Wound Healing Flashcards
When does the inflammatory/debridement phase occur?
- Day 3-5
What is the main cell type in the inflammatory/debridement phase?
- White blood cells
What type of debridement do white blood cells perform?
- Selective, autolytic debridement
- This involves getting rid of bacteria, foreign material and necrotic host tissue
What two things do white blood cells perform in order to achieve selective, autolytic debridement?
- Phagocytosis
- Secretion of proteolytic enzymes
When does the repair phase of wound healing occur?
Day 3-5 to 2-4 weeks
What are the main cells involved in the repair phase?
- Fibroblasts (granulation tissue)
What are the three main processes that occur during the repair phase and in what order?
- Granulation tissue formation
- Epithelialization
- Contraction (same time as epithelialization)
What are the main cell types during granulation tissue formation, and what do they do?
- Fibroblasts (build ECM)
- Endothelial cells (build vessels)
What are the main cell types during epithelialization, and what do they do?
- Epithelial cells
- Traverse GT and build new skin
What are the main cell types during contraction, and what do they do?
- Myofibroblasts (pull skin over the wound from the center of the granulation tissue)
Do epithelialization and contraction occur independently of each other?
- Yes
What other cells do WBCs attract during the inflammatory/debridement phase?
- More WBCs for debridement
- Fibroblasts and endothelial cells for repair phase
What two simultaneous but independent processes occur during the repair phase?
- Epithelialization (builds new skin)
- Contraction (pulls pre-existing skin over the wound)
What cell type should you think like when addressing wounds, and what does this mean functionally?
- Think like a WBC
- Get rid of contamination and necrotic tissue
- Stimulate formation of granulation tissue
What is the last stage of wound healing?
- Maturation or remodeling phase
When does the maturation or remodeling phase occur?
- Months to years
What occurs during maturation or remodeling phase?
- Continues for months to years, during which collagen becomes better aligned along lines of force and stronger due to cross-linking
What do you wear and use for debridement?
- Caps and masks
- Sterile gloves and instruments
To summarize, what are the three main phases of wound healing?
- Inflammatory/debridement phase
- Repair phase (which has Granulation tissue formation, epithelialization, and contraction)
- Maturation or remodeling phase
What is required for each phase of wound healing to occur?
- Needs to have spent time in the previous stage of wound healing
Describe a clean wound
- Wound made via surgery under aseptic conditions; no entry into the oral cavity or respiratory/GI/urogenital tract
Are traumatic wounds ever clean?
- No
Describe a clean-contaminated wound
- Wound made via surgery with entry into the oral/respiratory/GI/urogenital and no significant spillage
- Wound made via surgery with minor break in aseptic technique
- Clean surgical wound that contains a drain
Describe a contaminated wound
- Wound made via surgery with spillage of Gi contents/infected urine
- Wound made via surgery + major break in aseptic technique
- Traumatic wound without purulent discharge
Dirty wound definition
- Contains purulence, devitalized tissue, foreign material, feces
What should you do to a wound before debriding it? Why?
- Put lubrication into the wound before clipping to keep hair from sticking in the wound
What are the steps of prepping a wound for debridement?
- Put lube in it before clipping
- Clip
- Use surgical scrub on the skin around the wound, not in the wound
What is the purpose of debridement?
- Remove damaged tissue and foreign material
What are 5 benefits of debridement?
- Remove media for bacteria
- Remove physical barrier to perfusion and granulation
- Decrease exudate production
- Improve ability to assess the wound
- Release pro-healing inflammatory mediators that stimulate healing
What are the two main types of debridement?
- Mechanical debridement
2. Selective, autolytic debridement
What are two methods by which mechanical debridement is achieved? Which is the preferred method?
- Surgery (preferred)
- Removing a bandage that has adhered to the wound (not standard of care)
How can we achieve selective, autolytic debridement?
- Moist wound healing techniques
What determines how aggressive you are with surgical debridement?
- Degree of tissue damage and stability of the patient relative (e.g. are they a good anesthetic candidate?)
Conservative debridement anesthesia and where done?
- Patient may be awake or sedated, may have a local block
- Typically done in prep area
What are you debriding with conservative debridement?
- Readily accessible, insensate tissue (or with esdation, tissue that is not highly sensitive)
What should you wear for conservative debridement, and what types of instruments should you be using?
