Wound Healing Flashcards
1
Q
When does the inflammatory/debridement phase occur?
A
- Day 3-5
2
Q
What is the main cell type in the inflammatory/debridement phase?
A
- White blood cells
3
Q
What type of debridement do white blood cells perform?
A
- Selective, autolytic debridement
- This involves getting rid of bacteria, foreign material and necrotic host tissue
4
Q
What two things do white blood cells perform in order to achieve selective, autolytic debridement?
A
- Phagocytosis
- Secretion of proteolytic enzymes
5
Q
When does the repair phase of wound healing occur?
A
Day 3-5 to 2-4 weeks
6
Q
What are the main cells involved in the repair phase?
A
- Fibroblasts (granulation tissue)
7
Q
What are the three main processes that occur during the repair phase and in what order?
A
- Granulation tissue formation
- Epithelialization
- Contraction (same time as epithelialization)
8
Q
What are the main cell types during granulation tissue formation, and what do they do?
A
- Fibroblasts (build ECM)
- Endothelial cells (build vessels)
9
Q
What are the main cell types during epithelialization, and what do they do?
A
- Epithelial cells
- Traverse GT and build new skin
10
Q
What are the main cell types during contraction, and what do they do?
A
- Myofibroblasts (pull skin over the wound from the center of the granulation tissue)
11
Q
Do epithelialization and contraction occur independently of each other?
A
- Yes
12
Q
What other cells do WBCs attract during the inflammatory/debridement phase?
A
- More WBCs for debridement
- Fibroblasts and endothelial cells for repair phase
13
Q
What two simultaneous but independent processes occur during the repair phase?
A
- Epithelialization (builds new skin)
- Contraction (pulls pre-existing skin over the wound)
14
Q
What cell type should you think like when addressing wounds, and what does this mean functionally?
A
- Think like a WBC
- Get rid of contamination and necrotic tissue
- Stimulate formation of granulation tissue
15
Q
What is the last stage of wound healing?
A
- Maturation or remodeling phase
16
Q
When does the maturation or remodeling phase occur?
A
- Months to years
17
Q
What occurs during maturation or remodeling phase?
A
- Continues for months to years, during which collagen becomes better aligned along lines of force and stronger due to cross-linking
18
Q
What do you wear and use for debridement?
A
- Caps and masks
- Sterile gloves and instruments
19
Q
To summarize, what are the three main phases of wound healing?
A
- Inflammatory/debridement phase
- Repair phase (which has Granulation tissue formation, epithelialization, and contraction)
- Maturation or remodeling phase
20
Q
What is required for each phase of wound healing to occur?
A
- Needs to have spent time in the previous stage of wound healing
21
Q
Describe a clean wound
A
- Wound made via surgery under aseptic conditions; no entry into the oral cavity or respiratory/GI/urogenital tract
22
Q
Are traumatic wounds ever clean?
A
- No
23
Q
Describe a clean-contaminated wound
A
- 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
24
Q
Describe a contaminated wound
A
- 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
25
Dirty wound definition
- Contains purulence, devitalized tissue, foreign material, feces
26
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
27
What are the steps of prepping a wound for debridement?
1. Put lube in it before clipping
2. Clip
3. Use surgical scrub on the skin around the wound, not in the wound
28
What is the purpose of debridement?
- Remove damaged tissue and foreign material
29
What are 5 benefits of debridement?
1. Remove media for bacteria
2. Remove physical barrier to perfusion and granulation
3. Decrease exudate production
4. Improve ability to assess the wound
5. Release pro-healing inflammatory mediators that stimulate healing
30
What are the two main types of debridement?
1. Mechanical debridement
| 2. Selective, autolytic debridement
31
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)
32
How can we achieve selective, autolytic debridement?
- Moist wound healing techniques
33
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?)
34
Conservative debridement anesthesia and where done?
- Patient may be awake or sedated, may have a local block
| - Typically done in prep area
35
What are you debriding with conservative debridement?
- Readily accessible, insensate tissue (or with esdation, tissue that is not highly sensitive)
36
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
37
What is the anesthesia for aggrssive debridement?
- Patient is anesthetized
38
Where is the procedure done for aggressive debridement?
- Operating room
39
What is done during expressive debridement?
- Extensive debridement and wound exploration
40
What are you wearing during aggressive debridement, and what types of instruments?
