Wound Care Flashcards
What are the stages of wound healing (3)
Inflammatory phase
Proliferative phase
Remodeling phase
Inflammatory phase
-time frame
-what occurs
-cells involved
days 1-4
-initial vasoconstriction followed by vasodilation
-neutrophils and macrophages are recruited
Proliferative phase
-time frame
-what occurs
-tensile strength at 14 days
days 3-21
-collagen synthesis provides tensile strength of wound
-at 14 days, tensile strength of wound equals that of suture
remodeling phase
-time frame
days 21 up to one year
At what stage of healing do chronic wounds stop progressing
at the proliferative phase
What is santyl
collagenase- an enzymatic debrider that digests collagen in necrotic tissue
What is Regranex
PDGF-1
Where is Regranex made
Puerto Rico
What is a normal value for serum albumin
3.4-5.0 g/dL
What is a low serum albumin level associated with (5)
-decreased wound healing
- edema
-impaired cellular immunity
-decreased collagen synthesis
-decreased fibroblast proliferation
What minimum ABI is necessary for wound healing
.35 for non-diabetic
.45 for diabetic patient
How does negative pressure wound therapy assist wound closure
negative pressure wound therapy applies mechanical shear stress to the wound site. This is believed to promote granulation by decreasing bacterial bioburden, reducing edema, and inducing capillary budding
How does hyperbaric oxygen therapy assist wound closure
Hyperbaric oxygen therapy increases the partial pressure of O2 in arterial circulation, which increases diffusion of O2 at the wound site. This is believed to increase growth factors promoting angiogenesis and collagen synthesis.
What is integra
bilayer graft composed of bovine tendon collagen with chondroitin 6- sulfate and a silicone layer to control moisture loss
What is oasis
extracellular graft matrix derived from porcine, small intestine submucosa
What is apligraf
bilayer graft derived from neonatal foreskin with dermal and epidermal layers
What is graft jacket
extracellular graft matrix derived from human tissue with intact vascular channels
What is tissue mend
acellular collagen matrix derived from fetal bovine dermis
Inflammatory Phase: 3 parts
-Vascular
-Hemostatic
- Cellular
Inflammatory Phase Vascular component
1)Vasoconstriction of the blood vessels. Fibrin promotes hemostasis and provides scaffolding for the ingrowth of cells at a later stage.
2)Vascular permeability: achieved through histamine (vasodilator)
Serotonin and kinins also increase the permeability
Neutrophils: when they get there, peak numbers, function
- Arrive at the wound in 6 hours
-Peak numbers occur at 1-2 days
-Responsible for wound debridement with the release of callagenolytic and fibrinolytic enzymes. Neutrophiles also ingest bacteria
Lymphocytes: peak numbers. Most important roles.
How they attract and activate macrophages
-Reach peak numbers in 6 days
-most important role is in the synthesis of lymphokines
-Migration Inhibition factor (MIF): attracts macrophages to the wound
-Macrophage Activation Factor (MAF): activates the macrophage
Macrophages:
Reasons why they are the most important cell for wound healing (4)
1) only cells able to tolerate low O2 tension at the wound edge
2)Appear in the wound during first 5 days and have a long life span
3)Wound healing severely limited by their absence
4)Process and presents antigens to the lymphocytes
-Cells that produce collagen
-When does collagen synthesis begin
-What is fibronectin and what does it do (3)
-Migratory fibroblasts (mesenchymal cells) produce collagen
-Collagen synthesis begins on the 5th day and lasts for 2-4 weeks
-Fibronectin (produced by fibroblasts)
— Coats macrophages to aid in opsonization and phagocytosis
— Found on surface of fibroblasts where it aids in the adhesion of these cells to the ECM
—Fibronectin corss lings with collagen and glycosaminoglycans
Proliferative phase: 3 parts
-Epidermal regeneration
-Neoangiogenesis
- Collagen synthesis
Epidermal regeneration components
-cells at wound edge
-fibronectin network
- basement membrane
-Cells at wound edges flatten out to develop pseudopods to migrate at a rate directly proportional to oxygen tension of the tissue (hyperbaric)
-Fibrin- fibronectin networks serves as a framwork over which this migration can occur
-Basement membrane under epidermal cells begin to change
—Epidermal cells elongate in direction of the wound
—mitotic activity of epidermal cells increases
—division and movement of epidermal cells under the direction of epidermal growth factor
Neoangiogenesis
-timing of new capillary buds
- Capillary formation influenced by
-oxygen’s role
-Formation of new cap buds near the wound occurs at same time as migration of epidermis
-development of capillaries toward center of wound is under influence of growth factors from macrophages
- As O2 tension increases with formation and opening of new vascular channels the growths factors are inhibited
Collagen synthesis
-relation to O2 tension
-maximum levels
-As O2 tension further increases fibroblasts begin synthesizing collagen
-Amount of collagen reach maximum levels at 2-3 weeks post injury
Remodeling phase:
-how long it takes
-2 weeks tensile
-1 month tensile
-Equilibrium
-Wound contraction
-lasts up to 1 year
-2 weeks: 35% tensile strength
-1 month: 40-50% tensile
-Entire remodeling an equilibrium between lying and resorbing old collagen and formation of new collagen.
