1
Q
What cells produced TNF alpha?
A
M1 macrophages
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2
Q
Anti-TNF monoclonal antibodies and recumbent, soluble receptors help with what diseases in humans
A
Crohn’s disease and rheumatoid arthritis
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3
Q
Where do white blood cells marginate?
A
Post capillary venules and pulmonary capillaries
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4
Q
What pro inflammatory cytokines do M1 macrophages produce?
A
IL-1B, IL-6, TNF-a
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5
Q
What are the neutrophil granules and what do they produce?
A
Primary/azurophils: myeloperoxidase, defensins, lysosome hydrolases, proteases
Secondary: MMPs
Tertiary/gelatinase: preformed receptors
IL-1a, IL-1b, IL-6, TNF-a
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6
Q
What is the precursor prostaglandin?
A
PGH-2
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7
Q
The intracellular fluid compartment is what fraction of total body water and what percent of weight?
A
2/3 total body water
40% of weight
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8
Q
The extracellular fluid compartment is what fraction of total body water, and what percent of weight? What are the two sub compartments and their percentages?
A
ECF is 1/3 total body water, 20% body weight
Plasma/IVF: 25%
Interstitial fluid: 75%
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9
Q
How long does it take for isotonic crystalloids to equilibrate, and how much is left in the intravascular space?
A
20-30 or 30-60 min
Only 25% remains in IV space
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10
Q
What is two times maintenance for IVF?
A
4-8 mL/kg/hr
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11
Q
What are side effects of hypertonic saline?
A
Phlebitis and hemolysis
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12
Q
Hypertonic saline is useful for what conditions
A
Head trauma or cardiovascular shock in patients more than 30 kg that need a large amount of IV fluids, but don’t have much time
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13
Q
How long does IV volume expansion last after hypertonic saline?
A
Less than 30 minutes
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14
Q
What are side effects of synthetic colloids?
A
They decrease factor 8 and vWF, impair platelet function, and decrease stability of fibrin clots by increasing fibrinolysis
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15
Q
What are risks of 25% human albumin?
A
Potentially fatal, acute or delayed hypersensitivity reactions, volume overload, coagulopathy
Patient will have an increase in IgG against human albumin, so no repeat dosing
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16
Q
What is the rate of treatment of chronic hypernatremia?
A
</= 0.5 mEq/kg/hr
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17
Q
What is the calculation for free water deficit?
A
0.6 x weight x ((Na patient / Na normal) -1)
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18
Q
What does a negative base excess mean?
A
Non-respiratory acidosis
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19
Q
What is the equation for anion gap?
A
(Na + K) - (Cl + HCO3)
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20
Q
Most blood gas analyzers report a value for base excess that…
A
Can only be used to assess the metabolic component of acid/base disturbances and is the difference between normal buffer base and the patient buffer base
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21
Q
How do you calculate the amount of bicarbonate needed?
A
0.3 x body weight x base deficit
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22
Q
What are the four types of shock?
A
Hypovolemic, cardiogenic, distributive, hypoxic
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23
Q
What is the equation for oxygen delivery?
A
DO2 = CO x CaO2
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24
Q
What is the equation for arterial oxygen content (CaO2)?
A
CaO2 = (1.34 x Hgb x SaO2) + (0.003 x PaO2)
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25
Q
What is the equation for oxygen uptake? VO2
A
VO2 = CO x (CaO2 - CvO2)
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26
Q
What is the oxygen extraction ratio equation?
A
O2ER = (VO2 / DO2) x 100
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27
Q
How can lactate increase even with normal perfusion
A
Type B lactic acidosis: impaired mitochondrial function due to sepsis, diabetes, neoplasia, drug/toxins
Type A is due to inadequate DO2
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28
Q
What is CVP and what is it a surrogate for? What is normal?
A
CVP is hydrostatic pressure, but is a surrogate for preload
Normal is 0-5 cmH2O
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29
Q
What is the lifespan of a platelet?
A
6 to 8 days
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30
Q
What is the method of action of antithrombin
A
Binds and inactivates thrombin (f2) and f10a
Neutralizes Kalinin, f7, f9, f11, and f12
Rate of neutralization increases when antithrombin binds heparin
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31
Q
What is a normal BMBT and what does it test?
A
Dogs < 3 min, cats 34 - 105 sec
Primary hemostasis
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32
Q
How does a vitamin K deficiency impact PT and aPTT
A
Prolongs PT because of short half-life of f7 (4 to 6 hrs)
Prolongation does not occur until a factor is less than 25 to 30% of normal
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33
Q
What is the best test for detecting hypercoagulability?
A
Thromboelastography (TEG)
Anemia: hypercoagulable
Polycythemia: hypocoagulable
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34
Q
How does desmopressin (DDAVP) work?
A
Binds V2 receptors and induces release of subendothelial vWF stores
For type I vWD
Works in 30 min, lasts 4 hrs
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35
Q
M1 vs M2 macrophages: which is pro-inflammatory and what does it secrete?
A
M1 are pro-inflammatory, secrete IL-1B, IL-6, and TNF-a
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36
Q
What are the primary functions of TNF-a?
A
Initiates production of pro-inflammatory cytokines, ROS, and chemotaxins
Has anti-tumor activity
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37
Q
What are the pro-inflammatory cytokines?
A
TNF-a, IL-1B, IL-6, IL-8
(alpha-beta-68)
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38
Q
What are the anti-inflammatory cytokines
A
IL-10, IL-1ra
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40
Q
Which COX enzyme is constitutively expressed?
A
COX-1
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41
Q
What induces expression of COX-2?
A
trauma, growth factors, pro-inflammatory cytokines
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42
Q
What are the functions of TXA-2 and what cells secrete it?
A
vasoconstriction and platelet aggregation
secreted by platelets and macrophages
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43
Q
What is the action of nitric oxide (NO) and how does it exert this effect? Is it pro- or anti-inflammatory?
A
Vasodilation - has direct effect by diffusion into smooth muscle
BOTH pro and anti-inflammatory
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44
Q
Acute phase proteins change by what % during inflammation? What is the major negative APP?
A
change by 25%
ALBUMIN is the major NAPP
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45
Q
What are the deoxyribonucleotide pairs in DNA?
A
Purines to pyrimidines:
Adenine to thymine
Cytosine to guanine
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46
Q
What are exons and introns in DNA?
A
Exon = coding DNA
Intron = non-coding DNA
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47
Q
What are the 4 types of stem cells?
A
embryonic
adult
fetal/perinatal
induced-pluripotent
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48
Q
What are the 3 types of stem cell potentcy?
A
Totipotent: cells from all layers, including fetal membranes
Pluripotent: cells from 1+ germ layer but not fetal membranes
Multipotent: limited to germ layer they originated from (hematopoietic, mesenchymal, neural)
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49
Q
What anti-inflammatory agents are produced by MSCs?
A
TSG6, IL-1ra, PGE2
(Study guide also says TNF-a?)
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50
Q
What is PRP?
A
Plasma that has a platelet concentration 3-5x > peripheral blood
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51
Q
IRAP (conditioned autologous sera) has a high concentration of what cytokine?
A
IL-1ra –> competitively inhibits IL-1B
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52
Q
How do you calculate an IVF rate that includes correcting dehydration?
