11. Regional Anesthesia and Epidurals Flashcards
what stage of the pain pathway does regional anesthesia block?
transmission
why use regional anesthesia?
reduces amount of drugs needed and thus their side effects post before and after anesthesia
topical or surface anesthesia?
- larynx to avoid spasm during intubation
- splash block (open wound, or before closing)
- corneal (for eye exam, proparacaine, don’t use regular lidocaine, its acid)
EMLA cream
- type of topical anesthetic for venipucture or small mass removal
- long onset of action, and only lasts 30 minutes
Line block
- local anesthetic over incision line, some surgeons don’t like the swelling it causes
- desensitizes linea alba
- used for c-sections to avoid opiods
local infiltration
infection of local anesthetic into or around planned surgical field, NOT A SPECIFIC NERVE
- line block
- intratesticular block for castration
- ring block (extremity, tail, dehorning) HUGE volume of anesthetic
Epidural anesthesia target?
spinal nerves before exiting
limits of the epidural space?
vs. spinal anesthesia?
- **interarcuate ligament and dura mater
vs. spinal anesthesia is in subarachnoid space (in CSF)
lumbo sacral space used in small animals why?
spinal cord ends before then, no risk of hitting it, only would hit dural sac (end of subarachnoid space, its small, but possible to hit)
landmarks for epidural?
- iliac crest
- medial sacral crest (spinal process of sacrum)
- spinous process of L7
You don’t feel most of the structures the epidural needle pierces (supraspinous ligament,interspinous ligament) but you can feel piercing the _______
interarcuate ligament (the roof of the epidural space)
some say ‘2 pops’ = interspinous and interarcuate ligaments
tuohy needle is curved to ?
push the dura down instead of piercing it, can feel each tissue as you pierce it
hanging drop technique
advance needle until percieved interarcuate ligament. fill hub of needle with saline. when needle enters epidural space the drop should be* aspirated!! Can be a false negative.
Loss of resistance technique
- advance needle, attach syringe, apply pressure to plunger and advance needle thru interarcuate ligament.
- RESISTANCE DROPS suddenly in epidural space
drugs in epidural?
- local anesthetic
- low concentration bupivicaine can cause sensory block without motor blockade - opioids
- morphine, fentanyl
- analgesia without motor blockade