Wound Series Part 2d: Wound Dressings (FL INITIAL Autonomous Practice-Pharmacology)

Gauze comes in various forms, sizes, shapes, and layered products. The most common gauze products are sterile or aseptic (packaged individually, in packages of 2 or in bulk packages of 50 or 200 cotton gauze, woven, 8 or 12 layered, 4” x 4” or 2” x 2” sizes). Telfa is gauze, coated with a plastic film to help render it “non-adhesive.” Gauze also comes in larger bulk dressings such as ABD pads (originally known as Army Battlefield Dressings, but now are commonly referred to as “abdominal dressings”). Today, these dressings are commonly made with bulky absorbent layers of cotton batting and woven gauze in larger sizes such as 5” x 9” or 8” x 10.” Gauze dressings are also manufactured in woven gauze of one rolled length (roll gauze) in a variety of widths (such as 2” of 4” or 6” widths). Care should be taken when using certain roll gauze or woven gauze as a primary dressing in a wound bed. Some gauze products may leave behind small pieces of organic cotton material, becoming foreign bodies in the wound and perhaps facilitating bacteria’s growth or promoting hypergranulating tissue. Gauze may be used as primary and secondary dressings and may already be impregnated with other substances such as calamine, petrolatum, wound gels, silver, etc. Also, combination products may have layers of gauze combined with layers of other wound products such as charcoal, alginates, adhesive backings, or borders.

Whereas wet-to-dry dressings are moistened with saline and allowed to dry out (therefore not recommended for routine wound care), wound gels are a good alternative that effectively maintains a moist wound bed. The clinician may moisten the gauze with the wound gel or use a pre-packaged gel-impregnated gauze. Typically, this only needs to be changed once a day instead of 2-3 times per day. The wound gel dressing changes would be less painful than wet-to-dry. Wound gels come in amorphous gels (in tubes) or sheets of flexible semisolid gel. Wound gels are commonly made of organic polymers that maintain moisture in the wound bed and swell with water or the wound drainage. Also, wound gel may contain silicone, water, glycerin, polyethylene oxide, alginate, or collagen. These wound gels’ common brand names include (this is not meant to be all-inclusive):

• SAF-gel®
• Vigilon®
• Elastogel®
• Curasol®
• Solugel®
• Intrasite Gel®
• Purulon Gel®
• DuoDERM gel®
• Stimulen collagen gel®
• Carrasyn®
• Curagel®
• Nu-Gel®
• Restore®
• XCell®

Some gel sheets, such as Vigilon®, come with polyethylene film covers on each side that should be removed before placing gel sheets on the wound (this will allow more vapor permeability). Gel products may absorb up to 5 times their body weight in wound drainage yet will not dry out or dissolve. Typically, the gel product is placed in the wound bed and covered with a secondary dressing to secure it in place (such as gauze or foam). These products are typically changed daily, though gel sheets on certain wounds, such as superficial wounds and skin tears, may be left on for one week if the skin tear is clean (non-infected) with a well-approximated flap that is not heavily exudating. Wound gel sheets that come with adhesive borders may typically be changed three times per week. Wound gels are appropriate for full-thickness, shallow, or deep wounds with scant to small or varying drainage amounts. The wound bed may sometimes dry out. Silicone gel sheets may also help prevent or treat scarring of the wound (keloid/hypertrophic tissue) up to one year after the wound's closure.

Care should be taken to manage moisture so that excessive moisture cannot seep over the surrounding wound edges, causing maceration. Skin barrier wipes or creams may help protect peri-wound skin from adhesives (barrier wipes) or excessive moisture (barrier creams such as zinc oxide or dimethicone). These are applied at each dressing change.

Another simple dressing to use is impregnated gauze. Pre-packaged impregnated gauze products are typically impregnated with petrolatum, hydrogel, Bismuth Tribromophenate, hypertonic sodium chloride, zinc, or crystalline iodine compound (iodoform), or oil emulsions, to name a few. These dressings’ common brand names include (this is not meant to be all-inclusive):

• Vaseline Gauze®
• Adaptic®
• Xeroform®
• Curasalt®
• Mesalt®

The most basic and inexpensive petrolatum impregnated gauze may average $40 or less per box of 50. These dressings conform and may be a good choice when filling tunnels or tracking as long as one piece and not multiple pieces are packed loosely into the tunnel. These dressings provide a non-drying and moisture-retaining wound interface. They conform to the wound bed and may help protect periwound skin if shallow abrasions may be placed on the wound overlapping the edges. Usually, these dressings are changed daily and covered with a secondary dressing such as gauze pads or roll gauze, foam, bandage, or wraps.

Hydrocolloid dressings are typically opaque, self-adherent “patch” type dressings made of sodium carboxymethylcellulose, pectin, and gelatin mixed with polymers and adhesives. They also have a semipermeable film or foam sheet covering, making them generally waterproof. However, waterproofing does not mean it can be submerged in a bathtub or pool. These dressings are flexible wafers of differing sizes, thicknesses, and shapes (some may be cut to the desired size and shape). They can conform to many areas of the body. These dressings’ common brand names include (this is not meant to be all-inclusive):

• Restore®
• DuoDERM®
• DuoDERM CGF®
• Tegasorb®
• Comfeel®
• Granuflex®
• 3M Tegaderm® hydrocolloid thin

When exposed to exudate (wound drainage), the polysaccharides & other polymers absorb water and swell but remain in the adhesive matrix. Some have marks to indicate when the wound drainage exceeds the dressing’s limit, and it is time to change. If cut to size, most should be cut larger than the wound. These dressings are typically changed every 2-5 days. Applying a skin barrier wipe to the periwound skin is best before applying the hydrocolloid.

