Compression bandages are frequently used in medical and sports applications requiring a strong and reliable, yet comfortable and easily applied, means of securing a limb or other body segment for prolonged periods of time. For example, strains and sprains can cause inflammation and the accompanying accumulation of fluid around a sprained joint. Wrapping the affected joint securely with an elastic bandage can prevent excess fluid from accumulating and causing additional tissue damage.
In addition, chronic venous disease, including valve insufficiency and venous wall damage, and leg ulcers of various origins, including venous stasis ulcers, arterial (ischemic) ulcers and neurotrophic ulcers, are common medical problems. Leg ulcers are wounds or open sores that do not heal, or otherwise recur repeatedly, and cause persistent swelling as well as burning, itching, irritation and discoloration of the skin. Treatment of leg ulcers generally includes compression in addition to topical protection of the wound and antimicrobial treatment of the affected area.
Therapeutic compressive pressures are based on the principle that extra-vascular pressure should equal excess venous pressure in order to restore normal venous flow from the extremities back to the torso, e.g., from the foot to the thigh. Stress on the venous system is already the greatest in the leg in standing position because the veins must move blood against the force of gravity. Ideal leg compression mirrors the leg's natural degressive pressure gradient, i.e., higher pressure at the ankle and lower pressure at the thigh, which results from the gradual increase of leg diameter from the ankle to the thigh. Thus, therapeutic compressive pressure goals vary from patient to patient and at different locations in each patient's leg based on venous pressure measurements.
Traditionally, compression therapy for leg ulcers has involved wrapping a patient's leg with a layer of cotton batting followed by a compression bandage or sleeve. Better results are now achieved with the application of a 3 to 4 layer bandage system, by which different types of bandages are combined to achieve and sustain a suitable therapeutic sub-bandage compressive pressure. A common example is the four-layer system described in “The Function of Multiple Layer Compression Bandaging in the Management of Venous Ulcers,” D D I Wright et al., SWM, 10, 109-10 (1988). The four layers include (1) a skin-facing layer of cotton wool, (2) a lightweight bandage, (3) a light compression bandage, and (4) a flexible cohesive bandage.
Despite their potential to deliver therapeutic compressive pressure, the process of applying such 3 to 4 layer bandage systems is time intensive, which reduces patient compliance. Also, the bandages in these systems often require pleats or tucks in order to conform to the patient's leg and may slip or wrinkle following application, all of which can irritate the underlying skin and make the results of compression highly variable. Patient comfort and compliance is further reduced by the high profile or thickness and lack of thermal and/or moisture regulation of 3 to 4 layer systems, which can be difficult to wear under existing clothing or footwear and cause the uncomfortable buildup of body heat and moisture under the bandages.
Alternatively, other compression bandage systems have been proposed in attempts to counteract the complexities and time demands involved with the application of 3 to 4 layer bandage systems. For example, U.S. Pat. No. 7,854,716 discloses a two-part compression bandage system. The first part is an inner multi-layer elastic bandage comprising (1) an elastic substrate layer with a self-adhering outer face and an inner face affixed to (2) a foam layer having a skin-facing exposed face not affixed to the substrate layer. The second part of the system is a separate outer elastic layer with self-adhesion and compression properties. In application, the inner multi-layer bandage is wrapped around the patient's leg with the elastic substrate outer face configured and adapted to adhere to the separate outer elastic layer to prevent slippage or migration. Thus, the only purpose of the expensive elastic substrate layer of the inner bandage is to facilitate adhesion with the separate outer elastic layer. In addition to cost concerns, the two-part system falls short of optimizing patient comfort and, as a result, patient compliance with regard to its thickness, conformability, heat retention, and moisture regulation.
Moisture regulation in a compression bandage system is particularly important due to the seeping of serous fluid and other wound transudate and/or exudate from leg ulcers or other chronic wounds. Traditionally, cotton batting has been used under compression bandages for fluid absorption; however, the cotton often sticks to the affected area upon removal. Also of concern is the ability of any sub-bandage absorbent padding to remain compression neutral and minimize friction against the skin.