A
BW x % dehydration = deficit in LITERS
+ estimated ongoing losses (urine 1-2 mL/kg/hr; insensible losses 20 mL/kg/day)
+ maintenance rate (rec: 70x(BW^0.75))
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53
Q
LRS, P-Lyte, and Norm-R use which buffers?
A
LRS = lactate
P-Lyte and Norm-R = acetate and gluconate
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54
Q
What can happen if HTS is administered at >1 mL/kg/min?
A
Vagally mediated hypotension, bradycardia, bronchoconstriction
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55
Q
What is the blood volume of a dog? Cat?
A
Dog: 90 mL/kg
Cat: 50 mL/kg
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56
Q
What are the actions of PTH?
A
Increase Ca levels:
- Mobilizes Ca from bone
- Increases resorption of Ca in renal tubules
- Activates Vit D/calcitriol to increase GI absorption
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57
Q
What is the action of calcitonin
A
Antagonizes PTH by inhibiting Ca resorption/release from bone to decrease Ca levels in blood
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58
Q
Distributive shock is characterized by what single major systemic change? What is its effect on afterload?
A
Massive vasodilation
Decreases afterload
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59
Q
Equation for MAP
A
MAP = DAP + (SAP - DAP)/3
also
MAP = CO x SVR
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60
Q
O2 toxicity occurs at an FiO2 of __% for __ hrs
A
> 60% for 24 hrs
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61
Q
What is the primary physiologic activator of the clotting cascade?
A
Tissue factor (f3)
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62
Q
What is the most important activator of platelets?
A
Thrombin (f2)
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63
Q
What are the 3 anticoagulant pathways?
A
- Antithrombin: inactivates circulating coag proteins, activated by HMW heparin
- Activated Protein C: created when thrombin binds thrombomodulin –> inactivates f5 and f8 –> enhances fibrinolysis
- Tissue Factor Pathway Inhibitor: inactivates f10 and f7/TF complex, increased by heparin
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64
Q
PT tests which clotting pathways?
A
Extrinsic (TF/f7), common
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65
Q
aPTT tests which clotting pathways?
A
Intrinsic, common
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66
Q
ACT tests which clotting pathways?
A
extrinsic, intrinsic, common
Less sensitive than aPTT
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67
Q
D-dimers are sensitive indicators for what conditions?
A
Thrombotic conditions (DIC/TE)
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68
Q
What are the 3 types of vWD?
A
- Type 1 = presence of all multimers in REDUCED concentration (most common); If severe ( < 20% vWF) –> spontaneous bleeding
- Type 2 = disproportionate loss of HMW multimers
- Type 3 = almost complete absence < 1% vWF –> severe hemorrhage before 1yr
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69
Q
What is a positive ELISA result for vWD?
A
<50%
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70
Q
What is Virchow’s triad?
A
endothelial injury + vascular stasis + hypercoagulability = thrombotic tendency
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71
Q
What is the target aPTT during unfractionated heparin therapy?
A
1.5-2.5x normal
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72
Q
How does heparin work?
A
Inactivates f2 (thrombin) and f10
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73
Q
What is the pathogenesis of DIC? What is the mortality rate in dogs and cats?
A
Systemic activation of coagulation –> microvascular thrombosis –> compromises organ perfusion –> organ failure
50-75% mortality in dogs (sepsis, malignancy); 93% in cats (neoplasia, pancreatitis, sepsis, infection)
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74
Q
RER formula
A
30(BW) + 70
or
70(BW^0.75)
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75
Q
What albumin level is associated with increased postoperative complications?
A
<2 g/dL
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76
Q
Neutrophil killing depends on a PO2 of
A
PO2 > 40 mmHg
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77
Q
Angiogenesis is stimulated by what?
A
Macrophages and platelets
FGF, PDGF, TGF-B, VEGF, adhesins
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78
Q
What cells secrete the most VEGF?
A
Keratinocytes
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79
Q
Fibroblasts become myofibroblasts via
A
TGF-B1
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80
Q
Unwounded dermis primarily has what collagens in what %? Healing wounds have primarily what type of collagen?
A
Normal dermis: 80% type I, 20% type III
Healing dermis: primarily type III
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81
Q
How strong is a final scar?
A
Only 70-80% of unwounded tissue strength
Only 10% type III collagen in final scar
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82
Q
Order the breaking strength of the following tissues from most to least:
Skin, stomach, colon, bladder
A
Bladder > stomach > colon > skin
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83
Q
The strength of a GI closure significantly decreases during the first ____ due to _______ activity
A
During the first 48 hrs due to COLLAGENASE activity
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84
Q
Bladder gains 100% strength in ____ days
A
21 days
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85
Q
What are the differences in healing between dogs and cats?
A
Breaking strength of cutaneous wounds at 7 days better in dogs than cats
Granulation tissue earlier and more in dogs than cats
Contraction/epithelialization faster in dogs than cats
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86
Q
What is the critical colonization level for bacteria in tissue to result in infection?
A
10^5 bacteria/g
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87
Q
What is the strength of skin at 10-14 days post wounding? At 3 weeks?
A
5-10% at 10-14 days
25% at 3-4 weeks
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88
Q
What are the 3 classifications of SSI?
A
Superficial - skin/SQ only
Deep - fascia/muscle
Organ/space - anything deeper
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89
Q
How does surgical time affect the risk of a SSI?
A
Risk of SSI doubles for each hour of surgery
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90
Q
What is the reported SSI rate for clean surgery?
A
2.5 - 4.8%
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91
Q
What is a nosocomial infection?
A
Infection that occurs 48 hrs after hospital admission
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92
Q
Expected bacteria and prophylactic abx for each surgery type:
- Skin/recon + elective ortho
- Head/neck
- Open Fx
- Upper GI
- Hepatobiliary
- Lower GI
- Urogenital
A
- Skin/recon + elective ortho: Staph = cefazolin
- Head/neck: Staph/Strep/anaerobes = clinda, cefaz
- Open Fx: Staph/Strep/anaerobes = clinda, cefaz +/- aminoglycosides/fluoroquinolones
- Upper GI: Gram + cocci, Gram - bacilli, anaerobes = cefoxitin
- Hepatobiliary: Clostridium, Gram - bacilli, anaerobes = cefoxitin
- Lower GI: Enterococcus, Gram - bacilli, anaerobes = cefoxitin
- Urogenital = Strep/Staph/E. coli/anaerobes = cefazolin, ampicillin
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93
Q
What are the classifications for surgical procedures in terms of contamination level?
A
Clean = non-traumatic, uninfected + no break in asepsis + no inflammation elective, primarily closed 2-5% infection rate
Clean-Contaminated = controlled entry to hollow viscus, minor break in asepsis
Contaminated = open/fresh wound, incision into site with nonpurulent inflammation, major break in asepsis
Dirty = pus encountered, perforation of viscus, traumatic wound with devitalized tissues
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94
Q
What are the challenges of treating abscesses with antibiotics?
A
Pus = acidic pH, hypertonic, protein binding of selected drugs (aminoglycosides will bind to sediment)
Not good for penicillins (inactivated at pH < 6), aminoglycosides, and enro (work better in alkaline environments)
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95
Q
How do bacteria evade B-lactam antibiotics?
A
Beta-lactamase production
loss/change in porins
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96
Q
In addition to perioperative abx, what other things (3) will decrease the risk of SSI in surgery?
