Wound healing

Complex biologic and molecular events including cell migration, proliferation and extracellular matrix deposition.

Wound healing is a highly organized and complex process involving hemostasis, inflammatory response, proliferation and remodeling.

For wound healing to occur there must be: adequate tissue perfusion, an intact immune system, appropriate wound hydration, removal of necrotic/non-viable tissue, and management of infection if present.

Tissue repair following a wound occurs in a range from underhealing, as occurs in chronic wounds, to over healing, as seen in fibrosis.

A fibroproliferative response mediated by growth factors and cytokines.

Quality and adequacy affected by systemic factors such as nutritional, hormonal, metabolic, and circulatory status of the host tissue, and local factors including the size, location, infection, mechanical factors.

The nature, size and depth of skin injury affect cellular and molecular healing events at the cellular level.

Foreign bodies at a wound site affects the healing process.

Scalpel skin injuries cause less tissue damage than do thermal or radiation injuries resulting in less scarring.

Acute cutaneous wounds with no preceding underlying pathophysiological defect is associated with rapid repair with scar and no regeneration.

In chronic wounds such as in a diabetic ulcer impaired healing occurs.

As many as 4 1/2 million people have been estimated to have chronic wounds.

Three phases: First-exudative phase days 1-4 dominated by vascular, cellular and enzymatic processes that do not add holding strength to the wound. Second-proliferative phase days 5-20, during which epithelialization, wound contraction and connective tissue repair add 15-30% of original tensile strength. Third-remodeling phase during which rearrangement and cross-linking of collagen fibers occur from day 21 to several years with tissue regaining up to 80% of original tensile strength.

Chronic wounds result from a variety of pathological states including: arterial or venous insufficiency, diabetes, undue skin pressure, the presence of a foreign body, and infection.

Dressing management for chronic wounds include: maintaining a moist wound environment, preventing or treating infection, and minimizing skin irritation or friction between the wound and clothing or devices such as wheelchairs.

Dressings do not heal the wound, the body does.

Factors in wound care include protecting periwound skin, forming an effective bacterial barrier that conforms to the wound shape, producing minimal pain during dressing changes, avoiding non-biodegradable fibers being placed into the wound, and maintaining optimal wound temperature and pH.

Dressings deliver debridement or antimicrobial agents.

Absorbent dressings are useful for wounds with heavy exudate.

A moisturizing dressing such as hydrogel is used for dry wounds.

Steile gauzed dressings are standard care.