Lecture 12: Open Wound Management (Exam 2) Flashcards
When should wounds be covered w/ a clean & dry bandage
- Immediately after injury
- When the animal is brought for treatment
T/F: Further wound management should be done before life threatening injuries are treated & the animal’s condition stabilized
False
What are the fundamentals of wound management
- Temporarily cover the wound to prevent further trauma & contamination
- Asses the traumatized animal & stabilize its condition
- Clip & aseptically prepare the area around the wound
- Culture the wound
- Debride dead tissue & remove foreign debris from the wound
- Lavage the wound thoroughly
- Provide wound drainage
- Promote healing by stabilizing & protecting the cleaned wound
- Perform appropriate wound closure
What is the golden period
- First 6 to 7 H btw/ wound contamination @ injury & bacterial multiplication to greater than 10^5 CFU per gram of tissue
When is a wound classified as infected rather than contaminated
When bacterial #s exceed 10^5 CFU per gram of tissue
Define contamination
Presence of microbes on a surface
Define colonization
Surface microorganisms are replicating
Define infection
Invasion & replication of microbes w/in the tissue
What is the equation for microbial burden
(# of microorganisms x virulence)/ Host Resistance
Describe a class 1 wound
- 0 to 6 hours old
- Minimal contamination & tissue trauma
Describe a class 2 wound
- 6 to 12 hours old
- Microbial levels may not have reached critical level consistent w/ dev of infection
Describe a class 3 wound
- Older than 12 H
- Microbial levels may have reached critical level consistent w/ dev of infection
List the categories of wounds
- Abrasions
- Puncture wound
- Laceration
- Avulsion or degloving injury
- thermal burn
- Decubital ulcers
Describe abrasions
- Superficial & involve destruction of varying depths of skin by friction from blunt trauma or shearing forces
- Sensitive to pressure or touch & bleed min
- Heal rapidly by reepithelialization
Describe puncture wounds
- Small skin opening w/ deep tissue contamination & damage
- Wound depth & width vary depending on the velocity & mass of the object creating the wound
- The extent of tissue damage is directly proportional to missile velocity
- Pieces of hair, skin, & debris can be embedded in wounds
What can cause puncture wounds
- Penetrating foreign objects (stick, wire, or bone)
- Bite wounds
- Gunshot injuries
Describe lacerations
- Created by tearing which damages skin & underlying tissue (muscles & tendons)
- May be superficial or deep & have irregular edges
- Minimal peripheral trauma to the wound edges unless it is a concurrent avulsion injury)
Describe Avulsions
- The tearing of tissues from their attachments & the creation of skin flaps
- Exposed wound bed
- Common on distal limbs
What is degloving
Avulsion injuries on limbs w/ extensive skin loss
Define anatomic degloving
Skin & various levels of underlying tissue are torn off the limb
Define physiologic degloving
Skin surface is intact but separated or avulsed from underlying subQ tissue & blood supply (results in delayed necrosis of the skin)
Describe thermal burns
- May be partial or full thickness
- Caused by heat or chemicals
What can cause thermal burns
- Fire
- Cage dryers
- Heating pads
- Heat lamps
- Hot liquids
- Malicious incidents
What can deep extensive thermal burns cause
- Severe fluid loss
- Electrolyte loss
- Protein loss
Risk of infection & sepsis is (high/low) w/ thermal burns
High
T/F: Strict classification of burns is no longer in favor due to delayed microvascular damage
True
Describe crush injuries
Can be a combo of other types of wounds w/ extensive damage & contusions to skin & deeper tissue
Describe decubital ulcers
- Result of compression of the skin & soft tissues btw/ a bony prominence & a hard surface
- Results in skin loss over the bony prominence
- Can extend into deeper soft tissue & bone
- Often seen in the recumbent animals
Where are decubital ulcers common
- Greater trochanter
- Lateral elbow
- Lateral hock
Describe primary wound closure (first intention healing)
- wound edges are apposed & allowed to heal by first intention
- Occurs in most surgical wounds
What is primary wound closure indicated in
- Clean sharply incised wounds
- Min trauma
- Min contamination
- W/in hours of injury
Describe delayed primary closure
- Appositional closure w/in 3 to 5 days
- Before granulation tissue has been produced in wound bed
