The test JB's version Flashcards
3 processes by which a skin graft obtains nutrition
Plasmatic imbibition, inosculation and re-vascularization
Cat specifics when it comes to skin
Decreased vascularity vs dogs
Longer healing time - lower rates of granulation (2x’s longer than dogs), epithelialization, contraction
Critical to preserve the Sub Q
Deploarizing neuromuscular blockade
Name 2 and how do they work “briefly”
Succinylcholine, decamethonium
These drugs mimic ACh
Binds acetylycholine receptors, result in persistent depolarization (Na channels left open = Na inactivation). And receptor burn out - reason uncertain
Non-depolarizing neuromuscular blockade
Name 2 and how do they work “briefly”
Atracurium, pancuronium, vecuronium
These drugs block ACh.
Block ACh post synaptic receptors so no ACh stimulation
Clinical highlights of depoloarizing NM blockade?
Deploarizing = Initially get muscle fasciculation. Paralysis due to prolonged depolarization of the motor end plate. Paralysis is not reversed by anti-cholinesterase drugs but rather metabolism by pseudocholinesterase
Clinical highlights of non-depoloarizing NM blockade?
Gradual relaxation (no mm fasiculations) Can be partially reversed by anti cholinesterase drugs: Neo or Pyrido stigmine, edrophonium
Succinylcholine adverse effects
- Sore next day (fasciculation?)
- Hyperkalemia (K from skeletal mm)
- Malignant hyperpyrexia - Fast wicked high rise in temp +/- rigidity. Usually if give with halothane. Tx signs and use bicarb and dantrolene sodium (1-2mg/lb)
- Histamine release
- Tachycardia and hypertension (symp stim). but can sometimes get brady cardia
Decamethonium adverse effect
Same as succinylcholine except -
- no histamine release
- no metabolism (excreted by kidneys [so no usey if bad kidneys])
- longer duration of action (not metabolized by plasma cholinesterase)
Pancuronium (highlights)
non depolarizing
no histamine or catecholamine release
effects enhanced by inhalants
Major portion excreted unchanged in pee
Atracurium
- non depolarizing
- can give as infusion
- Hoffman elimination (chemical run) no liver or kidney involved
Vecuronium
- non depolarizing
- short onset and duration
- potential choice for renal failure (40% eliminated in bile, 15% through kidney)
What affect, if any could temp have on blockade?
hyperthermia
-prolongs depolarizing and antagonizes non-depolarizing
hypothermia
- prolongs non-depolarizing
What affect if any does respiratory acidosis have on blockade
Augments non-depolarizing blockade
Vicious cycle = inadequate reversal causes depressed ventilation which causes reap acidosis
Why would you give atropine with a neuromuscular blockade reversal
Reversals are anti cholinesterase drugs. By blocking AChesterase they increase the amt of ACh to compete with non-deploarizing blockers for the receptor.
Also get muscarinic stimulation (salivation, bradycardia, increased intestinal motility)
Atropine is an anticholinergic and will help decrease those side effects
Can you reverse succinylcholine
No. Paralysis is reversed by metabolism by pseudocholinesterase
How much trachea can be removed in
Adult
Puppy
Adult - 25-50%
Puppy - 20-25%
tobias says experimentally 15-27 rings
What kind of muscle is the trachealis muscle?
Is it dorsal or ventral
Primarily composed of transversely oriented smooth muscle fibers
Dorsal
What is the blood supply to the trachea
Segmental - from the cranial and caudal thyroid attires. Except near the corona - here it shift primarily to the bronchoesophageal arteries.
How are AB’s incorporated into PMMA beads released?
Bimodal manner (rapid phase then slow)
How much of the antibiotic used is released in the rapid phase and how long is this period
5% of total AB used is released in first 24 hours.
What affect does the addition of Metronidazole have on polymerization of PMMA? And what does that mean for you clinically?
The addition of metronidazole even at very low concentrations (100:1) significantly delays polymerization (hardening). Taking up to about 48 hours (apposed to the normal 5-10 minutes)
Local AB tissue concentrations have been reported to reach up to _______x’s greater than when given systemically
200 (per Saygeh Compend 2003)
20 (per Ramos etal vet surg 2003)
It is estimated that the area receiving therapeutic levels of AB’s may reach?
