Principles of surgery Flashcards
What are Halsted’s principles and what are their purpose?
Lay out guidelines to optimise the outcomes of surgery.
1) handle tissues gently
2) be meticulous in controlling haemorrhage
3) Preserve blood supply to tissues
4) Observe strict aseptic technique
5) Ensure tissues are accurately apposed
6) Obliterate dead space
What is dead space?
Space remaining in tissues as a result of failure of proper closure of surgical or other wounds, permitting accumulation of blood or serum.
What are heavy + blunt ended scissors, fine vascular scissors, serrated dissecting forceps, and toothed dissecting forceps used for?
blunt - for blunt dissection and cutting sutures
fine vascular - for dissection of fine/delicate tissue, serrated and toothed are for grasping tissue
What are haemostats and retractors?
Haemostats - clamp blood vessels to stop bleeding
Retractors - retract tissues and allow the surgeon to visualise structures
What are some methods to ensure aseptic technique?
wear appropriate scrubs, clip the fur of the animal and disinfect with appropriate antiseptic, clean instruments and suture materials, autoclave swabs and drapes, have a room solely for procedures
How long should you wash your hands for when preparing for surgery
At least 5 minutes
What size innoculum is enough for infection to be established?
105/g
How to decrease risks of post-operative infection
Use animals that are young/healthy
Create small surgical incisions.
Short duration of surgery
What is the “no touch” technique?
The instrument tips come into contact with the animal, and the tips are re-sterilised between each animal to avoid breaks in aseptic technique
What technique may be used to sterilise instruments during batch surgery?
Hot bead steriliser
Can you re-sterilise scalpel blades?
No, as this will result in the blade becoming more blunt
When may it be appropriate to undertake surgery in a general-purpose lab?
If the procedure is non-recovery
What are the components for aseptic surgery?
Areas for surgical support
Animal preparation
Preparation of the surgical team
Operating
Post-operative recovery
What components of a surgery ROOM for aseptic surgery should be present?
Positive pressure (effective ventilation), surgical lighting (cold light source), adjustable height surgical table, patient warming, preparation area, post-op recovery area
What are the main ways of physical (thermal) sterilisation?
Thermal energy:
Wet heat: boiling water is considered disinfection rather than sterilisation, and this is not suitable for rubber.
Steam sterilisation: autoclave
Dry heat: hot air ovens sterilise things that cannot be exposed to moisture. Hot bead steriliser is useful for batch surgery involving rodents - tips of instruments are placed in a heated beaker of plastic beads at 250C for 10-15 seconds.
What is cold chemical sterilisation and what solution is usually used for chemical sterilisation?
Ethylene oxide
Involves soaking instruments in disinfectant solutions over a long period of time (doesn’t kill spores and viruses)
Why is haemorrhage a problem during surgery?
It obscures the surgical field
May cause shock/death
Provides a medium for bacterial growth
Forms haematomas in dead space, inhibiting proper healing and further increasing risk of infection
How can bleeding be controlled during surgery (3)?
Pressure - through a moistened gauze swab for at least 2 mins, a clot should seal the hole.
Electrocautery - uses electrical current to seal the vessel
Ligatures - metal clips can be used for clamping blood vessels, or absorbable sutures can be used
What are the definitions of clean wound, clean contaminated, contaminated, and dirty?
clean - no infection
clean contaminated - a minor break in aseptic technique or a minor hollow organ is opened
contaminated - extremely rarely, where gross spillage from a hollow organ or a major break in aseptic technique has occurred
dirty - should not be encountered
What are the different types of wound closure?
Primary closure - closing the wound with a minimum of granulation tissue
delayed primary closure - closed several days after the wound occurs because it is too contaminated to close at first
Secondary closure: leaving the wound open for several days until a granulation bed is established
What are round-bodied needles used for?
To separate tissue fibres rather than cut them, and are either used for soft tissue (fat) or muscle
What are characteristics of suture materials?
Easy to handle
Promotes rapid healing
Holds the wound together and has high tensile strength
Non-irritant
Describe how to place a suture
Use needle holders to position needle perpendicular to the long axis of the holders, in the middle third of the needle, nearer the eye than the tip
Use forceps to stabilise the tissue
Drive needle through in a single rotating motion
Pull the suture through the wound and tie the knot
What is the theory of knot tying (principles) and what are the main suture patterns?
Use the simplest knot to provide the security required
Do not over-tighten knots
Do not use any crushing instruments (haemostats)
Keep the ends of the suture as short as possible
Interrupted stitch (horizontal mattress)
Continuous stitch (subcuticular pattern
Which stitch should be used on the muscle layer?
Interrupted suture pattern
How far apart should clips be placed, and what is a disadvantage of them?
8-10 mm, should be removed 8-days after
Potential for over-tightening
