Wound Assessment

Question 1

What is wound healing by primary intention?

Answer 1

Primary intention is the healing of a clean wound without tissue loss e.g. surgical incision

Question 2

What is wound healing by secondary intention?

Answer 2

Secondary intention is the healing of a wound with considerable tissue loss and in which the edges cannot be brought together

Question 3

What are the phases of wound healing?

Answer 3

1. Hemostasis
2. Inflammation
3. Proliferation
4. Remodelling

Question 4

How long does the substrate (inflammatory) phase of wound healing last for?

Answer 4

Up to 5-7 days

Question 5

Explain the inflammatory phase of wound healing

Answer 5

Inflammatory cells migrate into the wound (chemotaxis) and promote the inflammatory phase, which is characterised by the sequential infiltration of neutrophils, macrophages, and lymphocytes.

Question 6

Explain the proliferative phase of wound healing

Answer 6

Once the wound is cleared of devitalised tissue, the arrival of fibroblasts produce collagen (type I and III) within the wound bed which cross-links and imparts strength to the scar. Wound revascularisation also occurs at this time.

Question 7

What characterises the maturation or remodelling phase of wound healing?

Answer 7

A gradual gain in tensile strength due to continued collagen deposition and collagen remodelling (type III collagen is replaced with type I)

Question 8

How does RhA lead to anaemia?

Answer 8

During conditions in which hepcidin level is abnormally high, such as inflammation (e.g. RhA), serum iron falls and this typically leads to anaemia due to an inadequate amount of serum iron being available for developing RBCs

Question 9

How does anaemia (secondary to RhA, SLE, etc.) or hypoxia (secondary to PVD) affect wound healing?

Answer 9

An anemic state decreases the amount of oxygen available to the tissues, which increases the opportunity for bacterial colonisation. In addition to hypoxia, PVD also results in a reduction of nutrients to the tissues and cells necessary to fight bacteria

Question 10

How does smoking affect wound healing?

Answer 10

The nicotine and other chemicals present in tobacco have vasoconstrictive properties, thus inducing hypoxia to the tissues and impeding wound healing

Question 11

How does infection affect wound healing?

Answer 11

Bacteria compete with the newly forming tissue for nutrients and oxygen and leads to eventual tissue starvation (anoxia). Tissue anoxia produced by bacteria results in further tissue breakdown; aerobic bacteria complicate this environment further due to their high oxygen consumption.

Question 12

Why are WBCs recruited during the inflammatory phase?

Answer 12

Neutrophils and monocytes are recruited to debride the wound by phagocytosis

Question 13

How do glucocorticoids impair wound healing?

Answer 13

1. Recruitment of WBCs in the inflammatory phase is suppressed
2. Inhibit fibroblastic proliferation
3. Reduce collagen production

Question 14

What’s the difference between a hypertrophic and a keloid scar?

Answer 14

Hypertrophic scar is a result of unchecked (excessive) proliferation of fibrous tissue but remains confined to the skin injury, whereas a keloid scar invades the surrounding normal skin i.e. beyond the incision scar

Question 15

What’s gold standard to offload diabetic foot/heel ulcer?

Answer 15

Total contact cast (TCC)

Question 16

Name the stages of bone healing

Answer 16

1. Inflammation
2. Induction
3. Remodelling

Question 17

Describe the inflammation stage of bone healing

Answer 17

• There’s haemorrhage between bone ends
• Inflammatory cells accumulate (cellular proliferation) at # line and macrophages phagocytose tissue debris
• Bone necrosis occurs as a result of tearing of blood vessels

Question 18

Describe the induction stage of bone healing

Answer 18

Provisional callus (trabecular and cartilaginous tissue) immobilises bone fragments

Question 19

Describe the remodelling stage of bone healing

Answer 19

Collagen initially forms a fibrous union of # gap, which is later remodelled, resorbed and ossified to become bony tissue

Question 20

What are the harvesian systems?

Answer 20

Narrow cannals in (cortical) bone containing blood vessels

Question 21

What is Wolff’s law?

Answer 21

‘Bone follows function’: bone is laid down where needed and resorbed where not needed.

Question 22

What is the function of PTH (parathyroid hormone)?