2-3mm
How long does elution of AB’s persist from PMMA?
21 days in a uniform dose dependent manner is commonly reported (probably longer)
How much of the total ab incorporated into the PMMA elutes
2.3-11% has been reported for a variety of AB’s tested
How much of the total cumulative elution occurs in first hour? First 24 hours?
1/3 in first hour, 2/3 in first 24 hours
What does the elution rates of AB’s from PMMA beads depend on?
Bead associated factors - Size of bead, pore size, permeability and type of cement used, exposed surface area Antibiotic factors -diffusion coefficient -concentration -mixing of some AB's Tissue factors -circulation in the area -amount of fluid surrounding bead
Requirements for AB to be used in PMMA beads
Should be bactericidal, effective against expected bact at MIC, and above all = HEAT STABLE
What is the most common concentration (recipe) of antibiotic to PMMA used
1g AB for every 20g of cement
What AB’s cant you use in PMMA beads? And why?
Polymixin B, tetracyclines, chloramphenicol. Not heat stable enough
Thomas LA, Bizikova T, Minihan AC. In vitro elution and antibacterial activity of clindamycin, amikacin, and vancomycin from R-gel polymer. Vet Surg. 2011
- 2 formulations:
- amikacin + clindamycin
- amikacin + clindamycin + vancomycin
- concentrations eluted over breakpoint MIC for 9 days, Staph was inhibited for all 10
- conclusion: R-get is an effective carrier for at least 9-10 days
Watts AE, Nixon AJ, Papich MG, Sparks HD, Schwark WS. In vitro elution of amikacin and ticarcillin from a resorbable, self-setting, fiber reinforced calcium phosphate cement. Vet Surg. 2011 Jul;40(5):563–70
- FRCP beads (“Norian”-Synthes) resorbable
- with amikacin, ticarcillin-clavulinate, or both
- “biphasic pattern of release”
- beads with either Abx were suitable carriers for elution
- beads with combination of Abx were not! Inhibited eachother’s elution.
- Do not use even two types of beads together (discussion)
Baez LA, Langston C, Givaruangsawat S, McLaughlin R. Evaluation of in vitro serial antibiotic elution from meropenem-impregnated polymethylmethacrylate beads after ethylene oxide gas and autoclave sterilization. Vet Comp Orthop Traumatol. 2011;24(1):39–44.
- meropenem is a carbopenem that is resistant to B-lactamase AND cephalosporinase
- in PMMA beads, its elution stayed above “breakpoint sensitivity limit” for 15 days
- ethylene oxide sterilization did not affect elution
- autoclaving destroyed meropenem activity
Atilla A, Boothe HW, Tollett M, Duran S, Diaz DC, Sofge J, et al. In vitro elution of amikacin and vancomycin from impregnated plaster of Paris beads. Vet Surg. 2010 Aug;39(6):715–21
- plaster of paris is absorbable and osteoconductive
- Amikacin does not work!
- left POP beads so quickly that staph grew within 24 hours
- when mixed with vancomycin, it decreased vancomycin’s efficacy
- Vancomycin worked
- steady release for 12 weeks, suppressed staph growth for 8 weeks
Max screw angulation through a DCP longitudinal and sideways
Through an LcDCP
DCP - 25 degrees longitudinal, 7 degrees sideways
LcDCP - 40 degrees and 7 degree respectively
Benefits of an LcDCP vs DCP
Decreased contact with bone = increased periosteal blood supply (less disruption)
Decreased stress concentration at screw holes
Movement of the bone fragment when placing screws load and neutral guide
- 5mm DCP, LcDCP and 3.5 DCP?
- 7 DCP
- 5 and 2.7 LcDCP
- 5mm DCP, LcDCP and 3.5 DCP = 1mm for each screw loaded up to a max of 4mm. 4.5mm = 0.1mm in neutral guide
- 7 DCP = load guide 0.8mm, neutral is 0.08mm
- 5 and 2.7 LcDCP = 0.75mm and 0.075mm respectively
With respect to a plate rod construct with plate in buttress or a buttress plate and a rod 50% of the IM diameter -
How much stress reduction and what increase in fatigue life is obtained?
