Sx Skills- Physiology of Wound Healing

untimely's version from 2015-05-01 19:28


Question Answer
open wounds are considered contaminated or infected. examples of open wounds? (examples of closed wounds?)OPEN: abrasion, laceration, puncture, burn, avulsion, degloving. CLOSED: contusion or crushing
*******What are the 4 degrees of contamination?(1) clean (2) Clean-contaminated (3) contaminated (4) infected (dirty)
Degrees of Contamination--> explain the degree: CLEAN. examples?This is usually a surgical wound (incision) where there has been NO BREAK IN ASEPTIC TECHNIQUE! Also, when Sx does not involve entry into non-sterile luminal organs (such as organs (respiratory, GI, oropharyngeal, urogenitaltract). Examples of CLEAN procedures are Spay/neuter, exploratory laparotomy.
Degrees of Contamination--> for a CLEAN wound, what is the sx infection rate? are there any actions you must take with a clean wound?SSI rate is 0-6%. Use pre-operative antibiotics only where indicated (ie. orthopedic sx) and discontinue within 24 hours
Degrees of Contamination--> explain the degree: CLEAN-CONTAMINATED. examples?Sx involving non-sterile luminal organs but with no unusual contamination (ie. no spillage, no infection present in viscera). Such as enterotomy, cholecystectomy. Other instances of CLEAN-CONTAMinaTED are Placement of a drain in an otherwise clean wound, OR Minor break in sterility (ie. perforated surgical glove)
Degrees of Contamination--> for a CLEAN-CONTAMINATED wound, what is the sx infection rate? are there any actions you must take for this kind of wound?SSI rate: 4.5-9%. Prophylactic antibiotics recommended
Degrees of Contamination--> explain the degree: CONTAMINATED. Examples?this is like if there is a Sx of luminal organs with leakage of visceral contents (Eg. bile spillage during cholecystectomy, cystotomywith spillage of infected urine), OR Serious break in sterility, OR Early open traumatic wound
Degrees of Contamination--> for a CONTAMINATED wound, what is the sx infection rate? are there any actions you must take for this kind of wound?SSI rate: 6-28%. Antibiotic prophylaxis, lavage, debridement
as sx time inc, what else inc?risk of infxn
Degrees of Contamination--> explain the degree: INFECTED (DIRTY). Examples?Established infection present in traumatic wound OR traumatic wounds >12 hours post-injury. Examples: perforated viscera, abscess, peritonitis, fecal contamination.
Degrees of Contamination-->what actions should you take for an INFECTED (DIRTY) wound?Antibiotics, lavage, debridement, drainage, +/-wet-dry bandages
how long after trauma would you just go ahead and assume it is infected?12 hours or more.
CQ: what is the most appropriate needle to use when repairing a ruptured tendon?tapercut
Healing process is initiated by (__1__) released by (__2__) and sustained through the action of (_3+3_) secreted by (_4+4+4_)(1) cytokines (2) platelets (3) cytokines & growth factors (4) macrophages, endothelial cells and fibroblasts
**what are the three phases of wound healing?LAG PHASE, REPAIR PHASE, MATURATION / REMODELLING
inflammation and debridement happens during the-- which phase of wound healing?LAG phase
proliferation happens during the-- which phase of wound healing?repair phase
scab is akaeschar
explain the process of coagulation during an injuryvasoconstriction for 5-10 min--> vasodilation (fibrinogen)--> platelet aggregation--> thromboplastin activates extrinsic coag system--> blood clot---> eschar (scab)
wound strength has to do with what?collagen
LAG PHASE: whats going on in this phase? how long is this phase?inflammation and debridement predominate, where the body preps for repair (LAG bc no inc in wound strength). USually days 0-5
Lag phase--> which cells are doing what when during this phase?first neutrophils migrate to wound soon after injury. Then the neutrophils are followed by macrophages, and together they initiate DEBRIDEMENT. Lymphocytes appear later in debridement phase
when does debridement usualy start to occur?within 6 hours of injury during lag phase
which cell is essential for wound healing?macrophages!
(lag phase) Inflammation & Debridement--> what do neutrophils do?remove bacteria & extracellular debris via phagocytosis
(lag phase) Inflammation & Debridement--> what do macrophages do?debridement, secrete growth & chemotactic factors essential for granulation tissue formation
(lag phase) Inflammation & Debridement--> what do lymphocytes do?secrete factors which help to control cell migration & protein synthesis
by the end of the LAG phase, what has happened?a provisional extracellular matrix has been laid down at the wound site –a precusor of granulation tissue
what are the 4 processes which happen during the repair phase?angiogenesis, fibroplasia, epithelialization, wound contraction
