Wound Stuff (Cav)-Exam 1 Flashcards
What type of wound has no infection and asepsis was maintained?
Clean wound
What type of wound deals with a hollow organ but no bacteria contamination involved or there was a minor break in asepsis?
Clean-contaminated
Ex: foreign body retrieval
What type of wound deals with a hollow organ that has open and spilled or a major asepsis break occurred?
Contaminated
Ex- BITE WOUND
What type of wound contains pus or contents of perforated organ implying infection?
Dirty
Define asepsis
minimize incidence of sx wound infection
What is the relationship of time and risk in surgery?
Risk doubles every hour in sx- TIME IS TRAUMA
What are the three risk factors for infection?
- duration of sx
- increasing number of persons operating
- dirty sx site
What are the six risk factors contributing to infection/inflammation?
- duration of anesthesia
- duration of postop stay
- wound drainage
- Increased patient weight
- dirty sx site
- antimicrobial prophylaxis
What is the most common source of operating wound infections?
Patients’ endogenous flora- GI/skin
What is the difference of prophylactic and therapeutic antibiotic use?
Prophylactic: administration of Ab PRIOR to wound contamination/creation of wound
Therapeutic: infection already present
What is the minimum time that Ab should be administered prior to sx?
30 minutes before (not longer than24 hrs.)
How can postoperative infections be minimized?
Good nursing care- incision lines protected, wash hands/glove up between patients, remove catheters and drains in a timely manner
What is the lag phase of wound healing and when does it occur?
First 3-5 days
Inflammation & debridement predominate and wounds have not gained much strength
What are the four phases of wound healing?
- Inflammatory phase
- Debridement phase
- Repair
- maturation/Remodeling phase
When does the inflammatory phase occur?
Within minutes of injury
inflammation is a positive response that is initiated by what?
Tissue damage
What are some examples of cellular response in the inflammatory phase?
Increased permeability of blood vessels, recruitment of circulatory cells, release of growth factors & cytokines and activation of WBC
What is the first response to injury?
Hemorrhage
What process controls hemorrhage with a fibrin clot (glues edges of wound together)
Vasoconstriction
What process dissolved plug in lymphatics turning clot into a scab?
Fibrinolysis
What process increases permeability causing a release of inflammatory mediators
Vasodilation
What initiates the debridement phase?
Leakage of WBC into wound
Where does the debridement phase occur?
In the wound bed when neutrophils and monocytes arrived
What prevents infections and phagocytize organisms and debris?
Neutrophils
What cell is ESSENTIAL for wound healing?
Monocytes
Lymphocytes/neutrophils are NOT essential
What do macrophages secrete?
Collagenases- removes necrotic tissue, bacteria, and foreign material
Chemotactic factors- direct macrophages to injured tissue
Growth factors- initiate, maintain & coordinate formation of granulation tissue
What occurs in the repair phase?
Macrophages stimulate fibroblast & DNA proliferation
What type of environment do fibroblasts prefer?
Acidic and oxygen rich environment
What is angiogenesis?
Capillaries infiltrate wound under fibroblasts- relies on interaction of extracellular matrix w/ cytokines
What is formed with the combination of fibroblasts, new capillaries and fibrous tissue development 3-5 days post wound?
Granulation tissue
What are the functions of granulation tissue?
Barrier to infection
External source of special fibroblasts
Surface for epithelial migration
What is epithelialization?
Mobilization, proliferation & differentiation of epithelial cells
What is the time period of epithelialization for sutured wounds vs. opened wounds?
Sutured wounds: 24-48 hrs
Open wounds: 4-5 days
T/F: Migration of epithelial cells is random but guided by collagen fibers
TRUE
What is the term for when there is contact on all sides w/ other epithelial cells inhibiting further cell migration?
Contact inhibition
What environment does fast epithelialization occur in?
Moist
T/F: Oxygen rich environment prevents epithelial migration and mitosis
FALSE- anoxic environment
What type of bandages delay re-epithelialization?
wet-to-dry bandage
What is wound contraction?
size of wound reduced from fibroblasts, reorganizing collagen in granulation tissue & myofibroblast contraction at the wound edge
What does wound contraction occur simultaneously with?
Granulation & epithelialization
What is necessary for initiation of contraction?
Fibroblastic invasion
What is contraction inhibited by?
skin around wound being fixed, inelastic, under tension or when myofibroblasts are inadequate
When does the maturation phase begin?
