Wound Healing Flashcards
What are the four phases off wound healing?
Haemostasis
Inflammatory
Proliferative
Maturation & remodelling
how long does it take for haemostasis and moon healing to occur?
This happens 5 to 10 minutes post injury.
Essentially this begins with endothelial injury and subsequent vasoconstriction. Platelet activation results of the side of kinds of growth factors been released. And then fibrin clot forms.Essentially this begins with endothelial injury and subsequent vasoconstriction. Platelet activation results in the side of kinds of growth factors been released. And then fibrin clot forms.
What point does the does the inflammatory phase of wound healing occur?
Day zero to day 4 post injury
In the inflammatory phase of wound healing, what are the cells that are first to arrive?
Leucocytes
What is the role of monocytes in the inflammatory phase of wound healing?
a. Vital for normal wound healing
b. Signaling normal fibroblast production
c. Predominant cell in wound exudate after the first 48 hours
d. Continue débridement and conclude the inflammatory response.
e. Secrete nitric oxide, which is bactericidal (particularly against Staphylococcus aureus)
At what point does the proliferative phase of healing occur?
Day one to three weeks post injury
At what phase of wound healing do fibroblast migrated to the wound?
Proliferative phase
What are the three events that occurred during the proliferative phase?
Collagen deposition
Epithelialization.
Angiogenesis.
When does maturation and remodelling phase of the healing occur?
Three weeks to one year post injury
Describe the phases of tensile strength and how it increases overtime.
a. At 1 week: 3%
b. At 3 weeks 20%
c. Final tensile strength: 80% of uninjured skin (never reaching the strength of normal skin)
d. Type I collagen: 90%, type III: 10% (similar to uninjured skin)
What are the 12 factors that affect wound healing?
Oxygenation.
Infection.
Nutrition.
Steroids.
Smoking.
Age
Foreign bodies
Edema
Chemotherapy
Radiation
Diabetes.
General health.
Why is oxygenation important in the healing?
- Fibroblasts are O2 sensitive, require partial pressure of oxygen (PaO2) of 30 mm Hg, and can be stimulated to proliferate and synthesize collagen if PaO2 > 40 mm Hg.
- Wound hypoxia is the most common cause of wound infection.
- Acute anemia secondary to hemorrhage is not associated with decreased wound strength.
- Vasoconstriction secondary to pain, temperature, hypovolemia, etc. can cause local tissue hypoxia.
Why does malnutrition affect wound healing?
Serum protein less than 2 g prolongs the inflammatory phase, decreases fibroplasia, and therefore delays tensile strength.
What vitamin is essential in wound healing?
Vitamin C is an essential cofactor in collagen synthesis (no benefit to supranormal levels of vitamin C).
Why do steroids affect wound healing?
- Steroids inhibit wound macrophages, fibroplasia, angiogenesis, and wound contraction.
- They increase the risk for infection.
What vitamin helps in mitigating the effects of steroids on Wound healing?
Vitamin A supplementation, 25,000 international units (IU) oral daily preoperatively and 4 days postoperatively, aids in promoting epithelialization and collagen synthesis.
Why does smoking affect wound healing?
Nicotine—vasoconstrictor—decreases cellular migration and oxygenation.
How long do dry dressing that are placed intraoperatively stay on?
Intraoperatively placed dry dressings are typically left in place, after being applied under sterile conditions, for 48 hours. This allows for epithelialization to occur. Soiled dressings should be changed.
What are the two traumatic wounds that cannot be closed primarily?
Infected wounds
Human bites
What is the benefit of negative-pressure treatment?
Increases wound oxygenation and granulation tissue
What is the benefit of hyperbaric oxygen?
Tissue oxygen tension is improved via hyperoxygenation.
What is the purpose of wet-to-dry dressings?
Débride wound exudate and cellular debris, and prevent desiccation.
Gauze is moistened with 0.9% sodium chloride.
When does wound infection typically occur post-operatively?
Postsurgical wound infections usually present approximately 3 days after surgery.
What are the two most common bugs that lead to early infection post-operatively?
Streptococci and Staphylococci
How do you prevent a seroma?
Closed suction drains
What is a clean wound
Elective, non traumatic wound
E.g. sternal wounds
What is a clean contaminated wound?
Operation on the GI or respiratory tract witout contaminaiton
What is a contaminated wound
Acute inflammation, traumatic wound, GI tract spillage, or a major break in
sterile technique
Characteristics of a dirty wound (3)
Pus present
Perforated viscus
Dirty traumatic wound
What is the infeciton rate of a dirty wound?
33%
Indications for antibiotics after drainage of a subQ abscess? (4)
Diabetes mellitus
Immunocompromised state
Prosthetic heart valve
Surround cellulitis
What is the triple therapy for nec fasc?
Pip-tazo
Vanco
Clindamycin
What are the signs/symptoms of nec fasc?
Fever
Crepitus
Pain
Discolouration
Blood blisters
Weeping skin
Inceased WBCs
Subq air
Septic shock
What is the most common aerobic bacteria found in stool?
E.coli
What is the most common anaerobic bacteria found in stool?
Bacteroides fragilis
What is thee most common ICU Pneumonia bacteria?
Gram negative organisms
POD #1 with bright red wound infection
Streptococcus infection
POD #1 with painful wound and weeping bronze-colored fluid
Clostridial wound infection
