CAL: Open Wound Management

Question 1

A 9-year-old Labrador is receiving chemotherapy. Five days after his last injection of chemotherapy into his left saphenous vein, he presents with a wound on his left back leg where the catheter was

Which surgical instrument would you choose to cut away the necrotic skin with?

Answer 1

• Number 10 Scalpel Blade
• Sharp cutting with a blade results in minimal tissue trauma and accurate cutting to minimise removal of healthy tissue.
• The number 10 blade has a curved edge for cutting skin along a line.
• The number 11 blade is pointed for stab incisions

Question 2

Which stages of wound healing are evident in the photo after removal of necrotic skin?

Answer 2

• Inflammation and Proliferation
• The creamy exudate suggests a wound fluid with a high white cell component and the possibility of infection.
• Thick red granulation tissue is present under the exudate. This granulation tissue is covering the muscles: you cannot see normal muscle fibres.
• Granulation tissue is composed of proliferating endothelial cells and fibroblasts, as well as macrophages.

Therefore both inflammation and proliferation are present.

• Note that inflammation inhibits epithelialisation i.e. growth of epithelial cells from the wound edges over the granulation tissue

Question 3

Which solution would you choose for wound lavage, to reduce bacterial counts, whilst minimising toxicity to cells?

Answer 3

Sterile 0.9% saline

Question 4

Following wound lavage the wound will be dressed for continued care. The owner of the dog is keen for a cost-efficient solution. They do not want the dog to stay in the hospital and they are only able to bring the dog to the vet every other day. Which dressing would you choose?

Answer 4

• Hydrogel (intrasite)
• The wound is still inflamed and may be contaminated/infected. A debriding dressing is therefore needed.
• All options are debriding except the polyurethane foam.
• Negative pressure wound therapy only needs to be changed every 3rd day, but requires hospitalisation.
• Wet-to-dry dressings need to be changed daily for very exudative wounds, because as soon as the wound fluid strikes through to the surface of the bandage, there is potential for bacteria to track from the environment, into this moist environment, to the wound.
• Sugar dressings need to be changed daily, as they are ineffective as soon as the wound fluid dilutes the sugar.
• Hydrogel dressings can be left in place for 48 hours with fewer adverse consequences compared to wet-to-dry and sugar dressings. This is the best solution given the restrictions imposed by the owner. The best way to assess how a wound will progress is to monitor it daily in the first instance

Question 5

What would be your approach to antibiotic treatment in this dog?

Answer 5

• Swab wound for bacterial culture after lavage and start amoxicillin clavulanate pending cultures.
• Always swab wounds after lavage. There may be many insignificant, non-pathogenic, environmental contaminants on the surface of an open wound, which flush off easily. You want to know what remains after lavage, as it is these bacteria that may result in infection.
• Infected wounds should always be treated on the basis of culture and sensitivity, so cultures should always be taken.
• Local wound debridement alone is effective in reducing bacterial numbers for many recent traumatic wounds. However this is a 5-day old wound.
• This dog is more prone to infection, as his immune system may be compromised by chemotherapy.
• Antibiotics are therefore indicated based on the initial wound appearance and compromised immune system, pending cultures

Question 6

A 5- year old cat undergoes removal of his left thyroid gland to remove a thyroid tumour. The wound is shown below. Cats hate neck dressings and are often more irritated by adhesive dressings than the surgical wound itself

Answer 6

Transparent polyurethane spray membrane (Opsite)

• A dressing is only required for a clean surgical wound until fibrin seals the wound, which takes up to 6 hours in an uncomplicated wound.

Question 7

A dog presents with a necrotic/ infected mammary gland. The skin and mammary gland are resected. The wound is left open for continued care

Answer 7

• Wet- to- Dry Dressing
• A debriding dressing is required.
• A tie-in wet-to-dry dressing will be ideal from a practical perspective.
• A lot of intrasite gel would be required to fill this wound and it will be difficult to keep it in the wound and contacting the entire wound surface.
• Negative pressure wound therapy requires an area around the wound, to which an adhesive film can be stuck, in order to create a seal and thus to permit creation of a vacuum. This dog’s ventrum is very undulating: a negative pressure wound dressing is unlikely to work from a practical perspective.

Question 8

A free skin graft has just been placed to close a wound on a cat’s back leg. A bandage must be applied to the graft to hold it in place while it heals and adheres to the wound bed. What dressing should be placed under the bandage?

Answer 8

Petrolatum impregnated gauze (Jelonet)

A superior non-adherent dressing is required.

Question 9

A dog has just undergone a clean knee surgery. The surgical wound is shown. The surgeon requests a supportive bandage. Which dressing should be placed over the wound and under the bandage?

Answer 9

Cotton/acrylic fibre pad with perforated polyester contact film and no peripheral adhesive (Melolin)

• A dressing to receive a small amount of post-op bleeding is required.
• A dressing without adhesive is best under supportive bandages.

Question 10

What would be the most appropriate dressing?

Answer 10

Polyurethane foam (Allevyn)

• The wound contains healthy granulation tissue.
• Peripheral epithelialisation indicates freedom from inflammation/infection.
• A dressing to promote moist wound healing is ideal.