Lectures 1&2: Wound Healing & Wound Management

Question 1

list 3 functions of the skin

Answer 1

protection, sensation, homeostasis/regulation

Question 2

What are the 3 phases of wound healing?

Answer 2

inflammation, proliferation, maturation

Question 3

what happens during the first phase of healing, inflammation?

Answer 3

prevents exsanguination (bleeding out), establishes an immune barrier, debridement and removal of contaminants, attract cells to modulate next phase

Question 4

What are the 3 phases of inflammation?

Answer 4

hemostasis, early inflammation, late inflammation

Question 5

name 4 things that happen in the hemostasis phase of inflammation

Answer 5

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

Question 6

in early inflammation, what happens to blood vessels and what is the main cell type doing the work?

Answer 6

the vessels vasodilate, bringing the signs of inflammation, and the primary cell to come is neutrophils

Question 7

name 4 things neutrophils can do

Answer 7

kill bacteria via reactive oxygen species

breakdown the ECM

phagocytosis

release cytokines

Question 8

what is the primary cell type in late inflammation? what is their main function?

Answer 8

macrophages

degrade the ECM to facilitate cellular movement into the next phase (mediate angiogenesis and fibroplasia)

Question 9

how does the inflammatory phase:

* prevent exsanguination

* establish an immune barrier

* debride and remove wound contaminants

* attract cells that will modulate the next phase

Answer 9

* 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

Question 10

what are the 4 processes that are happening in the proliferation phase of wound healing?

Answer 10

angiogenesis

fibroplasia

contraction

epithelialization

Question 11

what days does proliferation occur?

Answer 11

4-12

Question 12

what is angiogenesis?

Answer 12

new capillaries form starting at the edge of the wound and going inwards

Question 13

angiogenesis depends on and is modulated by ______, _____, and _____

Answer 13

platelets, macrophages, keratinocytes

Question 14

angiogenesis is also dependent on the ______

Answer 14

arterial partial pressure of oxygen

Question 15

what is the ultimate end goal of angiogenesis?

Answer 15

to provide the wound with oxygen and nutrients and develop a GRANULATION TISSUE BED

Question 16

describe the process of fibroplasia

Answer 16

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.

Question 17

what is proud flesh?

why is it a problem?

what is it often a result of?

How do you treat it?

Answer 17

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

Question 18

during wound contraction, fibroblasts become ______

Answer 18

myofibroblasts

Question 19

what do myofibroblasts do?

Answer 19

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

Question 20

what stimulates the myofibroblasts to contract?

Answer 20

tension

Question 21

what is wound contracture?

Answer 21

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

Question 22

describe epithelialization

Answer 22

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.

Question 23

what is the purpose of maturation?

Answer 23

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

Question 24

list the 4 types of wound closure

Answer 24

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)

Question 25

what are the 3 factors that impact wound healing?

Answer 25

wound factors patient factors environmental factors

Question 26

what are some examples of wound factors? list at least 3

Answer 26

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

Question 27

what are some examples of patient factors? list at least 3

Answer 27

immunosuppression, neoplasia, age, malnutrition, dehydration (the ECM needs fluid for cells to do their job), obesity, species differences

Question 28

what are some examples of environmental factors? list at least 3

Answer 28

drugs, radiation therapy, prolonged anesthesia, hyperbaric oxygen, laser therapy, wound dressings

Question 29

what phase of wound healing is the vet likely to have the biggest impact? Why?

Answer 29

Inflammation because we can physically change the wound (apply pressure, clean/debride it, etc)

Question 30

why are macrophages more essential than neutrophils for wound healing?

Answer 30

because macrophages drive the transition to the proliferation phase

Question 31

what is the VERY FIRST THING you should do when dealing with a wound?

Answer 31

PUT ON GLOVES

Question 32

# define the following: abrasion avulsion incision laceration

Answer 32

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

Question 33

# define the following: puncture wound penetrating wound perforating wound contusion

Answer 33

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

Question 34

name the 4 wound classifications

Answer 34

clean clean contaminated contaminated dirty and infected

Question 35

what classifies as a "clean" wound?

