Wounds and Wound Management Flashcards
Skin consists of two main layers –
the epidermis and the dermis.
Describe the epidermis
Avascular keratinized stratified squamous epithelium
The stratum corneum is the outer layer of the epidermis.
Describe the dermis.
Underneath the epidermis
- Thicker, vascular (blood and lymph vessels)
- Tough fibroelastic tissue
- Supportive and nourishing function
- Rests on a layer of loose connective tissue - subcutis (hypodermis)
Subdermal plexus is of major importance.
Subcutis is composed of
adipose tissue, the cutaneous trunci muscle
and direct cutaneous arteries and veins.
Superficial blood supply in animals is different from
humans (musculocutaneous vessels) → thus we have different reconstructive techniques for each.
Musculocutaneous arteries in animals:
* Perpendicular to the skin surface
* Supply small portions of the skin
Direct cutaneous arteries in dogs and cats, vascularize…
most of the skin.
- Parallel to the skin in the hypodermis
- Arise from perforator arteries
Subdermal plexus is of major importance.
If you had an inner thigh wound what vessel would you use for your flap?
epigastric vessel number 9
Classification of wounds broadly:
open wounds and closed wounds.
Open wounds can be: (8)
- Surgical incision
- Laceration
- Abrasion
- Avulsion
- Degloving
- Shearing
- Puncture
- Bite/sting: cat/dog; snake; insect; tick
- Firearm
- Burn: thermal; chemical; electrical; radiation
- Pressure sores
- Cast- and bandage-related
Closed wounds can be: (4)
- Contusion
- Hematoma
- Crush injury
- Hygroma
Open would type: Avulsion, can be due to: (2)
- Degloving
- Shearing
Open would type: puncture, can also be due to: (2)
- Bite/sting: cat/dog; snake; insect; tick
- Firearm
Describe Incisional injuries and lacerations
- Surgical or traumatic
- Edges generally clean and free from tissue damage
Tend not to get infected
- Minimal contamination
- Sufficient bleeding to decrease tissue colonization
- Rarely significant damage to surrounding tissues
- Deep wound requires physical exploration/imaging!
- Surgical management
Describe Abrasions
- Superficial damage not extending beyond the dermis
- Frictional forces when moving parallel to a rough surface, usually at speed
- Typically combination of graze, abrasion and avulsion
- Generally heavily contaminated
- Severe abrasions with ongoing tissue
necrosis might become avulsions - Surgical vs open wound management (more commonly)
Describe avulsions: degloving injuries
Avulsion is the separation of tissue from their deeper attachments (usually including muscle).
Degloving refers to skin and deeper tissues torn from an extremity, just as a glove is removed from a hand (mechanical vs physiological).
- Defects are often extensive and complex
- May be initially free of bacterial contamination, but without appropriate wound management rapid colonization and infection of necrotic tissue will occur.
- Degloved skin should be preserved where possible
- Surgical/open wound management/in combination
Describe avulsions: shearing injuries
- Usually involve loss of deeper tissues (including skin, tendons, muscle, possibly bone)
- The joints of the distal limb frequently exposed
- Heavily contaminated with bacteria and debris
- Extremely prone to infection
- Need for orthopedic surgery?
- Open wound management
What is meant by “physiological degloving” (versus mechanical)?
physiological degloving refers to skin sloughing off due to necrosis caused by a defect in e.g. vascularization.
mechanical degloving by an object such as a car at high speed.
Describe puncture wounds.
- Caused by any sharp object that pierces the skin to create a relatively small deficit or hole
- Bite wounds (also insects/snakes); impalement (full penetration); oropharyngeal; firearm wounds (lead!?)
- Contamination/infection variable
- Damage assessment!
- Risk of abscessation
Describe burn wounds.
- Caused by extreme temperature (hot or cold) or by contact with a corrosive chemical substance, electricity or radiation.
- 1st, 2nd, 3rd degree → thickness (damage)
- ‘’Rule of nines“? (not accurate in veterinary medicine)
- May require prolonged treatment, monitoring (inpatient)
- Treatment depends on the case
Describe pressure sores.
- Caused by pressure typically on the elbows and hocks of large dogs. Intact calluses don’t need treatment.
- Open or closed wounds (e.g. hygroma is a closed pressure wound)
- Hygromas are best treated medically (meaning not surgically), so bandaging, draining etc.
- Open sores prone to infection (bones and joints)
- Medical/surgical treatment for pressure sores.
Describe Cast- and bandage-related wounds
Iatrogenic wounds are common
* Ischemic injury due to overtight application of bandage
* Inadequate padding of vulnerable areas
* Excessive exercise, allowing bandage slippage
* Wet or dirty bandages (higher risk of bacterial strikethrough and infection)
Serious wounds may result in the loss of digits or limbs
Wound healing has four distinctive phases:
- Acute inflammatory phase
- Debridement phase (breakdown)
- Proliferation phase (reparation)
- Maturation phase (remodeling)
Several phases can occur at the same time.
Depending on the type of wound and its classification, one or several phases of wound healing can be (3) (characterize the healing)
accelerated, delayed or complicated.
