Epidural Anesthesia Flashcards
Does epidural or spinal anesthesia offer better control of the extent of motor and sensory blockade?
epidural
Distinct difference between epidural and spinal anesthesia?
epidural allows for continuous administration of anesthesia secondary to placement of a catheter
How do LA or analgesics injected in to the epidural space spread horizontally?
spread to the regions of the dural cuff, where it is able to diffuse in to the CSF and leak in to the intravertebral foramen and paravertebral spaces to achieve analgesia/anesthesia
How does epidural medication spread longitudinally?
cephalaud
Why do you have to use larger volumes of medication with epidurals than with spinals, and how much is the usual volume?
because the medication is diffusion dependent; 20 mL, spinals 1-2 mL
For an epidural where is the LA injected?
epidural space
How is the onset of an epidural in comparison to a spinal?
slower and not as dense
What do the arachnoid villi and granulations on the dural cuffs of the sleeves do?
reduce the thickness of the dura mater, which permits rapid diffusion of anesthetics from the epidural space thru the dura and into the CSF
What property of the anesthetics may account for differences in diffusion rates across the dura?
lipid solubility
Why/how does epidural anesthesia take longer to act?
medication be delivered to the subarachnoid space by the process of diffusion and spread
This type of anesthesia is useful for procedures of unpredictable duration, prolonged post op analgesia, and chronic pain control?
epidural
Only anesthesia available to relieve labor pain and minimally effect baby/maternal physiology?
epidural
What type of block is an epidural (ie sensory or motor)?
sensory w out motor block
What can you dilute the LA with in epidural?
opioid
5 indications for epidural?
longer lower dermatome surgery, postop analgesia, labor analgesia, pain treatment, combo techniques
Where does needle go in spinal versus epidural?
spinal: practitioner seeks CSF by piercing the dura; epidural: tip of epidural needle seeks fat filled space deep to ligamentum flavum and shallow to the dura
Typically, an epidural catheter is what size in comparison to the needle?
2 gauges smaller than the needle
What are the uniport and multiport epidural catheters?
uniport: single holed, open ended; multiport: lateral holed, closed tip
Studies show a significantly lower incidence of inadequate analgesia and higher incidence of inadvertent IV cannulation with what epidural catheters?
multiport
Manufacturers recommend that epidural catheter should be threaded how many cm into the epidural space?
3-5
Not threading catheter far enough in to the epidural space can cause? And threading it too far can cause?
inadequate analgesia; IV cannulation
The standard epidural needle is what size and how long?
16-18 g and 3 inches long
The blunted bevel and gentle curve of the epidural needle allow for what?
allow passage thru the skin and ligamentum flavum and abut against the dura, rather than penetrate thru the dura
Two most common epidural needles?
Tuohy and Hustead