- Full hat/mask/gown/glove/booties
| - Use sterile instruments and septic technique
41
Why should non-viable tissue be removed (2 reasons)?
1. Delays healing
| 2. Increases infection risk
42
What five characteristics can you use to assess wound viability?
1. Attachment
2. Color
3. Texture
4. Temperature
5. Bleeding
43
Attachment - when to remove non-viable tissue?
Unattached = no blood supply = not viable
- Remove from the wound
44
What colors can necrotic tissue be?
- Black
- Brown
- Yellow
- Gray
- White
45
What causes the difference in colors with necrotic tissue?
- Water content
46
Rank these from lowest to highest water content for necrotic tissue:
Yellow
White
Black
Brown
- Black (lowest)
- Brown
- Yellow
- White
47
What is the name for dry, leather-like necrotic tissue?
- Eschar
48
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
49
What is "slough"?
- Moist necrotic tissues that are yellow, grey, wet, and stringy
50
What should you do with slough?
- Remove it
51
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*
52
What are differentials for lack of bleeding when you cut into a tissue?
1. Tissue is not viable
2. Hypovolemia
3. Hypothermia
*Make sure you have treated patient for these other DDX FIRST before calling the tissue non-viable*
53
What are some examples of situations for "when in doubt, cut it out"?
1. There is only one opportunity to access that tissue AND/OR
2. There is plenty of residual tissue so it won't be missed AND/OR
3. Consequences of later necrosis are severe
- examples are damaged muscle deep in a wound or damaged tissues inside the abdomen or thorax
54
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.
55
What is the desirable lavage pressure?
- 7-8 PSI
56
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
57
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
58
What are the risks if lavage pressure is too high?
- Damage tissue
| - Drive bacteria and debris deeper
59
What are the risks of lavage pressure if it's too low?
- Microscopic debris and bacteria are harder to remove than macroscopic
60
Is sedation/analgesia NEEDED or NOT NEEDED when lavage is done with appropriate pressures?
- Likely needed!
| - Consider when planning the treatment for your patient
61
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
62
Lavage pressure with liter plastic bottle of fluids with holes poked on top
- Too low!
2-4 PSI
63
Lavage pressure with syringe or IV line without a needle
- TOO LOW
64
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?
1. DECREASE
2. 7-8 PSI
3. DOES NOT
65
What can you use for initial removal of gross contamination?
- Tap water
66
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
67
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
68
Chlorhexidine vs povidine-iodine spectrum
- Chlorhexidine has a wide spectrum
69
Chlorhexidine vs Povidine-iodine residual activity
- Chlorhexidine has good residual activity
| - Povidone-iodine has poor residual activity
70
Chlorhexidine vs povidone-iodine action in presence of organic matter
- Chlorhexidine works in the presence of organic matter, and povidone-iodine does not
71
Chlorhexidine vs povidone-iodine safety around the eyes
- Chlorhexidine is toxic to the cornea
| - Povidone-iodine is safer around the eyes
72
What is the desired concentration of chlorhexidine solution vs the stock solution?
- Desired is 0.05%
| - Stock is 2%
73
What is the desired concentration of povidone-iodine solution vs the stock solution?
- Desired is 0.1-1%
| - Stock is 10%
74
What's the issue with higher concentration solutions?
- May delay healing
75
What's the issue with lower concentration solutions?
- May not be antimicrobial
76
Can't you just dilute by eye based on the color of the solution?
- NO
77
Practice: To create 400 mL of chlrohexidine solution at the desired concentration for lavage, combine _____ mL of 2% chlorhexidine and ______ mL sterile saline.
- (400)*(0.05) = (x)(2)
| - 10 mL of 2% chlorhexidine and 390 mL of sterile saline
78
How do you create a wet-to-dry dressing? (NOT RECOMMENDED BUT WE NEED TO KNOW HOW IT WORKS)
- Saline-soaked gauze as a contact layer placed directly on the wound and bandaged in place
- bandage is changed after the dressing has dried onto the wound
- When the dressing is removed, the surface of the wound, which has adhered to the dressing, is peeled off
79
Why is mechanical debridement with adherent dressing not preferred?
- It removes not only necrotic tissue but healthy tissue that remained after the wound occurred as well as debriding white blood cells and cells involved in the repair
- It is a non-selective debridement and removes necrotic tissue, healthy tissue, white blood cells, and repair cells
80
What is the goal of dressings in moist wound healing?
