ANSWERS

1. What is meant by inflammation?
   The simple definition of inflammation is "the reaction of normal tissues to an irritant". It can be further defined as "a process which commences following an injury to the tissue and culminates in healing or the death of the damaged tissue".
2. State the 4 main functions of inflammatory exudate.
   • The dilution of irritant substances present in the affected tissue.
   • The delivery of cells involved in immune response to the affected tissue.
   • The delivery of immunoglobulins to the affected tissue.
   • The delivery of fibrinogen to the affected tissue.
3. List the 5 types of inflammatory exudate.
   • Fibrinous.
   • Haemorrhagic.
   • Mucous.
   • Purulent.
   • Serous.
4. List the 5 cardinal signs of inflammation.
   • Heat.
   • Loss of normal function.
   • Pain.
   • Redness (erythema).
   • Swelling.
   NB Also look out for signs of pain (restlessness, vocalisation, anorexia etc).
5. List 3 systemic signs of illness that may be associated with acute inflammation.
   • Leukocytosis.
   • Pyrexia.
   • Tachycardia.
6. Give 2 reasons why pain may be associated with inflammation.
   • Increased pressure on nerve endings due to swelling.
   • Direct irritating effect of toxins (these may be primary and arise from the actual cause of inflammation, but more commonly are a by-product of the inflammatory process itself).
7. Define necrosis.
   Cell death, and subsequent sloughing of the affected tissue.
8. What is the term that describes cell death associated with the loss of local blood supply and putrefaction of the tissues by bacteria?
   Gangrene.
9. What 2 categories of drugs are commonly used in the treatment of acute inflammation?
   • Corticosteroids (eg. Prednisolone).
   • Non-steroidal anti-inflammatories (eg. Ketofen).
10. Define chronic inflammation.
    An ongoing response to persistent irritants. It is characterised by marked monocytosis and proliferation of fibroblasts.
11. State the 3 major categories of chronic inflammation and give an example of each.
    • Persistent infection - fungal infections such as ringworm and malassezia.
    • Prolonged exposure to non-degradable irritant material - reactions to inorganic foreign material
    • Autoimmune disease - rheumatoid arthritis.
12. What are labile cells?
    Cells that divide and proliferate throughout life. They are highly capable of regeneration and are therefore important in wound healing. Epithelial cells, blood cells and lymphoid tissue are all labile.
13. What is the difference between stable cells and permanent cells?
    Stable cells are usually quiescent, but are capable of increased mitosis in response to certain stimuli, and thus may regenerate in some circumstances. Examples include the cells of bone and the endocrine glands. Permanent cells however, are only capable of mitosis in foetal life, and are unable to regenerate. Examples include neurons and cardiac muscle cells.
14. State 2 differences between first intention and second intention healing.
    • For a wound to heal by first intention, the wound edges must be close together, whilst in second intention healing, there may be a significant amount of tissue loss.
    • First intention healing is usually very much quicker than second intention healing.
15. What is another name that describes healing by second intention?
    Granulation.
16. State the 3 requirements necessary for a dressing that is applied to a granulating wound.
    • Moist environment.
    • Warm environment.
    • Reasonable absorptive capacity.
17. What type of wound would require a dressing that is non-adherent and provides a moist environment?
    A wound healing by re-epithelialisation.
18. Describe 10 factors that might contribute to the breakdown of a wound or delayed healing, and describe how each might be prevented.
    • Bacterial infection - antibiotic therapy; never suture an infected bite wound until the infection is under control.
    • Poor aseptic technique - ensure that theatre hygiene is scrupulously maintained and that instruments are properly sterilised (see Part II - Chapter 8 - Theatre Practice).
    • Reaction to suture material - ensure that appropriate materials are used and if a reaction does occur then the wound must be resutured using an alternative.
    • Poor wound closure technique - ensure that sutures are not overly tight and that there is a small tissue "bite" with an appropriate distance between each. In addition, it is worth bearing in mind that continuous sutures are more likely to result in dehiscence than interrupted sutures.
    • Pre-existing disease or poor general health - particular care must be taken if an animal is suffering from a condition in which the immune system is compromised such as FIV.
    • Dirty or wet dressings - ensure that dressings are always kept clean and dry otherwise they can be an ideal breeding ground for bacteria.
    • Drugs - some drugs such as corticosteroids, although useful in the treatment of inflammation, may delay the healing of surgical wounds, so take care in such instances. Also be cautious with regard to cytotoxics.
    • Seroma formation - ensure that the patient is kept rested, ensure that great care is taken with regard to wound closure and that a drain is used if deemed necessary.
    • Stress - ensure that the patient is treated with TLC and that any period of hospitalisation is made as pleasant as possible.
    • Patient interference - See Q17!
19. List 8 ways in which a patient might be prevented from interfering with a wound.
    • Elizabethan collar.
    • Clean, dry dressing/s.
    • Dressing of the feet to prevent injury by scratching.
    • Prevention of boredom and stress as far as possible (provide stimulation for outgoing patients and quiet for nervous animals).