A
Normothermia, euglycemia, oxygenation
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97
Q
What materials cannot be sterilized with H2O2 gas/plasma/vapor?
A
Linen and paper –> absorb the H2O2
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98
Q
What materials cannot be sterilized with EtO?
A
nylon, polyvinyl chloride, polyvinylidene chloride, or foil
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99
Q
How does steam sterilization work? How should bowls be positioned?
A
kills via coagulation/denaturation of proteins with moist heat (including spores)
Water is a catalyst and heat is transferred by condensation
Bowls should be placed UPSIDE DOWN to prevent air trapping
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100
Q
Guidelines for gravity-displacement steam sterilization
A
121C for 30 min + 15-30 min dry time
132C for 15 min + 15-30 min dry time
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101
Q
What materials is dry heat sterilization good for? What is the protocol?
A
Sharps, powders, glass
160C for 120 min
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102
Q
How does ethylene oxide (EtO) sterilization work? What materials is it good for? What materials should you be mindful of?
A
Alkylation of proteins/nucleic acids
Good for heat and water sensitive things
Glass RESISTS EtO and rubber/plastic ABSORBS (requires aeration step)
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103
Q
How does ozone sterilization work? What materials cannot be sterilized this way?
A
O3 molecule readily oxidizes other molecules to destroy microorganisms (30-35C for 4 hrs)
NOT for wood/paper
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104
Q
How does plasma sterilization work? What materials cannot be sterilized this way?
A
electromagnetic energy to create plasma from vapor of H2O2, O2, or peracetic acid/H2O2 mix –> free radicals deactivate cell processes
NOT for linens, liquids, wood
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105
Q
What are the broad classes of sterilization indicators?
A
Physical
Chemical
Biologic
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106
Q
What are the classes of chemical indicators?
A
Class 1 = sterilization tape –> pack processed but limited info on parameters met
Class 2 = test for air removal (Bowie-Dick)
Class 3 = react to specific indicator [temp or time]
Class 4 = react to > 1 parameter
Class 5 = react to all parameters
Class 6 = monitor more specific guidelines (parameter required to combat prion infection)
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107
Q
What bacteria are used for biologic indicators? What was the failure rate of chemical indicators caught by these?
A
STEAM + OZONE + PLASMA = Geobacillus stearothermophilus
EtO = Bacillus atrophaeus
12% failure rate detected on chemical indicators
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108
Q
What is the storage time for (sterilization and wrapping):
Double-wrapped autoclaved/steamed
EtO Cloth
EtO Paper
EtO Plastic/tape
EtO plastic/heat sealed
A
Double-wrapped autoclaved/steamed: 96 wks
EtO Cloth: 15-30 d
EtO Paper: 30-60 d
EtO Plastic/tape: 90-100 d
EtO plastic/heat sealed: 1 yr
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109
Q
What is the ideal tooth angle for a ratchet on an instrument?
A
39 deg angle (better than 45 deg) –> enhanced security/engagement of interlocking teeth
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110
Q
Different tenotomy scissors
A
Stevens - ring-handled
Wescott - spring-loaded
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111
Q
What is the difference between straight tipped and curved tipped scissors?
A
Straight = better mechanical advantage
Curved = greater versatility/visibility
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112
Q
What are the crushing and non-crushing tissue forceps?
A
CRUSHING [tissues intended for excision]: R angle (vessel isolation) + Babco*ck + Allis + Oshner-Kocher
NON-CRUSHING: Doyen (thin/bowed jaws, fine long grooves) + DeBakey (unique long ribs) + Satinsky (partial vessel occlusion]
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113
Q
What is the ventilation requirement for the OR?
A
Minimum 15 air exchanges per hour
30-60% humidity
temperature 20-30C (68-73F)
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114
Q
What are the 2 types of corrosion and what are they caused by?
A
PITTING [pinprick holes from Cl- – saline, blood, water]
FRETTING [discoloration on friction surface]
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115
Q
What combination of antiseptics for patient prep can have residual antimicrobial activity on the skin?
A
Chlorhexidine gluconate (4%) + isopropyl alcohol (70%)
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116
Q
Which hand is more likely to have glove perforations in surgery?
What were the perforation rates for single versus double gloves?
A
Non-dominant hand more likely to get a hole
Single glove perforation = 12-30%
Double glove perforation = 10-45% for outer; 4-13% for inner
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117
Q
What antiseptic agent kills MRSA?
A
Chlorhexidine
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118
Q
When should you clip patients?
A
Within 4 hrs of surgery to reduce incidence of SSI
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119
Q
Do you use cut or coag when combining monopolar electrosurgery with instruments?
A
Cut
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120
Q
What are the 3 tissue effects of COAG with monopolar electrosurgery?
A
- Fulgaration = holding electrode away from tissue in coagulation mode –> random dispersion –> carbonization + superficial coagulum instead of vaporization
oControls bleeding when no discrete bleeder »_space; smoke/char/necrosis - Desiccation = direct contact with tissue in coag mode –> dehydration + protein denaturation –> coagulum
oEschar from overheating; more efficient heat than fulgaration = deeper thermal necrosis/spread - Coaptive = desiccation coagulation when lumen of vessel is occluded by metal instrument –> collagen weld
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121
Q
What vessel sizes can be sealed with:
Monopolar electrosurgery
Ultrasonic/Harmonic scalpel
Bipolar vessel sealing
And what is the thermal spread of each technique?
A
Monopolar electrosurgery: <2 mm
Ultrasonic/Harmonic scalpel: < 3 mm; thermal spread 0-1 mm
Bipolar vessel sealing: < 7 mm; thermal spread 1-3 mm (EnSeal <2 mm)
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122
Q
What does laser stand for?
A
Light Amplification by Stimulated Emission of Radiation
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123
Q
How does wavelength impact tissue penetration and which lasers are associated with which categories?
A
Longer wavelength = shallow tissue penetration/absorbed by H2O –> high surface temp + good cutting + min collateral (CO2, Ho:YAG)
Short wavelength = deeper tissue penetration/not absorbed by H2O –> coagulative necrosis at unpredictable zones (Nd:YAG, Diode)
Ultrashort wavelength = vascular tissue/absorbed by Hb (Argon)
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124
Q
Rank the following lasers in terms of depth of penetration (least to most): Nd:YAG, Argon, Diode, Excimer, CO2
A
Excimer < CO2 < Argon< Diode < Nd:YAG
[excited cats are doing nothing]
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125
Q
How does the Argon laser work and what is it typically used for?
A
Blue/green light absorbed by Hb
good for vascular lesions and endoscopy
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126
Q
Define:
knot pull out strength
Knot strength
A
Knot Pull Out Strength = load required to break suture deformed by knot
Knot Strength = force to cause knot to slip
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127
Q
How does pH affect glycolide and PDS/nylon suture degradation?