- Dressings are designed to keep the wound fluid in contact with the wound, thus supporting the body's own healing mechanisms
81
What five things does wound fluid contain that are beneficial to wound healing?
1. Oxygen and nutrients
2. Cytokines and growth factors
3. Chemotactic factors
4. Systemic antibiotics if being given
5. White blood cells and their proteases
82
What two things carry out selective autolytic debridement?
- WBCs
| - The proteases that WBCs secrete 24 hours a day under the bandage
83
Benefits of selective autolytic debridement
- Allows you to get debridement going in patients that are too unstable to anesthetize or surgical debridement
84
What components of the repair phase does MWH enhance?
All three components
85
What are five ways that MWH helps fight bacteria?
1. Prevents necrosis, which makes affected tissue a media for bacteria
2. Support function of WBCs and proteases, which work best in moist environments
3. Lower oxygen tension in the wound --> decreases the pH --> inhibits bacteria
4. Stimulates angiogenesis, which improves the blood supply
5. If on systemic antibiotics, they will be in the wound fluid, and thus kept in contact with the wound
86
How does MWH comfort compare to wet-to-dry dressings?
- More comfortable because non-adherent
87
MWH temperature compared to wet-to-dry dressings
- Maintains the physiological temperature of the wound closer to normal, so cells function better
88
Do MWH require MORE or LESS frequent bandage changes than wet-to-dry or dry dressings?
- Less frequent bandage changes
89
Is MWH MORE or LESS expensive than wet-to-dry?
- It is LESS expensive because healing is faster and bandage is changed less often
90
What is the main potential disadvantage of MWH?
- Maceration when excess moisture damages tissue
91
How can you avoid maceration of tissues?
- Proper selection and application of the dressing
92
Should you be concerned if a compromised wound is larger or deeper after the first round of MWH?
- Not necessarily; it's often okay!
| - It just means that the process of selective, autolytic debridement is working and removing unhealthy tissue
93
If the MWH gel looks and smells like pus, should you be concerned about infection?
- No!
- It is not a sign of infection
- Assess the wound, not the dressing, for signso f infection
94
How does MWH stimulate the repair phase?
- Increased proliferation of cells involved in repair
| - Increased rate of each component of repair
95
What should you ask yourself when selecting a moisture retentive dressing (MRD) for MWH?
- How much exudate will this wound produce, and what are the needs of the wound (i.e. what part of the wound healing process is most needed by the wound, e.g. debridement, granulation, epithelialization)
96
List the following from most to least absorptive:
Polyurethane foam
Hydrogel
Calcium alginate
Hydrocolloid
1. Calcium alginate (most absorptive)
2. Polyurethane foam
3. Hydrocolloid
4. Hydrogel
97
Calcium alginate
- What part of the wound healing process is it most helpful for?
- Low/Mod/High exudate bandage?
- High exudate
| - Good if the wound needs debridement
98
Polyurethane foam
- What part of the wound healing process is it most helpful for?
- Low/Mod/High exudate bandage?
- High to moderate exudate
| - Good for promoting epithelialization
99
Hydrocolloid
- Low/Mod/High exudate bandage?
- Moderate to low exudate
100
Hydrogel
- What part of the wound healing process is it most helpful for?
- Low/Mod/High exudate bandage?
- For wounds with low to no exudate
| - Good for rehydrating dry wounds
101
Which bandages support selective, autolytic debridement and all parts of the repair phase?
- ALL OF THEM
102
Describe the process of applying a bandage for moist wound haeling?
1. Use aseptic technique
2. Cut MRD to fit in the wound in order to avoid maceration of surrounding skin
3. Cover with normal layers of soft padded bandage (cast padding, Kling, Vetwrap)
4. Change bandage before the dressing dries out or just as it becomes over-saturated
103
When should you change a MRD?