Transition from inflammatory phase (lag) to proliferative phase (repair) characterized by invasion of ___ and increased ___ content in woundfibroblasts, collagen
Transformation from provisional extracellular matrix to granulation tissue occurs ~_________ days after injury3-5
REPAIR PHASE--> Fibroplasia: explain what is going on, and what the functions of this areIt is Migration of fibroblasts into wound along fibrin strands within the clot. There are multiple functions: synthesize & deposit true extracellular matrix --> collagen, elastin and proteoglycans which mature into fibrous tissue
how long does the repair phase last?This phase can last 2-4 weeks (depending on wound type)
what three things is granulation tissue composed of?(1) FIBROBLASTS-->collagen (2) NEW CAPILLARIES (3) FIBROUS CONNECTIVE TISSUE
what are some of the awesome things that granulation tissue does?fills defects, protects wound, barrier to infection, scaffolding for epithelial cells, source of myofibroblasts
what cells are important for wound contraction?myofibroblasts
REPAIR PHASE-->Epithelialization: explain how it starts and movesBegins with mobilization and migration of epithelial cells from wound margin, proliferation then follows
Repair phase--> epithelization happens faster in what kinda environment?MOIST ENVIRO (bandages are good!)
if you are in the epithelization of repair phase, bandages are awesome. EXCEPT which bandages should you avoid?wet-dry bandages debride newly formed epithelium :(
REPAIR PHASE-->Epithelialization: Where there is scab present, what does the body do?migrating epithelial cells (starting from the edge of the scab) secrete collagenase which serves to dissolve base of scab facilitating its removal
REPAIR PHASE-->Epithelialization: since there is epithelization, what stops it from just keep growing?Contact inhibition inhibits cell migration when wound epithelialized
Methods of Epithelialization--> Full-thickness skin wound: explainmigration from margins only which occurs following granulation tissue (4-5 days post-injury)
Methods of Epithelialization--> Partial-thickness skin wound: explainmigration begins almost immediately from both wound margins & skin appendages (hair follicles, sweat glands)
Methods of Epithelialization--> Surgical incision: explainepithelializationbegins within 24-48 hours (no granulation tissue required)
“Suture abscess”: What causes a suture abscess? How can you avoid this?epithelial migration along suture tracts causing foreign body reaction when epithelial cells come in contact with connective tissue below and become keratinized. Can be avoided by early suture removal
REPAIR PHASE-->Wound Contractionis a reduction in wound much per day? How long till you see it? Which cells are responsible for this happening?Reduction in wound size (0.6-0.8mm per day), but Not evident for 5-9 days post-injury. Myofibroblasts act to pull wound margins together
what might cause wound contraction to cease prematurely?May cease prematurely if tension of surrounding skin exceeds the force of contraction
what is a contracture?wound contraction that has lead to a fixed deformity which causes a functional disability
Phase 3: Maturation & Remodelling--> what happens to the granulation tissue? how does the collagen change?Transition of granulation tissue to scar. There is a dec in type III (immature) collagen and an inc in type I (mature) collagen. The collagen fibers align along lines of tension and there is increased cross-linking of collagen fibers to INC WOUND STRENGTH.
Maturation & Remodelling begins when and ends when?Begins ~3 weeks post-injury and continues for up to years
why does a scar gradually get more pale?Scar becomes more pale as capillaries undergo apoptosis
how much of the original strength does the tissue get back after scarring?Tissue only regains up to 80% of original strength
what are the three factors in the maturation/remodeling phase which contribute to inc strength of tissue?Collagen fibers deposited, Fiber re-alignment (align along lines of tension), Increased cross-linking
*** what are the only tissues in the body to regain 100% of its pre-wound strength?BLADDER AND BONE! ( B&B are Badass)
*Critical wound repair period is up to when?up to 14-21 days post-injury
what are 4 things which promote healing?(1) Heat (30C/86F) + moisture (2) younger age (3) good blood supply (4) +/- bandaging (appropriately used and applied helps, but done wrong is gonna hurt)
what are factors which delay healing?Foreign material, Malnutrition, Endocrine dz, Wound infection, Excessive movement at site, Antiseptics (cytotoxic), Corticosteroids / Immunocompromise, Radiation, ↑ age
if you want to stitch together a wound that has developed granulation tissue, what must you do?you need to undermine (separate skin from gran tissue) and then freshen edges (because need bleeding edges for them to heal together)

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