Amorphous gels can help dry escharic wounds

By Liza G. Ovington, PhD 

Program Director, Wound and Continence Management 

Home Health Care Division, Southeast Florida 

Columbia Healthcare Corporation 

Ft. Lauderdale, FL

If you’re looking for a dressing that will provide moisture to the wound site, amorphous gels can have great benefits. They differ from other dressings in their ability to add moisture to a dry escharic wound and often are used to facilitate autolytic debridement in necrotic wounds. They also may be used on clean, granulating wounds to maintain a moist healing environment. 

Amorphous hydrogels are similar in composition to the sheet hydrogels in that they both begin as a solution of mostly water with a small amount of a polymer. If this polymer solution is exposed to an energy source such as electron beam irradiation, the polymer forms cross-links and results in a three-dimensional structure or sheet hydrogel. (See illustrations, at right.) 

In the case of the amorphous hydrogels, the difference is that the polymer solution has not been cross-linked and therefore does not take on a fixed shape. Also, without this cross-linking, the amorphous gels do not possess the cooling effect of the sheet gels.

Color, thickness differ

Amorphous gels usually are clear or pale yellow, although one is blue because it contains copper ions. They may differ from one another in several ways. The thickness or viscosity of one amorphous gel may be greater or less than another. This difference can be a point of clinical preference for one brand and may affect the handling characteristics of the gel. 

Depending on the viscosity of the amorphous hydrogel, it may be difficult to retain it in the wound bed. All gels will become less viscous as they warm up to body temperature. Improper use may lead to peri-wound maceration. 

In addition to the variations in viscosity, many amorphous hydrogels contain small quantities of additional ingredients such as collagen, alginate, copper ions, peptides, or complex carbohydrates. The addition of such ingredients is usually directed at boosting some parameter of performance, but does not change the product category. These products still function as amorphous hydrogels. For example, adding small quantities of alginate to give a gel absorbent capacity or thickness does not mean it can be used interchangeably with an alginate fiber dressing. 

Amorphous hydrogels vary most in their packaging, which includes foil packs, tubes, and spray bottles. Of practical concern to clinicians is the volume of gel in each package as it relates to reuse and sterility. 

Amorphous hydrogels can be retained over a shallow wound by covering them with a film dressing or a layer of petrolatum-impregnated gauze. In deeper wounds, it is not recommended to fill the entire cavity with gel but simply to line the wound with a quarter-inch layer of gel and fill loosely with gauze. It also is possible to apply the hydrogel onto a layer of gauze, compress it to "impregnate" the gel, and use the gel/gauze combination to maintain a moist wound environment. 

Many amorphous hydrogels are available pre-impregnated into a gauze dressing. This format often simplifies application of the gel to a wound and allows, in effect, "metered dosing." Also, at least one brand of amorphous hydrogel is available in a freeze-dried format that converts to an amorphous gel on contact with fluid. 

Below are the available amorphous hydrogel dressings, their manufacturers, and toll-free numbers.