A
Glycolide degrades faster in ALKALINE pH
PDS/nylon degrade faster in ACIDIC pH
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128
Q
What is special about CHROMIC catgut suture
A
curing with chromium salts –> increased collagen cross-links –> decreased absorption and decreased inflammatory reaction
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129
Q
Vicryl: generic name, how long until 50% tensile strength, and time for absorption
A
Polyglactin 910
50% TS at 2-3 weeks
absorbed 56-70 days
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130
Q
Dexon: generic name, how long until 50% tensile strength, and time for absorption
A
Polyglycolic acid
50% TS at 2-3 weeks
absorbed 90 days
131
Q
Caprosyn: generic name, how long until 50% tensile strength, and time for absorption
A
Polyglytone
0% TS at 2-3 weeks
absorbed 56 days
132
Q
Monocryl: generic name, how long until 50% tensile strength, and time for absorption
A
Poliglecaprone 25
50% TS at 1-2 weeks
absorbed 120 d
133
Q
Biosyn: generic name, how long until 50% tensile strength, and time for absorption
A
Glycomer 631
50% TS at 2-3 wks
absorbed 90-110 d
134
Q
PDS II: generic name, how long until 50% tensile strength, and time for absorption
A
Polydioxanone
50% TS at 5-6 wks
absorbed 180 d
135
Q
Maxon: generic name, how long until 50% tensile strength, and time for absorption
A
Polyglyconate
50% TS at 4-5 wks
absorbed 180 d
136
Q
What is the rule for vessel diameter compared to LDS vascular clip size? How do LDS staplers work?
A
Vessel diameter should be <2/3 but >1/3 the length of the clip
2 staples, divides in between them
137
Q
What are the open/closed staple heights for TA staplers?
A
White: 2.5 –> 1.0
Blue: 3.5 –> 1.5
Green: 4.8 –> 2.0
138
Q
When should you not use a circular stapler?
A
If combined tissue thickness is < 1 mm or > 2.5 mm
139
Q
What are the toxic byproducts of cyanoacrylate glue?
A
Cyanoacetate and formaldehyde
140
Q
What are Halsted’s Principles?
A
Gentle tissue handling
Meticulous hemostasis
Aseptic technique
Preservation of blood supply
Elimination of dead space
Accurate apposition of tissue planes
Minimize tension
141
Q
T/F: Sawing with a scalpel blade is appropriate for transecting a pedicle but not for skin
A
True
142
Q
What arteries can be permanently ligated? (4)
A
Both common carotids (NOT in cats)
Brachial A
Femoral A
External iliac A
143
Q
What veins can be permanently ligated? (7)
A
Both jugular veins (NOT cats)
Brachiocephalic V
Hepatic V
Both common iliac Vs
Both femoral Vs
LEFT renal V (dogs)
Vena cava caudal to liver (if chronic compression or with R nephrectomy)
144
Q
How long can the following vessels be temporarily ligated for?
Descending thoracic aorta
Portal triad
Hepatic A
Splenic a/v
Renal a/v
Abdominal aorta
A
Descending thoracic aorta: 5-10 min
Portal triad: 10-15 min
Hepatic A: 30 min
Splenic a/v: 15-20 min
Renal a/v: 30 min
Abdominal aorta: 30 min
145
Q
What is an Esmarch tourniquet? How to you calculate tourniquet pressure? What is the maximum time a tourniquet should be left on?
A
Elastic wrap applied from distal to proximal to remove blood
Tourniquet P = bandage tension / (radius of curvature of limb x bandage width)
Max time = 1.5-2 hrs
146
Q
How do mechanical hemostatics work?
A
Absorb blood to provide a mechanical barrier/tamponade, rely on normal hemostatic mechanisms, absorbable
147
Q
What are 5 types of mechanical hemostatics, an important fun fact, and their resorption time
A
- Gelatin (Gelfoam) - swells in contact with blood, resorbed by granulomatous inflammation in 5 wks
- Cellulose (Surgicel) - bactericidal, acidic so can denature thrombin, resorbed in 2-6 wks
- Polysaccharide spheres - concentrate solid components of blood by dehydration, increase in volume 500%
- Bovine type II collagen - enhances platelet response, absorbed by fibroblast remodeling in 8-10 wks
- Bone wax/ostene - mechanical blocking of bone surface
148
Q
What active hemostatic can be combined with gelatin (but NOT cellulose) to increase its efficacy?
A
Thrombin (f2)
149
Q
What is the major disadvantage of hemostatic sealants? How quickly are they absorbed?
A
Swelling 400%, resorbed in 4-8 wks
150
Q
Why do Greyhounds bleed?
A
Altered fibrinolysis. 1/3 will bleed within 3 days postop.
151
Q
How does desmopressin function in relation to clotting?
A
Stimulates vWF and f8 release from endothelial cells in dogs with vWD
152
Q
What is LaPlace’s Law for bandage pressure?
A
Bandage P = NT/RW
153
Q
How do alginates work for hemostasis?
A
Release of Ca promotes clotting cascade. NOT for intracavitary use
154
Q
At what fluid production rate should a wound drain be removed?
A
<0.2 mL/kg/hr
155
Q
What is Poiseuille’s Law for drain flow and what effect will doubling the drain’s diameter or halving its length have?
A
Laminar flow (F) = dP(pi)r^4 / 8nL
Doubling drain diameter increases flow by 16x
halving drain length increases flow by 2x
156
Q
What are the two types of vaporizer output?
A
Variable bypass (most common) = 2 flows merge before exiting
Measured flow = gas and diluent flow set independently
157
Q
What are the 3 vaporizer methods
A
Flow over (most common) = carrier as passes over inhalant reservoir
Bubble-through = carrier gas bubbled up through reservoir bottom
Direct injection (desflurane) = atomized inhalant into stream of carrier gas
158
Q
What are the two types of vaporizer circuit systems?
A
Out of circuit (most common) = constant dose regardless of minute vol
In circuit = output depends on minute vol
159
Q
What is the weight cut-off for rebreathing vs non-rebreathing systems?
A
Rebreathing for > 5 kg
Non-rebreathing for < 5 kg
160
Q
What does the internal pressure regulator on the anesthesia machine reduce the tank pressure to?
A
45-50 psi
161
Q
Pressure and volume of a full E/green O2 tank?
A
1900 psi
660 L
162
Q
What is the ideal I:E ratio for PPV?
A
1:2
range 1:1 to 1:4
163
Q
What is the starting PIP and tidal volume?
A
PIP 12 mmHg
Tidal vol 10-15 mL/kg
164
Q
Describe the capnograph for
Hypoventilation
Rebreathing
Leak
Hyperventilation
Arrest/Disconnected
A
Hypoventilation = progressively taller peaks
Rebreathing = progressive elevation of the baseline
Leak = shark fin
Hyperventilation = progressively shorter peaks
Arrest/Disconnected = sudden decrease to flatline
165
Q
What type of cycling is available for ventilators?
A
Time, volume, and pressure cycled
166
Q
What gas flow is required to prevent rebreathing of CO2 in a non-rebreathing system?
A
200-500 mL/kg
167
Q
What system should the O2 flush valve NOT be used with? What is the flow rate?
A
NOT for non-rebreathing systems - risk of barotrauma
30-50 L/min
168
Q
What is the difference between ascending and descending bellows?
A
Ascending = descend during inspiration, leaks are more obvious
Descending = descend during expiration
169
Q
How does a pressure-cycled ventilator work?
A
User sets the desired PIP and expiratory length in seconds
170
Q
What is the minute ventilation calculation?
A
RR x TV
171
Q
What is an animal’s residual capacity volume?
A
45 mL/kg
172
Q
What is normal CVP?
