Chapters 13, 15, 16, 17 FROM NOTES ONLY Flashcards
What is recommended size of OR
And if fluoro etc?
37m2 (400 ft2)
56m2 (600 ft2)
What are recommended OR settings for
Ventilation
Humidity
Temp
- Ventilation: 15 air exhanges/hour, horizontal laminar flow
- Humidity: 30 - 60%
- Temp: 20 - 23 Cº
N.B. Laminar airflow –> 61% reduced room bacteria and 92% decreased wound site bacteria
What is antiseptic/disinfectant MoA of:
Alcohols
Povodine-iodine
Chlorhex
- Alcohols: Protein denaturation, lysis, metabolic interruption
- Povodine-iodine: Free iodine oxidation/substitution –> protein denaturation
- Chlorhex: Cell membrane disruption
What is gene that confers chlorhex resistance to Staph aureus
qacA/B
What % solution chlorhex is used for skin prep?
And in wound
4% for skin
0.05% in wound
What 3 factors are associated with increased glove perf
- Non dominant hand
- Non-ST procedure
- Sx > 60 mins
What is rate of perf when single gloved/
Single gloved:
- 13 - 31%
Double gloved:
- 11 - 44% outer glove
- 4 - 13% inner glove
How does waveform (current) of cutting vs coagulating electrocautery differ
Cutting waveform continuous, 100% of time
Coag waveform is intermittent, only 6% of time
For what % of time is cutting coag waveform (i.e. current) ‘active’?
And for coag
100% for cutting
6% for coag
What effect does electrosurgery have on tissues at following temperatures?
40ºC
50ºC
70ºC
90ºC
100ºC
250ºC
40ºC –> inflammation + oedema
50ºC –> enzyme deactivated
70ºC –> protein denaturation
90ºC –> dessication
100ºC –> vapourization + cell rupture
250ºC –> carbonization
Name three contact types for coagulative electrocautery
- Fulguration coagulation: (not in contact –> arcs –> superfiial coagulum)
-
Dessication coagulation: Direct contact of electrode w tissues. Deeper necrosis + thermal spread than fulguration coagulation.
- Coaptive coagulation: Instrument grasping vessel –> collagen weld
On what size vessel can monopolar cautery be used?
And enseal/ligasure?
Harmonic scalpel?
Co2 laser?
Monopolar ≤2mm
Enseal/Ligasure ≤7mm
Harmonic scalpel <3mm
CO2 laser <0.6mm
What is conculsion re using monopolar cautery for skin?
(Scott, VetSurg, 2017)
(Meakin, VetSurg, 2017)
Scott, VetSurg, 2017
- Better haemostasis
- Faster
BUT
- Increased complications
- Delayed healing
Don’t do it.
Meakin, VetSurg, 2017
- Less blood loss
- Same duration
- Same complications/healing
List 2 advantages and 2 disadvantages of bipolar (vs monopolar)
- Less collateral damage
- Can be used when wet
BUT
- Cant cut
- Can adhere to surrounding tissue
List the three machanisms of injury from stray energy
- Insulation failure
- Direct coupling (metal - metal)
- Capacitive coupling (e.gg. current builds up in isolator (e.g. air)
What is thermal spread of ligasure?
And enseal?
harmonic scalpel?
1 - 3 mm Ligasure
2 mm EnSeal (only system to limit thermal spread)
0 - 1 mm Harmonic
At what vibration does harmonic scalpel funtion
55,000 vibrations/s
Cuts + coagulates simultaneously (vibration induced heat –> coaptive coagulation)
List 5 benefits of harmonic scalpel over BSVD
- Reduced smoke/vapour
- Cuts + coags at same time
- Lower temp (50-100 vs 150 - 400)
- Less thermal spread
- No char/dessication/sticking
Which device –> highest bursting pressure
And fastest sealing time
Enseal
Harmonic
What does LASER stand for
Light amplification by stimulated emission of radiation
List 4 characteristics of LASER photons
- Monochromic (same waveform)
- Spacial coherence (move parallel)
- Temporal coherence (in phase)
- Collimated (linear direction)
How does tissue penetration differ between long and short wavelength lasers
Give an example or a long wavelenght laser
And short
Long wavelength have lower tissue penetration
Long wavelenght: CO2, Ho:YAG, Erbium:YAG
Short wavelength: Nd:YAG (deepest tissue penetration!), diode
Relasers, what does YAg stand for
Yttrium - Aluminum - Garnet
What are the zones of injury from laser
- Zone of carbonization
- Zone of vapourization
- Zone of coagulation (all necrotic)
- Zone of hyperthermia
N.B. Burn wound zones are
- Zone of coagulation (necrotic)
- Zone of stasis (viable, can repair with support or may necrose)
- Zone of hyperaemia (viable)
List three modes of LASER tissue injury
- Photothermal
- Photochemical
- Photomechanical
What is wavelenght of CO2 laser
and Ho:YAG
CO2 10,600 nm
Ho:YAG 2100 nm
How does CO2 laser cut tissue
Intracellular water heated –> vaporization –> cell lysis
Name a specific feature of Er:YAG laser
Absorbed by hydroxyapatite so good for cutting bone
Which laser has deepest tissue penetration?
What is its wavelenght
Nd:YAG
1064 nm wavelenght
List 3 safety concerns re lasers
- Ocular damage
- Toxic smoke production
- Fire hazerd
- Mutagenesis
- Adverse effect on neighbouring tissues due to energy disipation
What are Halsted’s principles (7!)
- Gentle tissue handling
- Meticulous haemostasis
- Preservation of blood supply
- Accurate tissue apposition
- Obliteration of dead space
- Minimal tension
- Strict aseptic technique
$ scalpel motions
Slicing
Pressing
Sawing
Scraping
The forces by scissors
- Closing
- Shearing
- Torque
What instruent use accounts for most instrument related wasted surgical time
Inefficient needle holder use
List 4 needle holder grips
- Thumb-ringfinger
- Thenar (quick for simple continuous)
- Palmed (most powerful)
- Pencil (for v delicate)

