50 to the skin of a patient.

Fig. 2A and 2B illustrate another embodiment of the invention in which treatment space 62 employs a passively heated wound covering 80. Because the patient's skin surface continuously radiates heat, the insulating properties of the trapped air within the treatment volume 62 will result in reduced heat loss. By incorporating an infrared reflector 82 above treatment volume 62, infrared heat radiated from the body can be reflected back onto the skin to increase passive heating.

The edges 84 of the wound tracking grid 86 are preferably not attached to the barrier so as to form an envelope or pouch 94 between the wound tracking grid 86 and the barrier layer. A sheet of reflective sheeting 88 may be inserted into the pocket 94. A thin layer of barrier material 90 may be selectively attached to the foil layer 88 to enhance heat retention and provide additional resiliency to the foil layer 88. Tabs 92 are preferably attached to infrared reflector 82 to facilitate insertion and removal of infrared reflector 82 into and out of pouch 94 and wound covering 80.

Fig. 3A and 3B illustrate another preferred embodiment non-contact wound covering 108 using active heating of treatment volume 112. With the heater assembly 100, the wound can be safely and conveniently heated. The heater assembly 100 alternately includes a pressure sensitive switch 102, a barrier layer 104 and a sheet heater 106.

The pressure sensitive switch 102 may optionally be laminated to the upper surface of the heater assembly 100. The purpose of switch 102 is to turn off the power to sheet heater 106 in the event that an external force is applied to wound covering 108 and the force is sufficient to contact sheet heater 106 to the underlying skin or wound. This configuration prevents the possibility of heat and pressure simultaneously acting on the skin. It is known that the combination of heat and pressure can produce burns even at low temperatures (40℃.) because the pressure prevents blood flow into the skin and the skin is susceptible to thermal damage. The pressure sensitive switch 102 preferably covers the entire heater assembly 100 so that pressure applied anywhere on the heater assembly surface 100 will deactivate the sheet heater 106.

Those skilled in the art will appreciate that many devices are suitable for use as the pressure sensitive switch 102. A force sensitive resistor, similar to a membrane switch, that changes resistance in the opposite direction in response to an applied external force, is an example of a pressure sensitive switch. This type of device has the significant advantages of low cost, flexibility and durability. Other pressure sensitive switching devices may also be used.

Another safety feature contemplated by the present invention is a monitoring function that can be used to monitor a significant increase in the power consumption of the heater to maintain a certain operating temperature. Under normal operation, the heater is brought into proximity with the selected treatment area in a non-contact state, and the heater is programmed to operate at a temperature that may be a linear temperature value or an average of a duty cycle, treatment cycle or treatment sequence. If physical pressure is applied to the heater and the heater is brought into contact with the patient's body, the rate of heat loss from the heater is significantly increased due to the greater heat absorption capacity of the body. The control of the heater may sense this temperature drop and begin adjusting the duty cycle ratio or the energy output, or both, to compensate for the increased loss ratio. The safety aspect of the monitoring function is that it can overcome this increase and shut down the device, thus preventing the heater from heating the tissue when in direct contact with and under pressure from the heater.

The heater element 106 is preferably a commercially available thin film type of resistive heater. Such thin film resistive heaters utilize low voltages to minimize the risk of patient shock and provide flexibility in using batteries. Film heater 106 is preferably sized to fit each type of wound covering 108. In practice, the thin film heater 106 is preferably a thin plate with two electrical leads 110 on one side. Although an electrical resistance heater is a preferred embodiment of the invention, other heater arrangements are also proposed, such as warm water pads, heat generating chemical heating pads and phase inversion salt pads.

The heater block 100 is preferably inserted into the pocket 114 formed between the wound tracking compartment 86 and the barrier layer. Finally, a temperature monitoring device (e.g., a liquid crystal temperature monitor) is preferably disposed on the upper surface of the heater assembly 100 or within the treatment volume 112 to monitor the temperature within the treatment volume 112.

Another embodiment of a wound covering 10 is shown in fig. 4-7. In this embodiment, wound covering 10 includes a generally circular head, generally designated 12, which transitions into an elongated, knotless, collapsible air supply tube or hose 14.