A
0-8 cmH2O, 0-5 mmHg
173
Q
What changes will you see in CVP with a fluid challenge in a patient with
Hypovolemia
Hypervolemia
A
Hypovolemia - bolus may not change CVP
Hypervolemia - bolus will increase CVP by 3-4 and stay up or slowly come down
174
Q
What are methods for measuring cardiac output? (4)
A
Aortic banding = gold standard
thermodilution
Lithium
NiCO
175
Q
What strategies lead to increased intrapleural pressure over a respiratory cycle
A
Large tidal volume, increased PEEP, short expiratory times
176
Q
What 3 receptors do opioids work on?
A
Mu = analgesia/side effects
Kappa = analgesia
Delta = regulates mu
177
Q
Rank the potency of the following opioids from most to least: oxy/meperidine, methadone, fentanyl, hydromorphone, buprenorphine, morphine
A
Fentanyl (100x) > buprenorphine (40x) > oxy/meperidine (10x) > hydro (8x) > methadone (2x) > morphine (1x)
(Francine bought oranges Monday; Henry made macaroni)
178
Q
How does tramadol provide analgesia?
A
serotonin/adrenergic receptors
Cats are able to make a large amount of the M1 metabolite, but dogs aren’t
179
Q
Which benzodiazepine is safest for animals with hepatic dysfunction?
A
Midazolam - water soluble
180
Q
What is the alpha-2 selectivity of: xylazine, detomidine, romifidine, and medetomidine/dexmedetomidine
A
xylazine 160:1
detomidine 260:1
romifidine 340:1
med-/dexmedetomidine: 1600:1 (dexmed is 2x more potent than medetomidine)
181
Q
What are the side effects of ketamine?
A
muscle rigidity, increased salivation, mild sympathomimetic (increased cardiac work), and increased IOP/ICP
Depends on renal excretion
182
Q
What are the side effects of etomidate?
A
emesis, adrenal suppression that can last for up to 6 hrs postop so do not use in critically ill patients with Addison’s
183
Q
What is the MOA of alfaxalone and what are the main side effects?
A
Steroid GABA agonist
Decreases cardiac output and causes apnea (less commonly than propofol)
184
Q
Rank the inhalant anesthetics in order of highest to lowest MAC (halogen, desflurane, nitrous, sevoflurane, isoflurane)
A
Nitrous (200%) > desflurane (7.2%) > sevo (2.1%) > iso (1.3%) > halo (1%)
Cat MACs are all slightly higher than the dog MACs
[No Dogs Swim In Heaven] or alternatively, [No Dan, Sexual Innuendos are Harrassment]
185
Q
MAC can be reduced by… (3)
A
Other drugs, hypothermia (decrease 5% per 1 deg C), and decreased cardiac output
186
Q
How does lipophilicity affect the actions of local anesthetics? What is the relationship between bupivacaine and lidocaine in terms of lipophilicity and potency?
A
More lipophilic = slower onset and longer duration
Bupivacaine is more lipophilic and 4x more potent than lidocaine
187
Q
Are a or C fibers more susceptible to local blocks?
A
a fibers (periphery, myelinated)
188
Q
What is the difference between depolarizing and non-depolarizing neuromuscular blockers? Which drugs are commonly used in each category?
A
Depolarizing = Succinylcholine –> triggers depolarization but doesn’t allow repolarization, trigger for malignant hyperthermia
Non-Depolarizing = Atracurium/Vecuronium –> binds receptor but doesn’t depolarize –> smoother onset, shorter duration , MUST use PPV
189
Q
What are reversals for neuromuscular blockers, what is their MOA, and when do you administer them?
A
Neostigmine and edrophonium, anticholinesterases, administer after all train-of-4 twitches return
can give anticholinergic beforehand to prevent bradycardia, sinus arrest, bronchospasm, and salivation
190
Q
What is the MOA of anticholinergics? What are the primary 2 drugs we use?
A
Parasympatholytics - decrease vagal tone by binding muscarinic receptors
Mimic the sympathetic nervous system
Atropine and glycopyrrolate
191
Q
What are the differences between glycopyrrolate and atropine in terms of potency, onset/duration, and ability to cross the BBB?
A
Glyco has 4x potency
Atropine can cross the BBB and has faster onset/shorter duration
Glycopyrrolate takes several min for onset and lasts longer (1 hr)
192
Q
What does the breaking strength of 2-0 barbed polypropylene suture correlate to in smooth suture?
A
3-0 smooth polypropylene
193
Q
How is the EtCO2 value related to PaCO2?
A
EtCO2 is 2-6 mmHg less than PaCO2
194
Q
What is the best opioid for epidurals?
A
Morphine –> has low lipophilicity and will provide analgesia for 12-24 hrs
195
Q
What dose of atropine will increase the heart rate by 50% for 30 minutes?
A
0.04 mg/kg IV
196
Q
T/F: Propofol has extrahepatic metabolism
A
True, good for patients with hepatic disease
197
Q
How does etomidate work?
A
GABA agonist
Causes adrenal suppression
198
Q
COX1:COX2 ratios of
Carprofen
Meloxicam
Mavacoxib
Firocoxib
Robenacoxib
Etodolac
A
Carprofen: 17
Meloxicam: 3
Mavacoxib: 21
Firocoxib: 300-400+
Robenacoxib: 150
Etodolac: 0.5
199
Q
What is tepoxalin?
A
Non-selective COX/LOX inhibitor –> inhibits COX1/2, LOX5, and TXA2
LOX activity may reduce GI toxicities
200
Q
Which 3 NSAIDs undergo enterohepatic circulation? Why is this significant?
A
Naproxen, carprofen, etodolac
Increased risk of GI upset
201
Q
Low stroke vol from myocardial dysfunction should be addressed with a positive inotrope. Which two drugs are most commonly used and what is their MOA?
A
Dobutamine: B agonist
Dopamine: B agonist and alpha agonist
202
Q
What two alpha-adrenergic vasopressors can be selected as a first line to reverse vasodilation?
A
Phenylephrine: a1/2 agonist
Dopamine: a1/2 agonist and B1/2 agonist
203
Q
What are the differences in the effect of dopamine based on the dose?
A
Low dose: vasodilation from B2
Medium dose: increased heartrate from B1 effects
High dose: Vasoconstriction from A1 effects (10-20 mg/kg/min)
204
Q
Clinically, norepinephrine lacks effects at which a/B receptor?
A
No clinical effects at the B2 receptor
205
Q
What is the MOA of amantadine?
A
NMDA antagonist and dopamine agonist
206
Q
Bioavailability of chondroitin sulfate?
A
5% bioavailability in dogs
Chondroitin sulfate is the most common glycosaminoglycan in the body
207
Q
What percent of glucosamine is absorbed?
A
90%
208
Q
What is the most effective anti-inflammatory fatty acid?
A
Eicosapentoic acid (EPA)
209
Q
How does HCM affect cardiac function?
A
diastolic dysfunction and impaired ventricular filling –> decreased SV and CO
210
Q
What anesthetic agents should be avoided in patients with cardiac disease?
A
Alpha2 agonists, ketamine (HCM), anticholinergics (increase HR and O2 demand), and lidocaine if in 3rd deg AV block
211
Q
What two drugs should be avoided for patients with hyperthyroidism? For patients with Addison’s?
