Methods for using polymer foam absorbent materials in wound dressings
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Publication Number
US-10004646-B2
Publication Date
2018-06-26
Expiration Date
Abstract
Disclosed are methods for using open-celled polymeric foam wound dressings made from high internal phase emulsions (HIPEs). The wound dressings have a high capillary pressure and may reduce or obviate the need for treatments like negative pressure wound treatment (NPWT). Also disclosed are structures for HIPE foam wound dressings. The HIPE foam wound dressings typically include at least two layers of HIPE foam with different, but homogeneous, average cell sizes. The average cell sizes form a cell size gradient, with cell size typically decreasing from the front or face layer of foam toward the back layer of foam. The back layer of foam may be a collapsed layer, while the front layer or layers may be expanded. Compared with HIPE foams for other absorbent applications, the wound dressing foams may be higher in hydratable salts and higher in initial moisture levels.
Core Innovation
The document describes HIPE-derived open-cell polymer foam wound dressings that include at least a first and a second contiguous layer, where the first layer serves as a wound-facing layer and the second layer serves as a back layer. The first and second layers are open-cell foams produced by polymerizing high internal phase emulsions (HIPEs), and the layers have different average foam cell sizes and different average hole sizes between adjacent foam cells.
In the wound dressing, an average cell size and an average hole size of the first layer are greater than an average cell size and an average hole size of the second layer. The second layer is adjacent to and in fluid communication with the first layer of foam, with the second layer having second average cell size and second average hole size less than the first average cell size and the first average hole size, respectively.
The dressing architecture is used in a wound-treating method by placing the dressing on the wound and replacing the dressing when the dressing exhibits a characteristic indicating a defined level of at least partial saturation. The document further relates the foam structure and saturation behavior to capillary suction pressure and negative pressure wound therapy (NPWT), including a cell-size/capillary suction pressure gradient concept across layers.
Claims Coverage
The independent claims cover 2 inventive features: a wound-treating method and a wound dressing structure using contiguous open-cell HIPE foam layers with different average cell and hole sizes.
Wound treatment using at least two contiguous open-cell HIPE foam layers with different cell and hole sizes and replacement based on partial saturation
A method for treating a wound by placing a dressing on the wound, where the dressing includes at least first and second contiguous layers of open-cell foam produced by polymerizing HIPEs, the first layer serving as a wound-facing layer and the second layer serving as a back layer, the first and second layers having different average foam cell sizes and different average hole sizes between adjacent foam cells with the first layer having greater average cell size and average hole size than the second layer, and replacing the dressing when it exhibits a characteristic indicating a defined level of at least partial saturation.
Wound dressing with a first open-cell HIPE foam layer and an adjacent second open-cell HIPE foam layer in fluid communication with smaller cell and hole sizes
A wound dressing comprising a first layer of open-cell foam produced by polymerizing a HIPE, generally homogeneous in internal structure and having a first average cell size and first average hole size, and a second layer of foam adjacent to and in fluid communication with the first layer, the second layer being open-cell foam produced by polymerizing a HIPE and having a second average cell size and a second average hole size less than the first average cell size and the first average hole size, respectively.
Overall, the claim set focuses on dressing designs made of open-cell HIPE foams using a two-layer structure where the wound-facing layer has larger average foam cell sizes and hole sizes than the back layer, and where the dressing may be used in a treatment method with replacement when saturation reaches a defined level.
Stated Advantages
Provides high capillary pressure comparable to lower-end NPWT.
Draws wound exudate away using a cell-size/capillary suction pressure gradient across layers.
Potentially reduces or obviates NPWT.
Reduced fluid retention at the face layer correlated with Delta CSP.
Moisture management via an optional backing/film having defined MVTR to reduce re-collapse and manage moisture loss.
Documented Applications
Treating a wound by placing a dressing on the wound and replacing the dressing when it exhibits a characteristic indicating a defined level of at least partial saturation.
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