Wound Healing Flashcards
Regeneration
Replacement of lost tissue with cells
of the same type
Regeneration Cell Types
- Labile
- Stable
Labile cells
divide constantly rapid regeneration (skin, lymphoid organs, bone marrow, mucous membranes, GI,
GU)
Stable cells
regenerate when an organ is injured (liver, pancreas, kidneys, bone cells)
Repair
Healing as a result of lost cells being replaced by connective tissue
Which is more common, repair or regeneration?
Repair
Which is more complex, repair or regeneration?
Repair
What usually results in scar formation?
Repair
Repair cell type
Permanent (CNS, cardiac muscle)
Three types of repair
- Primary Intention
- Secondary Intention
- Tertiary Intention
What is primary intention?
- Takes place when wound edges are approximated
* i.e. – surgical incision, paper cut
Three phases of primary intention?
- Initial Phase
- Granulation Phase
- Maturation Phase and Scar Contraction
How long does the initial phase of primary intention last?
3-5 days
What happens during the initial phase of primary intention?
- Blood fills into incision forms clot – provide matrix for WBC migration
- Inflammatory reaction occurs
- Injured area -fibrin clot, RBCs, neutrophils, debris
- Macrophages clean up (eat) debris, fibrin fragments, RBCs
- Fibrin clot is the mesh framework for future capillary growth and migration of epithelial cells
How long does the granulation phase of primary intention last?
3 days to 5 weeks
What happens during the granulation phase of primary intention?
- Granulation tissue: fibroblasts, capillary sprouted (angioblasts), various types of WBCs, exudate, loose - semifluid ground substance
- Fibroblasts – immature connective tissue – secretes collagen which once organized and restructured will strengthen the site
- Wound is pink and vascular with numerous red granules (young budding capillaries) are present
- Wound is friable, at risk for dehiscence, resistant to infection
- Surface epithelium at the wound edges regenerate in a few days with migration of a thin layer of epithelium across the wound surface
How long does the maturation phase of primary intention last?
7 days, and can last for several months or even years
Overlaps with the granulation phase
What happens during the maturation phase and scar formation?
- Further organization of collagen
- Remodeling process occurs
- Myofibroblast movement causes contraction of the wound and wound edge closure
- Mature scar is formed – avascular and pale; can be more painful than during granulation phase
What is secondary intention
- Wounds from trauma, ulceration, infection
- Characterized by large amounts of exudate, irregular wound edges, extensive tissue loss
- Larger inflammatory response (more debris, more cells, more exudate)
- Debris may need to be cleaned away or debrided before healing can take place
- Infected wound healing by primary intention my reopen (dehiscence) and healing by secondary intention takes place
Main differences between secondary and primary intention?
- Greater defect
- Gaping wound edges
- Heals from edges inward and from bottom of wound upward
- More granulation tissue
- Larger scar
What is Tertiary intention?
- Delayed primary intention
- Healing occurs with delayed suturing of a wound
- Contaminated wound left open and sutured closed after the infection is controlled
- Usually, results in a larger, but deeper than 1° or 2°
How are wounds classified?
- Cause (surgical, non-surgical, acute, chronic)
- Level of contamination
- Depth of tissue infected ( superficial, partial thickness, full thickness)
- Based on color (red, yellow black) – may have one, two or all three colors; classified by the least desirable color present
Adhesions
• Bands of scar tissue between/around
organs
• Abdominal cavity (may cause obstruction), between lungs and pleura
Contracture
• Contracture is part of normal wound healing
• Excessive contracture causes deformity d/t
shortening of muscle and/or scar tissue d/t
excessive scar formation – esp. near a joint
Dehiscence
Separation and disruption of previously joined wound edges
Which intention does dehiscence usually occur with?
Usually occurs with wounds healing by primary closure
Contributing factors to dehiscence
- Infection - increased inflammation
- Granulation tissue (fragile!) – not strong enough to impose forces on the wound
- Obesity – adipose tissue interferes with wound healing
Evisceration
Dehiscence to the extent that intestines protrude
Excess granulation tissue
- aka hypergranulation tissue
- aka proud flesh
- Protrudes above the surface of wound
- Cauterized or sharp debrided off
Fistula
Abnormal passage between organs or a hollow organ and the skin
Risk factors of infection
- Necrotic tissue
- Decreased blood supply
- Depressed immune system
- Patient malnourished
- Multiple stressors
- Diabetes
Hemorrhage
Excessive bleeding
Some Causes of Hemorrhage
• Suture failure • Clotting abnormalities • Infection • Dislodged clot • Erosion of blood vessel by foreign object (tube, drain)
Hypertrophic Scars
large, red, raised and hard but confined to wound edges and regresses in time
Keloid
extended beyond wound edges and may form
tumor-like mass, permanent, do not subside, often tender with pain and hyperesthesia; hereditary link, more common in dark skin persons
Cause of hypertrophic scars and keloids
excessive collagen production
Pressure Ulcers
Localized injury to the skin or underlying tissue, usually over a bony prominence.