Once adequate levels of collagen are reached (17-20 days post injury)
What type of collagen fibers increase vs. decrease?
Increase- Type I
Decrease- Type III
When does the most rapid gain in wound strength occur?
Between 7-14 days post injury b/c of rapid collagen accumulation
T/F: Normal tissue strength is regained months after inury
FALSE- never regained. Only about 80% strength is regained
What class of wound has minimal contamination or tissue damage?
Class I- 0-6 hrs. post wound
What is the golden period?
insufficient microbial replication to cause infection and can manage with primary closure
What class has microbial replication to critical level possible and at what time frame is this seen?
Class II- 6-12 hrs. post wounding
What class does microbial replication at critical level allow for infection?
Class III- >12 hrs. post wounding
What type of wounds will receive primary closure?
Class 1 & some 2 wounds
What is delayed primary closure and what class is associated with this?
Appositional closure before granulation tissue develops Good for class 2 wounds
What is secondary closure?
Appositional closure after granulation tissue has developed
What is second intention healing?
Healing by contraction/epithelialization or open wound management
What are the 8 fundamentals of wound management?
- Assess patient
- Prevent nosocomial infections
- Aseptically clip/scrub area
- Lavage
- Procure culture of wound
- Debridement
- Select appropriate surgical closure method
- Provide drainage if necessary
T/F: Scrub the area around and the wound itself
FALSE-only scrub around the wound- can cause irritation, toxicity, pain and potentiate wound infection if scrubbed inside wound
Why should alcohol never be used on open wounds?
Damages open tissue
How does lavage reduce bacterial numbers?
loosening and flushing bacteria and associated necrotic debris away
What is the preferred lavage solution?
Sterile isotonic saline or balanced electrolyte solution
T/F: Antiseptics have little effect on established infection
TRUE
What should be used for initial cleaning of heavily contaminated wounds?
Running, luke worm tap water
What is a potential disadvantage of tap water when dealing with wound cleaning?
Causes hypotonic tissue damage
What is the goal of lavage?
Remove particulate debris/bacteria w/ mechanical contact, inertial force and exudate infected wounds and remove toxins associated with infection
What is the ideal lavage pressure?
7-8 psi
When should your wound culture be taken?
initial debridement- preferred
What are the most common organisms that cause infection?
Staph and E. coli
What type of cultures should be requested in heavily contaminated wounds?
Aerobic/anaerobic
What type of wounds is topical antimicrobials use?
Open wounds-applied in 1-3 hrs. of contamination infection is prevented
What route of antimicrobials would be used for heavily contaminated wounds?
Topical/systemic antimicrobial therapy
What prevents topical Ab from reaching effective levels in tissues deep in the wound and prevents systemic antibiotics from reaching superficial bacteria?
Wound coagulation
What must be performed to allow Ab access to bacteria in wound?
Wound debridement
Which topical antimicrobials are used for superficial skin wounds?
Bacitracin, neomycin & polymyxin
Which bacteria do topical antimicrobials have poor efficacy against?
Pseudomonas spp.
Which topical antimicrobial can retard wound contraction?
Zinc bacitracin
What topical antimicrobial is effective against most gram +/- and fungi?
Silver sulfadiazine
What is the drug of choice used to treat burn wounds?
Silver sulfadiazine
What is the process of removing dead/damaged tissue, foreign material & microorganisms from wound?
Debridement
What are the two types of surgical debridement?
Layered and En bloc
What is the difference of layered vs. en bloc debridement?
Layered: devitalized tissue sx excised in layers beginning from surface and progressing into wound
En bloc: entire wound can be excised if sufficient healthy tissue surrounds the wound & vital structures can be preserved
What is the advantage of en bloc debridement?
Wound care greatly accelerated
What must you be careful of in terms of cats and debridement?
Don’t take extensive SQ in cats as it may delay wound healing
What is the difference of autolytic and biosurgical debridement?
Autolytic: creation of a moist environment to allow endogenous enzymes to dissolve nonviable tissue
Biosurgical: maggot therapy using greenbottle fly larvaeas the maggots secrete proteolytic digestive enzymes into wound
What is autolytic debridement highly selective for?
Devitalized tissue ONLY
Why is fluid accumulation detrimental to wounds?