~2 fold stress reduction and 10 fold increase in fatigue life
Hulse et al VCOT 2000 reported what changes in stiffness and plate strain associated with the addition of an IM pin of 3 various sizes to a 3.5mm DCP
6, 40 and 78% increases in stiffness and 19,44 and 61% decreases in plate strain with pins 30, 40 and 50% the diameter of the bone respectively
What 3 elements in a 316L stainless steel plate provide corrosion resistance?
Chromium 18% - corrosion resistance
Nickel - strength
Molybdenum - resistance to pitting corrosion
Who is stronger? 4.5mm DCP or 3.5mm broad? Why?
3.5mm broad. Smaller and more screw holes per unit length
How much pressure does one screw in compression apply to the fracture?
50-80kp (kilopascal)
Tramadol MOA
Weak action at mu receptor. Analogue of codeine.
Analgesic properties related to serotonin and adrenergic receptor effects centrally.
Cox 2 constitutively expressed in?
And…..
Brain, kidney
mediates a cytoprotective effect in damaged or inflamed GI mucosa
What does MIPO stand for?
Minimally invasive plate osteosynthesis
What is the rate limiting step in prostaglandin and leukotriene synthesis
The release of arachidonic acid from membrane phospholipids by Phospholipase A
Some things Cox-1 does
Generates PG ass with mucosal defense -secretion of bicarb and mucous -mucosal blood vessel attenuation -mucosal epithelial regeneration Generates thromboxanes necessary for platelet fnct and vasoconstriction
Cox-2 and Nociception
Amplifies nociceptive input in CNS and PNS
Primarily medicate through PGE2
PGE2 and 1
-Makes PERIPHERAL nociceptors more sensitive to MEDIATORS (eg histamine and bradykinin)
PGE2
-Makes PERIPHERAL nociceptors more sensitive to ACTIVATION via increases in amts of cyclic AMP. This decreased their threshold to activation
-Lowers threshold for neuronal depolarization, increasing the # of action potentials and reptiive spiking in the CNS (CENTRAL sensitization)
How are NSAID’s metabolized?
Hepatic primarily and some undergo enterohepatic recirculation
NSAID mechanism of gastric injury
Dissociate in epithelial cells of g musosa into ionized form and trap H ion Decreased PG's = Reduction in hydrophobic nature of gastric mucous Decreased mucosal blood flow Decreased bicarb secretion Decreased mucus secretion Decreased epithelial proliferation Decreased mucosal resistance to inj
Why is Cox-2 considered to be the inducible iso-enzyme?
Upregulated (increases up to 20x’s) in inflammatory state
List some of the cytokines known to up regulate Cox-2
Il-1B, IFNY, TNF alpha, PAF, PGE2
Zeltzman 2011 compendium
How much blood does a typical dry 4x4 inch 12-ply WOVEN sponge absorb? A 4-ply NON-WOVEN? a 12x12 in woven moistened lap sponge?
Another way to estimate blood in a sponge and thus blood loss?
5-12.5ml
10-18.3ml
~50ml
You can also weigh the soaked sponges. Assume a 4x4 dry sponge has negligible wt and 1ml of blood weighs a gram
Best way to obtain desired wound flush pressure?
1L bag pressurized to 300mmHg and a 16, 18, 20 or 22g needle
Gall et.al. AJVR 2010
What does the 30, 50 and 90 in TA____ stand for?
The length of the staple line created in mm
What is the color - green, blue and white of the TA staple cartridge associated with
The length of the leg (in mm) of the staple when open
Green = 4.8
Blue = 3.5
White = 2.5mm
What are the dimensions of the, green, blue and white TA staple?
Green = crown is 4mm, leg is 4.8mm and the staple compresses to ~2mm
Blue = Crown is 4 mm, leg is 3.5mm and staple compresses to ~1.5mm
White - Crown is 3mm, leg is 2.5mm and staple compresses to ~1mm
What does a GIA do?
Fires 4 rows of staples and divides them between the 2nd and 3rd row leaving two rows of staggered staples on each end of the divided tissue (sealing it with two rows of staggered staples). 50 or 90mm long.
GIA cartridges come in 3 sizes.
They are?
And what are the dimensions of each?