What is delayed primary closure indicated in
- Mildly contaminated
- Min trauma
- Require some cleansing, debridement, & open wound management before closure
Describe healing by contraction & epithelialization (second intention healing)
- Wound left open to heal by contraction & epithelialization
- Eventually produces a continuous epithelial surface
- May be inefficient & fail to produce a functional outcome
- Where cleansing & debridement are necessary but primary or delayed closure is prohibited
- Continually assess to see if secondary closure could be used to expedite the process
What is healing by contraction & epithelialization (second intention healing) indicated for
- Dirty wounds
- Contaminated wounds
- Traumatized wounds
Describe secondary closure (third intention healing)
- Appositional closure more than 3 to 5 days after wounding
- Granulation tissue has formed in the wound bed
- Allows for third intention healing
- Development of granulation tissue in the wound bed provides a microbial resistant vascular substrate that facilitates healing
- Closure is performed over the granulation tissue
- Some debridement may be necessary to facilitate closure
What is secondary closure (third intention healing) indicated in
- Severely contaminated
- Severely traumatized
- Infected
Why should there be immediate wound care
- Reduce microbial burden
- Prevent further contamination
In an initial unstable patient what is immediate wound care
- Copious irrigation even if its with tap water (solution to pollution is dilution)
- Coverage of the wound w/ antimicrobial agent
- Bandage to protect wound
What might be needed for immediate wound care
- Often anesthesia is req for initial wound inspection & care
- Severely contaminated or infected wounds should be cultured after initial inspection
- The area surrounding the wound should be widely clipped & prepped
Explain clipping & prepping the wound
- May be protected from clipped hair & detergents by applying a sterile water soluble lubricant or by placing saline soaked sponges in the wound & covering w/ a sterile pad or towel
- May be temporarily closed w/ sutures, towel clamps, staples, or michel clips
- Hair can be clipped from the wound margin w/ scissors dipped in mineral oil to prevent hair from falling into the wound
- Povidone-iodine or chlorhexidine gluconate scrubs are used to prep clipped skin
Why is alcohol not to be used in clipping & prepping the wound
Is very damaging to exposed tissue & should be used only on intact skin
What should occur in initial wound management
- Removal of gross contaminants & copious lavage using a warm balanced electrolyte solution, sterile saline, or tap water
- Tap water is effective & less detrimental than distilled or sterile water
What is the preferred lavage solution
Sterile isotonic saline or a balanced electrolyte solution (lactated ringer’s solution) is the preferred lavage solution
What does wound lavage do
Reduces bacterial #s mechanically by loosening & flushing away bacteria & associated necrotic debris
How can noncytotoxic wound cleansers used as lavage
- Applied to loosen debris & soften necrotic tissue during bandage changes
- Act as a surfactant disrupting the ionic bonding of particles & organisms to the wound & allowing them to be easily rinsed off w/ saline or balanced electrolyte solutions
What do lavages with antibiotics or antiseptics do
- Reduce bacterial numbers
- May damage tissue
- Antiseptics have little effect on bacteria in established infections
Why is lavaging preferred to scrubbing the wound w/ sponges
Sponges inflict tissue damage that impairs the wound’s ability to resist infection & allows residual bacteria to elicit an inflammatory response
What is the most consistent irrigation delivery method to generate 7 to 8 PSI
A liter bag of fluid w/in a cuff pressurized to 300 mmHg
What can happen if using higher pressure (70 PSI) for irrigation
- More effective in reducing bacterial #s & removing foreign debris & necrotic tissue
- may drive bacteria & debris into loose tissue planes, damage underlying tissue, &/or reduce resistance to infection
Define debridement
Removal of dead or damaged tissue, foreign bodies, & microorganisms that compromise local defense mechanisms & delay healing
What is the goal of debridement
To obtain fresh clean wound margins & wound bed for primary or delayed closure
How is devitalized tissue removed
- By debridement
- Surgical excision
- Autolytic mechanisms
- Enzymes
- Wet dry bandages