A
Hyperthyroid: avoid ketamine (thyroid storm) and NSAIDs (occult renal insufficiency)
Addison’s: avoid ketamine (increases sympathetic stimulation) and etomidate
212
Q
What is the Branham reflex?
A
reflex decrease in HR after PDA ligation due to sudden increase in afterload
213
Q
What is the classic sign of V/Q mismatch on a blood gas?
A
Hypoxemia WITHOUT hypercarbia
214
Q
How does hypoalbuminemia affect many anesthesia meds?
A
Increases the amount of free circulating drug
215
Q
What is the only drug that has been shown to negatively affect neonatal survival in dystocias?
A
Xylazine
XYLAZINE KILLS BABIES (and also dogs, don’t give it to dogs)
216
Q
What are the 5 dental blocks?
A
Maxillary
Infraorbital
Major palatine
Inferior alveolar
Middle mental
217
Q
Describe the maxillary block
A
admin just caudal to last molar where maxillary n enters infraorbital canal thru maxillary foramen
218
Q
Describe the infraorbital block and what it blocks
A
admin at infraorbital foramen or inside infraorbital canal; blocks incisive bone + maxilla + maxillary teeth/soft tissues
219
Q
Describe the major palatine block and what it blocks
A
admin through thick palatal mucosa rostral to major palatine foramen (which is at level of upper PM4); blocks palatine shelf of maxilla
220
Q
Describe the inferior alveolar block and what it blocks
A
admin intraorally thru alveolar mucosa at lingual surface of mandible (or extraorally thru skin at notch of ventrolingual surface of mandible); blocks mandibular body + all mandibular teeth/soft tissues
221
Q
Describe the middle mental block and what it blocks
A
admin at middle mental foramen ventral to mesial root of PM2 (dog) or halfway b/w canine/PM3 (cat); blocks rostral mandibular body + teeth rostral to inj + soft tissues
222
Q
What two anesthetic drugs increase intraocular pressure?
A
Ketamine and propofol
223
Q
4 causes of hypothermia and what t% of heat loss they account for
A
Evaporation (minimal)
Conduction/cold surface (10%)
Convection/cold air (30%)
Radiation/body heat floating away (50%)
224
Q
What are the 5 causes of hypoxemia
A
Hypoventilation
V/Q mismatch
Low FiO2
Right to left shunting
Diffusion barrier
225
Q
What is malignant hyperthermia, what indicates that it is occurring in surgery, and how is it treated?
A
Inherited ryanodine receptor mutation
1st sign is abrupt increase in CO2, then increased temp/HR
Tx: dantrolene, aggressive cooling, remove trigger, O2
226
Q
Why is the ECG not a reliable indicator of cardiopulmonary arrest?
A
Electromechanical dissociation AKA pulseless electrical activity
227
Q
What is special about how introducer sheaths are measured? What size French is 1 mm?
A
Measured by INNER diameter
3 Fr = 1 mm
228
Q
What dose of contrast is ideal for IR procedures?
A
< 3 mL/kg of Iohexol
229
Q
What is the recommended light source for thoraco/laparoscopic procedures?
A
Xenon
230
Q
Insufflation limits in the chest/abdomen?
A
<3 mmHg in chest, 8-10 mmHg in abdomen
231
Q
What are the 3 routes of metastasis?
A
Hematogenous (sarcomas)
Lymphatic (carcinomas and round cell tumors)
Seeding
232
Q
What is the process of metastasis?
A
Process: detachment –> migration in surrounding tissue –> intravasation [entry of tumor cells into vascular/lymphatic vessel] –> circulation –> attachment to distant endothelial cell –> extravasation –> angiogenesis –> proliferation
233
Q
What size mets can be detected on TXR vs CT?
A
TXR >6 mm
CT 1 mm
234
Q
What are the 3 categories of margins?
A
Marginal (just outside pseudocapsule)
Wide (2-3 cm and 1 fascial plane deep)
Radical (entire compartment)
235
Q
What is considered a “close” margin?
A
< 3 mm normal tissue
236
Q
What are commonly used IHC stains for tumors?
A
Cytokeratin = epithelial/carcinoma
Vimentin = mesenchymal/sarcoma
237
Q
How much do tissue biopsies shrink by?
A
32%
238
Q
What nerves/spinal segments are assessed with the patellar reflex and the withdrawal in the front/back legs?
A
Patellar = femoral n, L4-6
Withdrawal in hind = sciatic n, L6-S1
Withdrawal in forelimbs = dorsal thoracic, axillary, musculocutaneous, median, ulnar, radial n (C6-T2)
239
Q
What nerve/spinal segments are involved in the cutaneous trunci reflex?
A
Lateral thoracic, C8-T1
240
Q
What cranial nerves are tested by vision and PLR?
A
CN 2, 3, 7
241
Q
What nerves contribute to the perineal reflex?
A
Cd rectal branch of pudendal n = voluntary motor to ext anal sphincter
Perineal branch of pudendal n = sensory
242
Q
What contributes the majority of parasympathetic innervation in the body?
A
Vagus n. - contains 75% of your body’s parasympathetic fibers
243
Q
What is bright on T1 vs T2 images (very broad)
A
T1 = fat bright
T2 = fat and fluid bright, more sensitive to pathology
244
Q
What separates the cerebral hemispheres? What separates the cerebellum from the rest of the brain?
A
Cerebral hemispheres separated by falx cerebri
cerebellum separated by tentorium cerebelli
245
Q
How does PaCO2 affect CNS perfusion?
A
A 1 mmHg inc/dec results in a 5% inc/dec in perfusion pressure
246
Q
How is cerebral perfusion pressure calculated?
A
CPP = MAP - ICP
247
Q
How does the Cushing’s reflex work?
A
Dec perfusion –> ischemia –> increased vasomotor tone –> incr MAP –> baroreceptor activation –> reflex bradycardia
248
Q
What is a normal ICP range
A
8-15 mmHg
249
Q
At what ICP do you get reduced cerebral perfusion?
A
ICP > 30 mmHg
250
Q
What makes up the BBB?
A
Tight junctions between endothelial cells
Astrocyte foot processes
Pericytes
Basal lamina
perivascular microglia
251
Q
What are the primary immune/phagocytic cells of the CNS?
A
Microglial cells
252
Q
Which antibiotics have the best penetration of the BBB?
A
TMS, fluoroquinolones, metronidazole, chloramphenicol, 3rd gen cephalosporins
253
Q
How does secondary injury occur after primary mechanical damage to the CNS?
A
Initiated by direct injury to neuronal/glial cell membranes
1. damaged membranes –> increased IC Ca/Cl/Na –> cell swelling AKA cytotoxic edema
2. Reduced uptake of K and glutamate by astrocytes –> increased glutamate –> + NMDA receptors –> further depolarizes cells (increased IC Ca and Na) –> + proteases and phospholipase A2 –> inflammation and apoptosis
3. Microglial cells release ROS and pro-inflammatory cytokines –> demyelination
254
Q
What connects the cerebral hemispheres?
A
corpus callosum
255
Q
What do the cerebellar peduncles connect
A
Inferior: spinal cord to medulla oblongata
Superior: cerebellum and midbrain/medulla oblongata
256
Q
What ligament is seen on a cervical ventral slot?
A
Dorsal longitudinal ligament
257
Q
What are the 3 effects of increased IC Ca in CNS cells?
