Dressings may be categorized as semiocclusive or occlusive. Semiocclusive dressings are semipermeable to gases (O₂, CO₂, moisture) and are impermeable to liquids; they provide the moist wound healing environment that optimizes wound healing. Occlusive dressings lack permeability to gases and liquids.

 Coarse gauze, used in a wet-to-dry dressing, nonselectively débrides the wound bed mechanically and absorbs wound fluid.

 Dressings such as calcium alginates, foams, and hydrofibers enhance wound exudate absorption; hydrogels, hydrocolloids, and transparent films provide moisture to nondraining wounds with minimal absorption.

 Wounds with excessive wound drainage also require protection of periwound skin (i.e., skin barrier wipes).

 Normal wound healing is often described as a progressive process that involves three overlapping phases: inflammation, proliferation, and maturation. The inflammatory phase is marked for hemostasis, increased vasodilation, and migration of neutrophils and macrophages to the area. The proliferation phase begins 2 to 4 days after injury and is the healing phase of the wound process in which epithelialization, angiogenesis, and collagen synthesis predominate.^8,9 The maturation phase involves the body remodeling collagen fiber and increasing tissue tensile strength.^8,9

 Most clean wounds heal by primary intention. Suturing each layer of tissue approximates the wound edges. These wounds typically heal quickly and require minimal wound care.

 Open wounds heal by secondary intention by granulating from the base of the wound to the skin surfaces and contracting and epithelializing from the wound edges; care must be taken to allow for uniform granulation and prevention of open pockets or tunneling.

 Tertiary intention involves a period of secondary healing to achieve edema reduction and decreased exudate production, followed by surgical closure for primary healing.

 Openly granulating wounds heal more slowly, may result in drying of granulating tissue and tissue death, and may be more painful for the patient.

 The presence of exudate is not synonymous with infection but is the natural result of the inflammatory response to maintain moisture and allow movement and replication of epithelial cells necessary for healing. A change in volume, color, or consistency of exudate may indicate impending infection.^2,4,12

 Cytotoxic cleaning agents (i.e., chlorhexidine, iodine, hydrogen peroxide) should be limited because they can delay healing.^1,4,9,12

 Wound cleaning solutions should be pH neutral.

 Normal saline (NS) solution is the cleaning agent of choice; however, tap water is safe and effective for cleaning of most acute and chronic wounds.^1,5,14

 The cleaning solution must be delivered with enough force to physically loosen foreign materials and bacteria without injuring the tissue. Effective wound cleaning is best achieved when solution is delivered at 8 to 13 psi (Fig. 126-2). A 35-mL syringe attached to an 18-gauge angiocatheter tip only delivers fluid at 8 psi. A 12-mL syringe with a 22-gauge angiocatheter tip provides 13 psi. (Increasing syringe size decreases the pressure of the stream, and increasing the bore of the catheter tip increases the pressure.) Pressures greater than 15 psi may actually force bacteria and debris deeper into the wound bed.^2,8,9,12

 Wound contamination is the presence of bacteria on the wound surface that are not actively multiplying. Signs and symptoms of infection are not present, and healing is not impaired.^4,12

 Colonization is the presence of bacteria in the wound that are actively multiplying or forming colonies. Colonization can delay healing but may not elicit signs of infection.

 Wound infection is present if organisms are present at 105 colony-forming units per milliliter (103 for virulent organisms like β-hemolytic strep⁴) in conjunction with clinical findings such as erythema, edema, pain, purulence, fever, and leukocytosis.