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83 Cards in this Set
- Front
- Back
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what are the 3 primary methods of wound care
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1) primary intention
2) tertiary/delayed primary intention 3) secondary intention |
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what is primary intention
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wound edges are brought together and closed surgically
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what is tertiary/delayed primary intention
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wound edges are surgically closed hours/days after initial procedure
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what is secondary intention
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wound is left open and must heal through granulation, contraction, and epithelialization
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time to heal is dependent upon?
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1) wound depth
2) location 3) geometric shape |
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based on location ____ wounds heal faster than _____ wounds
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facial wounds heal faster than sacral wounds
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based on geometric shape: which shape takes the longes to heal
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circular wounds take the longest
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what are the phases of the wound healing cascade
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hemostasis--> inflammation --> proliferation --> remodeling
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hemostasis occurs for how long
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0-3 hours
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inflammation occurs for how long
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0-3 days
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proliferation occurs for how long
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3-21 days
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remodeling occurs for how long
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21 days - 1.5 years
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what is the purpose of hemostasis
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1) form a clot
2) prevent more hemorrhage 3) limit external contamination |
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what are the characteristics of hemostasis
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1) initial vasoconstriction
2) platelet aggregation 3) fibrin deposited |
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what is the job of the depositied fibrin during hemostasis
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1) form a scaffolding for the clot
2) binds and stores growth factors 3) facilitates movement of cells into the wound site |
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what is a clot composed of
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- fibrin mesh
- aggregated platelets - embeded blood cells |
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what is the importance of a clot
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1) provides initial mesh in wound matrix which fibroblazsts and other cells migrate across
2) prevents further fluid and electrocyte loss 3) limits contamination from outside environment |
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what occurs in the inflammatory phase
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local vasodilation (following the VC from hemostasis) and cells begin to arrive platelets --> neutrophils --> macrophages
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what is the role of neutrophils
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prevent bacterial invasion
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what is the role of macrophages
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clean up debris
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what is the most important regulatory cell in the inflammatory reaction and tissue healing
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macrophages
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______ helps prepare the wound for healing
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inflammation
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what causes a wound to be in a chronic inflammatory state
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excess necrotic tissue
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what are the characteristics of the inflammation phase
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1) edema
2) erythema 3) pain 4) necrotic tissue 5) exudate |
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what are platelets
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- smallest ccell in blood
- provides initial burst of growth factors involved in clotting |
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what are erythrocytes
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RBC, contains hemoglobin
- main function is transport oxygen |
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what is a leukocyte
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WBC
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what are the two types of leukocytes
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polymophonuclear: neutrophils, eosinophils, basophils
mononuclear: monocytes, lymphocytes |
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what is occuring during the proliferation phase
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(all occuring simultaneously)
- granulation tissue fills wound bed - antiogenesis occurs - epidermal cells migrate across granulation tissue - myofibroblasts cause edges of wound to contract |
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what is angiogenesis
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forming of new blood vessels
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how quickly do myofibroblasts heal the edges of the wound
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usually 0.6- 0.7mm/day ~7mm/week
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what are the characteristics of the proliferation phase
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1) beefy red granulation tissue
2) transudate 3) start of epithelialization |
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what is a fibroblast
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synthesizes collagen and other extracellular matrix substances
--> responds to growth factors |
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what are myofibroblasts
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modified fibroblasts found at the periphery of the wound -- responsible for wound contraction
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what are glycosaminoglycans
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- provide the bulk
- maintain hydration in ECM - provide anchoring for proteins |
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what is a proteoglycan
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GAG+ 1 or more proteins
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what are the mediators for granulation
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1) integrin
2) fibroblasts (stimulated by cytokines and growth factors) |
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what are the two most important cytokines/growth factors that stimulate the migration of fibroblasts during proliferation
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PDGF
TGD-B |
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what can impede migration of fibroblasts during proliferation
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residual debris in/on the wound
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what is the role of TGF-B
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simulates the fibroblasts to secrete MMPs to facilitate migration
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what is teh purpose of angiogenesis
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1) reestablish vascular supply to new tissues
2) proliverative cells require increased oxygen supply, so angiogenesis helps supply the increased demand |
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what are the characteristics of angiogenesis
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- endothelial cell budding and migration
- tube formation - loops formation |