A
- Activates IC proteases –> apoptosis
- Activates phospholipase A2 –> eicosanoid production and inflammation
- Binds IC Phos –> further reduced energy stores
258
Q
What are the 3 types of CNS edema and their causes
A
Vasogenic - increased vascular permeability due to inflammation
Cytotoxic - increased IC Na/Cl/Ca
Interstitial - increased intraventricular hydrostatic pressure from CSF
259
Q
What cells maintain CNS homeostasis
A
Astrocytes
260
Q
What is the primary collagen type in bone? Cartilage? Fibrocartilage? Tendons?
A
Bone = 90% type I collagen
Cartilage = 50% dry weight type 2 collagen
Fibrocartilage = type I collagen
Tendon = type I collagen
261
Q
What are the zones of articular cartilage?
A
Zone 1 = superficial
Zone 2 = transitional
Zone 3 = radial (has increased proteoglycan and reduced collagen to resist compression)
TIDEMARK
Zone 4 = cement line, mature/calcified cartilage
262
Q
What are the two types of entheses?
A
**Fibrous entheses = mm attach to diaphyseal bones –> dense collagen bands (Sharpey’s fibers) that merge w/ periosteal membrane
Fibrocartilaginous = no periosteum, zone of fibrocartilage at osteotendinous/ligamentous attachment –> forms transition between collagen fibers of tendon/lig and bone
263
Q
How does an action potential cause muscle contraction on a cellular level?
A
Individual fibers innervated by terminal branch of motor axon –> action potential –> Ach binds to sarcolemma –> depolarization + Ca+ release from SR –> Ca+ binds troponin –> conformational change in tropomyosin –> exposure to myosin binding site on actin –> myosin engages actin + releases ATP –> sliding of actin/myosin to shorten sarcomere
264
Q
What are the two muscle fiber types?
A
Type 1 = Slow twitch, have more mitochondria for sustained but weaker contraction, use oxidative metabolism
Type 2 = Fast twitch, have fewer mitochondria for fast, strong contraction, anaerobic metabolism
265
Q
What is the difference between large and small diameter fibrils in tendons/ligaments?
A
Large diameter - more stiffness/strength
Small diameter - larger surface area so more viscoelastic properties, are found in higher concentrations within the scar of healed tendons
266
Q
Where in bone are MSCs most commonly found?
A
cambrium layer of the periosteum
267
Q
What are the zones of the growth plate?
A
Resting zone (only vascular zone)
Proliferative zone –> type II collagen
Hypertrophic zone –> type X collagen and little ECM, predisposed to SH Fx
Zone of mineralization
Zone of ossification
268
Q
What is Young’s modulus?
A
Stiffness. Slope of elastic portion of stress-strain curve
269
Q
What are the two types of primary bone healing and their criteria?
A
Primary bone healing = intramembranous ossification
Contact healing = < 0.01 mm gap, <2% strain, bone deposited parallel to long axis of bone
Gap healing = < 1 mm gap, <2% strain, bone deposited parallel to FRACTURE
270
Q
What is the most common cause of failure with elastic plate osteosynthesis?
A
Plate bending (plastic deformation)
271
Q
T/F: Cutting cones cause bone resorption and reduce interfragmentary strain
A
False. They cause simultaneous resorption and formation of bone
(the statement in this question is referring to secondary bone healing, where the bone ends are resorbed and the callus is formed, both to reduce strain)
272
Q
What are the 5 steps in secondary bone healing?
A
Inflammation/granulation tissue formation
Intramembranous ossification
Soft callus formation
Hard callus formation
Bone remodeling
273
Q
What are the classifications for open fractures?
A
Type 1 = wound < 1 cm (inside-out)
Type 2 = wound > 1 cm (outside-in)
Type 3 = extensive ST damage (a = adequate ST; b = periosteal stripping/bone exposure; c = arterial injury)
274
Q
How many twists are needed to maintain tension in a twist cerclage wire? For a single loop cerclage? What is the strongest cerclage knot?
A
1 twist for twist wire
1.5 twists (with the wire tightener) for single loop
Strongest is the double loop cerclage
275
Q
What is AMI proportional to for a nail? For a plate?
A
Nail: r^4
Plate: thickness^3
276
Q
What % of medullary canal diameter should your implant fill for:
IM pin “alone”
IM pin + plate
ILN
Threaded pins for ESF (bone diameter not canal)
A
IM pin “alone” = 70%
IM pin + plate = 35-40%
ILN = 80% (70-90% of isthmus)
ESF pins 20-30% bone diameter
277
Q
Why do locking screws have a larger core diameter?
A
They have greater bending/shear at the bone-screw interface
278
Q
What do the colors on the DCP drill guide represent? Where is the screw positioned relative to the center of the hole with each side of the guide?
A
Green = neutral/load, 0.1mm offset
Gold = compression, 1 mm offset
279
Q
What degree of compression can be achieved with a single eccentric screw in a 3.5+ plate? In a 2.7 plate?
A
3.5 mm = 1 mm compression
2.7 mm = 0.8 mm compression
280
Q
For each 10% increase in medullary canal fill with an IM pin, how much is plate strain decreased by?
A
20%
281
Q
With an ESF, where should pins be placed in relation to the fracture ends, the joint space, and the physes (in young dogs)
A
1/2 bone diameter from fracture ends
3/4 bone diameter from the joint
1 cm or 3 pin diameters from the physis
282
Q
What are the types of viable and non-viable nonunions?
A
VIABLE NONUNION
oHypertrophic = excess callus, excessive motion/lack of adequate mechanical environ, exceeds tolerable strain of tissues (elephant foot)
oOligotrophic = no evidence of callus (hard to differentiate from nonviable), due to lack of cell activity, loose implants may contribute
NONVIABLE NONUNION
osteosynthesis cannot occur even with adequate fixation
oDystrophic = poorly vascularized intermediate frag with callus formation at one end but not other
oNecrotic = major frag of comminuted fx undergoes devascularization & necrosis (sequestrum)
oDefect = large bone defect (lost from trauma, sx, necrosis/resorption), gap at fx site too large
oAtrophic = most extreme; defect at fx with resorption of frag at both ends
283
Q
How tight should the screw driver be twisted for 2.0, 2.7, and 3.5 screws?
A
2.0 = 2 fingers
2.7 = 3 fingers
3.5 = whole hand
284
Q
What are the core diameters for the following cortical screws:
1.5
2.0
2.5
2.7
3.5
4.5
5.5
A
1.5 = 1.0
2.0 = 1.4
2.5 = 1.7
2.7 = 1.9
3.5 = 2.4
4.5 = 3.1
5.5 = 3.9
(+0.1 mm for cortical drill bit size)
285
Q
What are the 3 components of a biofilm?
A
Offending microbe
Microbe-produced glycocalyx matrix
Host-produced conditioning layer
286
Q
What are the 3 mechanisms that allow bacteria in biofilms to be more resistant to antimicrobial agents?
A
Biofilm acts as molecular filter – glycocalyx impedes perfusion of antimicrobials to cellular targets
Quiescent/dormant growth of biofilm microbes (abx that rely on bacterial growth don’t work)
Harsh microenvironment adversely affects antimicrobial agents (lower pH, increased pCO2, decreased PO2, hydration)
287
Q
What are the 4 properties of autogenous cancellous bone grafts?
