L06: Wound Healing "Flesh and Bood" (Case) Flashcards Preview

Surgery (Spring 2015) > L06: Wound Healing "Flesh and Bood" (Case) > Flashcards

Flashcards in L06: Wound Healing "Flesh and Bood" (Case) Deck (31):
1

skin functions

-maintain hydration and thermoregulation
-defense against pathogens and chemicals
-vitamin D synthesis
-sensory (e.g. mechanoreceptors)
-storage (H2O, electrolytes, fat, proteins)
-insulation

2

chars. of Epidermis

-superficial
-cuboidal/stratified epithelium
-avascular (completely reliant on underlying blood supply)
-variable thickness depending on location

3

chars. of Dermis

-below epidermis
-collagen/elasticity
-vascular plexus, lymphatics, nerves
-hair follicles, glands
-vessels susceptible to collapse under too much tension

4

chars. of Hypodermis

-assoc. with dermis
-mostly fat/CT
-contains panniculus
-contains subdermal plexus and direct cutaneous artery and vein, which runs PARALLEL in dogs/cats**

5

5 stages of wound healing and length of time for each**

Coagulation (<5 min)
Inflammation (0-24hrs)
Debridement (2-5d)
Proliferation (Repair) (4-21d)
Maturation (21d-2 years)

6

main players of primary coag. (formation of platelet plug)

platelets
vWF
subendothelial collagen

7

Describe process of inflammation

-vasodilation (redness, heat)
-egress of leukocytes and serum (swelling)
-fibrin cross-links through platelet plug
-neuts come first to engulf bacteria, release proteases, and prepare wound for macs (24-48hrs)
-macs engulf dead neut debris and clean up wound (2-5d)
-platelets >>cytokines

8

1st and 2nd phases of wound healing

1st: inflammatory
2nd: proliferative

9

Describe process of debridement

-removal of necrotic tissue and debris by macs
-aka lag phase

10

lag phase

critical period when wound is becoming weaker and you must rely solely on suture technique to hold it together
-duration dependent on: amt. of necrotic tissue, tissue type (presence of collagenase, metalloproteinase? what pH?)

11

Describe process of proliferation

-influx of fibroblasts (max @ 7-10d) signaled by mac after adequate debridement has occurs
-random, rapid deposition of type 1 collagen
-rapid gain in tensile strength "log phase"
-angiogenesis
-granulation tissue formation
-cytokine dependent
-pink, glistening
-epithelialization as myofibroblasts contract edges of wound

12

describe process of maturation

-collagen remodeling
-"second lag phase"
-linearization
-cross-linking
-continues for weeks to years

13

at how many days is tensile strength of tissue relatively equal to strength of tissue?

7-14 days

14

intrinsic wound factors

hypoproteinemia
anemia
malnutrition
uremia
DM
hyperadrenocorticism
infection

15

Extrinsic wound factors

mechanism (shear, crush, laceration, etc.)
foreign material
irradiation
antiseptics

16

T?F:steroids will delay collagen formation and wound healing

T

17

3 classes of wounds based on TIME and CONTAMINATION***

1) class 1: 0-6hrs, minimal contamination, 1ary closure common
2) 6-12 hrs, moderatie contamination, may use 1ary closure in some cicumstances
3) >12 hours, gross contamination, never use primary closre

18

What is a "clean" wound?

wound created by surgery, not entering GI or respiratory tract. No contamination or break in asepsis. (ie spay/neuter; SSI 5%)

19

irradiation and steroid effect on wound healing

delay wound healing

20

What is a "clean-contaminated" wound?

GI or resp. tract entered, minor break in asepsis.
(ie. enterotomy or lung lobectomy; SSI = 10%)

21

What is a "contaminated" wound?

> GI with gross contamination, inflammation, major break in aspepsis (ie enterotomy with spillage; SSI = 30%)

22

What is a "dirty" wound?

devitalized or necrotic tissue, gross debris, pus. (ie. infected bite wound)

23

Abx use in Class 1 and clean wounds

rarely necessary, unless systemically unhealthy.
-exceptions: time, foreign material

24

Abx use in Class 2-3 and clean-contaminated, contaminated, dirty

Should use broad spec penicillin or cephalosporin.
-takes 3-5days to do culture and sensitivity testing
-monitor well if wound based

25

what to use for debridement and lavage

sterile saline 0.9%, liberal volume. (betadine can kill fibroblasts if too high conc.)

26

wet to dry bandage

use physiologic/hypertonic saline and gauze as primary layer to suck moisture out of wound
-honey, sugar, antiseptics unnecessary

27

negative pressure bandage

-use porous sponge with subatmospheric pressure
-continuous removal of bacteria, exudate and edema fluid
-improves perfusion and granulation tissue

28

nonadherent dry to dry bandage

-indicated following debridement, to protect wound, encourage moist healing and epithelialization

29

semiocclusive nonadherent dry to dry bandage

-has evaporative fluid loss
-doesn't harm wound bed
-ie. telfa and Ca alginate

30

types of drains

Active (preferred, creates vacuum in wound to remove exudative fluid and eliminate dead space; Jackson-Pratt)
Passive (relies on gravity and appropriate use to work; Penrose)
**drains are always temporary - 3-5d max because presence of tube keeps debridement phase active, even though it is allowing drainage**

31

Types of wound closure

Primary (immediate, 6hrs but before granulation 2d)
Second intention (no sx closure, dependent on wound healing)