Wound Healing Flashcards
1
Q
Big Factors of wound healing?
A
- nutrition
- diabetes
- smoking
- PAD
- Venous insufficiency
2
Q
What are the 4 stages of wound healing?
A
- hemostasis/coagulation
- inflammation (1st PMNs arrive and then macrophages)
- migration/proliferation
- angiogenesis
- epithelization
- contraction
- fibroplasia - remodeling
3
Q
What is involved in the coagulation stage?
A
- vessel rupture: platelet aggregation, coagulation
- platelets degranulate: release cytokines and growth factors:
PDGF
TGF-B1
IGF-1
PAF
PDEGF
Fibronectin
Serotonin - fibrin clot formation
4
Q
What is involved in inflammation stage?
A
- attraction/activation of infiltrating cells
- neutrophils:
bacteria and matrix phagocytosis, not essential unless wound contaminated - macrophages:
debridement/matrix turnover, major source of stimulatory signals, impt for wound healing
5
Q
What are the diff roles of macrophages in wound healing?
A
- phagocytosis, antimicrobial fxn
- wound debridement
- cell recruitment and activation
- angiogenesis
- matrix synthesis regulation
6
Q
What is involved in angiogenesis stage (migration/proliferation)?
A
formation of vessels:
- begin as endothelial cell buds
- progress toward wound space, following O2 gradient
- immature vessels differentiate into capillaries, arterioles, and venules
- macrophages and keratinocytes provide angiogenic stimuli
7
Q
What is involved in epithelization stage (migration/proliferation)?
A
- epidermal covering (keratinocytes) reconstituted from wound margin and hair follicle remnants
- keratinocytes migrate across wound
- during and after migration, differentiation and stratification of neodermis occur
- epithelization aided by moist environment
8
Q
Diff roles of keratinocytes in wound healing?
A
- migration/proliferation
- ECM (extracellular matrix) production
- growth factor/cytokine production
- angiogenesis
- protease release
9
Q
What is involved in fibroplasia (migration/proliferation) stage?
A
fibroblasts:
- migrate into wound site and replicate
- dominant cell type at wound edge
- synthesize and deposit collagen and proteoglycans
- matrix deposition dependent on O2 and substrate availability as well as growth factors
10
Q
Role of fibroblasts in wound healing?
A
- migration/proliferation
- ECM production
- growth factor/cytokine production
- angiogenesis
- protease release
11
Q
What is involved in the remodeling stage?
A
- changes in matrix composition over time
- lead to extracellular matrix and then collagen and lastly a scar
12
Q
Cell types involved in coagulation process?
A
- platelets
13
Q
Cell types involved in inflammatory process?
A
- platelets
- macrophages
- neutrophils
14
Q
Cell types involved in migratory/proliferative process?
A
- macrophages
- lymphocytes
- fibroblasts
- epithelial cells
- endothelial cells
15
Q
Cell types involved in remodeling process?
A
- fibroblasts
16
Q
Healing is retarded by what factors?
A
- ischemia
- dry wound enviro
- infection
- fbs
- anti-inflammatory therapy (don’t use NSAIDs)
- nutritional deficiency
17
Q
What are local factors that affect wound healing?
A
- mechanical injury
- infection
- edema
- ischemia/necrotic tissue
- topical agents
- ionizing radiation
- low O2 tension
- fbs
18
Q
What is impt info to know about your pt?
A
- age
- nutritional status
- circulation
- diabetes
- smoking (vasoconstriction, alters collagen metabolism, response to bacteria)
- steroids (decreases inflammatory process)
- support system
19
Q
What are essential nutrients involved in wound healing?
A
- calories
- carbs
- proteins
- fats
- vitamin A
- vitamin C
- zinc
- water
20
Q
Eval of pt w/ a healing wound?
A
- hx
- physical exam including pulses
- other injuries, comorbidities
- if wound not healing: A1C, check for other neuropathies (B12 def)
21
Q
What are Halsted’s principles?
A
- gentle handling of tissues
- careful hemostasis
- aseptic technique
- avoidance of tension
- sharp dissection
- obliteration of dead space
22
Q
Diff intentions of wound healing?
A
- primary intention: just epidermis and dermis involved - wound edges brought together by staples, sutures, tape, minimize scarring
- secondary intention: wound allowed to granulate, pack w/ gauze or have drainage system, slow healing time, higher risk of infection, daily wound care
- third intention: initially cleaned, debrided, left open early and closed later on, use tissue grafts
23
Q
What is primary intention healing?
A
- wound is closed w/ stitches or staples
- covered w/ sterile dressing
- may drain a small amt of blood or serosanguinous fluid
- generally kept protected from getting wet w/ plastic coer for 2-10 days depending on site, if allowed to get wet - shower only
- monitor for erythema, swelling, warmth and drainage
- note: wound is intact, no erythema or drainage, dressing is dry, wound redressed
24
Q
What is secondray intention healing?
A
- epidermis and dermis not closed, sometimes other layers not closed allowed to granulate in
- usually if there has been contamination, an infected wound, peritonitis
- has to be packed daily to q other day w/ saline moistened gauze or sponges and covered w/ sterile dressing
25
Pros of the wound vac?
- decreases edema
- enhances granulation and vascularity
- lower bacterial counts
- excellent results
26
What is surgical site infection (SSI)? How common is this?
- refers to infection at incision site, but also infections that extend to adjacent deeper structures
- among surgical pts SSIs MC nosocomial infection (accounting for 38% of nosocomial infections)
- death is directly related to SSI in over 75% pts w/ SSI who die in postop period
27
Common etiologies of SSIs?
- most are acquired at time of surgery
- MC source direct inoculation of pt flora (S. aureus and coag neg staph)
- when a viscus is opened pathogens reflect flora from viscus and are usualy polymicrobial
- more MRSA and candida are being isolated
- exogenous sources can occur from operating room personnel carrying Group A strep
28
Pt related RFs for SSIs?
- DM
- obesity
- cigarette smoking
- systemic corticosteroids or other immunosuppressive drugs
- malnutrition
- pre-op nasal carriage or colonization w/ S. aureus
- presence of remote focus of infection
- duration of preop hospitalization
- preop severity of illness of pt
29
What are the most impt factors for prevention of SSIs?
- general health of pt
- meticulous operative techniques
- timely admin of pre-op abx:
given w/in 60 min prior to surgical incision
cefazolin 1-2 g IV preferred for most procedures, for bowel procedures: cefoxitin or ampicillin/sulbactam, vanco if PCN allergic
30
Abx prophylaxis for colorectal surgery?
- can be oral, IV or both
- oral is equal to IV
- oral regimen is neomycin and erythromycin w/ bowel prep
- IV regimens:
cefoxitin or cefotetan
cefazolin + metronidazole
31
Hair removal correlation w/ SSI?
- most studies have shown increased risk of SSI in pts undergoing pre-op hair removal, one study showed the highest w/ shaving, then clipping and the least w/ depilatory
- lowest rate of SSI were reported when hair was removed just prior to surgical incision