Std = 4mm crown, 4mm legs and compresses to 1.75mm Pediatric = 4mm crown, 3mm leg and compresses to 1.25mm Disposable = 3mm crown, 3.85mm leg and compresses to 1.5mm
Ulman et al “open intestinal anastomosis with surgical stapling equipment vetsurg 1991
Technique used?
Compared to std sutured technique
Compared to other stapling technique
GIA and TA to perform open anti-peristaltic side to side anastomosis (functional end to end). Put a suture in the crotch (greatest tension)
Same complication rate as sutured, faster surgical time, higher bursting during lag phase of healing, higher tensile strength after 7 days, minimal inflammatory response (less tissue manipulation and staples are inert)
Larger lumen diameter than other stapling techniques
EEA stapler does what?
dbl row of staples connecting the lumina of two hollow organs forming a true inverting anastomosis
What clamp can you use to help perform the anastomosis using the EEA stapler
Modified Furniss purse string clamp
- What is the difference between eletrocautery and electrosurgery?
Electrocautery is the use of electrical current to heat an instrument, which is then used to cauterize tissue in the same manner as a branding iron affects tissues. Electrosurgery is a form of energy transfer via electrons from the instrument to tissues.
- When the current of electrosurgical units is intermittent instead of continuous, what happens?
When the current flow is intermittent, or the oscillations in the current are dampened, hemostasis is accomplished without cutting
- What temperature is needed for collagen denaturation, and at what temperature do cells die?
Temperature range considered necessary for collagen denaturation and subsequent tissue shrinkage- (65° to 75° C); cells will die at (45° C)
- What are the disadvantages of electrosurgery versus cold knife dissection?
Extensive use of cutting cautery creates increased susceptibility to infection and seromas when compared with cold knife dissection
- How do bipolar vessel sealing devices work?
Provide hemostasis by denaturing collagen and elastin from the vessel wall and surrounding connective tissue
- What tissues/ vessels are bipolar sealing devices approved for?
Approved for use on blood vessels 7 mm or smaller in diameter and on bundles of tissue as large as can be accommodated within the jaws of the instrument
- How do ultrasonic energy systems work and at what frequency?
Ultrasonic waves at about 55,000 vibrations per second (55.5 kHz). The high-frequency vibrations of the instrument cause both an “oscillating saw” effect and vibration-induced heat and coagulation
- What method and temperatures are used by electrosurgery/lasers versus harmonic systems for hemostasis?
Harmonic technology controls bleeding through coaptive coagulation at low temperatures ranging from 50° to 100° C
Electrosurgery and lasers coagulate by burning (obliterative coagulation) at higher temperatures (150° C to 400° C)
- What are the three essential categories of laser-tissue interactions?
photochemical effect, photothermal effect, photomechanical or photoionizing effect
Is a laser better than electrosurgery?
Most comparative studies have shown that the CO2 laser is not superior to electrosurgery.
- What are the 5 most common types of lasers?
Argon, CO2, Nd:YAG, Ho:YAG, Excimer
- What are channel-swaged needles and Laser drilled swages?
Channel-swaged means that the suture is crimped in a depression in the body of the needle, whereas laser-drilled have the suture crimped in a hole drilled in the body of the needle so there is less tissue drag
What is the biggest safety concern with any cautery device? Most significantly?
As with the use of electrocautery devices, vaporization of tissue with lasers or radiofrequency devices produces a plume of steam or smoke that may generate safety concerns. The most significant of these is the possible spread of viral infection.
- With a nonswaged needle, which side should the suture be loaded from and why?
concave surface because the suture will be less prone to pulling out of the needle
What are polyblend sutures?
Have a core of one polymer and a braided exterior composed of a different polymer. They are very strong and resistant to failure.
- What antibiotic is commonly applied to suture material and how does it work?
Triclosan, inhibits bacterial fatty acid synthesis
- The following terms have been used to describe the properties and characteristics of suture; define them:
from?, physiologic action?
Table 1-2 pg 9
- What are the major mechanisms of suture absorption? In general, what types of sutures are broken down by each method?
Enzymatic (natural) and hydrolytic (synthetic)
- Absorbable suture is commonly defined as suture that loses most of its tensile strength within how many days?
