Chapters 13, 15, 16, 17 FROM NOTES ONLY Flashcards

1
Q

What is recommended size of OR

And if fluoro etc?

A

37m2 (400 ft2)

56m2 (600 ft2)

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2
Q

What are recommended OR settings for

Ventilation

Humidity

Temp

A
  • 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

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3
Q

What is antiseptic/disinfectant MoA of:

Alcohols

Povodine-iodine

Chlorhex

A
  • Alcohols: Protein denaturation, lysis, metabolic interruption
  • Povodine-iodine: Free iodine oxidation/substitution –> protein denaturation
  • Chlorhex: Cell membrane disruption
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4
Q

What is gene that confers chlorhex resistance to Staph aureus

A

qacA/B

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5
Q

What % solution chlorhex is used for skin prep?

And in wound

A

4% for skin

0.05% in wound

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6
Q

What 3 factors are associated with increased glove perf

A
  • Non dominant hand
  • Non-ST procedure
  • Sx > 60 mins
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7
Q

What is rate of perf when single gloved/

A

Single gloved:

  • 13 - 31%

Double gloved:

  • 11 - 44% outer glove
  • 4 - 13% inner glove
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8
Q

How does waveform (current) of cutting vs coagulating electrocautery differ

A

Cutting waveform continuous, 100% of time

Coag waveform is intermittent, only 6% of time

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9
Q

For what % of time is cutting coag waveform (i.e. current) ‘active’?

And for coag

A

100% for cutting

6% for coag

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10
Q

What effect does electrosurgery have on tissues at following temperatures?

40ºC

50ºC

70ºC

90ºC

100ºC

250ºC

A

40ºC –> inflammation + oedema

50ºC –> enzyme deactivated

70ºC –> protein denaturation

90ºC –> dessication

100ºC –> vapourization + cell rupture

250ºC –> carbonization

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11
Q

Name three contact types for coagulative electrocautery

A
  • 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
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12
Q

On what size vessel can monopolar cautery be used?

And enseal/ligasure?

Harmonic scalpel?

Co2 laser?

A

Monopolar ≤2mm

Enseal/Ligasure ≤7mm

Harmonic scalpel <3mm

CO2 laser <0.6mm

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13
Q

What is conculsion re using monopolar cautery for skin?

(Scott, VetSurg, 2017)

(Meakin, VetSurg, 2017)

A

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
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14
Q

List 2 advantages and 2 disadvantages of bipolar (vs monopolar)

A
  • Less collateral damage
  • Can be used when wet

BUT

  • Cant cut
  • Can adhere to surrounding tissue
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15
Q

List the three machanisms of injury from stray energy

A
  • Insulation failure
  • Direct coupling (metal - metal)
  • Capacitive coupling (e.gg. current builds up in isolator (e.g. air)
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16
Q

What is thermal spread of ligasure?

And enseal?

harmonic scalpel?

A

1 - 3 mm Ligasure

2 mm EnSeal (only system to limit thermal spread)

0 - 1 mm Harmonic

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17
Q

At what vibration does harmonic scalpel funtion

A

55,000 vibrations/s

Cuts + coagulates simultaneously (vibration induced heat –> coaptive coagulation)

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18
Q

List 5 benefits of harmonic scalpel over BSVD

A
  • Reduced smoke/vapour
  • Cuts + coags at same time
  • Lower temp (50-100 vs 150 - 400)
  • Less thermal spread
  • No char/dessication/sticking
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19
Q

Which device –> highest bursting pressure

And fastest sealing time

A

Enseal

Harmonic

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20
Q

What does LASER stand for

A

Light amplification by stimulated emission of radiation

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21
Q

List 4 characteristics of LASER photons

A
  • Monochromic (same waveform)
  • Spacial coherence (move parallel)
  • Temporal coherence (in phase)
  • Collimated (linear direction)
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22
Q

How does tissue penetration differ between long and short wavelength lasers

Give an example or a long wavelenght laser

And short

A

Long wavelength have lower tissue penetration

Long wavelenght: CO2, Ho:YAG, Erbium:YAG

Short wavelength: Nd:YAG (deepest tissue penetration!), diode

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23
Q

Relasers, what does YAg stand for

A

Yttrium - Aluminum - Garnet

24
Q

What are the zones of injury from laser

A
  • 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)
25
Q

List three modes of LASER tissue injury

A
  • Photothermal
  • Photochemical
  • Photomechanical
26
Q

What is wavelenght of CO2 laser

and Ho:YAG

A

CO2 10,600 nm

Ho:YAG 2100 nm

27
Q

How does CO2 laser cut tissue

A

Intracellular water heated –> vaporization –> cell lysis

28
Q

Name a specific feature of Er:YAG laser

A

Absorbed by hydroxyapatite so good for cutting bone

29
Q

Which laser has deepest tissue penetration?

