Surgical Procedures Flashcards
What is meant by the term infection?
The invasion and multiplication of pathogens
What is meant by the term asepsis?
the absence of pathogens
What is meant by the term antiseptic?
A substance that stops or slows down the growth of
microorganisms. Applied to the body
What is meant by the term disinfectant?
A substance that stops or slows down the growth of
microorganisms. Applied to nonliving surfaces.
What is meant by the term sterilisation?
Elimination of all forms of life and other biological agents
What is meant an aseptic technique?
Procedures to prevent contamination with pathogens
What is meant by the term antisepsis?
Practice of using antiseptics to reduce risk of infection
What is meant by a sterile technique?
What two factors help reduce post-operative complications?
Hygiene and asepsis in combinaton with good surgical techniques helps to reduce post- operative complications.
Give six examples of good surgical techniques
- Asepsis
- Gentle tissue handling
- Minimal dissection of tissue
- Appropriate use of instruments
- Correct use of suture and correct pattern
- Effective hemostasis (mechanism that leads to cessation of bleeding from a blood vessel.)
Give five possible sources of contamination
- Surgery room
- The surgeon
- Instruments
- The animal
- Other materials and solutions
Give three possible ways to prevent contamination from the surgery room
- Clean the room
- Disinfect work surfaces
- Flow cabinet
Give three possible sources of contamination from the animal
Breath
Fur
Feces
Give three ways to prevent contamination from the animal
- Remove hair from incision site
- Treat skin with antiseptic
- Cover residual hair
In what manner should you shave the hair?
Only shave around the ROI and not at the surgical table; shaven hair can be a source of infection
What options are there for antiseptics?
Ethanol, Chlorhexidine, Iodine
What possible sources of contamination are there from the surgeon?
Hair
Breath
Skin
How can you prevent contamination from the surgeon?
- Sterile gloves
- Clean labcoat
- Hairnet
- Surgery mask
Behaviourally, how can infection occur from breathing?
Can be hovering over animal focused not attending breathing; don’t turn away for sneeze, can come out sides of mask
What sources of contamination are there from your instruments
Cleanliness
Storage
How can you prevent contamination from the instruments?
- Sterilize your instruments: autoclave before every surgery, germinator can even be used during surgery
- Store them clean
What other materials could be sources of contamination ?
ANY material you use could be
a source of contamination e.g:
pads
needles
solutions
sutures
How can you prevent contamination from these materials?
- Buy sterile packaged
- Autoclave
Give five steps that should be involved in your pre-operative preparation
● Checklist equipment and necessities
● Assess animal health status
● Pre-emptive analgesia
● Hair removal
● Animal positioning
What is meant by pre-emptive analgesia?
Have analgesia ready to use before the start of surgery so you can immediately when necessary.
Why is animal positioning important?
Position the animal in a certain way so you don’t have to re-adjust during the surgery.
Give two methods of anaesthesia administration
Inhalation
Injection
Compare the two methods of anaesthesia administration in terms of induction
Inhalation: Quick induction
Injection: Slower induction
Compare the two methods of anaesthesia administration in terms of recovery
Inhalation: Quick wake-up and recovery
Injection: Slower wake up and recovery
Compare the two methods of anaesthesia administration in terms of accuracy of dosage
Inhalation: Easy to change depth of the anesthesia- quick response to adjusting depth, can moniter heart, lung activity and adjust accordingly e.g tail clamp can be used to measure oxygenation of blood
Injection: Less accurate dosage; Once it’s in the system, you can’t take it out; have to be very careful about overdose.
Is inhalation or injection of anaesthesia better for longer surgeries?
Inhalation; due to flexibility of dosing over time, injection is less accurate for longer procedures
What is a benefit of injection of anaesthesia?
Animal does not have to be intubated and is therefore movable
Is inhalation suitable for very short procedures?
Yes
What is commonly used as an inhaled anaesthesia?
Isoflurane
What inhalation method can be used for long surgeries ad why would in be used?
Artifical ventilation via intubation or trachea cannulation. This can be used for long surgery in order to maintain physiological parameters. Instrument depicted shows animal upright with tube going down mouth.
What are the surgical instruments used dependent on? (3)
- Animal species
- Incision size
- Macro- or microsurgery
What advice did Gerjan give regarding surgical instruments? (2)
There is an infinite amount of instruments available; Recommends going through these tools and think about what they’re appropriate for e.g what animalk what size
Make sure instruments are still sharp before each surgery.
Give two things to think about when making an incision
Really think about where you make the incision: what kind of tissue you may encounter, will it cause a bleed.
Give six type of scissor tools with separate functions
Regular surgical scissors
Precision scissors
Iris scissors
Bulldog clamp
Tweezors
Needle holder
What is the most occurring complication in any surgery?
Bleeding
Why is it important to minimise/ control bleeding during surgery? (5)
Bloodloss:
- Creates an ideal environment for bacterial growth.
- Leads to poor recovery and stress.
- Increases recovery time.
- Increases the chances of death.
- May introduce research variables.
Why is tissue type important when making an incision?
