Non-survival surgeries

Non-survival surgery


Anesthesia:

  • Animal anesthetized with ketamine injection

    • Once down, inject with Atropine and Dexamethasone

    • *all doses can be found in drug chart found in controlled substances cabinet, should prep drugs in morning before beginning surgery

  • Shave animal

    • Shave head, base of tail, and side

  • Place isoflurane mask on animal, with gas level set to 2

  • Place clips on toes and connect heart monitor

  • Place temp probe in animal

    • First tape base of tail, then insert probe, then tape again around both tail and probe


Vitals:

  • Temperature probe:

    • Heating pad is IR feedback, optimal animal temperature is 37 degrees

  • Gas levels:

    • During surgery, NO:O ratio should be set 2:1

      • (NO will be set to 0.8L, O will be set to 400mL on gas panel, units are different)

    • During imaging this ratio will be adjusted to 1:1

    • Isoflurane levels set to 2

      • Once heart rate stabilizes around 250-300, can adjust isoflurane levels to 1.5

  • CO2 levels:

    • Can be read on monitor under table

      • Top number: level of CO2, bottom number: pump rate (respiration rate

    • Target range: 25-30 (use chart on table to easily convert to % of CO2 to be recorded in record)

      • If CO2 level too high, then increase pump rate slightly

  • Be sure to record HR, respiration rate (read on CO2 monitor, does not need to be counted), Isoflurane level, CO2 level, body temp


IP tube insertion:

  • Fill 10 mL syringe with 5% dextrose in Ringer’s soln (use 18G needle to retrieve from bag found in fridge)

  • Place syringe in pump machine, set machine to desired flow rate (find flow rate on chart above counter near sink)

  • Cut long piece of IP tubing (must be long enough for stereotax to be moved under scope)


  • Inserting IP tube into IP cavity of animal:

    • Flip animal onto its back, exposing its belly

    • Insert end of IP tubing into 18G needle

    • Pinch skin, then feel for the membrane layer underneath skin. Insert needle with tubing through this second layer

    • Once needle inserted into IP cavity, thread tubing into cavity and remove needle

    • Use Vetbond to glue to tubing to skin

    • Place end of IP tubing that will attach to pump in 30/31G needle, attach needle to syringe

  • Start pump

  • Take moment to watch and ensure that fluid is pumped through tube


Tracheostomy:

  • Inject 0.1 mL bupivacaine subcutaneously into throat area.

    • Wait 30 seconds

  • Make incision down midline of throat using 10 size blade

    • 3-4 cm in length

  • Carefully remove muscle tissue from around trachea using blunt tip scissors

  • Slide curved forceps under trachea

  • Make small incision (~40% of circumference of trachea) in trachea

  • Insert trachea tube

  • Immediately switch tubing to big respirator

  • Using size 0 thread, loop under trachea and make a tie around front and back of trachea, holding tube in place. I usually do this twice so you have 4 ties total to ensure that tube does not come out.

  • Using staple tool, close skin with metal staples (one in front, one in back)

    • May need three staples if a large opening was made


Place animal on stereotax:

  • Place a stack of paper towels onto stage of stereotax

  • Wrap heating pad in paper towels, tape, and place on top of stack

  • Unhook heart monitor, flip animal onto belly and carefully place on heating pad

  • Set ear bars and mouth and nose bars


Eye Sutures:

  • Using size 2 small needles and 5.0 size sutures

  • Pierce needle through upper eye lid, thread suture through leaving plenty of excess

  • Do the same for bottom eye lid


Head Incision:

  • Inject 0.1 mL bupivacaine subcutaneously to midline of scalp

  • Make incision down midline of scalp

  • Remove muscle tissue using spatula (slide spatula underneath muscle, push down and away from midline)

  • Use 18G needle to thread through skin and muscle of head, pull to side and tape out of way


Craniotomy:

  • Mark V1 using chart on wall, make craniotomy


Animal is now ready for mapping and electrode insertion


Prior to starting recordings, switch out syringe delivering Ringers + Dextrose and start Gallamine administration. Doses for Gallamine are found in chart on wall.


Euthanize animal:

  • Inject 1 mL of Euthasol into belly of animal

  • Wait 10-30 min for heart rate to slow

  • CO2 machine alarm will sound, press “audio” in order to stop sound

  • When heart rate has drastically slowed, turn off CO2 machine, unhook animal from probes and place in black bag

    • You may either dispose of animal in freezer now, or perfuse animal and then dispose