Acts as a growth medium for bacteria, separates tissue planes that should be healing together, creates pressure leading to pain and decreased blood flow
What are the two classifications of drains?
Active and Passive
How does a penrose drain operate?
Relies on gravity dependent flow of fluid in dead space
T/F: Fluid travels through a penrose drain?
FALSE- flows on either side of it, no need to fenestrate the drain
How long should a drain be left in typically?
5-7 days-longer risks infection
Where should drain exit sites be placed?
most dependent area of dead space at least 1 cm from wound
Why shouldn’t the drain exit through the primary incision line?
increases risk ofwound dehiscence
Why should cold compress be avoided in the wound?
Freezes fluid in wound
What is the gold standard active drain?
Jakson pratt
How does the jackson pratt drain work?
Relies on concept of active removal of wound fluid w/ negative suction-complete seal needed to create suction
T/F: No need to make fenestrations with a Jackson Pratt drain
FALSE- fluid travels in the drain-relies on fenestrations
What is the difference of the exit site of a Jackson Pratt drain as opposed to a penrose drain?
Jackson pratt drains exit dorsal to wound in NON-DEPENDENT portion of wound
What is a major advantage of the Jackson Pratt tube?
quantification of drain production at home
How much fluid does the body produce as a reaction from the drain?
1-2 mL/kg/day
At what rate of drainage should you remove the drain?
Decreased below 5 mL/kg/day= < 0.2 mL/kg/hr
What is the most common problem of active drains?
Loss of suction during healing- make sure grenade is securely attached to tube and evacuation port is closed (common problem)
What is the first step of open wound management?
Debridement-removes all contaminants
What is the most selective type of debridement?
Autolytic debridement- spares healthy cells by only targeting necrotic/damaged tissue
What is the least desired form of debridement?
Mechanical debridement (nonselective)- physical removal of tissue adhered to a dried on dressing
What are the three layers of bandages?
Primary (contact) layer (sterile)
Intermediate (secondary) layer (non-sterile)
Outer (tertiary) layer (non-sterile)
What is the adherent layer used for?
Mechanical debridement of necrotic tissue and debris and absorption of wound exudate
When is non-adherent bandage used?
When granulation tissue has formed but current wound care standards recommended use of hydrophilic nonadherent contact layers for all wounds
What is the most commonly used bandage in veterinary medicine?
Semi-occlusive
Wet-to dry and dry-to-dry bandages are examples of what type of bandage?
adherent bandage
Telfa, adaptic, hydrogels and hydrocolloids are examples of what type of bandages?
Non-adherent bandage
T/F: once granulation tissue has formed you can still use wet-to-dry bandages?
FALSE- only used in early wound management
What kind of debridement does wet-to-dry bandage use?
Mechanical debridement- moving away from these bandages
___ MVTR strongly correlates w/ positive wound healing outcome and predictive of healing
Low MVTR (moisture vapor transmission rate)
What should bandages be covered with?
3-layer modified Robert Jones
How often should bandages be changed during the inflammatory phase?
Q2-3 days
How often should bandages be changed once granulation tissue has formed?
Q5-7 days
What are three different substances used in open wounds?
Manuka honey, sugar and low-level laser therapy
What pressure increases blood flow to a wound, accelerates rate of granulation tissue formation, decreases bacterial counts &improves flap survival?
125 mmHg NPWT
When are negative pressure wound therapy used?
Large open & effusive wounds devoid of granulation tissue; chronic non-healing wounds, postop mgt of tissue flaps, open abdominal mgt for septic abdomen
T/F: Not all bites are considered contaminated
FALSE- all bites are contaminated wounds
Why are all bite wounds considered contaminated?
contain polymicrobial flora reflecting the flora of the oral cavity of biter, skin of victim and environmental pathogens
What is the most common pathogen cultured from bite wounds?
Pasteurella multocida
What kind of injury is caused by a K9 dog bite?
Crushing, tearing and avulsion injury
What is the iceburg effect?
appearance of wound doesn’t look bad but the damage underneath is extensive
Where do bites occur in large breed dogs vs. small dogs?
Large breed dogs: neck & face
Small breed dogs: dorsum
Cat bites have more of puncture wounds, what concern rises from that?
Higher risk of infection
Cervical injuries have risk for damaging what leading to what two major side effects?
trauma to trachea potentially leading to pneumomediastinum w/ potential for respiratory embarrassment
What should always be done when a patient is presented with thoracic and abdominal wounds?