Some tissue types bleed more than others: Highly vasculated tissues bleed more than tissues that are less vasculated.
Muscle tissue is very vasculated and can cause a lot of bleeding; should be avoided! Connective tissue is less vasculated.
Give 5 ways to minimise bloodloss
- Dissect along tissue planes
- Do not cut across muscle when possible
- Identfy, isolate and retract large vessels
- Know the anatomy
- Apply good hemostasis technique
Name 4 hemostasis methods
Direct pressure
(electro) Cautery
hemostatic products
ligation enzymes
When may a bulldog clamp be used?
Bulldog clamp can be used to close large blood vessels
Give an example of a hemostatic product
Haemostatic tissue can stop bleeding.
Give four examples of invasive techniques
- Ectomies
- Implantations
- Perfusion
- Steriotactical procedures
What is meant by an ectomy?
Removal of (part of) an organ
Why may an ectomy be carried out?
e.g for a specific animal model
Give two examples of ectomies in the endocrine system and why they are carried out
– Hypophysectomy (surgical removal of the pituitary gland), study growth hormone
– Pancreatectomy, diabetus
Give three examples of ectomies in the immune system
Thymectomy: thymus gland
lymphadenectomy: lymph nodes
splenectomy: spleen
Give 3 examples or implantation surgery
- Tumor cells
- Slow release osmotic pump
- Recording devices
Where and why would you implant an osmotic pump?
Osmotic pump goes under skin and releases solutes & pharmaceuticals.
What function does biotelemetry serve?
Biotelemetry gives the option to
take long term measurements in
a freely moving animal
What is carried out in biotelemetry?
Senors are implanted in the abdominal cavity
What can be measured through biotelemtry? (4)
Heart rate
blood pressure
temperature
ECG
What is the benefit of biotelemtry compared to single repeated measurements?
More stable measurements
One invasive surgery then no stress involved in non-invasive measurements over a lot of trials
What is the purpose of stereotactical procedures?
The steriotact is used to fix the head of a live animal. In this way specific brain regions can be targeted
Describe characteristics of stereotactic surgery
Head is fixed in the stereotact with a tooth, ear and nose clamp. The skull is used as a reference to target specific brain structures.
How do you determine the coordinates of a brain area during stereotactical procedures and what are they relevant to?
- Determine coordinates in an
anatomical atlas - Coordinates are relative to bregma
What is perfusion used for?
Perfusion is a method to remove the
blood from (part of) an organ
Is anaesthesia required for a perfusion
Yes, always under deep anaesthesia in a terminal experiment
What happens during or following blood removal
Blood is replaced by other fluid
(Saline or fixative)
Describe the first two steps to begin a perfusion
- Cannula is placed in the artery for fluid replacement
- The opposing vein/ atrium is punctured to release blood
What is the benefit of live imaging techniques?
Imaging techniques in live animals can be used to measure physiological parameters without sacrificing the animal
Is anaesthesia typically used for live imaging?
Yes, usually under deep general anesthesia. G.A as fixating can be stressful although it is possible to train animal but can take time and is difficult.
How can live imaging techniques apart from being used as the primary metric (2)
Used in combination with other techniques
Imaging after treatments
How are live imaging techniques helpful in cancer research?
Following tumor development
In a perfusion what organ apart from the heart can be cut to release the blood? What effect does this decision have?
Although incision to the liver can leave lower organs less well perfused; Easier and can be suitable for brain experiments.
What method us often used to treat wounds?
Suturing to restore original anatomy
Name four tools required for suturing
Needle holder
Needle
Forceps
Thread
Describe the characteristics of a needle driver/ holder
Has a blunt end to prevent tissue damage
Width of jaw provides extra surface area to firmly secure or hold the needle
Joint of the instrument is offset so that the movement arm of the jaw is quite short, this allows considerable pressure to be applied to the needle ensuring stability in the jaws while the suture is being placed.
The surface of the jaw is serrated with small triangular grooves increasing the coefficient of friction to hold the needle in place.
How should a needle holder be held?
Thumb and ring finger in handle, fingers should not be inserted beyond the distal interphalangeal join. This allows you to disengage you finger and thumb easily if necessary. The index finger can be placed close to the joint of the needle driver which allows better control of the tip. The tip should be placed a third up the needle and should be pushed away from you.
Name five variable characteristics of needles
- Curve
- Traumatic or Atraumatic
- Separate or attached thread
- Size
- Point style
What does choice of traumatic/ atraumatic depend on and what is most often used in practice?
Depends on what kind of tissue; traumatic: causes more damage but has higher penetrative power or atraumatic: causes less damage but less penetrative power, in practice often atraumatic
What are the main options with point style?
Triangular cutting point
round point
trocar point
What does point style depend on?
Round point causes less damage
Tough tissue may require a triangular point which requires less force
Trocar point is halfway.
There are many types of threads with different properties but what are the two main types?
Absorbable: absorbtion
starts after about two weeks
Non-absorbable
Give two examples of absorbable thread types
vicryl, dexon
Give three types of non-absorbable thread types
silk
nylon
stainless steel
When are the two thread types typically used?