The apparatus shown in fig. 4 is connected by a suitable supply line or pipe 16 to a schematically depicted source of thermal control air 18. The term air as used herein refers to a gas mixture containing a control component. The device is configured to provide an uninterrupted flow of thermally controlled gas to the wound treatment space.

The details of the particular form and construction of the device are best understood by reference to the drawings and the description. The overall appearance of the wound covering is shown in fig. 4 and 5. The device is preferably constructed from top and bottom layers of heat sealable thin polymer film that are stacked upon one another. The top sheet or layer 20 overlies the bottom sheet or layer 22 and is heat sealed together along a plurality of seal lines, including continuous outer seams 24, extending into a circular head 12 and continuing in a sinusoidal or convoluted manner forward to form the hose 14. A continuous annular internal seam 26 is best seen in figures 6 and 7. The internal seam 26 ensures that the layers are joined together along a continuous circle to form an annular inner wall defining the supply space 28.

In the plane of the centre of the supply space 28 there are two layers 20 and 22, the inner circular parts of which form walls 30 separating a lower wound treatment space 32 from an upper compartment 34. The wall 30 includes a plurality of slits 36 formed by forming and cutting small circular seals 38 in the small circular seals 38 and removing the circular portions of the circular seals. In this way, a wall 30 having a plurality of apertures 36 is formed between the wound treatment space 32 and the isolation chamber 34. A plurality of small holes 40 are formed in a common annular wall surrounding the treatment space 32 for delivering and distributing heated air or gas from the supply space 28 to the wound treatment space 32.

The heated gas flowing into the treatment volume 32 bathes the injured surface of the patient's body 42. The gas, after circulating through the wound treatment space 32, passes through the apertures 36 into the upper layer or compartment 34 and then through the filter layer 44 which forms the outer wall of the compartment 34. The filter layer 44 filters gas from the wound treatment space 32, capturing contaminating material from the wound. The filter layer 44 may be constructed by bonding filter paper along its edges to the outer circumferential wall of the torus-forming cylinder 12. The filter paper also acts as a barrier to prevent heat loss by radiation through the upper wall 30.

The lower surface of the dome 12 as shown in figures 6 and 7 has a peripheral seal 46 of absorbent material (e.g. sponge) adhered to the wall of the dome 12 and to the skin 42 of the patient around the wound by a suitable adhesive. Preferably, the sponge or cotton perimeter seal 46 is of the removable type such that it is adhered to one side of the housing wall and to the other side of the patient's skin. Such adhesive or tape secures the device and prevents air from leaking between the device and the patient's skin. The absorbent material of the sealing ring absorbs the exuded blood or liquid and insulates the skin from direct conduction of heat from the rounded head 12.

The hose 14 made of a symmetrically convoluted flexible substance is designed as a knotless hose. The hose and housing are essentially a unitary structure, such as a membrane, that is integrally formed. The hose 14 is expandable in use with heated gas passing through the supply tube 16. The groove in the hose 14 allows it to bend without twisting, and a straight hose may twist when bent, the difference being that.

Because the thermal body treatment device and the supply hose portion of the present invention are formed from two thin films that are sealed together, the hose, and indeed the entire device, is collapsible. This prevents the possibility of applying heat and pressure to the skin that may occur when the patient turns around to press on the device. Instead, the weight of the patient's body collapses the device, blocking air flow and preventing heat from being applied to the skin.

The film is preferably transparent to allow viewing of the wound without removal. However, due to the use of cosmetics, the layer may become opaque. The filter paper 44 intersects the cut plane of the annular housing, which provides a large filter area for escaping gases. The rounded head 12 of the device is approximately one foot in diameter in most applications. However, for some other applications it may be made smaller.

Fig. 8A is an exploded view of another embodiment of a climate controlled non-contact wound covering 120 in treatment space 122, as shown in fig. 8B. The expandable structure 124 is preferably connected to the fluid inlet conduit 126 at a fluid inlet 129 on the circumference of the expandable structure 124. The inflatable structure 124 is preferably connected to an absorbent peripheral sealing ring 128, which sealing ring 128 is in turn adhered to the wound area 54 with a suitable adhesive 56. The peripheral seal ring 128 preferably has a sealing outer surface and a porous inner surface and functions in the same manner as the previously described peripheral seal ring 52. A barrier layer 130 with an exhaust filter 132 is attached to an upper surface 134 of the expandable structure 124.