Alginates are super absorbent fibers typically composed of calcium alginate manufactured from brown seaweed that becomes gel-like when exposed to sodium-rich wound exudates. It resembles angle hair and is manufactured from brown seaweed. They may absorb up to 20 times their weight in wound exudates. This makes them a good choice for highly exudating wounds. However, they are not recommended for dry or only slightly moist wound beds, as they will not remain a gel without the presence of moisture from the wound bed. Thus, they may dehydrate the wound bed or allow the wound bed to dry out. Alginates may be available as sheets or pads and ropes and are known for some hemostatic properties, making them a good choice for a wound bed that may ooze a small amount of blood after sharp debridement. Also, some alginates may have silver incorporated into the fibers as an antimicrobial agent. Alginates typically require a secondary cover dressing such as gauze or an ABD pad and are changed daily or as necessary to manage the wound exudates.

Hydrofiber dressings are non-wicking, primary absorptive dressings made of sodium carboxymethyl-cellulose fibers that absorb wound drainage and turn into a gel sheet. They may also keep the wound bed moist if the wound is dry (you would moisten them with saline or water). Hydrofibers act somewhat like alginate but will not promote hemostasis like alginates. Some hydrofiber dressings include 1.2% silver as an antimicrobial component (usually delineated by the silver element symbol “AG” in the hydrofiber name). They are appropriate for full-thickness wounds with minimal to moderate amounts of drainage. They are typically changed once every 1 to 3 days and require a secondary cover dressing.

Foam dressings are typically both absorptive and protective. They may be selected to provide conforming padding. If needed, they may be combined with other products (such as alginates or hydrofibers). Foams may be used as packing material in large wounds to fill dead space. Not all foam dressings are appropriate for infected wounds. Check manufacturer guidelines if an infection is an issue. Some foam dressings are impregnated with silver or other antimicrobial material (such as Methylene Blue and Gentian Violet or polyhexamethylene biguanide/PHMB) or coated with a silicone interface.

Silver ions may be incorporated in the wound gels, woven fabric dressings, foam, rope, alginates, or hydrofiber dressings. Most silver fabric dressings are not very absorbent. They are used primarily to deliver silver ions to the wound bed for the silver’s antimicrobial effects. However, silver alginates, hydrofibers, foams, or composite dressings are absorbent. Silver ions are activated by wound exudates or water; some silver products (Acticoat® three days or seven days) should not be moistened with sodium chloride (saline). Most ionic silver products should not be mixed with hydrogen peroxide or sodium hypochlorite (Dakin’s® or DiDaksol®) solutions because the ions will inactivate each other. Ionic silver products should not be combined with iodine products for the same reason. Silver dressings may need secondary dressings to hold them in place or provide extra absorption. Depending on the product, they may be changed daily up to every seven days.

A 10% povidone-iodine solution provides about 1% of available iodine and is commonly used as an antimicrobial. It should not be used in typical chronic wound care due to its cytotoxic properties (but may be used short-term if infection warrants it or “paints” stable dry, intact eschar). However, a cadexomer iodine is available, which has antimicrobial properties while remaining non-cytotoxic to the wound bed. Cadexomer iodine is available in a wound gel (thick paste) or impregnated on a flexible pad, which is typically applied to the wound bed with a secondary dressing on top and left in the wound bed for three days, or until the color changes from an orange-brown to a grey-brown. They are used for antimicrobial effects. They are effective against most bacteria, including pseudomonas, staphylococcus aureus, streptococcus, and fungus. Some literature suggests that caution should be exercised when using a slow-release iodine product in patients with thyroid disease due to iodine’s potential systemic uptake.

Compression dressings or bandage wraps are primarily used for lower extremity venous insufficiency (Gupta et al., 2017). Compression garments are also appropriate for extremities affected by lymphedema (such as mixed etiology lower extremity edema, and after cancer surgeries such as mastectomies with axillary lymph node removal) or burns (National Institutes of Health National Cancer Institute [NIH], 2020). Short-stretch compression is typically used for lymphedema (not ace bandages). Long-stretch compression (multilayer wraps and ace-type bandages) is typical for venous leg wounds. It is essential to verify arterial perfusion to the affected limb before applying compression. Compression may be applied in 2 to 4 layers. A therapeutic layer such as zinc oxide or calamine-impregnated strips is applied first, an absorbent layer next, possibly a bandage layer or Coban® layer on top. These dressings may be applied every few days to weekly, depending upon the amount of wound exudate. Once edema is under control and wounds healed, the patient should wear life-long compression stockings (apply daily first thing in the morning before ambulating and remove at night just before retiring to bed).

Composite dressings, or layered dressings, are combination dressings of various sizes made up of two or more different materials to address the unique needs of certain wounds. These dressings tend to be layered with a contact layer (non-adhesive), an absorbent layer, and possibly an antimicrobial layer or odor-absorbing layer (such as charcoal). They also may have an adhesive border to secure them to the wound site.