Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Surgery I > Wound Healing > Flashcards

Wound Healing Flashcards

1
Q

What is a wound?

A

A loss of integrity of the skin and underlying tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the 3 phases of wound healing? length?

A
  • Inflammatory phase
    • 0-5 days
  • Proliferative phase
    • 4-21 days
  • Maturation/remodeling phase
    • 21 days - 2 year
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What type of collagen predominates during wound healing?

A

Collagen Type III

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What happens during the Inflammatory phase of healing?

A
  • Hemostasis
  • Early inflammation
  • Late inflammation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How does hemostasis happen in the body?

A
  • within the first few minutes after injury vasoconstriction occurs
  • Platelets and coagulation cascade are activated
    • Platelets bind to exposed endothelium
    • circulating fibrinogen binds to receptors on adjacent platelets ⇢ forms fibrin clot
      • provides a scaffold for the migration of inflammatory cells
    • Platelet degranulation releases molecules that attract neutrophils, macrophages, endothelial cells, and fibroblasts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What happens during early inflammation in the Inflammatory Phase of healing?

A
  • Establishes immune barrier against invading microorganisms
  • Release of histamine and serotonin by platelet dense bodies and mast cells lead to vasodilation and increase endothelial cell permeability
  • w/in 24-48hr neutrophils enter the wound
    • Kill bacteria through release of oxygen species
    • breakdown extracellular matrix
    • phagocytosis of debris
    • release of additional inflammatory cytokines
  • Clinically characterized by heat, redness, swelling, pain
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What role do neutrophils play in wound healing?

A
  • kill bacteria through release of reactive oxygen species
  • breakdown of extracellular matrix
  • phagocytosis of debris
  • release of additional inflammatory cytokines
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What happens during late inflammation in the Inflammatory Phase of healing?

A
  • Characterized by predominance of macrophages, erythema, and edema of the wound edges (3-5days)
  • Macrophages signaled by cytokines (platelet derived growth factor, TGF-β, leukotriene B4)
    • Reach wound ~48-72hrs after injury
    • become predominant leukocyte by 96hr
    • Role:
      • phagocytose bacteria/debris
      • recruit mesenchymal cells
      • stimulate angiogenesis
  • 3-5days after injury ⇢ influx of lymphocytes
    • modulate macrophages by inhibiting their exodus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What happens during the Proliferative Phase of healing?

A
  • Angiogenesis
  • Fibroblast Migration
  • Collagen Synthesis
  • Contraction
  • Epithelialization
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is angiogenesis? describe the process

A
  • formation of new blood vessels
  • Occurs through stimulatory cytokines released by macrophages and platelets
  • Endothelial cells migrate to the wound bed under the influence of fibroblast growth factors (platelet derived growth factor, TGF-β)
  • Cells then proliferate in response to vascular endothelial growth factor (VEG-F) and form new capillaries
    • VEG-F simulated by cell disruption and hypoxia
  • Occurs w/in 4-6 days
  • Provides the wound with oxygen and nutrients that allow granulation tissue to develop
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What happens during fibroblast migration of the Proliferative phase?

A

Quiescent mesenchymal cells adjacent to the wound bed will differentiate into fibroblasts and migrate into the wound and proliferate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What happens during Collagen Synthesis of the Proliferative phase?

A
  • Collagen type III initially predominates
  • Cross-linking configuration of collagen provides the initial tensile strength to healing tissues
  • as collagen accumulates and the vascular components regress granulation tissue becomes paler
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is granulation tissue?

A
  • highly vascular
  • provides a barrier to bacteria
  • source of myofibroblasts
  • provides a surface for epithelization
  • Initially bright pink appearance
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What happens during the contraction stage of the Proliferative phase?

A
  • After the development of granulation tissue the wound bed starts to contract
    • Occurs when fibroblasts within the wound bed transform into myofibroblasts
      • Myofibroblasts orient linearly along the line of tension and cause wound contraction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What happens during Epithelialization of the Proliferative phase?

A
  • Growth factors stimulate epithelial cells from the edges of the wound to proliferate, then migrate across the granulation tissue bd
    • Cells will migrate more quickly over smooth, nonexuberant granulation tissue
  • Migration continues until contact inhibition with other epithelial cells halts migration and a new basal lamina is established
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What happens during the Maturation Phase of wound healing?

A
  • Collagen production occurs rapidly in the first 6 weeks and continues to strengthen and form a scar over the next 12-18 months
  • Initial deposition is random, over time it is reorganized based on the lines of tension of the tissue
  • Collagen Type III from the proliferative phase is replaced with Collagen Type I
  • Final strength of the scar is approximately 70-80% of unwounded tissue
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What wound factors affect healing?

