Wound Healing Flashcards
What are the four stages of wound healing?
- Hemostasis/Coagulation (fibrin)
- Inflammation (PMNs in the first 24h, Mfgs in 48h)
- Migration/Proliferation (collagen, fibroblasts)
- Remodeling
Coagulation
-what comprises a thrombus?
Thrombus
-fibrin threads, erythrocytes, platelets
Inflammation
- What cells are involved?
- what is the function of the cells?
Cells
- Neutrophils
- -bacteria and matrix phagocytosis
- Mfgs
- -phagocytosis, wound debridement, cell recruitment and activation, angiogenesis, matrix synthesis regulation
Migration/Proliferation
- describe angiogenesis
- describe epithelization
- role of keratinocytes
- describe fibroplasia
Angiogenesis
-formation of vessels; endothelial cell buds follow oxygen gradient, differentiate into capillaries, arterioles, and venules. Mfgs and keratinocytes provide angiogenic stimuli
Epithelization
- Keratinocytes migrate across wound; during migration differentiation occurs.
- Epithelization aided by moist environment
Keratinocytes
-migration/proliferation, ECM production, growth factor/ cytokine production, angiogenesis, protease release
Fibroplasia
- fibroblasts migrate into wound site and replicate, synthesize and deposit collagen and proteoglycans
- matrix deposition is dependent on oxygen and substrate availability as well as growth factors
What is the dominant cell type at the wound edge?
What is that cells role?
Fibroblasts, yo.
Role
- migration/proliferation
- ECM production
- Growth factor/cytokine production
- angiogenesis
- Protease release
*This is the same as keratinocytes! The difference lies with the growth factors they release
Remodeling
-explain the changes in matrix composition over time
extracellular matrix… collagen… scar
Summing it up... What cell types are involved in each stage -coagulation -inflammation -migratory/proliferation -remodeling
Coagulation
-platelets
Inflammation
- platelets
- mfgs
- neutrophils
Migratory/proliferative
- mfgs
- lymphocytes
- fibroblasts
- epithelial cells
- endothelial cells
Remodeling
-fibroblasts
Factors that may cause slowed healing
Local factors that affect wound healing
Slowed
- ischemia
- dry wound environment
- infection
- foreign bodies
- anti-inflammatory therapy
- nutritional deficiency
Local factors
- mechanical injury
- infection
- edema
- ischemia
- topical agents
- ionizing radiation
- low O2 tension
- foreign bodies
Essential nutrients for wound healing
- calories
- carbs
- protein
- fats
- Vit A, C
- Zinc (Most important mineral for wound healing)
- Water
What are Halsted’s Principles?
- gentel handling of tissues
- careful hemostasis
- aspetic technique
- avoidance of tension
- sharp dissection
- obliteration of dead space
What is healing by primary intention?
secondary?
Third?
Primary: sutures, staples, pulling everything together nicely, covered with sterile dressing
Secondary: wound is not closed and allowed to granulate, slow healing, need a drain or daily wound care
Third: cleaned, I and D, left open for 4-5 days, and then closed
Benefits of the V.A.C.
Decrease edema
Enhances granulaiton and vascularity
Lower bacterial counts
Surgical site infections
- definition
- SSIs are the most common what
- MC bug
- pt related risk factors
Definition
-refer to infection at incision site, but also infections that extend to adjacent deeper structures
Most common nosocomial infection
MC bug is staph aureus and coag neg staph
Risk factors
- DM
- Obesity
- smoking
- systemic steroids or other immunosuppressive drugs
- malnutrition
- pre-op nasal carriage or colonization w/ staph aureus
- presence of remote focus of infection
- duration of preoperative hospitalization
- preop servity of illness of pt
What are the three most important factors for prevention of SSIs?
- general health of pt
- meticulous operative techniques
- timely administration of pre-op antibiotics
Abx prophylaxis for colorectal surgery
- route
- drugs
Route
- oral
- IV
- both
Drugs
- Oral: neomycin and erythromycin w/ bowel prep
- IV: cefoxitin or cefotetan or (cefazolin PLUS metronidazole)