Radiographs to ensure penetration into a cavity hasn’t occurred
Why are drains not needed in the head and extremities?
Natural drainage due to gravity
What confirms abdominal penetration?
Free peritoneal air, visible hernia- always explore and probe wound
What is required in a patient IMMEDIATELY when presented with abdominal bite wounds?
Immediate exploratory laparotomy
What is the term for when heat energy is applied at a faster rate than tissue can absorb &dissipate?
Thermal injury= coagulative necrosis & irreversible skin damage
What is the recommended source of heat in veterinary practice for patients?
HotDogTM- circulates warm water in a mat
What type of burn involves the outermost epidermis and typically heals spontaneously within 3 weeks via epithelialization?
1st degree burn
What type of burn involves full thickness epidermis & dermis, non-painful and dark brown in color?
3rd degree burn
what type of burn involves the epidermis and a portion of the dermis, painful and can spontaneously re-heal but takes months?
2nd degree burn
Burns involving <15% TBSA require what?
Minimal supportive therapy
Burns involving >20% leads to what?
Greater risk of systemic effects
Burns involving >50% may warrant what?
Euthanasia
When managing wounds, how should the hair be clipped?
WIDE- to ensure that there are no underlying bruises, small wounds or cuts under hair
What is the best protection agains wound colonization & infection?
Silver sulfadiazine
When are degloving injuries commonly seen?
limb caught beneath a car tire and dragged- typically involving the tarsocrural joint
What results from injury of collateral ligament or fracture of medial or lateral malleolus?
Subluxation
What results form injury of both medial & lateral collateral ligament complexes, fracture of both malleoli or fracture of one w/ injury to contralateral collateral ligament complex
Luxation
What type of wound closure is always the ideal choice?
Primary wound closure
What are the six goals of wound closure?
Minimal tension full return to function pain-free final outcome cost effective acceptable cosmesis satisfied owner
What are the Halsted Principles?
Gentle tissue handling Meticulous control of hemorrhage Observe strict aseptic technique Preserve blood supply to tissues Eliminate dead space Appose tissues accurately w/ minimal tension
What are the seven wound factors for decision making/planning?
Size, geometric shape, anatomic location, chronicity, bacterial load, structural damage, peri-wound status
What species has lower cutaneous perfusion and early wound breaking strength?
Cats
What type of closure patterns are used for fascial/intramuscular closure?
Simple interrupted or continuous
What is the most common suture material?
Polydioxanone (PDS)
What is the minimum amount of throws to start continuous PDS?
5
What is the minimum amount of throws to finish continious PDS?
7
What size suture is used for SQ wound closure?
3-0 & 4-0
What suture pattern is used for SQ wound closure?
Simple continious
What does adding 2 extra throws do?
Increases knot volume & tissue reactivity by factor of 1.5
What are the typical subcuticular –> intradermal closure patterns?
Continuous horizontal, continuous vertical or SQ-to-intradermal
What are the typical suture material for cutaneous wounds?
Ethilon or polypropylene
What type of wound closure should be avoided in wounds with tension?
Tissue adhesives (cyanoacrylate)
What happens if a wound was closed by direct approximation of edges?
Tension will lead to ischemia from suture pressure
What is commonly seen on wound closures of the extremities?
Biological tourniquet effect
CT orients in what direction in relation to tension?
parallel
What is the best way to close wounds in relation to tension lines?
Should be closed parallel with the tension lines
How are incision lines made in relation to tension lines?
Parallel to tension lines
How should you close wounds on extremities in relation to tension lines?
Perpendicular with tension lines
What is undermining and the purpose of it?
Draws upon full elastic potential of skin in closure used to allow for tension relief
What are the two methods to undermine tissue?
Blunt technique- closed to open blades. Performed in loose areolar hypodermal tissues associated w/ truncal skin
Sharp technique- open to closed blades. Appropriate in extremities
What are the three tension relieving suture patterns?
Mattress sutures (vertical/horizontal)
Far far near near
Far near far near
WHy is the horizontal mattress not ideal?
Concerned of potential compromised blood supply
What is the purpose of the far-far and near-near aspects of the tension relieving suture pattern?
Far-far eliminates tension-placed 1 cm from edge
Near-near apposes and placed 5 mm from wound edges
What is the purpose of the releasing incision?
