Wound Healing Flashcards
when does the inflammatory stage occur?
approximately day 0-5
when does the proliferation phase occur?
approximately day 4-12
what does the proliferation phase involve?
collagen production
capillary ingrowth
wound coverage
wound contraction
what is ground substance secreted by?
fibroblasts
when does epithelialization occur?
with no defect, begins immediately
with granulation tissue, begins day 4-5
what is granulation tissue a source of?
myofibroblasts
contract over tissue
what are myofibroblasts?
special fibroblasts transformed by TGF-beta
what do myofibroblasts do?
fibroblasts: secrete and synthesize collagen
smooth muscle characteristics: contractile
when does the maturation phase occur?
begins day 17-20
may continue for 12-18 months
does wounded tissue eventually achieve original strength?
no
50-80% of normal
what factors affect wound healing?
blood supply/vascular perfusion/anemia: systemic factors
tissue viability
wound fluid accumulation
mechanical factors
foreign material
drugs
infection
what are some systemic factors that affect wound healing?
immunodeficiency
cancer
age/older animals: decreased fibroplasia
what are some drugs that affect wound healing?
steroids and NSAIDs
for first stage of healing
what does exudate do in tissues in wounds?
separates tissues
why is wound infection bad for healing?
exudate separates tissues
necrosis due to bacterial enzymes and toxins
more debridement to remove necrotic material
prolonged inflammatory stage
delay or repair phase
what are the surgical wound classifications?
clean wound
clean-contaminated wound
contaminated wound
dirty wound
what is a contaminated wound?
open traumatic wounds
major break in sterile technique
spillage of GI contents or infected urine
what is delayed primary closure?
limited contamination
leave unsutured with dressing
close if clean day 3-5
minimal granulation tissue present
what is secondary closure?
contaminated wounds
open wound management
appositional closure more than day 5 after wound
direct skin apposition over granulation tissue
when is second intention healing useful?
dirty and infected wounds
when is adnexal reepithelialization useful?
cutaneous burns and abrasions
what are the methods of closure?
3-7 days after initial injury
may or may not even need closure
secondary closure
skin grafts
skin flaps
what diagnostics should you perform on draining tracts?
radiographs
fistulograms
ultrasound
CT
culture and biopsy tissue
when might you see non-healing wounds?
older or younger patients
concurrent disease
poor nutritional status
chronic inflammation
low-grade infection
repeated trauma to wound
chronic wet-to-dry bandages
should all seromas be drained?
small ones can be warm packed
large ones must be drained
what should you do in bite wound exploration?
clip area widely
open puncture with scalpel blade
hemostat to probe and examine area
excise necrotic tissue
copious lavage
drain placement and close
what should you not do with hygromas?
excise
what happens in the inflammatory stage?
hemorrhage
vasoconstriction then vasodilation
fibrin
inflammatory mediators present first 5 days
what is happening in granulation tissue?
capillary ingrowth
ground substance
collagen from fibroblasts
collagenases
what type of attachments do myofibroblasts have?
cell-to-cell
cell-to-stromal
when does contraction of myofibroblasts begin?
days 8-15
what happens with collagen in the maturation phase?
changed from type III to type I
what do steroids do that decrease wound healing?
prostaglandins are chemokines for fibroblasts into wound
decrease edema, fibrin deposition, and capillary dilation
decrease capillary proliferation
what is mandatory if the abdominal cavity is entered with bite wounds?
exploratory surgery