What are pressure ulcers caused by?
pressure, friction, shear – worsened by moisture (incontinence)
Where are pressure ulcers most commonly located?
Sacrum followed by heels
The degree of injury with a pressure ulcer is related to
amount of pressure (intensity), time of pressure (duration) and the ability of the tissue to tolerate the pressure
Manifestations of pressure ulcers
- Staged according to deepest level of tissue damage (I-IV)
- Deemed ‘unstageable’ if necrosis or slough is present (cleansing and debridement required - then can be staged)
- If infected – systemic signs and symptoms and local signs of increased pain, exudate, odour, heat, warmth, size.
- Most common complication is recurrence – site of previous ulcer should be documented and frequently assessed
- Sites of pervious ulcers are replaced with granulation tissue (fragile!)
- Staging is never downgraded as an ulcer heals i.e. - stage 3 becoming a stage 2 - rather termed ‘healing stage 3 ulcer’
Manifestation of infected pressure ulcer
systemic signs and symptoms and local signs of increased pain, exudate, odour, heat, warmth, size.
Pressure Ulcer risk factors
Advanced age Anemia Contractures Diabetes Mellitus Elevated body temperature Immobility Impaired circulation Incontinence Low diastolic blood pressure Mental deterioration Neurological disorders Nurtritional deficiencies Obesity Pain Prolonged surgery Prolonged use of steroids Vascular disease
Incision with blood clot
Edges approximated with sutures
Fine Scar
What type of intention?
Primary Intention
Irregular, large wound with blood clot
Granulation tissue fills in wound
Large scar
What type of intention?
Secondary Intention
Contaminated wound
Granulation tissue
Delayed closure with suture
What type of intention?
Tertiary intention
Intact skin with nonblanchable redness of a localized area, usually over a bony prominence. Darkly pigmented skin may not have visible blanching; Its colour may differ from the surrounding skin.
Which stage of pressure ulcer is this?
Stage I Pressure Ulcer
Partial thickness loss of dermis presenting as a shallow, open ulcer with a red pink wound bed without slough. May also present as an intact or open/ruptured, serum-filled blister.
Which stage of pressure ulcer is this?
Stage II Pressure Ulcer
Full thickness tissue loss. Subcutaneous fat may be visible, but bone, tendon, and muscle are not exposed. Slough may be present but does not obscure the depth of tissue loss. May include undermining or tunneling.
Which stage of pressure ulcer is this?
Stage III Pressure Ulcer
Full thickness tissue loss with exposed bone, tendon, or muscle. Slough or eschar may be present on some parts of the wound bed. Often includes undermining and tunneling.
Which stage of pressure ulcer is this?
Stage IV Pressure Ulcer
Purple or maroon localized area of discoloured intact skin or blood-filled blister due to damage of underlying soft tissue from pressure and/or shear. The area may be preceded by tissue that is painful, firm, mushy, boggy, warmer, or cooler compared with adjacent tissue.
Which stage of pressure ulcer is this?
Suspected Deep Tissue Injury
Full thickness tissue loss in which the base of the ulcer is covered with slough (yellow, tan, grey, green, or brown) and/or eschar (tan, brown, or black) in the wound bed.
Which stage of pressure ulcer is this?
Unstageable Pressure Ulcer
What are you seeing with red wounds?
Traumatic or surgical wounds, with a possible presence of serosanguinous drainage, pink to bright or dark red healing or chronic wounds with granulating tissue.
What are you seeing with a yellow wound?
Presence of yellow slough or soft necrotic tissue (ideal for bacterial growth); liquid to semiliquid slough with exudate ranging from creamy ivory to yellow-green.
What are you seeing with a black wound?
Black, grey, or brown adherent necrotic tissue, with the possible presence of pus.
What is the goal of the treatment of a red wound?
Gentle cleansing and protection.
What is the goal of the treatment of a yellow wound?
Removal of nonviable tissue and absorption of drainage.
What is the goal of the immediate treatment of a black wound?
Debridement of the nonviable eschar.
Red wound dressings/therapies
- Transparent film/ acrylic
- Too wet - Ca-alginate, hydrophilic dressings, foam (‘pus suckers)
- Too dry - Hydrogel, hydrocolloid
- Exposed bone and tendon should remain moist
Yellow wound dressings/therapies
- Too wet - Ca-alginate, hydrophilic dressings, foam (‘pus suckers)
- Too dry - Hydrogel, hydrocolloid
- Odour - Charcoal, NaCl dressing, foam
- Infection - antimicrobial, silver, enzymatic debrider
Black wound dressings/therapies
- Too dry - Hydrogel, hydrocolloid
- Odour - Charcoal, NaCl dressing, foam
- Infection - antimicrobial, silver, enzymatic debrider