- Wound contraction is a part of healing. Contraction progresses at .6mm-.7mm/day
Healing by 1st intents (8 steps)
1-narrow incision space immediately fills with clotted blood containing fibrin and blood cells
2- Dehydration of surface clot forms a scab
3- Within 24 hours neutrophils appear on the margin of wound
4- Within 24-48 hours the cut edges thicken from mitotic activity of basal cells.
—-epithelial cells from edges migrate along cut margins of the dermis to deposit basement membrane as they move
5- Day 3 Neutrophils replaced by macrophages
—increased granulation tissue at incision site
—collagen fibers begin to be manufactured
— thin epithelial cell layer thickens
6- Day 5: neovascularization is maximal. Epidermis back to original thickness
7-During 2nd week there is increased collagen and fibroblast activity
8-End of 1st month a scar starts to develop
—maximum tensile strength developed in several months
Factors that interfere with wound healing (8)
-age
-inadequate perfusion
-edema
-infection
-poor nutrition
-vitamin deficiencies
-steroids and cytotoxic meds
-radiation
5 growth factors important in wound repair
PDGF: platelet derived growth factor
PDAF: platelet derived angiogenesis factor
PDEGF: Platelet derived epidermal growth factor
TGFB: transforming growth factor beta
Platelet factor 4
Types of compression therapy (5)
-pressure achieved
- reason for use
Antiembolism stockings
–16-18mmHg. For DVT prophylaxis
Low compression
—18-24mmhg. Non-ambulatory patients
Low to Moderate compression
—25-35mmHg for edema secondary to venous insufficiency
Moderate compression stockings
—30-40mmHg. For edema with or without ulcer
High compression stockings
—40-50mmHg for lymphedema
Split thickness grafts
3- size and advantages
Thin: .008-.012inches
-excellent host tissue incorporation but a lot of contraction occurs
Intermediate: .012-.016inches
-more durable, contracts less but slightly less incorporation as well
Thick: .016- .02 inches
-Less chance of host incorporation but durability and contraction much improved
Skin graft complications (3)
-what are they
-how to prevent
Seroma: most common
-transudative fluid accumulation
-prevented through pressure dressing and pie crusting
Hemotoma:
-blood collection
-normal capillary bleeding necessary, to prevent need proper fenestration/pressure dressing application
Infection:
-strep pyogens and pseudomonas pyocyanes produce fibrinolysin which will disrupt fibrin bone and devastate the graft
Stages of skin graft healing (4)
-Timing and what occurs
Plasmatic stage:
-occurs 24-48 hours
-fibrin layer forms between graft and host bed to anchor and allow diffusion of nutrients
Inosculation Stage:
-begins at 48 hours
-revascularization of grafted tissue
-Lymph drainage established 4th-5th day
Reorganization stage
-continues for months
-connective tissue reorganizes and regulates vascular and lymphatic flow
Re-innervation:
-Occurs simultaneously with reorganization stage
-Process takes one-two years to complete
