Wounds Flashcards
(36 cards)
What are the primary goals of initial wound management in veterinary trauma cases?
- Ensure patient stabilisation before prioritising wound care, especially in polytrauma cases.
- Aim to allow healing at an optimal physiological pace.
- Avoid interventions that interfere with the healing process.
- Promote an environment conducive to natural healing or successful surgical closure.
- Note: Most visible wounds are not life-threatening unless involving arterial haemorrhage or body cavity compromise.
What are the three main stages of wound healing, and what events occur during each stage?
- Inflammatory Phase:
- Subdivided into haemostasis, early inflammation, and late inflammation.
- Involves vasoconstriction, platelet activation, neutrophil and macrophage migration, cytokine release.
- Proliferation Phase:
- Includes angiogenesis, fibroblast migration, collagen synthesis, contraction, and epithelialisation.
- Maturation/Remodelling Phase:
- Strengthening and reorganisation of collagen and epidermis.
- Reduction of cellular activity and wound tension as healing completes.
Describe the haemostasis sub-phase of the inflammatory phase in wound healing.
- Aims to prevent exsanguination via intense vasoconstriction.
- Activated platelets and coagulation cascade convert fibrinogen to fibrin.
- Platelets release thromboxane A2, histamine, and serotonin.
- Results in clot formation and recruitment of neutrophils, macrophages, fibroblasts, and endothelial cells.
What roles do neutrophils and macrophages play during wound healing?
- Neutrophils (Early Inflammation):
- Migrate to wound within 24-48 hours.
- Kill bacteria, phagocytose debris, release cytokines.
- Macrophages (Late Inflammation):
- Dominate after 48-96 hours.
- Phagocytose neutrophils, release metalloproteinases, further signal healing response.
Summarise key events in the proliferative phase of wound healing.
- Angiogenesis: New capillaries form from adjacent vessels.
- Fibroblast Migration: Formation of ECM and production of collagen, elastin, fibronectin.
- Collagen Synthesis: Mainly types I and III, forming granulation tissue.
- Contraction: Myofibroblasts align and contract wound edges.
- Epithelialisation: Keratinocytes migrate from wound edges and proliferate until coverage is complete.
What occurs during the maturation/remodelling phase of wound healing?
- Collagen cross-linking and reorganisation.
- Fibroblast and myofibroblast regression.
- Gradual increase in wound stiffness and tensile strength.
- Balance between collagen synthesis and degradation ensures structural integrity.
What are key differences in wound healing between cats and dogs?
- Cats have:
- Lower cutaneous perfusion in early healing.
- Slower granulation and epithelialisation rates.
- Reduced tensile strength and healing response.
- Greater reliance on wound edge contraction.
- More susceptible to complications from poor perfusion or wound tension.
- Clinical Implication: Leave sutures in cats longer and avoid excessive subcutaneous tissue removal.
What local factors can impair wound healing?
- Poor wound perfusion due to shock, hypotension, hypovolaemia, arterial/venous impairment, pain, diabetes
- Non-viable tissue prolongs inflammation; necrotic tissue must be debrided
- Wound fluid accumulation (haematoma/seroma) impedes healing and encourages infection
- Wound infection with >10^5 bacteria/gram tissue disrupts healing phases
- Mechanical stress (tension, motion, pressure) impairs healing
- Envenomation can also negatively impact wound healing
What systemic factors can impair wound healing?
- Immunocompromising diseases (e.g. FIV, hyperadrenocorticism, diabetes)
- Glucocorticoid use inhibits macrophages, fibroblasts, and collagen synthesis
- Cancer therapies such as chemotherapy and radiotherapy damage rapidly dividing cells and local vasculature
- Advanced age reduces dermal thickness, microcirculation, fibroblast proliferation
- Financial constraints may delay or limit comprehensive care
How are wounds classified based on contamination level?
- Clean: non-traumatic, non-infected, hollow organs not entered, aseptic, primarily closed
- Clean-contaminated: minor contamination, hollow organ entered under control, minor aseptic breach
- Contaminated: open traumatic wounds, significant aseptic breach, active non-purulent inflammation
- Dirty/infected: old traumatic wounds, pus, clinical infection, perforated viscera, >10^5 bacteria/g tissue
What are the basic wound closure options?
- Primary closure (first intention): immediate closure, clean wounds, rarely used in emergencies
- Delayed primary closure: within 3-5 days before granulation, mildly contaminated wounds
- Secondary closure (third intention): after granulation bed develops, for heavily contaminated wounds
- Second intention healing: natural contraction/epithelialisation, used when closure is not appropriate
What are advanced techniques for wound closure?
- Tension relieving techniques
- Local and subdermal plexus flaps
- Skin grafts
- Axial pattern flaps
What considerations influence wound healing and management decisions?
- Anatomic location (e.g., extremities, head, inguinal)
- Motion near joints or weight-bearing areas
- Tension and skin elasticity
- Degree of soft tissue damage
- Presence of infection
- Presence of implants and biofilm formation risk
What should be the first step when presented with a non-emergent wound in a systemically unstable patient?
Do not get distracted by the wound; initially perform appropriate stabilisation as guided by patient assessment.
What items are typically included in a wound management kit?
Lavage system (500ml-1L sterile saline, giving set, three-way tap, 30ml syringe, 18G needle), clippers, scalpel blades, suture kit, sterile lubricant, swabs, incontinence sheets, gloves, dressing material (all layers), topicals like Manuka honey.
What are Pavletic’s six basic steps in wound management?
- Prevent further contamination, 2. Debride dead tissue, 3. Remove foreign debris, 4. Provide soft tissue drainage, 5. Establish vascular bed, 6. Select appropriate closure method.
What is the preferred method for surgical debridement?
Using a scalpel is preferred over scissors as it reduces shear trauma; assess tissue viability and consider conservative debridement in anatomically delicate regions.
When and why should wet-to-dry dressings be avoided?
They should not be used beyond 72 hours post-wounding as they damage granulation tissue; they remove both necrotic and healthy tissue and are not considered biologically sympathetic.
Describe autolytic debridement and its contraindication.
Uses wound gels to support natural enzymatic breakdown of necrotic tissue. Contraindicated in deep infections as it may worsen them.
What are the benefits of Manuka honey in wound management?
Antimicrobial, promotes autolytic debridement, reduces oedema and inflammation, enhances granulation and epithelialisation.
What is pressure lavage and its recommended psi range?
Using a syringe or pressure bag setup to apply 8 psi lavage; effective range is 4-15 psi for wound cleansing.
When are drains typically unnecessary in wound management?
Drains are usually not required in open wound management because natural drainage is often sufficient.
What analgesia options are typically used in wound management?
NSAIDs, opioids (methadone, fentanyl, buprenorphine), local anaesthetics (lidocaine, bupivacaine), alpha-2 agonists, NMDA antagonists (ketamine, gabapentin), and paracetamol (dogs only).
How should systemic antibiotic use be approached in traumatic wounds?
Indicated for overt infections or high-risk wounds; ideally use culture-based, narrow-spectrum agents; tissue culture is preferred over surface swabs.
