Sx Skills - Physiology of Wound Healing

drraythe's version from 2016-05-05 11:26


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 Sx 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, urogenital tract). Examples of CLEAN procedures are Spay/neuter, exploratory laparotomy
Degrees of Contamination → for a CLEAN wound, what is the Sx infxn rate? Are there any actions you must take w/ a clean wound?SSI rate is 0-6%. Use pre-operative ABx only where indicated (i.e. orthopedic Sx) & discontinue w/in 24 hours
Degrees of Contamination → explain the degree: CLEAN-CONTAMINATED. Examples?Sx involving non-sterile luminal organs but w/ no unusual contamination (i.e. no spillage, no infxn 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 (i.e. perforated surgical glove)
Degrees of Contamination → for a CLEAN-CONTAMINATED wound, what is the Sx infxn rate? Are there any actions you must take for this kind of wound?SSI rate: 4.5-9%
Prophylactic ABx recommended
Degrees of Contamination → explain the degree: CONTAMINATED. Examples?This is like if there is a Sx of luminal organs w/ leakage of visceral contents (Eg. bile spillage during cholecystectomy, cystotomy w/ spillage of infected urine)
Serious break in sterility
Early open traumatic wound
Degrees of Contamination → for a CONTAMINATED wound, what is the Sx infxn rate? Are there any actions you must take for this kind of wound?SSI rate: 6-28%
Antibiotic prophylaxis, lavage, debridement
As Sx time ↑, what else ↑?Risk of infxn
Degrees of Contamination → explain the degree: INFECTED (DIRTY). Examples?Established infxn 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?Lavage → Debridement → Drainage → +/-wet-dry bandages → ABx
How long after trauma would you just go ahead & assume it is infected?12 hours or more
*What is the most appropriate needle to use when repairing a ruptured tendon?Tapercut
Healing process is initiated by (__1__) released by (__2__) & sustained through the action of (_3+3_) secreted by (_4+4+4_)(1) Cytokines
(2) Platelets
(3) Cytokines & growth factors
(4) Macrophages, endothelial cells & fibroblasts
**What are the 3 phases of wound healing?LAG PHASE
REPAIR PHASE (Medi-Honey used here!)
Inflammation & debridement happens during the _ phase of wound healing?LAG phase
Proliferation happens during the _ 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 w/ what?Collagen
LAG PHASE: whats going on in this phase? How long is this phase?Inflammation & debridement predominate, where the body preps for repair (LAG bc no ↑ in wound strength). Usually days 0-5
Lag phase → which cells are doing what when during this phase?1st neutrophils migrate to wound soon after injury
Then the neutrophils are followed by macrophages & together they initiate DEBRIDEMENT
Lymphocytes appear later in debridement phase
When does debridement usually start to occur?W/in 6 hours of injury during Lag Phase
**Which cell is essential (key) 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 precursor of granulation tissue
What are the 4 processes which happen during the repair phase?Angiogenesis
Wound contraction
Transition from inflammatory phase (lag) to proliferative phase (repair) characterized by invasion of ___ & ↑ ___ content in woundFibroblasts
Transformation from provisional extracellular matrix to granulation tissue occurs ~_________ days after injury3-5
REPAIR PHASE → Fibroplasia: explain what is going on & what the fxns of this areIt is migration of fibroblasts into wound along fibrin strands w/in the clot. There are multiple fxns: synthesize & deposit true extracellular matrix → collagen, elastin & 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 3 things is granulation tissue composed of?(1) FIBROBLASTS → collagen
What are some of the awesome things that granulation tissue does?Fills defects
Protects wound
Barrier to infxn
Scaffolding for epithelial cells
Source of myofibroblasts
What cells are important for wound contraction?Myofibroblasts
REPAIR PHASE → Epithelialization: explain how it starts & movesBegins w/ mobilization & 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: explainEpithelialization begins w/in 24-48 hours (no granulation tissue reqd)
“Suture abscess”: What czs a suture abscess? How can you avoid this?Epithelial migration along suture tracts causing foreign body rxn when epithelial cells come in contact w/ connective tissue below & become keratinized. Can be avoided by early suture removal
REPAIR PHASE → Wound Contractions 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 cz 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 czs an fxnal disability
Phase 3: Maturation & Remodeling → what happens to the granulation tissue? How does the collagen change?Transition of granulation tissue to scar. There is a ↓ in type III (immature) collagen & a ↑ in type I (mature) collagen. The collagen fibers align along lines of tension & there is ↑ cross-linking of collagen fibers to ↑ WOUND STRENGTH.
Maturation & Remodeling begins when & ends when?Begins ~3 weeks post-injury & 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 3 factors in the maturation/remodeling phase which contribute to ↑ strength of tissue?Collagen fibers deposited
Fiber re-alignment (align along lines of tension)
↑ cross-linking
*** What are the only tissues in the body to regain 100% of its pre-wound strength?BLADDER & 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 & applied helps, but done wrong is gonna hurt)
What are factors which delay healing?Foreign material
Endocrine dz
Wound infxn
Excessive movement at site
Antiseptics (cytotoxic)
Corticosteroids / Immunocompromised
↑ 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) & then freshen edges (bc need bleeding edges for them to heal together)