Absorbable: used in long term experiments
Non-absorbable: used in short term experiments or when the thread can be removed manually
What is meant by the terms monofil and polyfil?
- Monofil → made by one fibre
- Polyfil → plainted by several fibers
Give four main stitch types
(Do own research to learn different stitch types, there are plenty)
Interrupted stitch: knotted following each suture
Continuous stitch: criss crossed continually and knotted at the end
U-stitch eversion: two sutures are done and knotted together in u shape and knotted together with thread going across wound going under skin
U stitch inverson: two sutures are done and knotted together in u shape and knotted together with thread going across wound going over skin
What is the benefit of absorbable stitches?
Absorbable will be naturally dissolved by the body, don’t have to anaesthetise the animal again to remove the thread.
What is the benefit of non-absorbable stitches?
Non-absorbable holds it better and causes less inflammation
What are the benefits & drawbacks of monofilament threads?
+
- Penetrates the tissue smoothly
- Less tendency to colonise microbes - elastic, more flexible
- the knot is easily untied
- greater memory (the ability to return to its original shape after deformation.)– after the end of the fibre is cut, it sticks out and irritates the surroundings.
What are the benefits & drawbacks of polyfilament threads?
+
- easier to handle
- The knots hold better, they do not loosen and the ends do not stick out after the fiber is cut (suitable for skin eyelashes)
-
- There is capillarity, which allows infection to penetrate into the wound (on the other hand, this fiber can also be used as a capillary drain) - scrubbing during tissue penetration (this can be reduced by coating with a synthetic material - e.g. coated Vicryl).
What can determine whether monofil or polyfil is used?
Tissue type:
- Polyfil is more irritating but with knots the fat layer adheres and is more secure, important for tissue which moves a lot.
- More delicate tissue may require monofil to reduce damage and also for internal sutures
Discomfort/ stability
- Monofil itself may be more comfortable for the animal
- Usually in animal research you want to be sure it survives scratching and a polyfill may be used.
Compare the interrupted vs continuous stitch in terms of their benefits
Can adjust tension in continuous stitch to ensure even tension: you have to be good at applying tension for interrupted stitch as you cannot go back and more difficult to apply even tension.
If continuous stitch however if it becomes undone, it all becomes undone.
What is the benefit of the U stitch?
U stitch has more even tension and therefore is more resistant to strain.
What is the most common knot used when finishing a suture?
Surgeons knot: essentially just repeated square knots
What is a common mistake when tying the suture?
Tying a slipknot which comes loose very easily. It is important to remember to keep the needle driver in the middle when tying the knot, otherwise a slip knot may accidentally be carried out.
Where should the knot be tied?
Tying knot at side if suture is good common practice, and better if knot is close to suture.
When pulling to close the knot, how should this be done?
Pull over away from wound at end, not both directions like shoelaces.
Give four important aspects of post-op care
- Prevent hypothermia:
- Make sure the animal does not get dehydrated
- Pain relief
- Make sure the animals can reach their food and water
How is hypothermia typically avoided?
Keeping the animal warm using a heating mat
How is dehydration typically avoided?
Warm saline is often injected subcutaneously to prevent this
How is pain typically treated?
Give appropriate analgesics; can add antibiotics or pain relief to saline or water.
What can additionally be done to aid animals injestion?
Might want to wet the food initially to make ingestion and digestion easier.
Why should weight be monitored following surgery?
Animal weight may reach a certain point and they have to be sacrificed, under 10% of body weight indicates extra help may be needed.
What should be inspected daily following surgery?
Weight loss
Dehydration
Biting/scratching
Infection
Signs of pain/discomfort
What would biting/ scratching be indicative of?
Infection
What may be signs of discomfort?
Bulging in posture and squinting eyes are signs of illness or discomfort, typically do not show signs of discomfort as this can signal weakness to a predator so this is something to take seriously
Give three scenarios where you might want to restrain an animal
Administrate drugs
Inspect a wound (healing/infection)
Ear punch or identify the animal
Give four restraining methods
Neck scruff
Camilla’s method
Restraining shoulders
Mechanical restrainer
Describe how to neck scruff a rat
Place the rat on your arm
Hold the tail
Place your hand on the back of the rat
Gently push the rat to your arm to elongate the body
Grab the skin of the neck and back
Describe how to neck scruff a mouse
Place the mouse on a stable surface
Hold the tail
Gently push the mouse down with your other hand
Grab the skin of the neck and back
Describe Camilla’s restraining method
Place the rat on a towel or other cloth
Wrap the upperbody of the rat in the towel
Hold the rat in place by holding the shoulders
Describe how to do a shoulder restraint
- Place the rat on your arm
- Hold the tail
- Place your hand around the upper body
- Place your thumb and middle finger over the shoulders and fore paws
- Place your index finger in the neck
Describe how to restrain using a mechanical restrainer
Let the mouse or rat walk trough the cylinder a couple of times before closing it
Let the animal get used to being locked up by increasing the duration every time
Without any training the cylinder restraint causes a lot of stress
How is the mechanical restrainer used aside from restraining?
This method is used in stress related research to induce stress