Turning now to the assembly view shown in FIG. 8B, gas, indicated by directional arrow "A", enters the expandable structure 124 from an external gas source (not shown) through the inflow tube 126. The gas compresses the inflatable structure 124 to maintain the barrier layer 130 and the vent filter 132 in an elevated position relative to the wound area 54. The inner surface 136 of the expandable structure 124 preferably has a plurality of apertures 138 through which fluid may enter the wound treatment space 122. As the pressure in the treatment chamber increases, the excess pressure is released through the filter 132. In this way various liquids or gases may enter the wound treatment space 122.

Throughout this application all the term "fluid" refers to both liquid and gaseous substances and combinations of both. In one embodiment, oxygen may enter the treatment space 122 through the aperture 138 of the expandable structure 124. Oxygen in the wound treatment space 122 may increase the oxygen available to the growing cell surface layer within the wound area 54. Nitric oxide may be alternately injected into the treatment volume 122. Nitric oxide is a potent vasodilator, theoretically, absorbed through the wound surface and increases local blood flow. This effect can be achieved with very low concentrations of nitric oxide (parts per million). Nitric oxide may be pre-absorbed into the absorbent peripheral seal 128 and then actively diffused into the treatment space when applied to a wound. Finally, a gaseous or nebulized drug or compound may be introduced into the gas stream and into treatment volume 122.

FIGS. 9A and 9B illustrate another embodiment of the climate control system discussed above, wherein the fluid inlet conduit 140 may form part of the barrier 142. The barrier layer 142 is integral with the fluid inflow tube 140 and is preferably attached to an exhaust filter media 144 to allow excess pressure to be released from the wound treatment space 146. In this embodiment, the filter media 144 forms part of the barrier layer 142. Arrows "A" in FIG. 9B indicate the direction of fluid movement in fluid inflow tube 140, treatment volume 146, and exhaust filter 144.

FIG. 10 shows an alternative embodiment in which an exhaust filter 154 is captured in a recess 150 formed in one side of a peripheral seal 152. This configuration allows excess fluid to be drained through the edge of the peripheral seal 152 rather than being released through the top as shown in fig. 9A and 9B.

Fig. 11A is a perspective view of the embodiment of fig. 9A, wherein the connector 160 at the end of the fluid supply tube 162 engages the opening 164 of the fluid inlet tube 140. Fig. 11B shows a side view of the fluid supply tube 162 when engaged with the fluid inflow tube 140. Fig. 11C shows the embodiment of fig. 11A and 11B with the fluid inlet tube 140 folded over the top of the peripheral sealing ring 152 to seal the treatment volume 146 when the supply tube 162 is disconnected.

Fig. 12 shows another embodiment in which the fluid inlet 170 is coupled to a rigid connector 172 on a fluid inlet tube 174. The fluid inlet 170 is opened to a part of the peripheral seal 176. Which is in fluid communication with treatment volume 178. This configuration allows for quick separation of fluid inflow tube 174 from wound covering 180, providing more flexibility to the patient.

Fig. 13A is a perspective view of another embodiment of a non-contact wound covering 190 having a fluid inlet port connector 192, the inlet port connector 192 being attached to a top surface 194 of a peripheral seal 196. Fluid inlet connection 192 preferably contains inlet filter media 198. The rigid connector 200 on the fluid inlet tube 202 mates with the fluid inlet connector 192. As shown in fig. 13B, the protective layer 204 begins at the top of the fluid inlet connector 192, passes over the top of the peripheral seal 196 and engages the exhaust filter media 206 therein. Fig. 14 illustrates the embodiment of fig. 13A and 13B utilizing an un-disposable fluid supply tube 210.

Figure 15 is an alternative embodiment that uses a compound structure 220 as part of a fluid inflow tube 222 to evenly distribute fluid entering a treatment volume 224. The fluid inlet tube 222 preferably has a series of seals 226 along its periphery that are interrupted by a plurality of side openings 228 from which fluid can be delivered into the treatment volume 224. The embodiment disclosed in fig. 15 shows the exhaust filter 230 inserted into one side of the peripheral seal 232. However, it should be understood that the disclosed manifold structure 220 may have exhaust filters of different shapes.