- Before the dressing dries out or just as it becomes over-saturated
- Usually change q2-3 days early in the WH process; may go 5+ days between bandage changes in later WH
104
Indications for calcium alginate
- Good for autolytic debridement of contaminated, moderate to highly exudative wounds
- Good stimulator of granulation tissue
- Hemostatic
105
Contraindications for calcium alginate
- If insufficient exudate, will not gel and can dehydrate teh wound
106
Indications for polyurethane foam
- Good for autolytic debridement, stimulation of granulation, and especially epithelialization
- May inhibit exuberant granulation
- Use dry to wick moisture out of macerated skin
- Can pre-moisten for deri wounds with saline
107
Contraindications for polyurethane foam
- Insufficient exudate
| - Foam is too soft to provide protection to bony prominences
108
Indications for hydrocolloid
- Good for autolytic debridement, granulation, and epithelialization
109
Contraindications for hydrocolloid
- Too much exudate
110
Indications for hydrogel
- Dry wounds requiring autolytic debridement, granulation, or epithelialization
111
Contraindications for hydrogel
- Too much exudate
112
What three things do antibiotics not replace the need for?
- Debridement
- Lavage
- Drainage
113
Know the indications for antibiotics
- Go through the chart on page 57
114
When to give therapeutic antibiotics?
1. Wound is already infected (start right away)
2. If there was significant contamination or devitalization left post-op, infection was found, or patient was highly compromised (continue course of abx post-op)
115
When to give prophylactic abx?
- If you suspect or anticipate that surgery will be >90 min
- If you're entering a non-sterile lumen
- Devitalized or contaminated tissue
- Perineal or perianal surgery
- Orthopedic procedure
- Implant (old or new)
- Immunocompromised or severely traumatized patient
116
When to not give abx even prophylactically?
- Surgery <90 min
- Not entering a non-sterile lumen
- Tissue is healthy
- Healthy patient
117
What is pus?
- Liquid of inflammation and necrosis
118
What does pus contain?
- Leukocytes (especially degenerative neutrophils) and products of necrosis
119
# Fill in the blank:
Necrotic tissues and/or pus DO or DO NOT mean that bacteria and infection are present.
- DO NOT
120
How does risk of infection change as the amount of tissue damage increases?
- Risk of infection increases as the amount of tissue damage increases
121
Are antibiotics needed?
- Minimal contamination
- Little tissue damage
- Readily changed to clean with lavage and debridement
-NO
122
Are antibiotics needed?
- Open joint or fracture OR
- Sheared bone OR
- Polytrauma OR
- Extensive damage OR
- Immunocompromised
Yes
123
What three criteria must be met before closing a wound?
1. All remaining tissue is viable
2. All contamination has been removed
3. Can be closed without excessive tension
124
What are the two risks when premature closure of a wound?
- Dehiscence
| - Infection
125
If a wound must be closed prematurely (i.e. before meeting the criteria discussed in another flashcard), what additional step should be taken?
- Place a drain
| - Example is a perianal wound
126
Primary wound closure
- Immediately after wounding (and after debridement and lavage)
127
Are traumatic wounds usually closed using primary wound closure?
- They are not usually closed primarily unless there is minimal contamination, minimal tissue trauma, and they can be closed without tension
128
Delayed primary closure
- After some management as open wound but before granulation tissue forms
129
Secondary closure
- After some management as an open wound and after granulation tissue forms
130
Second intention wound closure
- Wound that is managed as an open wound until it closes without the aid of surgical closure
131
Open wound management
- means the wound has not been surgically closed
- Includes debridement (often surgical), lavage, and bandaging
- It has nothing to do with the wound being left open to air
132
What are three indications for placing a drain?
1. Possibility that there is still some residual contamination or infection
2. Possibility of that additional tissue may still necrose
3. Presence of large dead space where fluid will accumulate
133
Name 3 detrimental effects of fluid accumulating in a wound
1. It is a media for bacteria
2. It separates tissues that need to heal together
3. Pressure created by fluid can cause pain and compromise blood flow
134
Describe a Jackson Pratt drain
- fenestrated end of the drain is placed in the wound, and an air-tight seal is achieved as the wound is sutured
- After compressing the grenade to evacuate air out of the port with cap, the cap is closed, and the negative pressure in the grenade is transmitted to the wound
135
Describe a penrose drain
- One end of the Penrose drain is placed in the wound, and the other is tacked to an exit point ventral to the wound
136
What type of drain is a JP drain?
- Closed, active-suction drain
137
What type of drain is a Penrose drain?