Answer 22

Stimulated by low calcium: decreases renal excretion and stimulates vitamin D by increasing GI absorption of calcium and osteoclastic activity from bone to release calcium

Question 23

List common types of sutures and describe their main features

Answer 23

1. Monocryl - monofilament (non-braided) and absorbable
2. Vicryl (coated) - multifilament (braided) and absorbable
3. Ethilon - monofilament and non-absorbable
4. Polypropylene - monofilament and non-absorbable

Question 24

What are the differences/benefits between mono- and multifilament and absorbable and non-absorbable sutures?

Answer 24

• Single-stranded sutures resist harbouring of micro-organisms, tie easily and [due to its smooth surface] provides less resistance to passage through tissue
• Braided sutures are stronger and more pliable but increase drag (friction) through tissues and have a higher affinity to harbour bacteria

Question 25

How are sutures absorbed?

Answer 25

They are broken down by the action of hydrolysis and phagocytosis by inflammatory cells

Question 26

Outline the four types of wounds

Answer 26

Type 1 wounds (clean) Type 2 wounds (clean contaminated) Type 3 wounds (contaminated) Type 4 wounds (dirty)

Question 27

What are type 1 wounds?

Answer 27

Clean wounds made in a sterile environment (operating theatre)

Question 28

What are type 2 wounds?

Answer 28

Minimally contaminated wounds created with a sharp, clean instrument in a non-sterile environment

Question 29

What are type 3 wounds?

Answer 29

Contaminated wounds created in a dirty environment. There is no frank infection and minimal dead tissue

Question 30

What are type 4 wounds?

Answer 30

Infected wound/grossly contaminated or devitalised wound

Question 31

How does pulse oximetry work?

Answer 31

One side of the probe contains LEDs and the other a light sensor that measures changes in light absorbed. It works on the principle that the amount of light absorbed by a solution (i.e. oxyhaemoglobin and deoxyhaemoglobin present within blood) is proportional to the concentration (i.e. oxygen saturation).

Question 32

What is the function of neutrophils in the wound-healing process?

Answer 32

The clearance of invading microbes and cellular debris in the wound area. N.B. these cells also produce substances such as ROS that cause some additional damage.

Question 33

What is the function of macrophages in the wound-healing process?

Answer 33

Macrophages release cytokines that promote the inflammatory response by recruiting additional leukocytes. They’re also responsible for clearing apoptotic cells (incl. neutrophils) for the resolution of inflammation. As macrophages clear these apoptotic cells they stimulate keratinocytes, fibroblasts, and angiogenesis to promote tissue regeneration (i.e. they promote the transition to the proliferative phase of healing).

Question 34

Explain the hemostatic phase of the wound healing process

Answer 34

Hemostasis begins immediately after wounding, with vascular constriction, platelet aggregation and fibrin clot formation (thrombus). The clot and wound tissue release pro-inflammatory cytokines and growth factors

Question 35

How does oxygenation influence healing?

Answer 35

Temporary hypoxia after injury triggers wound healing: hypoxia induces cytokine (promoters of angiogenesis) and growth factor production (from macrophages). However, prolonged or chronic hypoxia delays healing as oxygen is important for cell metabolism to sustain the healing process.

Question 36

How does stress influence healing?

Answer 36

Stress upregulates glucocorticoids and reduces the levels of proinflammatory cytokines at the wound site: the glucocorticoid cortisol functions as an anti-inflammatory

Question 37

How does diabetes influence healing?

Answer 37

The impaired healing that occurs in individuals with diabetes involves: 1. Hypoxia (insufficient perfusion as small blood vessels are dysfunctional or occluded in patients with diabetes). 2. Dysfunction in fibroblasts (fibroblasts have limited reproductive capability in the presence of hyperglycaemia, thus resulting in abnormal amount of collagen). 3. Impaired angiogenesis and neovascularisation. 4. Decreased host immune resistance as hyperglycaemia decreases phagocytosis/the killing of bacteria by white blood cells. 5. Neuropathy.

Question 38

How do glucocorticoid steroids influence healing?

Answer 38

- They inhibit wound repair via global anti-inflammatory effects and suppression of cellular wound responses incl. fibroblasts proliferation and collagen synthesis. - Beyond effects on repair, systemic corticosteroids may increase the risk of wound infection

Question 39

How do chemotherapeutic drugs influence healing?