Made near defect to allow skin apposition
What is the purpose of walking sutures?
used to advance skin towards center of wound
When is a V-Y plasty indicated?
Chronic defects surrounded by inelastic skin & closing wounds near structures that would be distorted by closure under tension
Ex: eye
Which direction should the point of the chevron be made in terms of the defect?
Point of the chevron should be made away from defect
What direction of the central arm of the z-plasty made in terms of the wound direction?
Perpendicular to long axis of the wound
When is m-plasty used?
When one end of incision would be compromised by orifice, foot pad or for reconstruction of cranial aspect of mastectomy
What is the mechanical creep?
Skin can extend its natural boundaries through phenomenon
What is stress relaxation?
Less fore required to maintain collagen fibers because collagen loses natural recoil
Where should the first suture be placed when closing fusiform shaped defects?
Across widest part of wound-continue dividing in half with subsequent sutures
When closing crescent shaped defects, which side should have sutures placed farther apart?
Longer side of the wound- closes in a T
What stitch should be used to close the center of triangle shaped defects?
half-buried horizontal mattress stitch
What kind of suture pulls dog ear down and away from wound?
Apex cutaneous suture
What are the three distinct plexuses that make up subdermal plexus?
SQ- deep plexus
Cutaneous- middle
Subpapillary- superficial
Ensure adequate ___ & ___ of surroudning skin with subdermal pelxus flap
Redundancy & vascularity
What is the ideal flap length of a subdermal pleuxs flap?
1.5X length of wound
What is an advancement flap?
Shifting skin w/out rotation
What is a roatational pivotal flap?
Pivotal flaps that have curvillinear configuration- designed immediately adjacent to defect & best used to close triangular defects
What is a transpostition pivotal flap?
pivotal flap w/ linear axis
3:1 rule= flap length:width
How is a interpolation pivotal flap different from the transposition flap?
Base is located at some distance from defect
What areas on the body are flaps commonly predisposed to. seromas and why?
Flaps from lateral flank & thorax
Large amount of deadspace
What do axial pattern flaps rely on at the base of the flap?
cutaneous artery and vein
When are axial flaps most commonly used?
facilitate wound closure after tumor resection or trauma
What flap is most commonly used to repair caudal abdominal flank, inguinal, preputial, perineal, thigh and stifle defects?
Caudal superficial epigastric APF
What flap is good for sternal defects?
Cranial superficial epigastric APF
What flap is good for medial/lateral tibial defects?
Genicular APF
What is. the most common composite flap?
Myocutaneous
What composite flaps are commony used for forelimb defects?
Latissimus dorsi myocutaneous flap
What flap is used to repair prepubic tendon ruptures or femoral hernias?
Cranial & Caudal Sartorius MF
What are the four phases of graft incorporation?
- Adherence
- plasma imbibition
- Inosculation
- Vascular ingrowth
When does Phase I adherence occur in graft incorporation and what occurs in this phase??
0-72 hrs
Contraction of fibrin strands pulling graft closer to bed
When does Phase II adherence occur in graft incorporation and what occurs in this phase?
72 hrs-10 days
fibrin to fibroblasts, leukocytes, phagocytes –> fibrous adhesion (glue)
Describe the plasmatic imbibition stage of graft incoporation
0-72+ hrs
graft vessels dilate & pull fibrinogen free, serum like fluid & cells into graft via capillary action
nourishes wound prior to blood vessel development
When does inosculation stage occur in graft incorporation and what occurs in this phase?
48/72 h-6 days
anastomosis of cut ends of graft vessels w/ recipient bed
When does vascular ingrowth stage occur in graft incorporation and what occurs in this phase?
48 h-6/8 days
ingrowth of new vessels from bed into graft
What is vascular ingrowth controlled by?
Cytokines
How long until reinnervation occurs after graft implantation?
3 weeks
What is a common graft used that has multiple slits cut parallel in rows to allow the graft to expand in two directions and increase in size?
Full-thickness meshed skin graft
What does the meshing of the skin graft provide?
Drainage, flexibility, conformity & expansion
When would you use a full-thickness meshed skin graft?
Drainage from a wound w/ minor exudate
Cover large defects
Reconstruction of irregular shaped surfaces
What type of mesh graft is recommended for most grafting needs?
Non-expanded- full thickness mesh graft
