Lectures 1&2: Wound Healing & Wound Management Flashcards
list 3 functions of the skin
protection, sensation, homeostasis/regulation
What are the 3 phases of wound healing?
inflammation, proliferation, maturation
what happens during the first phase of healing, inflammation?
prevents exsanguination (bleeding out), establishes an immune barrier, debridement and removal of contaminants, attract cells to modulate next phase
What are the 3 phases of inflammation?
hemostasis, early inflammation, late inflammation
name 4 things that happen in the hemostasis phase of inflammation
vasoconstriction of arteries and capillaries
platelet aggravation and initiation of the coagulation cascade
insoluble fibrin clot becomes a scaffold for cell migration
platelet degranulation, cytokines attracting other cells
in early inflammation, what happens to blood vessels and what is the main cell type doing the work?
the vessels vasodilate, bringing the signs of inflammation, and the primary cell to come is neutrophils
name 4 things neutrophils can do
kill bacteria via reactive oxygen species
breakdown the ECM
phagocytosis
release cytokines
what is the primary cell type in late inflammation? what is their main function?
macrophages
degrade the ECM to facilitate cellular movement into the next phase (mediate angiogenesis and fibroplasia)
how does the inflammatory phase:
* prevent exsanguination
* establish an immune barrier
* debride and remove wound contaminants
* attract cells that will modulate the next phase
* hemostasis and clot formation
* neutrophils and macrophages, phagocytosis, ROS, etc
* same as above, mostly macrophages in late stages
* cytokines from every host cell but macrophages mostly signal for next phase
what are the 4 processes that are happening in the proliferation phase of wound healing?
angiogenesis
fibroplasia
contraction
epithelialization
what days does proliferation occur?
4-12
what is angiogenesis?
new capillaries form starting at the edge of the wound and going inwards
angiogenesis depends on and is modulated by ______, _____, and _____
platelets, macrophages, keratinocytes
angiogenesis is also dependent on the ______
arterial partial pressure of oxygen
what is the ultimate end goal of angiogenesis?
to provide the wound with oxygen and nutrients and develop a GRANULATION TISSUE BED
describe the process of fibroplasia
mesenchymal cells are activated and transform into fibroblasts which migrate and proliferate into the wound. These fibroblasts rebuild the ECM and lay down building blocks such as collagen.
what is proud flesh?
why is it a problem?
what is it often a result of?
How do you treat it?
excessive granulation tissue, it becomes thick and irregular
it interferes with epithelialization
it is often a result of chronic inflammation
treat by excising the tissue and giving antiinflammatories
during wound contraction, fibroblasts become ______
myofibroblasts
what do myofibroblasts do?
they anchor to each other as well as to the ECM and help the wound contract. they have contractile properties but are NOT muscle cells
what stimulates the myofibroblasts to contract?
tension
what is wound contracture?
a decrease in motion or function due to excessive scar tissue, muscle atrophy, or fibrosis. Essentially there is too much contraction, forming too much collagen and not enough elasticity for the excessive tension that is occurring
describe epithelialization
begins at the wound edge, the keratinocytes detach from the edge and tumble out into the wound. once the cells touch each other, they stop. there is no dermis formed so there are no adnexal structures made.
what is the purpose of maturation?
to reorganize and remodel the scar, reorganization of collagen and regression of the myofibroblasts (we don’t need them anymore), and focus on rebuilding as much strength as possible. the scar will never be as strong as the original tissue though
list the 4 types of wound closure
1st (primary) intention healing (close right away, wound edges apposed)
delayed primary closure (close it after 3-5 days before granulation tissue is present)
secondary closure (close after 5-10 days after granulation tissue has formed)
second intention (leaving it open to heal naturally with no intervention)
what are the 3 factors that impact wound healing?
wound factors
patient factors
environmental factors
what are some examples of wound factors? list at least 3
the amount of wound perfusion (is it getting enough oxygen)
tissue viability (is any of the tissue dead?)
fluid accumulation (too much can occlude vessels)
infection (overwhelm the neutrophils and other cells)
mechanical forces
envenomation
what are some examples of patient factors? list at least 3
immunosuppression, neoplasia, age, malnutrition, dehydration (the ECM needs fluid for cells to do their job), obesity, species differences
what are some examples of environmental factors? list at least 3
drugs, radiation therapy, prolonged anesthesia, hyperbaric oxygen, laser therapy, wound dressings
what phase of wound healing is the vet likely to have the biggest impact? Why?
Inflammation because we can physically change the wound (apply pressure, clean/debride it, etc)
why are macrophages more essential than neutrophils for wound healing?
because macrophages drive the transition to the proliferation phase
what is the VERY FIRST THING you should do when dealing with a wound?