Answer 39

Most chemotherapeutic drugs are designed to inhibit cellular metabolism and rapid cell division 1. These medications inhibit DNA, RNA, or protein synthesis, resulting in decreased neovascularisation (angiogenesis), and lower collagen production and fibroblast proliferation 2. Delay cell migration into the wound 3. Inhibit contraction of wounds 4. Weaken immune functions of the patient and thereby impede the inflammatory phase of healing and increase the risk of wound infection. 5. Induce neutropenia, anaemia, and thrombocytopenia, thus leaving wound vulnerable to infection, causing less oxygen delivery to the wound.

Question 40

How does obesity influence healing?

Answer 40

Higher rate of complications (e.g. wound infection, wound dehiscence) due to: 1. Hypoperfusion and ischaemia that occurs in subcutaneous adipose tissue 2. Increased tension in wound edges contributes to wound dehiscence. 3. Wound tension also increases tissue pressure, reducing microperfusion and the availability of oxygen to the wound.

Question 41

How does alcohol influence healing?

Answer 41

Alcohol impairs wound healing and increased the incidence of infection by: 1. Suppressing pro-inflammatory cytokine release in response to an inflammatory challenge i.e. impaired early inflammatory response 2. Decreased neutrophil recruitment and phagocytic function 3. Decreased angiogenic capacity (up to 60 %): this decrease in wound vascularity causes increased wound hypoxia and oxidative stress 4. Decreased collagen production

Question 42

How does smoking influence healing?

Answer 42

1. In the inflammatory phase, smoking impairs WBC migration, resulting in lower numbers of monocytes and macrophages in the wound site, and reduces neutrophil bactericidal activity. These effects result in poor wound healing and an increased risk of opportunistic wound infection. 2. In the proliferative phase of wound healing, smoking decreases fibroblast migration and proliferation 3. Nicotine interferes with oxygen supply by inducing tissue ischaemia as nicotine decreases tissue blood flow via its vasoconstrictive effects: nicotine stimulates sympathetic nervous activity, resulting in the release of epinephrine, which causes peripheral vasoconstriction. 4. Carbon monoxide also causes tissue hypoxia: carbon monoxide aggressively binds to haemoglobin with an affinity 200 times greater than that of oxygen, resulting in a decreased fraction of oxygenated haemoglobin in the bloodstream. 5. Hydrogen cyanide, a component of cigarette smoke, impairs cellular oxygen metabolism, thus compromising oxygen consumption in the tissues. 6. Beyond these direct effects, smoking increases the individual's risk for atherosclerosis and COPD, two conditions that might also lower tissue oxygen tension.

Question 43

How does nutrition influence healing?

Answer 43

1. A deficiency of protein can impair capillary formation, fibroblast proliferation, proteoglycan synthesis, collagen synthesis (collagen is a major protein component of connective tissue), and wound remodelling. 2. A deficiency of protein also affects the immune system, with resultant decreased leukocyte phagocytosis and increased susceptibility to infection. 3. Collagen synthesis also requires co-factors such as ferrous iron and vitamin C. Impaired wound healing results from deficiencies in any of these co-factors. 4. Arginine is a semi-essential amino acid and sufficient levels are needed to support collagen deposition, angiogenesis, and wound contraction. Arginine also improves immune function. 5. Omega-3 fatty acids improve the systemic immune function, thus reducing infectious complications 6. Vitamin C deficiency results in impaired healing in part due to decreased collagen synthesis and fibroblast proliferation, and decreased angiogenesis. Vitamin C deficiency also leads to an impaired immune response and increased susceptibility to wound infection. 7. Vitamin A deficiency leads to impaired wound healing as its properties include anti-oxidant activity, increased fibroblast proliferation, and increased collagen synthesis. 8. Vitamin E, an anti-oxidant, maintains cellular membrane integrity by providing protection against destruction by oxidation. Vitamin E also has anti-inflammatory properties and has a role in decreasing excess scar formation. Topical vitamin E has been promoted as an anti-scarring agent. 9. Magnesium functions as a co-factor for many enzymes involved in protein and collagen synthesis. 10. Copper is required for the optimal cross-linking of collagen. 11. Zinc deficiency impairs wound healing. 12. Iron is required for the hydroxylation of proline, so, severe iron deficiency can result in impaired collagen production.