Fig. 16A and 16B illustrate another wound covering 240 having a top barrier layer 242 and a lower layer 224 with a plurality of apertures 246. As shown in fig. 16B, the cap 243 forms the barrier layer 242 and extends substantially over the area of the peripheral seal 248. The lower layer 244 also extends past the peripheral seal 248. Thus, an upper spacer layer 250 is formed between the lower layer 244 and the top of the barrier layer 242. The fluid in the fluid inflow pipe 252 is introduced into the upper insulation layer 250. Fluid compressed in the upper insulation layer 250 enters the treatment space 254 through the aperture 246. The apertures 246 in the lower layer 244 provide a substantially uniform distribution of fluid in the wound treatment space 254. An optional pad 258 may be formed intermediate barrier layer 242 and underlayer 244 to provide additional structural support to these layers. An exhaust filter media 256 is positioned in a groove along one side of the peripheral seal 248 to reduce pressure in the treatment volume 254.

Fig. 17 shows another embodiment of a touchless wound covering 260 that utilizes a semi-rigid support 262 to hold a barrier layer 264 over the wound area. Those skilled in the art will appreciate that a variety of semi-rigid supports 262 may be utilized. For example, a plastic or elastomeric rubber material may provide sufficient support for the barrier layer 264 and minimize the possibility of injury to the patient.

Fig. 18A and 18B illustrate another exhaust filter media 270 having an enlarged surface area to accommodate a large flow of air through a non-contact wound covering 280. The exhaust gas filter is inserted into the fluid inflow pipe 272. The fluid inflow tube 272 in turn forms a portion of the barrier 274, which itself is connected to a circumferential sealing ring 276. As best shown in fig. 18B, fluid indicated by arrows "a" enters the fluid inflow tube 272, is directed into the wound treatment space 278, passes through the wound area, and is exhausted through the exhaust filter media 270.

Fig. 19 shows a bi-directional tube 290 with a central baffle 292. Fluid enters the fluid inlet tube 294 and enters the treatment space 298 through the fluid introduction port 296. The fluid is then forced through the fluid outlet 300, thereby being forced out of the treatment space 298 into the fluid outflow tube 302. Those skilled in the art will appreciate that it is possible to use separate fluid inflow and outflow pipes to achieve the same result.

Fig. 20 shows a schematic of an embodiment of the invention using active heating and control, the active heating means 310 comprising a heater 312, a heating wire 314 inside the heater 312, a controller 316 connected between the heating wire 314 and a power supply 318 via a connector 315 and using a heater temperature sensor 320, and an operator interface 322 adapted for an operator to input program parameters into the controller 316. The heating device 310 is useful in many different configurations, for example, as a heating layer provided for direct use in a pouch, as shown in fig. 3A and 3B with the heater 100 inserted into the pouch 114, or as a heating source for warm gas circulating over a wound, as shown in many of the embodiments in fig. 4-19.

In addition to the various fluid transfer heater "geometries" suggested in fig. 4-19, the present invention proposes the use of a number of possible heater wire 314 geometries in advance. An example of four such geometries is shown in fig. 21A, B, C, D, where diagram D shows another heater group geometry for the addition of heater filaments 314 in heater 312. In fig. 21A, the heating wire 314 is a linear structure. This geometry is suitable for non-uniform heating where maximum heating is required for the entire linear region, e.g., linear trauma where it is not necessary to heat the entire periwound region directly. Fig. 21B shows the geometry of the heating wire 314 used as a point heating source. Figure 21C shows an ovoid configuration of heating filaments 314 suitable for non-uniform heating of selected peripheral regions of a wound. Alternatively, such non-uniform heating may be accomplished by selecting a circular, square, rectangular, triangular or other geometry depending on the type and shape of wound encountered.

In operation, the heater module assembly 310 is programmable to control a number of parameters of a treatment cycle, such as heater temperature, duty cycle, treatment cycle, number of duty cycles per treatment cycle, average heater temperature per duty cycle, average heater temperature per treatment cycle, peak valley heater temperature per heating cycle, peak valley heater temperature per treatment cycle. A number of treatment protocol menus may be preprogrammed and provided at the time of manufacture. Furthermore, the programmability of the parameters may be entirely under the control of the operator and suitable for entering any number of predetermined treatment protocols.