What 3 sutures can be used in Si
simple interrupted
simple cont
modified gambee

What suture pattern is this?

Modified gambee
N.B. compare to vertical mattress
What continuous suture patterns are inverting.
How do they differ from one another
Cushing, connell, lembert
- Cushing and Connell take bites parallel with wound.
- Cushing and Lembert partial thickness

What suture pattern is this

Lembert
N.B. Compare with vertical mattress

What is relative knot security of monofilament absorbable
(relative knot security = knot holding capacity in % of tensile strength of suture)
67%
i.e. knot = weakest part
What is the definition of knot pullout strength?
And just “knot strenght”
Knot pullout strength: Load required to break suture deformed by a knot (deformation from knot usually –> 10 - 40% loss of strenght)
Knot strength: Force necessary to cause knot to slip
What is suture pull out value (wight required to pull suture loop from tissue) of following tissues
- Fat
- Muscle
- Skin
- Fascia
- Fat 0.2 kg
- Muscle 1.2 kg
- Skin 1.8 kg
- Fascia 3.8 kg
What are the netric sized of
4/0
3/0
2/0
0
1
4/0 –> 1.5
3/0 –> 2
2/0 –> 3
0 –> 3.5
1 –> 4
What are the two mechanisms of suture absorbtion?
Hydrolysis and enzymatic
(Synthetic ones absorbed by hydrolysis)
Which suture types lose strngth more rapidly in alkaline
vs acidic environment?
Which suture type is resistant to degradation regardless of pH
Alkaline: Sutures with glycolide componend i.e. polyglecaperone 25 (Monocryl) and polyglyconate (Maxon)
Acidic: Those with dioxanone component i.e pds
Polypropylene resistant
At what time do following sutures reach 50% strength?
And how long to be absorbed?
- Vicryl
- Monocryl
- PDS
- Vicryl: 50% strength at 2-3 weeks, absorbed 56 - 70d
- Monocryl: 50% strenght at 1-2 weeks, absorbed by 119d
- PDS: 50% strength at 5-6 weeks, absorbed by 180
N.B catgut (chromic or not, has 0% strength at 2 weeks and had unpredicatble absorbtion rate)
Where does silk come from
Bombyx mori silk worm
What is absorbability of silk
Considered ‘non-absorbable’ but lost 56% strength after 12 weeks and gone after 2 years
(by hydrolysis)
High tissue reactivity
What suture has highest break point
Polypropylene
List unique feature of polypropylene
V resistant to breakdown as doesnt have any hydrolysable bonds
V strong
What is the purpose of the low carbon in 316 L SS
Less carbon –> less corrosion
What is difference between woven and knitted mesh?
Woven is stronger and stiffer, but less porous
i.e. knitted more flexible and porous (porous desireable for collagen in-growth
What is recommended mesh overlap amount in areas of high tension?
And if not high tension
Overlap mesh 1 cm with native tissue if high tension
Otherwise overlap 0.6cm
List 4 principles of vacular clip application
- Skeletonize vessel
- Clip artery and vein separately
- Vessel size 33-66% of clip size
- Apply clip several mm from cut edge
What size do the following staples close to?
- 8mm (green)
- 5mm (blue)
- 5mm (white)
- 4.8mm (green) –> 2.0mm
- 3.5mm (blue) –> 1.5mm
- 2.5mm (white) –> 1.0mm
