A moist wound environment is critical for optimal healing of chronic wounds. [1] As a result, different types of wound dressings have been developed that help to optimize moisture in the local wound environment for efficient wound healing. Wound dressings also have been found to protect the wound from additional damage. Wound dressings are a principal component of effective wound care. Therefore, podiatrists and wound care specialists should familiarize themselves with the many different types of wound dressings that are available.

What Is An Ideal Wound Dressing?

Even though the characteristics of wound dressing can differ depending on the individual patient’s needs, there are certain properties that an ideal wound dressing should possess. These include:

• It can maintain a moist environment for optimal wound healing 
• It is available in varying shapes and sizes and can fit easily in inaccessible parts of the body
• It should be able to absorb excess exudate 
• It has microbicidal properties 
• It is minimally painful on removal
• It provides thermal insulation to the wound site 
• It is easy to apply
• It is readily available, cost-effective, and requires minimal dressing change
• It is transparent in appearance to allow podiatrists and wound care specialists easy monitoring of wound healing 

The majority of the time, a single dressing does not combine all of the desirable characteristics. Therefore, clinicians need to decide which property of the dressing would be most appropriate for a particular wound. 

Types of Wound Dressings 

Wound care technology has advanced tremendously in recent years which has led to the development of different wound dressings with their characteristics. The following are the main categories of wound dressings that are currently available:

• Traditional Wound Dressings: These include gauze, lint, plasters, bandages, and cotton wool. Gauze dressings are soaked with normal saline to provide moisture to the wound site. These are available in various sizes and are covered with a thick absorbent pad. Even though gauze dressings are useful in removing excess exudate, they tend to adhere to the wound which is painful on removal. Moreover, gauze dressings can also dry the wound which can delay wound healing. [2] Cotton bandages are another traditional wound dressings that are used either for compression or as an adjunct with lighter wound dressings. Traditional wound dressings have been replaced by modern dressings that are better specialized for wound care.

• Films: The examples of polymer films include Tegaderm, Bioclusive, and Cutifilm. These are sheets of synthetic, semi-permeable material which allow the diffusion of water and oxygen but are impermeable to larger molecules. This allows polymer films to retain wound moisture while allowing for insensible water loss. In addition, they are impermeable to bacteria and proteins which prevents infection. Transparent films have the lowest infection rates and fastest wound healing. [3] Additional advantages of polymer films include rapid epithelization, moisture retention, and self-adhesion. However, these dressings are not suitable for wounds with heavy exudate. 

• Foams: Foam dressings are similar to film dressings with the addition of absorbing capacity. Foam dressings have two layers: silicone or polyurethane-based foam which is pressed next to the wound, and a gas permeable, hydrophobic layer that prevents leakages. They are not suitable for wounds with minimal exudate as they might desiccate the wound skin. In addition, they might also need to be changed daily which can make them inconvenient. Trials that have compared the efficacy of foams and films in skin tears found better healing in patients using foams. [4]

• Hydrocolloid Dressings: On exposure to the wound exudate, hydrocolloid dressings absorb the fluid and form a gel-like substance. These are made of gel-forming agents like gelatin, pectin, and are available in the form of sheets or powder. Hydrocolloid dressings are also able to trap bacteria and reduce wound pH. This allows for the regular removal of bacteria and debris through a gentle, mechanical form of debridement. Hydrocolloid dressings are inappropriate for wounds with heavy exudates In addition, there is also a potential for malodor and contact dermatitis. [5] Therefore, hydrocolloid dressings should be changed at regular intervals of 2-4 days.

• Alginate dressings: Alginate dressings are composed of natural polysaccharides obtained from various algae. Alginate dressings are not soluble in water, but in the presence of wound exudate, they form a gel-like substance that covers the wound surface. While the absorbing capacity of alginate dressings depends on the type of polysaccharide, they are suitable for wounds with a heavy exudate due to their excellent absorbent capacity. Alginate dressings are not appropriate for dry wounds and are usually used in conjunction with the second layer of foam or hydrocolloid dressing. [6] Moreover, they might also have an associated bad odor which can limit their use. 

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• Hydrogel Dressings: Hydrogel dressings are composed of synthetic polymers and are formed into sheets or gels. These are sandwiched between two removable sheets. The hydrogel dressings can either absorb or transfer moisture depending upon the moisture status of the wound. These dressings also provide a cooling effect to the skin which can help in pain relief and minimizing discomfort. [7] Hydrogel dressings are ideal for dry wounds.

References

1. Field CK, Kerstein MD. Overview of wound healing in a moist environment. The American journal of surgery. 1994 Jan 1;167(1):S2-6.
2. Boateng JS, Matthews KH, Stevens HNE, Eccleston GM. Wound healing dressings and drug delivery systems: a review. J Pharm Sci. 2008;97(8):2892–923.
3. Rakel BA, Bermel MA, Abbott LI, Baumler SK, Burger MR, Dawson CJ, Heinle JA, Ocheltree IM. Split-thickness skin graft donor site care: a quantitative synthesis of the research. Applied Nursing Research. 1998 Nov 1;11(4):174-82.
4. Thomas DR, Goode PS, LaMaster K, Tennyson T, Parnell LK. A comparison of an opaque foam dressing versus a transparent film dressing in the management of skin tears in institutionalized subjects. Ostomy/wound management. 1999 Jun 1;45(6):22-4.
5. Grange-Prunier A, Couilliet D, Grange F, Guillaume JC. Allergic contact dermatitis to the Comfeel hydrocolloid dressing. InAnnales de dermatologie et de vénéréologie 2002 May 1 (Vol. 129, No. 5 Pt 1, pp. 725-727).
6. Rezvani Ghomi E, Khalili S, Nouri Khorasani S, Esmaeely Neisiany R, Ramakrishna S. Wound dressings: current advances and future directions. J Appl Polym Sci. 2019;136(27):47738.
7. Coats TJ, Edwards C, Newton R, Staun E. The effect of gel burns dressings on skin temperature. Emergency Medicine Journal. 2002 May 1;19(3):224-5.

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