Principles of Wound Healing

Question 1

What are the phases of wound healing?

Answer 1

Haemostasis and inflammation
Proliferation
Maturation

Question 2

Describe the haemostasis phase

Answer 2

Question 3

Describe the inflammatory phase

Answer 3

Occurs in first 72 hrs
Vasodilation (following vasoconstriction during haemostasis)
Cytokines in fibrin clot attract WBCs (neutrophils, then macrophages)
Cells destroyed by phagocytosis to ‘clean up’ bacteria and necrotic tissue

Question 4

Describe the proliferation phase

Answer 4

granulation tissue formed of macrophages, fibroblasts and new blood vessels (makes it red)
Fibroblasts proliferate and produce new extracellular matrix, elastin and collagen (starts to give wound strength)
Formation of new epithelial tissue (pale pink colour around edge)
Myofibroblasts cause wound contraction
Contact Inhibition (when epithelial cells come into contact with each other, it stops them from proliferation further)

Question 5

Describe the maturation phase

Answer 5

Remodelling
Type III (immature) collagen replaced by Type I (mature) collagen
Cross linking of collagen
Changes in components of extracellular matrix
Increase in tensile strength

Question 6

What patient factors can affect wound healing

Answer 6

age
co-morbidities (e.g., HAC, diabetes)
nutrition status

Question 7

What wound factors can affect wound healing

Answer 7

Infection
location (tension, movement, local blood supply)

Question 8

What concurrent treatments can affect wound healing

Answer 8

Corticosteroids - delays wound healing at all stages
Radiation - tissue fibrosis and vascular scarring