What is its wavelenght

A

Nd:YAG

1064 nm wavelenght

30
Q

List 3 safety concerns re lasers

A
  • Ocular damage
  • Toxic smoke production
  • Fire hazerd
  • Mutagenesis
  • Adverse effect on neighbouring tissues due to energy disipation
31
Q

What are Halsted’s principles (7!)

A
  1. Gentle tissue handling
  2. Meticulous haemostasis
  3. Preservation of blood supply
  4. Accurate tissue apposition
  5. Obliteration of dead space
  6. Minimal tension
  7. Strict aseptic technique
32
Q

$ scalpel motions

A

Slicing

Pressing

Sawing

Scraping

33
Q

The forces by scissors

A
  • Closing
  • Shearing
  • Torque
34
Q

What instruent use accounts for most instrument related wasted surgical time

A

Inefficient needle holder use

35
Q

List 4 needle holder grips

A
  • Thumb-ringfinger
  • Thenar (quick for simple continuous)
  • Palmed (most powerful)
  • Pencil (for v delicate)
36
Q

What 3 sutures can be used in Si

A

simple interrupted

simple cont

modified gambee

37
Q

What suture pattern is this?

A

Modified gambee

N.B. compare to vertical mattress

38
Q

What continuous suture patterns are inverting.

How do they differ from one another

A

Cushing, connell, lembert

  • Cushing and Connell take bites parallel with wound.
  • Cushing and Lembert partial thickness
39
Q

What suture pattern is this

A

Lembert

N.B. Compare with vertical mattress

40
Q

What is relative knot security of monofilament absorbable

(relative knot security = knot holding capacity in % of tensile strength of suture)

A

67%

i.e. knot = weakest part

41
Q

What is the definition of knot pullout strength?

And just “knot strenght”

A

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

42
Q

What is suture pull out value (wight required to pull suture loop from tissue) of following tissues

  • Fat
  • Muscle
  • Skin
  • Fascia
A
  • Fat 0.2 kg
  • Muscle 1.2 kg
  • Skin 1.8 kg
  • Fascia 3.8 kg
43
Q

What are the netric sized of

4/0

3/0

2/0

0

1

A

4/0 –> 1.5

3/0 –> 2

2/0 –> 3

0 –> 3.5

1 –> 4

44
Q

What are the two mechanisms of suture absorbtion?

A

Hydrolysis and enzymatic

(Synthetic ones absorbed by hydrolysis)

45
Q

Which suture types lose strngth more rapidly in alkaline

vs acidic environment?

Which suture type is resistant to degradation regardless of pH

A

Alkaline: Sutures with glycolide componend i.e. polyglecaperone 25 (Monocryl) and polyglyconate (Maxon)

Acidic: Those with dioxanone component i.e pds

Polypropylene resistant

46
Q

At what time do following sutures reach 50% strength?

And how long to be absorbed?

  • Vicryl
  • Monocryl
  • PDS
A
  • 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)

47
Q

Where does silk come from

A

Bombyx mori silk worm

48
Q

What is absorbability of silk

A

Considered ‘non-absorbable’ but lost 56% strength after 12 weeks and gone after 2 years

(by hydrolysis)

High tissue reactivity

49
Q

What suture has highest break point

A

Polypropylene

50
Q

List unique feature of polypropylene

A

V resistant to breakdown as doesnt have any hydrolysable bonds

V strong

51
Q

What is the purpose of the low carbon in 316 L SS

A

Less carbon –> less corrosion

52
Q

What is difference between woven and knitted mesh?

A

Woven is stronger and stiffer, but less porous

i.e. knitted more flexible and porous (porous desireable for collagen in-growth

53
Q

What is recommended mesh overlap amount in areas of high tension?

And if not high tension

A

Overlap mesh 1 cm with native tissue if high tension

Otherwise overlap 0.6cm

54
Q

List 4 principles of vacular clip application

A
  • Skeletonize vessel
  • Clip artery and vein separately
  • Vessel size 33-66% of clip size
  • Apply clip several mm from cut edge
55
Q

What size do the following staples close to?

  1. 8mm (green)
  2. 5mm (blue)
  3. 5mm (white)
A
  • 4.8mm (green) –> 2.0mm
  • 3.5mm (blue) –> 1.5mm
  • 2.5mm (white) –> 1.0mm