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what is the duration of angiogenesis
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day 2 onward
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how does angiogenesis occur
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-->signals from damaged tissue and ECM activat endothelial cells and dissolved hte basement membrane to prepare for endothelial cell proliferation and migration
--> creates spillage of plasma protein into perivascular --> endothelial cells form lumen and anastamose forming a capillary loop and blood flow begins |
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what helps migrate the endothelial cells during angiogenesis
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Integrins
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what dissolves the baseemtn membrane in angiogenesis
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MMPs
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what is anastamose
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branching out and reconnecting of the endothelial cells in angiogenesis
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what is the purpose of epithelialization
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reestablish a barrier
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what are the characteristics of epithelialization
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cell migration and proliferation
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what is the duration of epithelialization
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day 1 onward
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when does reconstruction of the epithelium begin
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almost immediately after the injury
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what role do hair follicles and sweat glands play in epithelialization
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- contribute migratory epithelial cells if not destroyed during the initial injury
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at what point in the healing phase is the wound essentially closed
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remodeling phase
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what happens in the remodeling phase
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tensile strength increases via collagen synthesis --> type 3 becomes type 1
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scar tissue is only ______ as strong as the original tissue
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only 70-80% as strong
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what are the characteristics of the remodeling phase
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1) decreased size of scar
2) decreased vascularization (lighter colored skin) |
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when does remodeling become the primary wound healing activity
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around day 21
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MMPs are involved in the breakdown of collagen.... why would we want to do this during remodelign?
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immature scar contains disorganized collagen fibers which are replaced by thicker fibers arranged in an orientation paralleling skin stresses
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_______ is essential to the formation of a strong scar
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remodeling
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MMPs belong to the family of
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protein-degrading enzymes
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what cells are responsible for synthesizing and secreting MMPs
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- neutrophils
- macrophages - fibroblasts - endothelial cells - epithelial cells |
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what are the main functions of MMPs
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responsible for tissue breakdown
- bodys natural debridement process - clear the way for cell migration |
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what are growth factors
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glycoproteins or peptieds that promote cell growth, division, migration and recruitment into injured tissue
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when are growth factors released in wound healing
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during all phases
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what cells produce growth factors
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- platelets
- macrophages - neutrophils -endothelial cells - fibroblasts |
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growth factors contribute to the proliferation and migration of cells that ____, _____, _____
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modulate epithelialization
angiogenesis collagen production |
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what growth factors directly affect growth of fibroblasts
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PDGF and FGF
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what growth factors have an angiogenesis effect
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VEGF
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wound healing is a BALANCE between
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growth factors and MMPs
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what are the characteristics of an acute wound
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- sequence of helaing is continuous and within an expected time frame
- usually achieved with few or no complications |
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what is a chronic wound
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fail to heal within an expected time frame for the underlying etiology
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chronic wounds can be cuased by a delay in any of the healing phases, but which is most common
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inflammation phase
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chronic wounds may be associated with (4)
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1) repeated trauma
2) poor perfusion/oxygenation 3) excessive inflammation 4) secondary disorders/genetic factors |
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what are the characteristics of chronic wounds
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1) ischemic
2) deficient in growth factors 3) diminished granulation tissue 4) delayed epithelialization 5) defective extracellular matrix formation 6) excessive proteases (MMPs) |
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chronic wounds have what type of cells
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senescent cells --- sleep or formant cells
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what are the local factors that may impede healing
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1) bioburden
2) tissue perfusion 3) hydration status of wound bed 4) foreign bodies 5) stressful situation 6) obesity 7) nutrition 8) temperature |
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what are the foreign bodies that may ipede healing
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sutures, mesh, necrotic tissue
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what is bioburden
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amount of bacteria present in a wound
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how does a stressful situation impede healing
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catecholamines, NE, and epi, may lead to VC and decrease tissue perfusion
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what are the co-morbidities that may impede healing
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1) diabetes
2) HIV 3) cancer 4) peripheral vascular disease 5) age |
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what are the clinician-induced factors that may impede healing
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- medications
- topical agents - physical technologies - dressings |
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what medciations can impede healing
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- overuse of antibiotics
- steroids - NSAIDs - immunosuppressive agents |
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what physical technologies may impede healing
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- whirlpool
- e-stim - intermittent pneumatic compression |