The inflammatory phase of wound healing can be characterized by: (5)
redness / rubor
pain / dolor
heat / calor
swelling / tumor
loss of function / functio laesa
Describe the inflammatory phase of healing:
Lasts approximately 5 days
What occurs after wound occurrence:
1. Filling with blood and lymph (from damaged vessels)
- Immediate vasoconstriction of the damaged vessels (lasts 5-10 min)
- Vasodilation (dilutes toxic substances, provides nutrients and results in a blood clot)
- Epithelial cells begin to migrate from the wound periphery onto the exposed tissue
- The blood clot dries to form a scab
- White blood cells leaking into wounds initiate the debridement phase
Describe the debridement (breakdown) phase of healing:
- Approximately 6-12 hours after injury (not always visible clinically)
- Formed inflammatory exudate provides all the necessary phagocytic cells and proteolytic enzymes to deal with the demarcation
- An exudate (of WBC, dead tissue, wound fluid) forms on the wound
- Necrotic tissue impedes wound healing
- Phase ends with the rejection of nonvital tissue
- Debridement/break down phase sometimes combines with inflammatory phase
Debridement phase also known as?
Proliferation phase also known as?
Maturation phase also known as?
- Debridement phase (breakdown)
- Proliferation phase (reparation)
- Maturation phase (remodelling)
Describe Proliferation phase granulation
- Red irregular surface
- Fragile tissue
- Functions as a barrier to infection and a scaffold for migrating epithelial cells
- Capillary network occurs through sprout formation of capillary endothelial cells on the wound surface
- Granulation tissue formed at each wound edge at a rate of 0.4 to 1 mm/24h
Describe Proliferation phase: wound contraction
- The surface and the cavity of the wound become smaller. Adjacent skin pulled closer to the center of the wound.
- Especially loose skin
- Begins 5-9 days after wounding
- Stops when edges connected/tension
too high - Risk of contracture
- Thinning of the surrounding skin
(temporary)
First 3 steps in wound management:
1) Stabilize the patient!
2) Stop active bleeding (pressure; special dressings for minor wounds
[adrenaline-soaked gauzes etc.])
3) Reduction of the level of contamination, clipping the area (ideally up to 4-6
hours after wounding to prevent bacterial infection).
Describe Autolytic debridement
- Creation of a moist wound environment to allow endogenous enzymes to dissolve nonviable tissue.
- Often preferred in wounds with questionable tissue viability.
- Highly selective for devitalized tissue
- Can be performed with interactive dressings such as hydrogels, hydrocolloids, hydrofibers and foam dressings.
- Use of honey or sugar topically (attraction of fluid).
- Painless
- Slow process
Describe Wound closure
- Decision whether or not to close the wound, and when?
- Primary closure
- Delayed primary closure
- Secondary closure
- Drainage/drains
- Tension lines (incisions/closure parallel to tension lines if possible)
Image depicts tension lines on illustrative dog.
Describe secondary wound closure.
- Closure of the wound after the formation of granulation tissue (usually approx. 5 days after wounding).
- Especially for contaminated or infected wounds.
Two methods:
* Leaving the existing granulation tissue intact, only separating the edge of the skin from the granulation tissue bed and advancing it over the wound.
or
* Excision of the granulation tissue bed followed by primary closure.
Second method is usually preferrable as:
* Wound edges more mobile
* Incidence of infection lower
* Cosmetic reasons
Describe wound drainage.
Necessary at times (moderate contamination or a large dead space).
The dead space resulting from suturing of large wounds promotes fluid accumulation, which is a good medium for growth of bacteria.
Passive drains (Penrose drain) are:
* Easier to insert, cost less
* Draining under gravity
* Risk of ascending infection
Active drains
* Creation of a vacuum that removes fluid by suction
* Can be placed anywhere on the body
* Containers need to be emptied regularly
Drain Removal as soon as possible (usually 2-4 days).
what’s this
pen rose drain or passive drain
- Easier to insert, cost less
- Draining under gravity
- Risk of ascending infection
what’s this
active drains
- Creation of a vacuum that removes fluid by suction
- Can be placed anywhere on the body
- Containers need to be emptied regularly
- e.g. Jackson Pratt drain
Wound dressings and bandages: difference.
Dressing materials are applied directly to the surface of a wound. It’s most important function is to allow moist healing.
No single dressing perfect for all wounds in all phases of wound healing – initial and follow-up assessments are necessary.
Bandage wraps are to hold plain and medicated dressings in place
(immobilization, pressure to control hemorrhage, obliteration of dead
space, protection from external trauma and contamination).
- Primary layer (contact dressing)
- Secondary (absorptive) layer
- Tertiary (protective) layer
Bandaging can be divided into 3 layers:
- Primary layer (contact dressing against actual wound)
- Secondary (absorptive for exudates) layer
- Tertiary (protective) layer
Functions of wound dressings.
- Provide a moist environment
- Provide a warm environment
- Protect from trauma
- Protect from external contamination
- Application of topical medication
- Immobilization of the wound
- Support of the wound edges
- Absorb exudate
- Prevent or reduce edema
- Provide an aesthetic appearance
Describe wound bandages in general.
- Appropriate materials of adequate width should be used.
- As smoothly as possible to prevent irritation and skin necrosis.
- Each turn of the bandage should overlap the previous turn by 50%.
- Patients should be observed for discomfort, swelling, appendage hypothermia, skin discoloration, dryness, or odor.
- (absorbent, adherent, non-adherent, stabilizing, pressure bandages, pressure relief bandages etc.)
Recite the Protocol for wound management. (10 steps)
- Use a clean room and aseptic technique.
- Obtain a complete medical history of the patient.
- Obtain information about the cause and age of the wound.
- Make a complete assessment of the wound.
- Debride necrotic tissue.
- Remove contamination.
- Choose the appropriate method of closure.
- Choose the appropriate dressing.
- Make regular assessments to monitor the progression of wound healing.
- When dealing with chronic wounds not responding to normal wound management, consider using an advanced technique.
Describe surgical closure of wounds.
- Possibilities limited mostly by imagination
- Note tension (‘’dog ears“)
- Skin stretching and expansion