A
Osteogenesis = supplies bone forming cells
Osteoinduction = capacity to induce bone formation
Osteoconduction = scaffold for MSCs
Osteopromotion = enhances (does NOT induce) bone regeneration
288
Q
What is the mechanism by which cortical allografts heal?
A
Creeping substitution –> slowly resorbed and substituted with host bone
289
Q
When can you repeat an autograft harvest from the humerus? From the tibia?
A
8 wks for humerus
12 wks for tibia
290
Q
What factors lead to the osteoinductive effect of demineralized bone matrix?
A
TGF-B, BMP2, BMP7
291
Q
What inflammatory cytokines are most associated with ECM degradation in OA?
A
IL-1
IL-17
IL-18
TNF-A
PGE2
Also ROS, MMPs, aggrecanases
292
Q
What are the 3 stages of OA?
A
(1) ECM degrades + aggrecan molecule shortening + H2O absorption ↑ + collagen damage –> ↓ stiffness of cartilage
(2) chondrocytes try to compensate with proliferation and ↑ metabolic activity
(3) chondrocytes cannot keep up –> cartilage loss/eburnation
293
Q
Which is the inducible COX enzyme? What cytokines classically induce it?
A
COX2 = inducible
TNF-a, IL-1
294
Q
What prostaglandins mediate the adverse effects of NSAIDs?
A
PGE2 = important for gastric mucosal health
PGE2 and PGI2 = important for maintaining renal blood flow
TXA2 = important for clotting
PGI2 = important for preventing thromboembolic disease
295
Q
What is the ideal ratio of avocados : soybeans?
A
1:2
296
Q
What are the cell counts (x10^9/L) and % MONONUCLEAR cells for synovial fluid:
Normal
OA
Rheumatoid A
Non-erosive IMPA
Septic A
A
Normal: <2 ; 94-100%
OA: 2-5 ; 88-100%
Rheumatoid A: 8-38 ; 20-80%
Non-erosive IMPA: 4-370 ; 5-85%
Septic A: 40-270 ; 1-10%
297
Q
N6 vs N3 fatty acids: which are pro- and which are anti-inflammatory?
A
N6 = pro-inflammatory
N3 = anti-inflammatory (EPA is most effective)
298
Q
What are the the 4 types of non-erosive IMPA? (not the subtypes of idiopathic)
A
Idiopathic (4 subtypes)
Drug-induced
SLE/SLE-related
Breed-associated (Shar Pei and Akita)
299
Q
What are the 4 subtypes of idiopathic IMPA
A
Type I: Idiopathic (most common, 50%) –> prednisone cures 60%, 1/3 relapse, 1/3 need continuous Tx
Type II: Infectious/Inflammatory (25%)
Type III: GI (15%)
Type IV: Paraneoplastic (unFOURtunate because you have cancer)
300
Q
What are the 3 types of erosive IMPA?
A
Rheumatoid
Greyhound polyarthritis
Feline chronic progressive
301
Q
What are the most common bacteria implicated in septic arthritis for dogs and cats?
A
Dogs: Staph pseud, Staph aureus, B-hemolytic Strep
Cats: Pasteurella, Bacteroides
302
Q
What is the benefit of starting antibiotics within the first 24 hrs of septic arthritis?
A
Decreased cartilage loss, however GAG will still be lost because they are degraded before collagen
303
Q
What are the 3 stages of muscle injury?
A
Stage 1 = myositis/bruising
Stage 2 = tearing of fascia
Stage 3 = fiber disruption + hematoma
304
Q
What are the two classes of tendons in relation to their vascularization? How does it impact their healing?
A
Paratenon = vascularized tendons, better chance for rapid healing (gastroc, triceps)
Sheathed tendons = avascular, healing depends on intrinsic blood supply
60% strength at 6 weeks, 80% at 1 year post injury
305
Q
What size arthroscope would be appropriate for a 20 kg dog?
A
2.7 mm 30 deg scope
306
Q
What size scope is appropriate for tarsal arthroscopy?
A
1.9 mm 30 deg scope
307
Q
What collagen is primarily found in the joint capsule?
A
Type 1 collagen
308
Q
What are the 3 forms of osteochondrosis?
A
OC latens - microscopic lesions
OC manifesta - radiographic and macroscopic lesions, subclinical
OC dissecans - attached or loose cartilage flap + clinical signs
309
Q
Sites of OCD
A
Humeral head
Medial humeral condyle
Medial coronoid process of ulna
Both femoral condyles
Both trochlear ridges
310
Q
What are the two types of OC?
A
Type 1 = in center of joint surface (humeral head, humeral condyle, femoral condyles)
Type 2 = at periphery, retains vascular attachments (MCP ulna, trochlear ridge)
311
Q
When does the medial humeral condyle fuse to the lateral?
A
6 weeks
312
Q
When does the femoral capital physis close?
A
7-11 mos
313
Q
When does the distal ulna/radius physis close?
A
8-12 mos
314
Q
When does the tibial tuberosity physis close?
A
6-8 mos
315
Q
What are the plexuses that supply the skin?
A
SQ/subdermal plexus, cutaneous plexus, subpapillary plexus
316
Q
How does cutaneous perfusion differ between dogs and cats?
A
Dogs have > density of collateral SQ vessels than cats [cats have smaller # + wider distribution of cutaneous perforating w/in trunk]
317
Q
Define:
Primary closure/1st intention
Delayed primary closure
Secondary closure/3rd intention
2nd intention healing
A
PRIMARY/1ST INTENTION = sutured; clean or clean-contaminated wounds
DELAYED PRIMARY = closed 2-5 days after wound; mild contamination + minimal trauma; BEFORE granulation tissue
SECONDARY/3RD INTENTION = AFTER granulation tissue; severely contaminated/traumatized
2ND INTENTION = via contraction/epithelialization; lower limbs
318
Q
How long does it take for necrosis to declare itself after a crushing injury of the skin?
A
3-7 days
319
Q
Differences between cats and dogs in terms of wound healing?
A
- Cats have ↓ cutaneous perfusion for 1st wk after sx with more rapid gain in 2nd wk (not diff from dogs at 2 wk)
- Cats have ↓ wound breaking strength at 1 wk
- Cats heal more by contraction dogs heal more by central pull from fibroblasts [cats contract]
- Cats have less granulation tissue with more peripheral location of granulation
320
Q
Honey is best for what phase of wound healing? In what ways does it exert its antimicrobial effects?
A
Inflammatory/early repair
- Hyperosmotic
- Produces H2O2 via glucose oxidase on glucose
- Phytochemicals + Low pH stimulate B/T-cell prolif
Also
Autolytic debridement and enhances granulation tissue formation
321
Q
What is the Inhibin Number for medical grade honey?
A
Amount of dilution to which honey retains antimicrobial properties
322
Q
What are the benefits of negative pressure wound therapy?
A
Improves wound perfusion
Decreases edema
Stabilizes granulation tissue formation
Reduces bacterial load
Removes exudate
Induces release of VEGF
323
Q
What wound VAC pressures are used for:
Standard wounds
Skin grafts
Septic peritonitis
Over gauze
A
Standard wounds: -125 mmHg
Skin grafts: -65 to -75 mmHg
Septic peritonitis: -75 to -125 mmHg
Over gauze: -80 mmHg
