Skin/Wounds

Question 1

Wounds can be classified into four types based on the degree of contamination. Name one example for each type.

Answer 1

1) Clean: surgical incision
2) Clean-contaminated: surgical entry into the GI tract
3) Contaminated: Bite wound
4) Dirty/Infected (contains > 10^5 organisms per gram of tissue; time frame is > 6hrs): Abscess

Question 2

How strong is a scar tissue compared to normal tissue?

Answer 2

80% of normal tissue

Question 3

Describe four stage of wound healing, the onset time and the hallmark for each phase.

Answer 3

1) Inflammation
- immediately after injury, lasting for about 5 days
- Hemorrhage, blood clot formation, inflammatory cytokines enter the wound (e.g. histamine, prostaglandin, leukotriene, growth factor, complement)

2) Debridement
- Simultaneously as inflammation phase
- Hallmark: WBCs enter the wound
- Neutrophils enter the wound first (within 6 hours of injury)
- Monocytes enter the wound at around 12 hours after injury, become macrophages at 24-48 hours post-injury.
- Macrophages stimulate fibroblasts activation, collagen synthesis and angiogenesis

3) Repair/Proliferation
- starting at 3-5 days post-injury and last for 2-4 weeks
- Hallmark: angiogenesis, epithelialization, granulation tissue formation

4) Maturation
- Starting at 17-20 days post-injury and can last for years
- Hallmark: wound contraction, remodeling of collagen fiber bundles

Question 4

What is the goal for wound management?

Answer 4

Providing healthy wound bed and good blood supply for tissue healing

Question 5

If you need to use chlorhexidine to flush a very dirty wound, what is the recommended concentration?

Answer 5

0.05%
(1 part of 2% Chx to 40 part with saline)

Question 6

What are the functions of the three layers of the wound bandage?

Answer 6

1) Primary: dressing directly contact the wound
- Adherent (for mechanical debridement) vs Non-adherent (provide/maintain moist environment in the wound and facilitate healing)
2) Secondary
- Padded materials to cover the primary layer and aid in absorb excessive discharge
3) Tertiary
- Protective effect and hold the first two layers in place

Question 7

What is the contraindication for calcium alginates dressing?

Answer 7

Do not use when the tendon, bone or necrotic tissue are exposed.

Question 8

When is the time to discontinue hydrogels?

Answer 8

When healthy granulation tissue is present
(it can promote exuberant granulation)

Question 9

What is the definition of secondary wound closure?

Answer 9

The wound is closed 5 or more than 5 days after the initial injury, when granulation tissue has formed in the wound bed.

Question 10

What is the definition of second intention healing?

Answer 10

The wound is left open and rely on wound contraction and epithelialization to close it.

Question 11

What is the common pressure set for negative pressure wound therapy?

Answer 11

-125mmHg

Question 12

What are the contraindications for negative pressure wound therapy?

Answer 12

1) Exposed vessels
2) Exposed organs
3) Exposed nerves
4) Exposed anastomotic site
5) Active hemorrhage or patient with bleeding disorder
6) Necrotic tissue with eschar present
7) Untreated osteomyelitis
8) Malignancy in the wound
9) Nonenteric and unexplored fistulas

Question 13

What are the components of provisional and definitive extracellular matrix?

Answer 13

Provisional:fibrin, fibrinogen, fibronectin, vitronectin
Definitive: collagen, elastin, hyaluronic acid

Question 14

How long does it take for GI mucosa to heal with direct apposition?

Answer 14

3 days

Question 15

True or False: During wound irrigation, copious amount of solution is more important than the sterility and antimicrobial property.

Answer 15

True

Question 16

What is hepatic-cutaneous syndrome also called?

Answer 16

Superficial necrolytic dermatitis
Metabolic epidermal necrosis

Question 17

What is the characteristic of the hepatic-cutaneous syndrome in dogs?

Answer 17

• Increased hepatic metabolism activity (either due to elevated glucagon or unknown stimulus)
• Amino acid deficiency +/- zinc, vitamin B deficiency

Question 18

In dogs with hepatic-cutaneous syndrome, what is the common findings on liver ultrasound?

Answer 18

Multiple hypoechoic hepatic nodules with hyperechoic borders in variable sizes (Swiss cheese–like appearance)

Question 19

How do you treat hepatic-cutaneous syndrome and what is the prognosis?

Answer 19

Supportive care (amino acid, zinc, vitamin B, essential fatty acid supplementation)

Poor prognosis :(

Question 20

Define Levine culture technique.

Answer 20

A sterile culturette swab was twirled over a 1-cm^2 area of the wound bed for a period of 5 seconds while applying sufficient pressure to express wound fluid or to cause minimal bleeding from the wound.