By way of example, and not to limit the scope of therapeutic versatility, fig. 22 is a graphical representation of one treatment cycle represented by a plurality of heaters and duty cycles. In fig. 22, a plurality of duty cycles are defined in one treatment cycle, and time (t) is represented in abscissa and heater temperature is represented in ordinate. t is t₀At 330 deg.C, the heater is at ambient temperature T_amb332, a first cycle of the plurality of duty cycles from t₀330 begins, turning on the heater to heat to a temperature of about T_peak334. Time t₁At 336, the temperature reaches T_peak334, turning off the power supply of the heater, and cooling the heater to T_min338. First duty cycle at t₁336 to turn off the heater. First heater cycle at t₂340 i.e. the heater is turned back on, the next duty cycle and the beginning of the heater cycle end. First and subsequent heater cycleMaintained at an average heating temperature T_set342. Duty cycle t₀-t₁Time period of (d) and t₀-t₂The ratio of the time periods indicates. Those familiar with heater effect control technology will appreciate that there are many ways to control heater effect, including using processor logic to achieve heater effect and control a maximum proportional effect controller. The treatment cycle in this example is from t₀330 to t_t344 during which the heating temperature drops to T_amb332, and at t_tThe heating schedule is re-heated at 334 to begin the next treatment cycle.

For the above example, the peak temperature T_peak334 may be a parameter of the input program. For the present invention where the protection of the heater function is anticipated, this range is preferably from above ambient to about 38 ℃. The present invention contemplates that another temperature option may be entered for use as the operating temperature. The first option is to establish an average heater cycle temperature. In FIG. 22, the concept is denoted by T_set342, respectively. For the present invention, this average heater cycle temperature should be in the same range, from above ambient to about 38 ℃. Alternatively, the temperature can be selected as T_peak334 and T_min338, the two temperatures are selected from the same range.

As another example (not to be limited in scope by the generality of the treatment), a plurality of treatment cycles are shown in FIG. 23, wherein the respective heater cycles for each treatment cycle are averaged for illustration purposes and are considered "on" for this purpose, with the first treatment cycle beginning at t₀350, expressed as heater "on", i.e. a series of heater cycles are initiated, the heater heats up to T_set352. This "open" segment lasts until t₁354, at which time the heater is "turned off" and cooled to T_amb356. The first treatment cycle at t₂358, where the heater is "turned on" again to begin a second treatment cycle. The second treatment cycle is heated to T as in the first treatment cycle_set352 and has a slave t₂358 to t₃360. At t₃The heater is "activated" at 360 to begin the third treatment cycle. To illustrate the anticipated versatility of the present invention, a third treatment cycle is assigned a different T_set362. Heater at t₄364 is "off". The entire duration of the multiple treatment cycles may still be part of the treatment sequence, as shown in fig. 23 from t₀350 to t_t360 comprise a period of three treatment cycles. The present invention contemplates the use of any number of treatment cycles, each cycle having any length or duration and different temperature settings.

Another aspect of heater treatment control is the averaging of treatment cycle and treatment sequence temperatures (as shown in fig. 24). This example is not meant to limit the scope of therapeutic versatility. In FIG. 24, the treatment cycle is from t₀370 start to t₁372, end. Average value T of heater temperature for the whole treatment period_ave374 may be preselected or programmed. The heater being at ambient temperature T_amb376 begin heating to an appropriate temperature for the "on" segment and then "off for an appropriate additional time, such that the total time period equals from t₀370 to t₁372 and the average temperature of the segment is equal to T_ave374。

Another method is also shown in FIG. 24, which anticipates a sequence of many treatment cycles as an element of a treatment sequence, in this case three treatment cycles that differ in time and heater temperature. The versatility of the current invention provides an average temperature T for a treatment sequence_ave378. Therapeutic sequence from t₀370 start to t_t380 is complete. The heater temperature and duration of the treatment cycle in the treatment sequence is controlled by the controller for the entire slave t₀370 to t_tAveraged over a 380 time period to achieve a therapeutic average temperature T_ave378. Each of these average temperatures, whether averaged over a treatment cycle or averaged over a treatment sequence, is predetermined to be within the same temperature range from above ambient temperature to about 38 ℃. Another consequence of the controller process is that if an average temperature is used, either through the treatment cycle and/orIn a treatment sequence, the total peak temperature reached by the heater may be substantially higher than the ambient temperature to about 38 ℃. These peak temperatures are relatively short lived and do not represent a safety concern.

