Wounds Flashcards
Mecahnical injuries
By far most common
Grazes, abrasions, erosions – heal relatively quickly by mitotic division and migration of underlying intact basal epithelium. Minimal involvement of inflammatory cells, capilleries etc.
Bruising, hematomas, contusions (=bruise + skin injury)
Puncture/penetrating wounds
Lacerations/incised wounds
Thermal injuries
Rare
Theramal burns
Friction rubs
Chemical injuries/irradiation
Rare
Acids - cause coagulation necrosis and protein precipitation
Alkalis - cause liquefaction necrosis
Clean wound
Elective/Surgical wounds created under aseptic conditions, primarily closed.
No break in technique or dirty space entered (i.e. respiratory, GI, UG)
Clean contaminated wound
GI, respiratory or UG tract (without urinary infection) entered without significant contamination.
Or minor break in aseptic technique
Contaminated wound
Traumatic wounds = always contaminated.
Or elective procedure with major break in aseptic technique
Dirty wound
> 1x10^5 bacteria.
Traumatic wound with devitalized tissues, FB, feces, chronic wound.
Transection of clean tissues to get to dirty (i.e. abscess, sinus surgery with pus in sinus)
Stages of wound healing
Inflammatory/debridement: haemostasis/acute inflammation
Proliferative/repair: tissue formation
Maturation/remodelling: tissue strengthens
Inflammatory/Debridement: hemostasis/acute inflammation
Immediate, lasting days to weeks
Neutrophils: removed damaged tissue and chemo attractants
Macrophages: Release O2 free radials, cytokines, tissue growth factors (thus initiating proliferative phase)
Proliferative/Repair: tissue formation
Day 3-14++
Angiogenesis, fibrous and granulation tissue formation, collagen deposition, epithelialization, wound contraction
Maturation/Remodeling: tissue strengthens
14 days++
Ends in the formation of scar tissue 1 to 2 years later
remains 15% to 20% weaker than the original tissue
Collagen fibers, which were once haphazardly arranged, are reestablished in bundles, cross-linked, and aligned along lines of tension by fibroblasts to progressively increase the tensile strength.
Most important history to check after a wound
Tetatnus status of the horse
How much blood can a horse loose without concern
A 500kg horse can lose up to 5 L without too much concern
How to control haemorrhage from superficial vessels
Tight pressure bandage for around 20 minutes
Surgical haemostasis
Applying a haemostat to the vessel
Topical agents for haemostasis
often expensive.
Include fibrin adhesives, Chitosan-based dressings (Celox gauze or granules) calcium alginate products, oxidised cellulose or collagen sponges (all of which provide a substrate for clot formation) and cyanoacrylate adhesives (e.g. vet-bond).
Most are suitable for surface use only.
What should you not use on the open wound surface?
Anti-septics that contain soap on the open wound surface
Hydrogen peroxide
Hypochloride
Salicylic or aceetic acid
What should you use for wound lavage?
Warm isotonic fluids
Povidine iodine solution
Chlorhexidine
Aseptic synoviocentesis
Mandatory to assess synovial structure involvement, provided that iatrogenic contamination can be avoided. i.e. don’t pass a needle directly through the wound to access the joint, access the joint from another point e.g. if the wound is on the medial fetlock, tap the joint from the lateral side.
Heel bulb laceration
Common injury (‘over-reach’)
ID structures involved (rule out coffin joint, DDFT, and navicular bursa involvement)
Primary or delayed primary closure best
Hoof cast reduces movement to allow faster healing and better comfort - Easy to apply, Horse must be box rested
Coronary band laceration
If deep can affect coffin joint/DFTS
Suture if possible to prevent healing with the CB misaligned -> hoof wall defects
Hoof cast also good
Eyelid injuries
Must be sutured to prevent deformities -> problems with tear distribution and secondary ulceration
Even if contaminated, usually heal primarily
Check globe and orbit
Close with small gauge suture material - keep knots away from cornea
Axilla injuries
Stake injuries common
Pneumomediastinum (+/- pneumothorax) can occur due to air being pumped up when foreleg moves
Box rest may prevent this
Thorax injuries
Check for rib fracture + pleural penetration (digital exploration will tell you a lot)
If pleural penetration, can hear air being sucked in or horse in respiratory distress; radiographs
Usually a referral case - the collapsed lung plugs mediastinum so horse can usually breath with unaffected lung while travelling
Emergency chest drain?
§ Chest tube/teat cannula with 60ml syringe and 3 way stop clock to evacuate air
§ Place in upper 1/3 chest - safest
Broad spectrum antibiotics
Abdomen injuries
Careful palpation will often help to decide whether abdominal wall has been fully penetrated
Abdominocentesis can help but changes take several hours (esp if a small penetration)
Often just monitor for CS of peritonitis e.g. colic, pyrexia, high HR
If large wound and risk evisceration, plug hole with damp gamgee pads and wrap with belly bandage before referral
Flexor tendon lacerations of the lower limb
If referring a horse with a tendon laceration, splinting of the leg (dorsal cortices aligned) and broad spectrum antibiosis are indicated prior to transport.
Postoperative external coaption for a prolonged period is likely to be involved in the treatment after surgical repair
Extensor tendon lacerations
in the absence of synovial sepsis of the extensor tendon sheath are frequently managed without primary surgical repair of the tendon.
Splinting should be applied for the first few days until the animal learns to accommodate for its gait deficit.
Radiographs of wounds
Fractures
Foot penetrations - radiograph with nail still in place
Osteomyelitis - old wounds
Foreign bodies - if radiopaque
Gas opacity to determine if wounds tracking near joints or bon
Ultrasound of wounds
Gas opacity from wound often inhibits use, but occasionally useful
Soft tissue damage - i.e. wound over flexor tendon
Foreign bodies
Gas opacity to determine if wounds tracking near joints or bones
Primary closure of wounds
Clean wounds with minimal contamination are good candidates.
Will give fastest healing time + best cosmetic result.
Partial closure can be used for large wounds and often speeds healing whilst allowing drainage.
Necrotic tissue should be debrided.
Upwards pointing ‘V’ skin flap often poorly vascularised, even if it subsequently dies it acts as a biological dressing - like a full thickness skin graft.
If wound edges are under tension, tension relieving suture patterns e.g. vertical or horizontal mattress or cruciates should be used.
Stent-supported sutures provide extra tension relief of the wound margin but not often needed.
Immobilisation with a bandage cast or splint will also help to stabilise the suture line in wounds that are closed under tension.
Degloving wound has good primary closure: proximal limb bandage placed to protect flap during transport.
Best suture material for equine wounds
Polypropylene is the least reactive suture material available and is therefore the best for equine skin, but other synthetic materials are also suitable (nylon, PDS).
Standing repair or GA
fractious horse, ££, other structures involved e.g. joints