- Open, passive drain
138
Advantages for the route of drainage of JP drains
- No skin excoriation (closed system)
- Decreased chance of ascending infection
- Easy to quantify and assess fluid character
139
Advantages for mechanism of action with JP drains
- Predictable and consistent
- Seals leaky lymphatics
- Closes down dead space
140
Advantage for the exit site of the JP drain
- Exit anywhere around the wound
| - Exit where convenient
141
What are advantages with the mechanism of action of Penrose drains?
- Airtight seal not required
142
Mechanism of action of JP drain vs Penrose
- JP drain: Active suction drain
| - Penrose drain: Capillary action, gravity, overflow, body pressures
143
Exit site for Penrose drain
- Gravity dependent
144
Bandage for Penrose drain
- Needed
145
Relative risk of ascending infection for JP drain vs Penrose drain
- JP drain is lower
146
Need for air-tight closure of wound in JP drain vs Penrose drain
- Required for JP drain and not required for Penrose
147
Relative ability to bring tissues into contact with JP drain vs Penrose drain
- Higher for JP drain
| - Lower for Penrose drain
148
For drain placement, what type of technique and instruments?
- Aseptic technique and sterile instruments
149
When do you place a drain relative to other aspects of wound management?
- Place the drain after you debride and lavage but before closing
150
Exit site for a drain
- What type of tissue?
- Is the exit site through the incision?
- Healthy tissue
- Exit site IS NOT through the incision itself
- Suture the drain to the exit site
151
When to bandage a drain and why?
- ALWAYS bandage the exit site of the drain regardless of type
- Reduce maceration!
152
What are three indications that it is time to remove a JP drain?
1. Gross quality of the exudate: Serosanguinous
2. Cytological quality of exudate shows healthy cells
3. Volume of exudate has DECREASED and then PLATEAUED
153
Why shouldn't you wait for drainage to reach zero before pulling a drain?
- Presence of the drain stimulates some production of fluid
154
How are the vast majority of drains removed?
- Cutting the anchoring suture and pulling the drain out
| - Patient can be awake and often doesn't even notice it coming out
155
What to do with the exit site of a drain?
- Leave it open because it is at best a clean contaminated or contaminated wound
- Let it heal by second intition
156
When do you use a stent?
- Helps keep a wound from getting bigger and can be used to gradually pull skin over the wound
157
Materials for stents
- Cut pieces of red rubber tubes
- IV tubing
- Penrose drains
- Gauze roll
158
How do you place a stent?
- Material is placed on either side of the wound (~0.5-1 cm from the edges) and anchored with a horizontal mattress suture pattern which spans the wound
159
Stent management
- As the skin stretches, stents can be intermittently tightened (slightly!) with hemoclips or split shot placed under the knot.
- Excess tension on the stent can lead to necrosis of the skin edges and pull through of the stent
160
Degloving or shearing wounds - what is prognosis?
- Look bad but prognosis is good!
161
What is one of the main issues with degloving or shearing wounds?
- Extensive loss of tissue
162
How to manage degloving or shearing wounds?
- May need multiple surgeries, long open wound care
| - Often need a skin graft at the end
163
What is required if there is penetration into the abdomen, and why (3 primary reasons)?
- EXPLORATORY SURGERY IS MANDATED
1. High risk of damage to the GIT (life threatening)
2. May not see signs until days later, when they are septic
3. Default is to err on the side of the explore
164
What are the primary issues with bite wounds? Explain what tip of the ice berg means when you have a patient with small punctures from a bite
- Multiple forces: Shear, tear, crush
- Skin moves with teeth; teeth tear underlying tissues
- 140-450 PSI
- Inoculate bacteria
165
Treatment for bite wounds
- They should be opened and debrided to their deepest extent, even if the dog appears stable
- It can take multiple days before signs of underlying necrosis and infection from bite wounds set in, and the patient may then rapidly deteriorate due to septicemia and septic shock
- Inadequate treatment can occur when the client and/or DVM is hesitant to proceed with surgery because they do not appreciate the full import of the iceberg effect
166
What should you do if there is penetration of the bite wound into the abdominal cavity?
- Surgical explore!
167
Gunshot wounds special considerations
- Contaminated (bring in bacteria, dirt from the surface of the skin)
- Wave of cavitation energy goes out perpendicular to path of bullet and causes collateral damage beyond the bullet tract
168
What should you do if there is penetration of the bullet into the abdomen?
- Explore!
