Wound Management

Question 1

Which species is the most sensitive to tetanus?

Answer 1

Horses

Question 2

What is the “Golden Period”

Answer 2

Period of time before which there is less than 10^5 bacteria/g of tissue

Question 3

T/F: There is no “Golden Period” of wounds in equine wound management

Answer 3

TRUE

Question 4

What is primary intention closure for?

Answer 4

Immediate closure of Clean and clean contaminated wounds

Question 5

What’s delayed primary closure for?

Answer 5

-2 – 5 d after injury, before granulation tissue production -Contaminated wounds/Questionable Viability -Edema/Tension

Question 6

What is secondary closure for?

Answer 6

-Closure >5d after injury. -Contaminated/infected wound

Question 7

What is healing by second intention?

Answer 7

Granulation tissue, wound contracture and epithelialization

Question 8

What are the 3 Phases of Wound Healing?

Answer 8

 Inflammation/Lag (Hemostasis and acute inflammation)  Proliferative (Tissue formation)  Remodeling (Regaining of strength)

Question 9

What are the 3 steps in the hemostasis portion of the inflammation/lag phase?

Answer 9

Platelet aggregation – seal vessels, release growth factors, fibrin deposition, 24-48 hours

Vasoconstriction (5 – 10 min) then vasodilation

Fibrin deposition

Question 10

What happens in the inflammation portion of the inflammation/lag phase?

Answer 10

1. Activated platelets release wound repair mediators
   
   1. PDGF, TGF-B,
   2. PMNs, Macrophages, Fibroblasts
      
      1. Remove damaged tissue, release chemoattractants
      2. PMNs decrease after day 2
      3. Macrophages present for days to weeks

Question 11

What happens in the proliferative phase of wound healing?

Answer 11

TISSUE FORMATION!

 Macrophage release of tissue growth factors initiates proliferative phase

 Angiogenesis

 Fibroplasia and granulation tissue formation

 Collagen deposition

 Epithelialization

 Wound contraction

Question 12

What conditions are responsible for initiating angiogenesis

in the proliferative phase of wound healing?

Answer 12

Initiated by decreased O2 tension, high lactate, low pH in wound

Question 13

What do fibroblasts do?

Answer 13

Fibroblasts migrate into wound

Release collagen, GAGs, HA, glycoproteins

Release proteases to digest fibrin clot

Question 14

Collagen production begins _______ after wounding

Answer 14

2 – 3 d

Question 15

Describe collagen production in wound healing

Answer 15

Initially ~40% Type III collagen due to dense blood vessel population

Shifts to more Type I as wound remodels

Question 16

Fibroblasts help arrange collagen molecules into fibers then bundles aligned ______ to wound surface.

Answer 16

parallel

Question 17

Epithelialization starts _______ after wounding

Answer 17

immediately

Question 18

Contraction: Begins 2nd ____ after injury

Answer 18

week

Question 19

Contraction reduces original wound by

______% via centripetal movement

Answer 19

40 – 80%

Question 20

Fibroblasts differentiate into _______ allowing for contraction

Answer 20

myofibroblasts

Question 21

When does contraction stop?

Answer 21

Stops when skin tension is greater than the ability to contract

Question 22

Remodeling Phase begins in the ________

and can last 1 – 2 years

Answer 22

2nd week

Question 23

Final scar is ______ weaker than original

Answer 23

~15 - 50%

Question 24

In the remodeling phase,

collagen fibers become cross-linked and

aligned along ___________

Answer 24

lines of tension