- Biosurgical methods
How is surgical debridement be done
Excised in layers beginning @ the surface & progressing to the depths of the wound
* Sharp dissection, electrosurgery, or laser
How long should muscle be debrided
Until it bleeds or contracts
T/F: Extensive debridement of SubQ tissue should be avoided
True
What should happen to contaminated fat
Liberally excised
What should happen to cutaneous vessels
They must be spared to maintain the viability of overlying skin
What is an alternative to surgical debridement
The entire wound can be excised en bloc if sufficient healthy tissue surround the wound & vital structures can be preserved
What is the danger of surgical debridement
Removal of an excessive amount of possible viable tissue
What might need to be done with penetrating or puncturing wounds for debridement
May be necessary to enlarge the wound to assess the extent of injury & allow debridement
What should happen after surgical debridement
- Often treated as open wounds w/ hydrophilic dressing & bandages
- Provision of adequate wound drainage & viable vascular bed is important to wound healing
- Wound should be closed when it appears healthy or when a bed of healthy granulation tissue has formed unless wound closure by contraction & epithelialization is anticipated
What is autolytic debridement
Creation of moist wound environment to allow endogenous enzymes to dissolve nonviable tissue (often preferred over surgical or bandage debridement in wounds w/ questionable tissue viability
How is autolytic debridement accomplished
With hydrophilic, occlusive, or semiocclusive bandages to allow wound fluid to remain in contact w/ nonviable tissue
How do wet to dry bandages or dry to dry bandages accomplish mechanical debridement
- Adhere to the wound surface & pull the debris & strip the superficial layers off the wound bed when removed
How do wet to dry wound dressings provide adequate wound protection & coverage
They maintain a moist wound environment & absorb moderate amounts of wound exudates
When is bandage (mechanical) debridement most effective
- Early stages of wound healing or in the management of wound infection
What are the cons of bandage debridement
- Painful
- Nonselective
When is enzymatic debridement beneficial for pxs
- That are poor anesthetic risks
- When surgical debridement may damage healthy tissue necessary for reconstruction
Describe maggot therapy (Biosurgical debridement)
- Using greenbottle fly larvae debrides wounds as the maggots secrete proteolytic digestive enzymes into the wound
- Sterile medicinal maggots are bred specifically for biosurgery
- Best suited to necrotic, infected, or chronic nonhealing wounds
What do maggots due
- Remove necrotic tissue
- Disinfect the wound
- Promote granulation tissue formation
When is antibiotic therapy beneficial
In severely contaminated, crushed, or infected wounds, or wounds older than 6 to 8 hours
How should antibiotics be selected
Based on culture & susceptibility testing
Describe using topical antimicrobials & antibiotics
- Eliminate or reduce the # of microorganisms that destroy tissue in a wound
- Topical rather than systemic antibiotics are preferred for open wounds
- If applied w/in 1 to 3 hours of contamination often prevent infection
- Powders act as foreign bodies & should not be used
Describe the use of triple antibiotic ointment
Is more effective for preventing infections than for treating them
What is the drug of choice to treat burn wounds
Silver sulfadiazine
What topical is especially effective in controlling gram-neg bacterial growth
Gentamicin sulfate
What antimicrobial is effective against gram-pos & some gram-neg organisms
Cefazolin
What topical/spray is particularly useful on severely contaminated wounds
Mafenide
Describe using honey in open wound management
- Enhances wound debridement
- Reduces edema & Inflammation
- Promoting granulation tissue formation & epithelialization
- Improves wound nutrition
- Should be used early in the course of wound healing & discontinued once a healthy granulation bed is present
Explain how sugar can help in open wound management
- similar hypertonic effects to honey
- Attracts macrophages
- Accelerates sloughing of devitalized tissue
- Provides cellular energy source
- Promotes formation of a healthy granulation bed
What is the benefits of vacuum assisted closure
- Increased rate of granulation
- Accelerated healing times
- Wound cleaning
- Improved blood flow
- Reduced edema
