Wounds and wound healing Flashcards
cutaneous blood supply is the direct vessel supply to the skin without musculocutaneous vessels T/F
True
Is the cutaneous blood supply mobile?
yes (cutaneous trunci and platysma)
What are the 3 plexi of blood supply to the skin?
Subdermal (deep), cutaneous (middle), subpapillary (superficial)
noooo bf in the top layer of skin
Phases of wound healing:
Inflammatory, proliferative, remodeling
When does the inflammatory process of wound healing begin? When does it end?
begins IN SECONDS must end by 7 days (any time after 7 days is not normal)
___ phase is responsible for the four cardinal signs of inflammation
Inflammatory phase
____ phase is when granulation tissue is formed as fibroblasts proliferate and secrete collagen, contraction of wound edges and re-epithelization over new granulation tissues
proliferative
Proliferative phase begins how long after wound
starts in 2-5 days
What is the lag phase of wound healing aka the weakest point in wound healing?
The proliferative phase
*Fibroplasia and angiogenesis =
GRANULATION TISSUE*
*______ + _____= granulation tissues
Fibroplasia and angiogenesis (occurs in the proliferative stage of wound healing)
____ is the fragmentation of the basement membrane- migration of the endothelial cells- proliferation- capillary and capillary tube formation
Angiogenesis
Granulation tissue appears __-__ days after injury
3-5 days
What is epithelization?
detachment of basilar keratinocytes for migration and differentiation, starts at inflammatory phase (scarring)
Must develop _______ tissue before ______
granulation tissue before epithelialization
What is wound contracture?
contraction of a wound causes distortion of an adjacent orifice or joint, NOT DESIRABLE, abnormal
What is wound contraction???
myofibroblasts, occurs when wound edges meet or tension of surrounding skin equals or secedes the force of contraction
Contraction is normal unlike ___
contracture
_____ occurs over weeks to months and involves granulation tissue that is replaced by mature connective tissues/collagen/scars
remodeling
The final stage of remodeling can take months to two years, what occurs during this time?
decreased cell count and vasculature to make a scar, reaches max of 80% of original tensile strength of skin
(Reaches 100% tensile strength in bladders and bones!)
___ is a subset of the remodeling phase where granulation tissue is replaced with mature CT, fibronectin and type 3 collagen are replaced by type 1 collagen and creates basket weave bundles lying parallel to the wound
Maturation phase
What are factors affecting healing?
host, wound characteristics, wound depth, and time in sx
Infection is ______ organisms per gram of tissue
> 10^5
Partial thickness-
shallow wounds, involve epidermal loss and partial loss of dermis
Full thickness-
total loss of epidermis and dermis, extending to subQ with possibly into deep fascia, muscles, and/or bone
Which bite wounds must be tx aggressively?
- BDLD where big dog picks up and shakes little dog
- Location of wounds (ex: chest or airways or abdomen)
- Clinical assessment of severity of trauma
Anatomic vs physiologic degloving–>
anatomical is tissues completely gone
physiologic degloving is tissues still present but bf damaged so sloughed
Thermal burns are classified based on ___ and _____ involved
depth and percentage involved
What is the most common secondary infection of a thermal wound/ burn or frostbite?
Pseudomonas
Are burns proportional to pain??
No
What are the 6 basic steps of wound care???
- prevent further wound contamination
- debride the dead and dying tissues
- remove the foreign debris and contaminants
- provide ideal wound environment
- promote a viable vascular bed
- select appropriate closure
about up to 90% of bacteria and debris can be removed out of a wound with what technique?
Warm sterile saline used for wound lavage (or can use balanced electrolyte like LRS)
7-8 psi pressure desired which is 35 or 60mL syringe with 18 gauge needled pushed as hard as possible
Culture before or after lavage?
After
What are the most common lavage solutions?
LRS or 0.9% saline
LRS is least cytotoxic- more balanced
Saline is more hypertonic
Why do we usually not use plain water for lavage?
Hypotonic solutions burst cells which makes it cytotoxic by definition and can delay healing
What are the methods for wound debridement?
Surgical, enzymatic, chemical, mechanical
How can we do sx debridement of wounds?