PUT ON GLOVES
define the following:
abrasion
avulsion
incision
laceration
abrasion: skin rubbed or scraped
Avulsion–>
complete: complete displacement/tearing of tissue segment
partial: partial detachment of a tissue segment (like a skin flap)
degloving: traumatic partial avulsion in a circumferential fashion
incision: cut of orderly depth with sharp instrument
laceration: irregular cut of non orderly depth, jagged edges
define the following:
puncture wound
penetrating wound
perforating wound
contusion
puncture: hole or wound created by a sharp pointed object
penetrating: puncture in which the object enters but does not emerge beyond it
perforating: puncture in which the object enters and exits
contusion: skin not broken but capillaries are ruptured causing pain and swelling as well as discoloration
name the 4 wound classifications
clean
clean contaminated
contaminated
dirty and infected
what classifies as a “clean” wound?
not traumatic, not infected, made in aseptic conditions, think surgery
also none of the “tracts” leading to the outside world were entered such as the Gi tract, oropharyngeal, respiratory, urogenital
what classifies as a “clean contaminated” wound?
the “tracts” are entered in controlled conditions, no unusual contamination (remember contamination just means bacteria are present, it doesn’t mean infection!)
define the following:
contamination
colonization
infection
contamination: bacteria are present but not replication
colonization: bacteria are present and replicating but are not harmful or pathologic
infection: bacteria are present, replicating, and harmful
what classifies a contaminated wound?
open and fresh traumatic wounds, maybe a major break in sterile technique, incisions in the colon, spillage of the GI tract like in a FB surgery, wounds less than 6 hours old
what classifies a dirty and infected wound?
old traumatic wounds, clinical infections with pus, perforated viscera, 10^5 organisms per gram of tissue have contaminated the wound
what is the golden period?
less than 6 hours from wounding, intervention within this grace period can reduce the risk of infection. it is an outdated idea.
what are the basic wound management steps? there are 6
- prevent futher contamination
- debride dead/dying tissue
- remove debris and contaminants
- provide wound drainage
- establish a viable vascular bed
- select method of closure
P-prevent
D-debride
R-remove
D-drainage
V-vascular bed
C-closure
please dont run, dogs very cute
what are some ways to prevent further contamination of your wound?
wear PPE, temporary protective bandages (non adherent), fill wound with sterile lube, clip the fur, evaluate the wound, scrub the wound, rinse the wound
what is the difference between nonselective and selective debridement techniques? Give examples of each
nonselective: using surgical technique or surgical tools
example: cutting something, mechanical like wet to dry bandage and then tearing it off
selective: facilitate debridement to happen on its own
example: enzymatic, autolytic, biotherapeutic like maggots
list the advantages and disadvantages of nonselective vs selective debridement
nonselective: fast, good for large necrotic areas, BUT can traumatize healthy viable tissue
selective: necrotic tissue os targeted with minimal damage to viable tissue BUT it is slow and not suited for areas or large necrosis
in general, ______ provides optimal drainage for contaminated or infected wounds
open wound mnagement
can a drain be used INSTEAD of cleaning the wound of debris?
NO duh
give examples of wounds you can close by primary intention
wounds with little to no contamination like an incision
contaminated wounds converted to clean with debridement and lavage
skin defects after excision of smaller areas of infection (just cut the wound out!)
when the skin can close WITHOUT tension
give examples of wounds you would close with delayed primary closure
wounds with borderline contamination despite debirdement and lavage
wounds with moderate tissue trauma where there is a risk of infection after debridement and lavage
wounds with questionable tissue viability
wounds that require additional debridement
wounds where there is too much tissue swelling (causing tension) preventing primary closure
give exmaples of wounds you would close via secondary closure
when delayed primary closure isn’t possible usually because of infection
when there is persistent necrotic tissue that requires additional debridement for more than 5 days
when a severe inflammatory response persists
give examples of wounds you would let heal via secondary intention
skin defects that you can’t reasonably close at all
dirty and infected wounds where other methods are just not advisable
moderate to large trunk wounds on very young animals
surgical wounds you want to heal via secondary itnention
a dog is brought to you after a dog fight and has a bite wound. list the steps you would take (in simple terms) to address the wound
assess the wound, look for signs of infection
remove gross contamination, debride, and lavage
consider closure
aftercare
How would you close a wound with little to no contamination and minimal tissue trauma?
primary intention
how would you close a wound where there is adjacent skin available to close without tension?
primary intention
how would you close a skin defect after complete excision of smaller localized areas of contamination and infection?
primary intention
how would you close a contaminated wound converted into a clean wound with lots of debridement and copious lavage
primary intention
ow would you close a wound with significant tissue swelling?
delayed primary closure
ow would you close a wound with borderline contamination despite exploration and debridement/lavage of the wound?
delayed primary closure
would you close a wound with questionable tissue viability?
delayed primary closure
w would you close a wound with moderate tissue trauma or one that is at risk of infection after debridement/exploration/lavage?
delayed primary closure
how would you close a wound that requires serial debridement?
delayed primary closure
how would you close a wound where delayed primary closure is not possible due to the presence of an infection?
secondary closure
how would you close a wound that had a persistence of moderate to severe inflammatory response ?
secondary closure
how would you close a wound where there was a persistence of necrotic tissue requiring additional debridement and care beyond 5 days?
secondary closure
if you had a moderate to large trunk wound on a very young animal how would you close it?
leave it for secondary intention
how would you close a skin defect that couldn’t easily be closed?
i wouldn’t, i would leave it for secondary intention healing