The present invention develops a safe, effective, non-contact heater wound covering that provides heat to a patient's wound by a heater that is controlled to a temperature ranging from above ambient to about 38℃ or an average temperature ranging from above ambient to about 38℃. While particular embodiments and examples of the present invention have been described, it will be obvious to those skilled in the art that various changes and modifications can be made without departing from the scope and spirit of the invention. It is to be understood, however, that the scope of the present invention is to be limited only by the terms of the appended claims. TABLE 1

Time (minutes)	Subcutaneous temperature (mean value of C. + -. standard deviation (S.D.))
		-600306090120180240300	33.8±1.734.4±1.336.1±0.936.4±0.836.6±0.736.9±0.635.8±0.635.9±0.535.6±0.6

TABLE 2

Time (minutes)	Skin temperature in wound dressing (. degree. C. mean. + -. standard deviation)
		-600306090120180240300	32.9±1.433.5±1.035.8±0.836.2±0.636.2±0.636.4±0.534.9±0.534.9±0.434.9±0.6

TABLE 3

Time (minutes)	Laser Doppler (Doppler) flow (ml/100g/min mean. + -. standard deviation)
		-600306090120180240300	49±3174±6583±75199±262132±127110±11689±7376±6571±53

TABLE 4

Time (minutes)	Subcutaneous oxygen pressure (P)sqO2) (mean value of mmHg. + -. standard deviation)
		-600306090120180240300	55±981±2690±32112±56123±66134±74126±65129±49131±52

Claims (47)

1. A wound covering for application to a selected treatment area of a patient's body, the wound covering comprising: a heater adapted to provide heat to a selected treatment area; flexible attachment means for attaching the heater in a non-contact position proximate the selected treatment area; and a control device operatively connected to the heater for controlling the temperature of the heater over a temperature range from ambient temperature to about 38 ℃.

2. The wound covering of claim 1 in which the heater comprises a resistance wire.

3. The wound covering of claim 1 in which the heater comprises a heat source selected from the group consisting of a hot water pad, a heat-generating chemical heating pad and a phase-change salt pad.

4. The wound covering of claim 1 in which the heater is adapted to heat the selected treatment area uniformly.

5. The wound covering of claim 1 in which the heater is adapted to non-uniformly heat the selected treatment area.

6. The wound covering of claim 1 in which the flexible attachment means comprises a sealing ring having upper and lower surfaces and defining an open cavity and sealing around the selected area of treatment.

7. The wound covering of claim 6 in which the sealing ring comprises a conformal polymeric ring.

8. The wound covering of claim 7 in which the conformable polymeric loop comprises a polymeric foam.

9. The wound covering of claim 1 further including a layer spanning the flexible attachment means adapted to maintain a treatment volume proximate the selected treatment area.

10. The wound covering of claim 9 in which the sheet comprises a flexible sheet material.

11. The wound covering of claim 10 in which the flexible sheet material comprises a polymer film.

12. The wound covering of claim 11 in which the polymeric film is selected from the group consisting of cellulose, cellulose acetate, polyethylene, polyvinyl chloride, polyurethane and polypropylene.

13. The wound covering of claim 9 in which the sheet comprises a gas permeable material.

14. The wound covering of claim 1 in which the flexible attachment means comprises a pouch releasably attached to the heater.

15. The wound covering of claim 1 further including a pressure sensitive switch to turn off the heater when pressure is applied to the wound covering.

16. The wound covering of claim 9 in which the sheet is sealed to the flexible attachment means as a barrier layer.

17. A wound covering for application to a selected treatment area of a patient's body, the wound covering comprising: a heater layer adapted to provide heat to a selected treatment area; means for attaching the heater layer proximate the selected treatment area in a non-contact position; and a control device operatively connected to the heater layer to control the temperature of the heater layer over a temperature range from ambient temperature to about 38 ℃.

