Acute wounds include:
- Burns
- Abrasions
- Punctures
- Laceration
Burns
Wounds caused by thermal, electrical, chemical, or ultraviolet ratiation (UVR) exposure
Thermal Burns
Skin contact with flames, scalding liquids, hot objects, or inhalation of smoke or hot vapors
Chemical Burns
Occure secondary to exposure to corrosive or reactive chemicals that cause tissue damage, ulceration and sloughing. The necrotic tissue often acts as a reservoir allowing continued absorption of the chemical.
Sunburn
Too much exposure to ultraviolet A (UVA) and ultraviolet B (UVB) light produced from natural sunlight and by commercial tanning beds
Abrasions
Rubbing or friction injury to the epidermal portion of the skin and extending to the upper most portion of the dermis
Puncture
Sharp object that has pierced the epidermis and may reach into the dermis or depper tissues
Laceration
Sharp objects cutting through the various layers of the skin
What are the phases of wound healing?
- Inflammatory
- Proliferation
- Maturation (remodeling)
Inflammatory Phase
The bodies immediate response to injury. This phase lasts about 3-4 days and is responsible for preparing the wound for subsequesnt tissue development and consists of two primary parts:
- Hemostasis
- Initiated by the release of thromboplastin from injured cells to form a clot to stop bleeding and allow healing to proceed.
- Inflammatory
- Debris and bacteria are removed from wound bed. Collagen is formed to stimulate would healing, and epithelial cells migrate to cover the wound bed and provide the initial (one-cell-thick) layer of new skin that will cover the wound.
Proliferative Phase
The wound is filled with new connective tissue and covered with new epithelium. This phase starts on about day 3 and continues for about 3 weeks. It involves the formation of granulation tissue, which is a collection of new connective tissue, new capillaries, and inflammatory cells
Maturation (remodeling) Phase
The longest phase, beginning at about 3 weeks after the wound is completely closed by connective tissue and resurfaced by epithelial cells. It involes the continual process of collagen synthesis and breakdown, replacing earlier, weak collagen with high-tensile-strength collagen; this process peaks approximately 60 days after the injury has occured.
Factors affecting the wound healing process
- Local Factors
- Tissue perfusion and oxygenation
- Infection
- Wound Characteristics
- Systemic Factors
- Poor Vascularization
- Bacterial Contamination
- Inadequate Nutrition
- Coexisitn Medical Conditions
- Medication
- Tissue perfusion and oxygenation
- Infection
- Wound Characteristics
- Poor Vascularization
- Bacterial Contamination
- Inadequate Nutrition
- Coexisitn Medical Conditions
- Medication
How does poor vasculation lead to delayed wound healing?
- Results in poor oxygenation leading to:
- impaired leukocyte activity
- decreased production of collagen
- decreased epithelialization
- reduced resistance to infection
- impaired leukocyte activity
- decreased production of collagen
- decreased epithelialization
- reduced resistance to infection
Common disorders that may cause decreased perfusion
- diabetes
- severe anemia
- hypotension
- peripheral vascular disease
- congestive heart failure
How do localized infections delay wound healing?
Delays collagen sythesis and epithelialization, prolongs the inflammatory phase, and causes additional tissue destruction
- Most commonly caused by bacteria
- Streptococcus pyogens
- Enterococcus faecalis
- Staphylococcus aureus
How does nutrition play a role in wound healing?
Adequate nutrition provides the building blocks for wound repair
- Vitamin C deficiency
- leads to decreased collagen synthiesis and fibroblast proliferation
- decreased angiogenesis
- increased capillary fragility
- impaired immune response
- increased suseptability to wound infection
- Vitamin E
- anti-inflammatory properties
- decreases excess scar formation in chronic wounds
How does obesity affect wound healing?
Adipose tissue lacks blood flow causing poor perfusion
How does poorly controlled diabetes affect would healing?
- reduces collagen synthesis
- impairs wound contration
- delayed epidermal migration
- reduced polymorphonuclear leukocyte chemotaxis and phaocytosis
Strict special attenstion should be given to patients with diabetes
Medications that delay wound healing
- Glucocorticosteroids
- inhibit wound repair through global anti-inflammatory effects
- suppress celluar wound responses
- fibroblast proliferation
- collagen synthesis
- Systemic Steroids
- cause woulds to heal with incomplete granulation tissue
- reduced wound contraction
- Chemotherapeutic Drugs
- delay cell migration into wound
- decrease early wound matrix formation
- lower collagen production
- impair proliferation of firbroblasts
- inhibit contraction of wounds
- inhibit wound repair through global anti-inflammatory effects
- suppress celluar wound responses
- fibroblast proliferation
- collagen synthesis
- cause woulds to heal with incomplete granulation tissue
- reduced wound contraction
- delay cell migration into wound
- decrease early wound matrix formation
- lower collagen production
- impair proliferation of firbroblasts
- inhibit contraction of wounds
Describe skin structure and function
(Look in chapter 32)
Stage I skin injuries
Involve only the epidermis, with no loss of any skin layers, and consist primarily of reddened, nonblanching unbroken, nonblistering skin
Stage II skin injuries
Includes blistering or parieal thickeness skin loss that involves all the epidermis and part of the dermis.
