9 Flashcards

1
Q

phases of wound healing

A
  1. inflammation/debridement2. proliferation/repair3. maturation/remodeling
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2
Q

Inflammation and debridement phase of wound healing

A

hemostasis (constrict–>dilate, permeability)PMN–>monocytes/macrosphagocytosis, cytokine release, enzyme activation (MMP)1-3 days

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3
Q

proliferation/repair phase of wound healing

A

fibroblast, endothelial cells, epithelial cellscollagen production (TGFb), capillary ingrowth (VEGF), wound contraction (myofibroblasts–TGFb), wound coverage (TGFa,EGF)granulation tissue4-12 days

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4
Q

type of collagen in wounds

A

III initially then type I (TGF beta)fibroblasts

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5
Q

what is granulation tissue composed of

A

capillary bedfibroblastsmacrophagesground substance of collagen, fibronectin, HA

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6
Q

maturation and remodeling phase of wound healing

A

strengthening of collagen decr III incr Imost important phase

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7
Q

strength of tissue at 1 week vs 3 weeks vs 3 months

A

1 week 10 %3 weeks 30%3 months 80%

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8
Q

comparison of breaking strength of different tissues across time

A

bladder > stomach > colon > skin

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9
Q

GI tract has 4 layers EXCEPT in what areas

A

serosa, muscularis propria, submucosa, mucosaEXCEPT esophagus, rectum

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10
Q

what layer of the GI tract carries the majority of the strength and what proportions of collagen does it contain

A

SUBMUCOSAtype I 68%type III 20%type V 12%

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11
Q

difference btwn skin and GI epith in terms of collagen production

A

skin collagen is made by fibroblasts, contains I, IIIGI collagen is made by fibroblasts < sm muscle cells I, III, V

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12
Q

“lag phase” of GI wound healing

A

strength of anastomoses decreases sign in first 48 hours due to collagen breakdown (colon the most)net loss in strengthcollagenase activity is higher days 0-3 compared to skin (leads to decr strength)

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13
Q

stress applied to GI healing that is not evident in skin healing

A

sheer stress due to increased intraluminal P, peristalsisalso bacterial flora of aerobic and anaerobicvascular perfusion is more critical to GI vs skin; hypoperfusion/shock more dramatically affect GI healing > skin

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14
Q

T/F retrospective 225 dogs with GI sx, showed intraop hypotension as a risk factor for developing septic peritonitis and death post op

A

TRUE

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15
Q

at what level of PO2 does mature collagen fail at

A

PO2 < 40 mm Hg mature collagen will failPO2 < 10 mm Hg halts angiogenesis, epithelialization

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16
Q

critical components of success to GI healing

A

local factors–preserve blood supply, avoid tensionsystemic factors–maintain perfusion, CO, PO2

17
Q

why is fascial healing prolonged compared to skin and GI

A

prolonged in fascia bc inflammatory cells and fibroblasts must migrate a longer distance before reaching the relatively avascular/acellular fascial layertakes 14 weeks to achieve 60% strength

18
Q

how far should you space fascial sutures

A

3 mmstudies in rats show sutures placed 1.5 mm vs 3. 0mm3.0mm sutures showed 3x greater wound strength and retained strength at 2 days

19
Q

how fast does the bladder re-epithelialize

A

2-4 days

20
Q

peak collagen synthesis and strength of bladder healing

A

collagen synthesis in bladder peaks at day 5 and achieves 100% strength within 21 daysmaybe dues to KGH and TGHa

21
Q

breaking strength of first intention healing of linear wounds dogs vs cats

A

Bohling et albreaking strength was less in cats and was equivalent to only half of that achieved by dogs

22
Q

breaking strength of second intention wounds dogs vs cats

A

granulation tissue was observed faster in dogs (4.5 d) vs cats (6.3d)mean time to cover wound completelydog 7.5 d vs cat 19 d

23
Q

role of subcutaneous tissues in the wound healing of dogs vs cats

A

removal of SQ was associated with decrease in the rate of production of granulation tissue and wound contraction (more so in cats than in dogs)

24
Q

local factors to impede wound healing

A
  1. wound perfusion2. tissue viability3. wound fluid accumulation4. wound infection5. mechanical factors
25
Q

systemic factores to impede wound healing

A
  1. immunodeficiences2. Cancer3. Age
26
Q

T/F patients with DM endocrinopathy are prone to delays in wound healing

A

FALSENicholson et al reported that patients with endocrinopathy are 8.2 x as likely to develop postop wound infectionNONE were diabetic

27
Q

what is fibrotic microangiopathy

A

condition that results in O2 levels within the wound that are below those necessary to support normal wound healingoccurs in radiation therapy patients and impedes wound healing