18. The wound covering of claim 17 in which the heater layer is adapted to uniformly heat the selected treatment area.

19. The wound covering of claim 17 in which the heater layer is adapted to non-uniformly heat the selected treatment area.

20. The wound covering of claim 17 in which the attachment means comprises a sealing ring having upper and lower surfaces and defining an open cavity and sealing around the selected area of treatment.

21. The wound covering of claim 20 in which the sealing ring comprises a conformal polymeric ring.

22. The wound covering of claim 21 in which the conformable polymeric loop comprises a polymeric foam.

23. The wound covering of claim 17 in which the heater layer includes a cross-connection means adapted to maintain a treatment volume above the selected treatment area.

24. The wound covering of claim 17 in which the heater layer comprises a flexible sheet material.

25. The wound covering of claim 24 in which the flexible sheet material comprises a polymer film.

26. The wound covering of claim 25 in which the polymeric film is selected from the group consisting of cellulose, cellulose acetate, polyethylene, polyvinyl chloride, polyurethane and polypropylene.

27. The wound covering of claim 24 in which the heater layer comprises a gas permeable material.

28. The wound covering of claim 17 in which the attachment means comprises a pouch releasably attached to the heater.

29. The wound covering of claim 23 in which the heater layer includes a seal to the attachment means as a barrier layer.

30. A wound covering for application to a selected treatment area of a patient's body, the wound covering comprising: a heater adapted to provide heat to the selected treatment area; a flexible attachment means for attaching the heater in a non-contact position proximate the selected treatment area; and a control device operatively connected to the heater for controlling the average temperature of the heater over a temperature range from ambient temperature to about 38 ℃.

31. The wound covering of claim 30 in which the heater is adapted to heat the selected treatment area uniformly.

32. The wound covering of claim 30 in which the heater is adapted to non-uniformly heat the selected treatment area.

33. The wound covering of claim 30 in which the control means includes a selectively preset average temperature setting.

34. The wound covering of claim 30 in which the control means is programmable to provide heat at an average temperature throughout the treatment cycle.

35. The wound covering of claim 30 in which the control means is programmable to provide heat at an average temperature throughout a treatment sequence.

36. The wound covering of claim 30 in which the control means is pre-programmed to provide heat at an average temperature throughout the treatment cycle.

37. The wound covering of claim 30 in which the control means is pre-programmed to provide heat at an average temperature throughout a treatment sequence.

38. A wound covering for application to a selected treatment area of a patient's body, the wound covering comprising: a heater layer adapted to provide heat to a selected treatment area; means for attaching the heater layer in a non-contact position proximate the selected treatment area; and a control device operatively connected to the heater layer to control an average temperature of the heater layer over a temperature range from ambient temperature to about 38 ℃.

39. A method of treating a skin wound in a patient, the method comprising the steps of: selecting a wound treatment area of the patient's skin including a wound; providing a heater; providing a control device operably connected to the heater; attaching a heater in a non-contact position proximate to the selected wound treatment area; heating a heater over at least a portion of the selected treatment area; and controlling the heater so as to control the temperature within a temperature range of ambient temperature to about 38 ℃.

40. The method of claim 39 further comprising the step of programming the control means to control the heater temperature throughout the duty cycle.

41. The method according to claim 39, further comprising the step of programming the control device to control the temperature of the heater throughout the treatment cycle.

42. The method according to claim 39, further comprising the step of programming the control device to control heater temperature throughout the treatment sequence.

43. The method of claim 39 wherein controlling the heater comprises controlling the heater temperature with an average heater temperature.

44. The method according to claim 43, further comprising the step of programming the control device to control the average temperature of the heater throughout the treatment cycle.

45. The method according to claim 43, further comprising the step of programming the control device to control the average temperature of the heater throughout the treatment sequence.

46. The method of claim 39, further comprising the step of inputting a temperature to the control device within a temperature range of from ambient temperature to about 38 ℃.

47. The method of claim 39, further comprising the step of inputting an average temperature to the control device over a temperature range of ambient temperature to about 38 ℃.