Layered- most common or you can incise around it and remove. “En Bloc”
What is the mechanism of most topical wound medications?
most work by modulating macrophage functions BUT CAN DELAY WOUND HEALING OR CAUSE RESISTANT INFECTIONS
Under what circumstances can we use primary (first intention) closure?
clean wounds <6 hours old and bacteria <10^5 CFU/g tissue, DO NOTTT close bite puncture wounds
What is it called when we convert to clean wound and close before granulation (1-3 days)
Delayed primary
What is involved with secondary healing of a wound?
initial treatment as open wound, formation of health granulation bed, closure of wound after development of healthy granulation tissue (min. of 3-5 days), suture wound edges (primary closure) and flaps, grafts with secondary closure
What is involved with SECONDARY INTENTION wound healing?
allow to heal on its own, avoid over high motion areas, may not heal completely, watch for contracture, can take up to 5 days for vitalized tissues to arrive
What is the golden rule for decision making of wound healing?
Golden rule is NO TIME PERIOD FOR CLOSURE, BUT NUMBER OF BACTERIA MATTER
<10^5 ORGANISMS/GRAM TISSUE OR NO GROSS CONTAMINATION
All drains increase risk of infection and must be protected with bandage/sterile cover. T/F
True!!!
What is an example of a passive drain? What does it involve?
Penrose drain
fluid drain around and not through, depends on gravity, REQUIRES STERILE COVERING
What is an example of an active drain. What does it involve?
JP drain, depends on vacuum, drains out deeper structures, works better than passive drains, lower risk of infection but obstruction is the main concern, empty reservoir every four hours or when half full
what are the rules for drain placement?
Make a separate stab incision for the drain, do NOT exit the drains through the initial wound/incision, drain should not lie directly under the suture line, secure the drain to the skin, do NOT tack in place with buried sutures, COVER ALL DRAINS!!!
Drain removal- when to know when to remove?
Remove if:
- discharge becomes transudate
- when draining decreases to like 1-2 ml/kg/day
- removal is usually in 3-7 days but most impt is to look at when draining decreases to gauge when to remove it
Main bulk of healing is the ____ phase
proliferative
What 4 goals are involved with proliferative phase?
Fibroplasia, angiogenesis, epithelialization, contraction
____ put down collagen and ECM
Fibroblasts
capillary tube formation =
angiogenesis
? is resistent to infection and acts as a biological band aid to the wound
Granulation tissue
How long does it take for a sutured wound to have epithelialization?
1-2 days
When does contraction occur?
5-9 days after injury
define clean wound
surgically created, no hollow viscous organ entered, aseptic without infections
define clean contaminated wound
surgical wounds that enter hollow viscous organ or minor break in aseptic technique (hole in glove)
Contaminated wounds
operative wounds with major break in technique, hollow viscous organ opened with gross spillage or traumatic wounds
Dirty wound definition
purulent exudate, or contents of perforated hollow viscous organ, infected, more than 10^5 orgs per gram of tissue
What is the most common source of surgical infection?
Endogenous flora- bacterial residents to the areas in or adjacent to the site
with burns were are mostly worried about what 3 things?
Loss of albumin, metabolic derangements, dehydration
examples of chemical debridement
trypsin, castor oil, Balsam of Peru
examples of mechanical debridement
dry to dry or wet to dry bandages
A sharp laceration with soil in it that is 2 hrs old needs that closure?
delayed primary
open wound management for 1-2 days then close
degloving injury with exposed tendons and bone with road debris would need what type of wound healing?
Secondary closure
Ascending infection is greater with what type of drains?
active drains
Infection rates ___ for every hour in surgery and increase __% per every anesth hour
double; 30%
Conc of iodine to flush wounds vs chlorhex
Iodine 1%
Chlorhex 0.05%
Where should we NOT use healing by secondary intention methods?
High motion areas
methicillin/oxacillin resistant staph
- staph with mecA gene
- allows for resistance to penicillin and Beta lactams
which antibiotic has poor bioavailability in the dog for treating bacterial pyoderma
Ciprofloxacin
What is adnexal healing?
- similar to second intention
- used with partial thickness wounds
- hair follicles are the source of epithelial cells for wound healing
- healing from the inside and outward
