76.Open wounds

Question 1

4 steps of wound healing

Answer 1

1. fibrin-platelet clot–INFLM2. recruit WBC–DEBRIDE3. neovascularization/cell proliferation–REPAIR4. remodeling–MATURATION

Question 2

types of degloving injury to skin

Answer 2

1. anatomic—loss of skin attachment2. physiologic—skin is intact but separated/avulsed from underlying subcutaneous tissue and blood supply (may lead to delayed necrosis of skin)

Question 3

classifications of thermal injury to skin

Answer 3

classified by depth1. superficial partial–epithelial2. deep partial–epithelial and partial dermal3. full thickness

Question 4

contamination vs infection

Answer 4

contamination—presence of microbes on surfacecolonization–replicating/dividinginfection–invasion and replication within tissue10^5 CFU/gm tissue(# microbes x virulence)/host resistance = the effect of microbial burden

Question 5

classes of wounds

Answer 5

Class 1. minimal contamination 0-6 hours old (“golden”)Class 2. 6-12 hrs enough time for bacT to replicate but may not have reached threshold levelClass 3. >12 hrs microbes replicate and have reached threshold for infection

Question 6

distribution of granulation tissue in cats vs dogs

Answer 6

cats heal slower with less GT and epithelialization and strength is poorerGT is more peripheral CATScentral DOGSat 14 days epith and healing34% and 84% cats89% 98% dogs

Question 7

irrigation fluid for wounds

Answer 7

should be isotonic (tap water, normal saline is hypotonic)large volumes is better than sterilitygoal 7-8 PSI achieved with 18-19 gauge needle on 35 ml syringeOR GALL ET AL AJVR 2010one liter bag with pressure bag at 300 mm Hg and 16 gauge need = 7-8 PSI

Question 8

types of topical antimicrobials

Answer 8

–antibiotic ointments–silver based dressings–hyperosmotic dressings (20% HTS, sugar, honey)

Question 9

solutions to clean skin after clipped

Answer 9

0.05-0.1% chlorohexidine solution (1:40 dilution of 2% stock)0.001-0.01% povidone iodine solution (1:100 or 1:1000 dilution of 10% stock)

Question 10

list debridement agents

Answer 10

–surgical debridement (scalpel layered or enbloc)–mechanical debridement (wet to dry, green blow fly maggots Lucilia sericata)–enzymatic or chemical debridement (trypsin, collagenase, urea); most are nonselective–nonenzymatic debridement: HTS 20%, sugar, honey which dehydrate microbes, tidal and inhibitory effect on growth

Question 11

hydrophilic moisture retentive dressings

Answer 11

hydrogel (curafil)hydrocolloid alginate (calcium alginate)

Question 12

nonadherent semiocclusive dressings

Answer 12

telfapetroleum impregnanted (adaptic)

Question 13

layered surgical debridement and fasciotomy

Answer 13

excess fat and fascia should be removed and intact fascia derided to allow vascular muscle underneathfasciotomy/fascial excision decreased time until GT coverage (9-10days) vs fascial abrasion only or control (18 days)

Question 14

T/Fremoving the subcutis decreases total healing and percent epithelialization

Answer 14

TRUEwith SQ intact: epith at 21 days was 34% cats and 89% dogswithout SQ: epith at 21 days was 20% cats and 61% dogsremoval of SQ reduced wound perfusion

Question 15

MOA honey

Answer 15

hyperosmolar–dehydrates microbesproduces H202 which quickly makes o2 free radicals that damage microbesnonperoxide antibacterial substance (special factor)medical grading is based on inhibin numbers

Question 16

types of Ab in Ab topical ointments

Answer 16

bacitracin zincneomycin sulfatepolymyxin Bpoorly absorbed systemically, lack cytotoxic effects

Question 17

negative pressure wound therapy

Answer 17

local application of subatm P across wound (-125 mm Hg)coarse open cell foam (400-600 micrometer pores)drainage tubeocclusive dressing/seal

Question 18

benefits of negative pressure wound therapy

Answer 18

reduce edemaimprove wound perfusionstimulate granulation tissue decrease bacterial colonization (per TJ)remove exudate

Question 19

blood flow at wound edge with -125 mm Hg negative pressure wound therapy

Answer 19

at -125 mm Hgpeak blood flow was seen in muscle 2.5 cm from wound edgeand in subcutaneous tissue 3.5 cm from wound edgepressures from -75 to -100 mm Hg may effectively stimulate blood flow while minimizing hypo perfusion

Question 20

negative pressure wound therapy recommended over grafts

Answer 20

-75 mm Hgmay facilitate stabilization of graftreduce fluid accumulation under graftprevent desiccation of graft and possible microbial contamination over graft

Question 21

T/Fporcine SIS has been shown to enhance epithelialization and contraction in cutaneous wounds in dogs

Answer 21

FALSEapplication of porcine SIS to acute wounds has NOT shown any benefits in two controlled studies.

Question 22

removal of SQ tissues has a more negative effect on second intention healing in which species

Answer 22

cats