- Minimum of hat, mask, and sterile gloves
- Use sterile instruments and aseptic technique
What is the anesthesia for aggrssive debridement?
- Patient is anesthetized
Where is the procedure done for aggressive debridement?
- Operating room
What is done during expressive debridement?
- Extensive debridement and wound exploration
What are you wearing during aggressive debridement, and what types of instruments?
- Full hat/mask/gown/glove/booties
- Use sterile instruments and septic technique
Why should non-viable tissue be removed (2 reasons)?
- Delays healing
2. Increases infection risk
What five characteristics can you use to assess wound viability?
- Attachment
- Color
- Texture
- Temperature
- Bleeding
Attachment - when to remove non-viable tissue?
Unattached = no blood supply = not viable
- Remove from the wound
What colors can necrotic tissue be?
- Black
- Brown
- Yellow
- Gray
- White
What causes the difference in colors with necrotic tissue?
- Water content
Rank these from lowest to highest water content for necrotic tissue:
Yellow
White
Black
Brown
- Black (lowest)
- Brown
- Yellow
- White
What is the name for dry, leather-like necrotic tissue?
- Eschar
What can you do with an eschar and what must you rule out first?
- You can leave it in place as a biological bandage
- No evidence of infection
What is “slough”?
- Moist necrotic tissues that are yellow, grey, wet, and stringy
What should you do with slough?
- Remove it
What are differentials for cold temperature to tissues?
- Non-viable
- Hypovolemia
- Hypothermia
- Make sure you have treated patient for these other DDX FIRST before calling the tissue non-viable*
What are differentials for lack of bleeding when you cut into a tissue?
- Tissue is not viable
- Hypovolemia
- Hypothermia
Make sure you have treated patient for these other DDX FIRST before calling the tissue non-viable
What are some examples of situations for “when in doubt, cut it out”?
- There is only one opportunity to access that tissue AND/OR
- There is plenty of residual tissue so it won’t be missed AND/OR
- Consequences of later necrosis are severe
- examples are damaged muscle deep in a wound or damaged tissues inside the abdomen or thorax
What are some specific examples of “when in doubt, if it’s superficial or skin, leave it in”?
- There will be multiple opportunities to assess the tissue, AND
- The tissue is needed for later closure, AND
- consequences of later necrosis are not severe
- E.g. damaged skin on a distal limb. There is not much redundant skin available here, so you would like to save it if at all possible, and you can easily reassess it during a bandage change and remove it at that time if it becomes non-viable.
What is the desirable lavage pressure?
- 7-8 PSI
How do you achieve 7-8 PSI lavage pressure?
- 18g needle on a standard IV drip set attached to a 1 liter bag of fluids pressurized to 300 mm Hg with an emergency pressure sleeve
Is the lavage pressure needed to remove microscopic particles HIGHER or LOWER than that required to remove gross debris? What is the implication?
- It’s higher than that required to remove gross debris
- Thus, just because a wound looks clean does not mean that lavage has been adequate
What are the risks if lavage pressure is too high?
- Damage tissue
- Drive bacteria and debris deeper
What are the risks of lavage pressure if it’s too low?
- Microscopic debris and bacteria are harder to remove than macroscopic
Is sedation/analgesia NEEDED or NOT NEEDED when lavage is done with appropriate pressures?
- Likely needed!
- Consider when planning the treatment for your patient
What is the traditional lavage technique, and what’s considered the main problem with this lavage technique?
- 35-60 CC syringe and 18g needle
- However, it had an inconsistent pressure and was often high
Lavage pressure with liter plastic bottle of fluids with holes poked on top
- Too low!
2-4 PSI
Lavage pressure with syringe or IV line without a needle
- TOO LOW
Bacterial load and contamination 1. INCREASE or DECREASE as lavage volume increases as long as the lavage is delivered at the appropriate pressure of ____. Volume DOES or DOES NOT compensate for inadequate pressure?
- DECREASE
- 7-8 PSI
- DOES NOT
What can you use for initial removal of gross contamination?
- Tap water
Why shouldn’t you use tap water for the entire lavage?
- Because it is cytotoxic to fibroblasts
- Spray hose off the skin is not likely to provide appropriate pressure
What should tap water lavage be followed by?
- Lavage with a sterile isotonic solution at 7-8 PSI
- Options include sterile saline, LRS, or diluted antiseptic solution