A
  • Tissue perfusion is important to reverse the effects of tissue ischemia and decrease the rick of local infection
  • Devitalized or necrotic tissue can inhibit wound healing
  • Accumulation of fluid within the wound can impair healing
  • Hematoma/seroma can serve as a medium for bacterial proliferation
    • Infection can impair many of the processes in all the phases of wound healing
      • Depletes platelets
      • impairs white blood cell function
      • cause tissue damage
      • diminish the ability of fibroplasia, angiogenesis, and epithelialization to occur
      • Endotoxins can lead to the breakdown of collagen and subsequently reduce the wound’s strength
  • Tension, motion and pressure can affect healing
    • minimized through differing closure techniques, bandaging/splinting, and adequate nursing care
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What systemic factors affect wound healing?

A
  • Patient comorbidities that lead to immunosuppression
    • FIV, Cushing’s, Hypothyroidism, Diabetes mellitus
  • Exogenous steroids can slow wound healing
    • glucocorticoids impair macrophage activity, fibroblast proliferation and collagen synthesis
  • Chemo/radiation
    • may need to delay treatment until after the acute phase of wound healing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the different types of wounds?

A
  • Abrasion
  • Puncture wound
  • Laceration
  • Degloving injury
  • Thermal burn
  • Decubital Ulcer
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Define an abrasion

A

a partial thickness wound that generally heals quickly through re-epithelization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Define Puncture wound

A

caused by a penetrating object and is associated with a small skin opening, however deep tissue damage and contamination typically occur and can be significant

22
Q

Define laceration

A

has sharp skin edges and may extend into deep tissue

23
Q

Define degloving injury

A

These injuries are associated with extensive loss of skin and underlying tissue, and are most common on the distal limbs

24
Q

Define thermal burn

A

A thermal burn occurs due to close proximity or direct application of heat to the skin. These burns can be severe and cause serious systemic compromise, such as fluid, electrolyte, and protein loss. This leads to an increased risk of infection and subsequent sepsis

25
Q

Define Decubital Ulcer

A

The result of compression on the skin and soft tissues over a boney prominence. Most common locations are over the greater trochanter, caudal elbow/olecranon, and lateral hock

26
Q

What are methods for classifying wounds?

A
  • Duration of contamination
  • Degree of contamination
27
Q

What are the different classes of wounds based on Duration of Contamination?

A
  • Class I: 0-6 hours following injury with minimal contamination. This is considered the “golden period” and is most amenable to primary closure
  • Class II: 6-12 hrs following injury with significant contamination
  • Class III: >12 hrs following injury with gross contamination and in some cases active infection present. It is prudent to avoid primary closure in these situations
28
Q

What is the critical threshold for infection?

A

105 CFU/g tissue

29
Q

What are the classifications of wounds based on Degree of Contamination

A
  • Clean
  • Clean-contaminated
  • Contaminated
  • Dirty/infected
30
Q

Define a Clean wound

A

Atraumatic and made in aseptic conditions. Includes surgical procedures not entering the respiratory or gastrointestinal tract, or urinary tract with an active UTI

31
Q

Define a Clean-contaminated wound

A

Minor contamination with healthy appearing tissue, and contamination can be effectively removed. This includes surgery of the gastrointestinal tract or respiratory tract, or a minor break in aseptic technique

32
Q

Define a Contaminated wound

A

open traumatic wounds with visible debris or a major break in aseptic technique

33
Q

Define a Dirty/Infected wound

A

Wound with devitalized tissue, organic material and/or purulent material representing active infection or chronicity

34
Q

What are the different types of closures?

A
  • Primary Closure
  • Delayed Primary Closure
  • secondary Closure
  • Second-Intention Healing
35
Q

What is a primary closure?

A
  • Surgical closure of a wound within the golden period (0-6 hrs)
  • Indicated for wounds with mild contamination that can be managed open initially with debridement to decrease the likelihood of infection
  • A unstable patient may need to be stabilized before a wound can be addressed, and therefore closure may then occur outside the golden period
36
Q

What is a Delayed Primary Closure?

A
  • Surgical closure of a wound after the golden period, however before the appearance of granulation tissue
  • Indicated for wounds with mild contamination that can be managed open initially with debridement to decrease the likelihood of infection
  • Patient that presents unstable may need to be stabilized before a wound can be addressed, and therefore closure may occur outside the golden period
37
Q

What is a Secondary Closure

A
  • Surgical closure following the proliferative phase of healing ⇢ after the formation of granulation tissue
  • Generally reserved for wounds with moderate to severe contamination, greater soft tissue damage, or infection
38
Q

What is Second-Intention Healing?

A
  • Leaving the wound open to heal without surgical intervention
  • Healing occurs by granulation tissue, contraction, and epithelialization
  • Any wound can heal through second-intention healing
    • however process is inefficient and may not produce a functional outcome depending on location and patient factors
39
Q

What should be completed during initial wound managment?