60-90 days
In sterile urine, PDS loses all strength after ____days. Polyglycolic acid lost 64% of its initial breaking strength after _____ days. When urine was infected with Proteus bacteria, PDS and Dexon lost all strength after _____ day. In that study infected and sterile urine had little effect on catgut suture. A similar study that followed found that PDS, Monocyl, Maxon, and Biosyn disintegrated after ____ days in Proteus infected urine.
3, 10, 1, 7
pH also has a significant effect on suture. Sutures with a glycolide component will degrade more rapidly in a ________ environment, whereas sutures with a dioxanone component will lose tensile strength rapidly in an ________ environment, as will nylon even though its considered a non-absorbable.
basic, acid
Suture degradation is affected by the method of suture tying. For polyglycolic acid for example, the slower and tighter a knot is tied, the greater is its ability to withstand tensile loads during hydrolysis. Also, prestraining suture as is done to reduce suture memory, will _______ suture degradation.
enhance
List other factors that may affect suture degradation.
Irradiation, type of sterilization, presence of free radicals, type of environmental electrolytes, suture surface modifications, temperature, presence of bacteria, and presence of synovial fluid
What is catgut made from? What does chromic refer to and what is the advantage of doing it?
SI submucosa of sheep or intestinal serosa of cattle; chromic means the suture undergoes additional curing or tanning with chromium trioxide salts to help increase collagen cross-linkages, delays suture absorption, and reduces tissue inflammation.
How is leader line different from regular fishing line?
It is designed to connect fishing or fly line to the bait and is made to withstand high loads, used primarily in saltwater fly fishing or fishing for larger fish with powerful jaws and sharp teeth.
At about ______days following implantation, there is a degradation in bursting strength, followed by an increase in strength to levels above native tissues. Approximately 3 months following implantation, porcine small intestinal submucosa is not histologically apparent.
10
When mesh is under tension, an approximately ____cm overlap with native tissue is recommended. When little or no tension is present, approximately ___cm overlap is recommended.
1 cm, 0.6
with TA staplers, what is the beginning and compressed staple height for blue cartridges? Green cartridges? White cartridges? Width for each? How many rows of staples does each have?
Blue – 3.5mm, closes to 1.5mm, 4mm width, 2 rows; Green – 4.8mm, closes to 2mm, 4mm width, 2 rows; White is 2.5mm, closes to 1mm, 3mm width, 3 rows
What are the 4 principles for vascular clip applications?
- Skeletonize
- Diameter of the vessel should be no less than 1/3 and no more than 2/3 the length of the clip
- The clip is applied several millimeters from the cut edge of the vessel
- Arteries and veins are clipped separately
What does the “L” stand for in 316L stainless steel?
Denotes a low concentration of carbon which increaases corrosion resistance
- What are the disadvantages of electrosurgery versus cold knife dissection?
Extensive use of cutting cautery creates increased susceptibility to infection and seromas when compared with cold knife dissection
- How do bipolar vessel sealing devices work?
Provide hemostasis by denaturing collagen and elastin from the vessel wall and surrounding connective tissue
- What tissues/ vessels are bipolar sealing devices approved for?
Approved for use on blood vessels 7 mm or smaller in diameter and on bundles of tissue as large as can be accommodated within the jaws of the instrument
- How do ultrasonic energy systems work and at what frequency?
Ultrasonic waves at about 55,000 vibrations per second (55.5 kHz). The high-frequency vibrations of the instrument cause both an “oscillating saw” effect and vibration-induced heat and coagulation
- What method and temperatures are used by electrosurgery/lasers versus harmonic systems for hemostasis?
Harmonic technology controls bleeding through coaptive coagulation at low temperatures ranging from 50° to 100° C
Electrosurgery and lasers coagulate by burning (obliterative coagulation) at higher temperatures (150° C to 400° C)
- What are the three essential categories of laser-tissue interactions?
photochemical effect, photothermal effect, photomechanical or photoionizing effect
- What are the 5 most common types of lasers?
Argon, CO2, Nd:YAG, Ho:YAG, Excimer
Is a laser better than electrosurgery?
Most comparative studies have shown that the CO2 laser is not superior to electrosurgery.