    • Distraction (such as food/light exercise).
    • Use of bitter spray (but never on an open wound as this is likely to cause irritation).
    • Adequate pain relief (a patient is less likely to interfere with a non-painful wound).
    • Antibiotic therapy if indicated (an infected wound is more likely to be painful; see above).
20. State 3 important preoperative procedures that can help to prevent the incidence of wound infection and breakdown.
    • Pre-operative bathing with a suitable antiseptic solution such as chlorhexidine (Hibiscrub).
    • Pre-operative clipping (ideally approximately 2 hours prior to surgery).
    • Bowel preparation.
21. List 4 types of dressings suitable for the initial management of a contaminated wound and briefly describe each.
    • Occlusive dressings - retain moisture in order to rehydrate necrotic tissue and encourage sloughing.
    • Hydrogels - contribute to the rehydration of necrotic tissue but must be kept covered as they dry if left exposed to the air.
    • Wet packs - gauze soaked in sterile saline (a cheap, effective, alternative to occlusive dressings and hydrogels).
    • Alginate dressings - a protein based foam suitable for wounds with significant tissue loss and heavy discharge of exudate (helps with both blood clotting and wound healing).
22. What is a hydrocolloid?
    An occlusive dressing (impervious and designed to concentrate a topical application so that it will be absorbed through the skin or to protect a wound from outside contaminants).
23. What type of dressing would be most suitable for a wound with light to moderate exudation?
    Hydrocolloid or hydrogel.
24. What type of dressing would be most suitable for dressing severe burns, and why?
    Alginate; burns have a very high exudation.
25. State the 2 broad categories of skin graft and briefly describe each.
    • Skin flap - the transfer of an entire portion of skin and subcutaneous tissue complete with its own blood supply from one body area to an adjacent area.
    • Free skin graft - the transfer of one or more pieces of skin with no blood supply to a clean revascularised surgical site or to a well-established bed of granulation tissue.
26. By what other name is a skin flap commonly known?
    Pedicle graft.
27. State the 3 main ways in which a free skin graft can be classified.
    • By source (usually autogenous ie. from skin elsewhere on the same animal).
    • By thickness (split thickness or full thickness).
    • By design (pinch, mesh, strip or stamp).
28. A split thickness graft may be harvested by using a graft knife or scalpel, but there is a specialised instrument available for this purpose. What is it called?
    A dermatome.
29. What is the main advantage of a split thickness graft?
    This type of graft will "take" more readily than a full thickness graft.
30. State 3 disadvantages of a split thickness graft.
    • Not particularly strong.
    • Poor hair growth.
    • Likely to undergo contraction.
31. What is the function of the open spaces created by graft patterns such as mesh and strip grafts?
    Drainage.
    Enables a smaller size graft to be taken (eg. as the mesh/drip pattern = stretching of graft).
32. For how long should wound drains left in place?
    Passive drains 48-72 hours.
    Active drains 3-5 days (possibly longer).
33. Why might a drain be indicated?
    • To abolish dead space.
    • Therapeutic drainage of a contaminated wound.
    • To remove air from a body cavity.
34. Give an example of a situation in which a closed passive drain might be indicated.
    To collect urine from a cat with an indwelling urinary catheter following hydropropulsion.
35. What is the main difference between an open and a closed drain?
    Open drains are always passive (rely on gravity or capillary action) whilst closed drains may be active (employing a suction device) or passive.
36. What is the name of the soft latex open drain commonly used in small animal wound management?
    Penrose drain.
37. What is a sump Penrose drain?
    A Foley catheter is placed within a fenestrated Penrose drain. Fluid can pass via the outside of the Foley (sump) drain, but the placement of the Penrose means that tissue cannot adhere to the Foley thus preventing continued damage. This type of drain can remain functional for long periods.
38. State the 3 main disadvantages of drains.
    • They may provide a route for secondary infection (especially open drains).
    • They are foreign bodies and their presence reduces the resistance of local tissues to infection.
    • They may cause tissue damage if incorrectly placed or if unsuitable materials are used.
39. Give 2 examples of complications that could occur if a drain is incorrectly placed.
    • Secondary haemorrhage.
    • Formation of fistulae.
40. Briefly describe the principles of drain management.
    • Document the volume/nature of exudate.
    • Ensure that there is no obstruction.
    • Avoid reflux of fluid when changing collection vessels as this may introduce infection.
    • Ensure that dressings are changed before they become soaked in exudate.
    • Maintain cleanliness around the drain and associated wound at all times.
    • Observe for leakage.
    • Observe for signs of local wound infection.
    • Observe for signs of systemic illness.
    • Shorten passive open drains to minimise the risk of accumulating infected material.
    • Anchor the end of the drain to the skin to prevent it from being retracted into the wound.
    • Prevent patient interference.
    • Remove drains using aseptic technique.
41. What is the difference between a fistula and a sinus?
    A fistula is an abnormal tube connecting two epithelial surfaces, whilst a sinus is a blind ended infected tract or drainage channel.