Answer 35

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

Question 36

what classifies as a "clean contaminated" wound?

Answer 36

the "tracts" are entered in controlled conditions, no unusual contamination (remember contamination just means bacteria are present, it doesn't mean infection!)

Question 37

# define the following: contamination colonization infection

Answer 37

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

Question 38

what classifies a contaminated wound?

Answer 38

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

Question 39

what classifies a dirty and infected wound?

Answer 39

old traumatic wounds, clinical infections with pus, perforated viscera, 10^5 organisms per gram of tissue have contaminated the wound

Question 40

what is the golden period?

Answer 40

less than 6 hours from wounding, intervention within this grace period can reduce the risk of infection. it is an outdated idea.

Question 41

what are the basic wound management steps? there are 6

Answer 41

1. prevent futher contamination 2. debride dead/dying tissue 3. remove debris and contaminants 4. provide wound drainage 5. establish a viable vascular bed 6. select method of closure P-prevent D-debride R-remove D-drainage V-vascular bed C-closure please dont run, dogs very cute

Question 42

what are some ways to prevent further contamination of your wound?

Answer 42

wear PPE, temporary protective bandages (non adherent), fill wound with sterile lube, clip the fur, evaluate the wound, scrub the wound, rinse the wound

Question 43

what is the difference between nonselective and selective debridement techniques? Give examples of each

Answer 43

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

Question 44

list the advantages and disadvantages of nonselective vs selective debridement

Answer 44

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

Question 45

in general, ______ provides optimal drainage for contaminated or infected wounds

Answer 45

open wound mnagement

Question 46

can a drain be used INSTEAD of cleaning the wound of debris?

Answer 46

NO duh

Question 47

give examples of wounds you can close by primary intention

Answer 47

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

Question 48

give examples of wounds you would close with delayed primary closure

Answer 48

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

Question 49

give exmaples of wounds you would close via secondary closure

Answer 49

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

Question 50

give examples of wounds you would let heal via secondary intention

Answer 50

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

Question 51

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

Answer 51

assess the wound, look for signs of infection remove gross contamination, debride, and lavage consider closure aftercare

Question 52

How would you close a wound with little to no contamination and minimal tissue trauma?

Answer 52

primary intention

Question 53

how would you close a wound where there is adjacent skin available to close without tension?

Answer 53

primary intention

Question 54

how would you close a skin defect after complete excision of smaller localized areas of contamination and infection?

Answer 54

primary intention

Question 55

how would you close a contaminated wound converted into a clean wound with lots of debridement and copious lavage

Answer 55

primary intention

Question 56

ow would you close a wound with significant tissue swelling?

Answer 56

delayed primary closure

Question 57

ow would you close a wound with borderline contamination despite exploration and debridement/lavage of the wound?

Answer 57

delayed primary closure

Question 58

would you close a wound with questionable tissue viability?

Answer 58

delayed primary closure

Question 59

w would you close a wound with moderate tissue trauma or one that is at risk of infection after debridement/exploration/lavage?

Answer 59

delayed primary closure

Question 60

how would you close a wound that requires serial debridement?

Answer 60

delayed primary closure

Question 61

how would you close a wound where delayed primary closure is not possible due to the presence of an infection?

Answer 61

secondary closure

Question 62

how would you close a wound that had a persistence of moderate to severe inflammatory response ?

Answer 62

secondary closure

Question 63

how would you close a wound where there was a persistence of necrotic tissue requiring additional debridement and care beyond 5 days?

Answer 63

secondary closure

Question 64

if you had a moderate to large trunk wound on a very young animal how would you close it?

Answer 64

leave it for secondary intention

Question 65

how would you close a skin defect that couldn't easily be closed?

Answer 65

i wouldn't, i would leave it for secondary intention healing