- What are channel-swaged needles and Laser drilled swages?
Channel-swaged means that the suture is crimped in a depression in the body of the needle, whereas laser-drilled have the suture crimped in a hole drilled in the body of the needle so there is less tissue drag
- With a nonswaged needle, which side should the suture be loaded from and why?
concave surface because the suture will be less prone to pulling out of the needle
What are polyblend sutures?
Have a core of one polymer and a braided exterior composed of a different polymer. They are very strong and resistant to failure.
- What antibiotic is commonly applied to suture material and how does it work?
Triclosan, inhibits bacterial fatty acid synthesis
- Absorbable suture is commonly defined as suture that loses most of its tensile strength within how many days?
60-90 days
what is the biggest safety concern with any cautery device? Most significantly?
As with the use of electrocautery devices, vaporization of tissue with lasers or radiofrequency devices produces a plume of steam or smoke that may generate safety concerns. The most significant of these is the possible spread of viral infection.
- What are the major mechanisms of suture absorption? In general, what types of sutures are broken down by each method?
Enzymatic (natural) and hydrolytic (synthetic)
In sterile urine, PDS loses all strength after ____days. Polyglycolic acid lost 64% of its initial breaking strength after _____ days. When urine was infected with Proteus bacteria, PDS and Dexon lost all strength after _____ day. In that study infected and sterile urine had little effect on catgut suture. A similar study that followed found that PDS, Monocyl, Maxon, and Biosyn disintegrated after 7 days in Proteus infected urine.
3, 10, 1
pH also has a significant effect on suture. Sutures with a glycolide component will degrade more rapidly in a ________ environment, whereas sutures with a dioxanone component will lose tensile strength rapidly in an ________ environment, as will nylon even though its considered a non-absorbable.
basic, acid
- The following terms have been used to describe the properties and characteristics of suture; define them:
a. Breaking strength
b. Capillarity
c. Creep
d. Plasticity
e. Pliability
f. Stress relaxation
g. Suture pull-out value
h. Tensile strength
a. Breaking strength – Stress value on the stress-strain curve at which suture acutely fails
b. Capillarity – Degree to which absorbed fluid is transferred along the suture
c. Creep – Tendency of a suture to slowly and permanently deform under constant stress
d. Plasticity – Degree to which a suture will deform without breaking and will maintain its shape after removal of the deforming force
e. Pliability – Ease of handling and ability to change the shape of suture
f. Stress relaxation – Ability of suture to reduce stress under constant strain
g. Suture pull-out value – The weight required to pull a suture loop from tissue
h. Tensile strength – Like ultimate, breaking or yield strength, it is a measure of a suture’s ability to resist deformation and breakage and the stress at which deformation (yield strength) or rupture (breaking strength) occurs
Suture degradation is affected by the method of suture tying. For polyglycolic acid for example, the slower and tighter a knot is tied, the greater is its ability to withstand tensile loads during hydrolysis. Also, prestraining suture as is done to reduce suture memory, will _______ suture degradation.
enhance
List other factors that may affect suture degradation.
Irradiation, type of sterilization, presence of free radicals, type of environmental electrolytes, suture surface modifications, temperature, presence of bacteria, and presence of synovial fluid
What is catgut made from? What does chromic refer to and what is the advantage of doing it?
SI submucosa of sheep or intestinal serosa of cattle; chromic means the suture undergoes additional curing or tanning with chromium trioxide salts to help increase collagen cross-linkages, delays suture absorption, and reduces tissue inflammation.
How is leader line different from regular fishing line?
It is designed to connect fishing or fly line to the bait and is made to withstand high loads, used primarily in saltwater fly fishing or fishing for larger fish with powerful jaws and sharp teeth.
At about ______days following implantation, there is a degradation in bursting strength, followed by an increase in strength to levels above native tissues. Approximately 3 months following implantation, porcine small intestinal submucosa is not histologically apparent.
10
When mesh is under tension, an approximately ____cm overlap with native tissue is recommended. When little or no tension is present, approximately ___cm overlap is recommended.
1 cm, 0.6
What is the equation for the a-a gradient
(FiO2x[Pb-PH2O]-1.2PaCO2)-PaO2
First part of equation is PAO2