A
  • Place water soluble sterile lubricant in the wound to prevent further debris from entering
  • Clip wide margins around the wound
    • allows for assessment of nearby structures and may uncover unnoticed wounds
  • Wash lubricant and other gross debris out through mechanical lavage
    • Ideally sterile isotonic solutions, antiseptics, or in large grossly contaminated wounds tapwater
    • Do not stop lavage until the wound has been cleared of all gross debris
    • Ideal pressure is ~7-8psi, excess pressure can injure underlying tissues and drive contaminants deep into the tissue
      • can use a 16 to 22 G needle to a fluid set and a 1L fluid bag pressurized to less than 300mmHg)
  • Collect samples (swab and tissue) for culture and sensitivity from:
    • where a resistant bacteria is expected
    • evidence of ongoing infection
    • cases of non-healing wounds
40
Q

What is Debridement? types?

A
  • The removal of all necrotic or damaged tissue from the wound bed
    • if questionable, may leave tissue and re-evaluate w/in 24hrs
  • If possible spare neurovascular structures, tendons, bones, and ligaments
  • Excessive debridement can lead to removal of important tissue that would contribute to wound healing
  • Types:
    • Surgical
    • Mechanical
    • Autolytic
    • Enzymatic
    • Biosurgical
41
Q

What is surgical debridement?

A
  • performed via sharp excision using a scalpel blade or scissors
    • Selective
  • Involves removing any devitalized or discolored tissue
  • May perform en-bloc removal of the entire wound
    • Non-selective surgical debridement
42
Q

What is mechanical debridement

A
  • Non-selective
  • Can include a wet-to-dry or dry-to-dry bandage
  • May include dressings with hyperosmotic agents that will dehydrate microorganisms and inhibit their growth
    • hypertonic saline, sugar, honey, or dextran
  • Wet-to-dry was considered standard, they are non-selective and have a potential to debride normal tissue and destroy healthy epithelial cells
    • No longer standard of care
43
Q

What is autolytic debridement?

A
  • Current standard of care
  • Moist wound healing - Application of hydrophilic dressing
    • endogenous enzymes dissolve non-viable tissues
      • facilitates autolytic wound debridement, and maintains the presence of cells, cytokines, and growth factors necessary for wound healing at the wound surface
  • Dry wounds - water based hydrogel dressing can be applied
  • Mild to moderately exudative wounds - hydrocolloid sheet, polyurethan foam dressing, or maltodextrin polymer flakes can be applied
  • Heavily exudative wounds - calcium alginate (colloidal dressing) can be applied
44
Q

What is enzymatic debridement

A
  • proteolytic enzymes degrade non-viable tissues
  • Ex: collagenase ointment, papain-urea-based ointment
45
Q

What is biosurgical debridement?

A
  • Medical maggots (green blow fly Lucilia sericata) secrete proteolytic digestive enzymes that clear necrotic tissues
  • Can damage healthy tissue, make efforts to protect surrounding tissues
46
Q

What is the purpose of a surgical drain?

A
  • allows accumulating fluid to drain from dead space in a wound
  • Rules:
    • place aseptically
    • never exit through the wound opening itself
    • never have an in and out drain
    • do not suture drain to deeper tissues
    • always cover/bandage the drain exit to keep it clean
    • remove as soon as clinically indicated
47
Q

What is the difference between an active and passive drain?

A
  • Active Drain:
    • Create negative pressure gradient⇢ suction exudates from wound
    • I.e Jackson-Pratt, Blake, butterfly
  • Passive Drain:
    • dependent upon gravity to function
      • exit should always be in a gravity-dependent location
    • Can act as a conduit for bacteria and environmental contaminants (greater risk of infection)
    • i.e. Penrose
48
Q

When should a drain be removed?

A
  • Fluid production will never be 0
  • Once fluid production has plateaued for approximately 24hrs, removal of the drain can be considered
  • In general drains are in place for approximately 3-5days
49
Q

What are the possible complications of drains?

A
  • Early removal
  • Contact dermatitis w/ exit of drain
  • ascending infections
  • incomplete removal
  • loss of negative pressure
  • becoming clogged
50
Q

What is Negative Pressure/”Vacuum” Therapy?

A
  • Application of subatmospheric pressure (-80 to -125 mmHg) to an open wound through on open cell foam
  • Benefits:
    • removal of bacteria and exudate
    • reduction in fluid accumulation
    • improved perfusion and granulation tissue quality
  • Process:
    • Negative pressure will alter interstitial fluid gradient and therefore potentially increase dermal perfusion
    • Changes in pressure gradients will increase tissue oxygenation and induce the release of growth factors

Surgery I (37 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions