Epidurals Flashcards
where does epidural work?
ant and post nerve roots & dorsal ganglia, and to a lesser extent ant/post rootlets and the spinal cord itself
distance from skin to epidural space?
typically 4-6cm, can be 2-9 though so be careful
what to do if you think epidural catheter is intravascular? (blood doesnt clear)
must remove catheter, try again one interspace higher
what happens to epidural veins in preganancy?
become engorged, they are more lateral than midline in teh epidural space
what size is tuohy needle?
18g
who is more likely to get PDPH?
young people
epidural catheter size?
19 or 20 guague
how far to thread epidural catheter into epidural space?
3-5cm
typicall epidural volume vs spinal volume?
epidural: 10-20cc
spinal: 1-2cc
how much LA do you give in epidural to acheive the level you want?
give 1-2cc per segment blocked.
which direction does the LA go in the epidural space?
both caudad and cephalad
when is epidural dosing decreased?
elderly, obese, pregnancy
physically how do you administer epidural meds?
give 3-5cc, wait 3-5min, give 3-5cc, wiat 3-5min, repeat until full dose given
how long does chloroprocaine last?
50-70min
how long does prilocaine last?
90-130min
how long does lidocaine last?
90-150
how long does mepivicaine last?
120-160
how long does bupivicaine last?
200-260
very important things to prepare for when give spinal or epidural?
airway mgmt and hypotension
what is usually the largest interspace?
L2-L3
where does epidural needle feel more secure and less flimsey?
in the interspinous ligament / ligamentum flavum, it will also feel more anchorded at this point. This is where you take out the stylet and connect saline/air filled syringe
what do each of your hands do when performing an epidural?
non dominant: controls how much the needle is advanced
dominant hand: check syringe for loss of resistance
what might you hit right before the epidural space?
the crunchies
what must you do every time before you inject anything in epidural space?
aspirate! look for blood and CSF
what is a test dose?
used to make sure you are not in an epidural vein. looking for HR to increaes 10-20bpm. Dont do during a contraction obviously
if epidural is actually intrathecal, what movemement might the patient have a hard time with?
gas pedal
medication doses for a test dose?
3ml of 1.5% Lidocaine (45ml) with 1:200,000 epi
what might patieint feel if the test dose lidocaine is given in the intrathecal space?
may feel legs getting warm and heavy. stop injecting!
totoal time for dosing and set up of an epidural?
20-30min
what level is sacral hiatus?
S4
in what pt population is the caudal epidural used?
pediatrics
how to do a caudal block?
ID sacral hiatus, and sacral cornu which is 2: above the coccyx.
use 22g short beveled needle at 45 degrees to the skin. you will feel pop or loss of resistance getting through the tough ligament. drop needle angle, adavance a couple cm and inject the drug
how long does it take to get a good caudal block?
15min
what surgeries are caudal blocks good for?
perineal surgeries
used in peds with GA
good for adults in perineal/rectal surgeries
peds caudal epidural dosing?
0.5-1ml/segment
what dermatome level needed for upper abd surgery?
T4
what dermatome level needed for intestinal, gynecologic, and urologic?
T6
what dermatome level needed for TURP?
T10
what dermatome level needed for vaginal delivery or hip surgery?
T10
what dermatome level needed for thigh surgery or lower leg amputation?
L1
dermatome needed for foot and ankle surgery?
L2
dermatome needed for perineal or anal surgery?
S2-S5 (saddle block)
bupivicane concentration?
0.0625%-0.5%
bupivicaine onset?
15-20min
onset of 2 cholorprocaine?
5-15min
onset of lidocaine?
10-20min
onset of ropivicane, bupivicane, and levobupivicane?
15-20min
what must you do if using depodur 15mg ER?
must do a test dose and flush with NS before using depodur.
also meant to be used alone without LA
Fentanly dose onset and doa?
50-100mcg
onset 5-10min
doa 2-6hr
morphine dose onset and doa?
3-5mg (duramorph 5mg-10cc)
onset 30min
doa 12-24hr
where do we want epidural opioids to end up?
get to the substania gelatinosa on spinal cord after getting through the dural cuff
why might you need higher opiod doses in epidurals?
because of the epidural fat, lipphilic drugs may be sequestered there
2 techniques for combined spinal/epdiural?
dural puncture epdidural technique
needle through needle technique
how far would you advance catheter into intrathecal space?
2-3cm
how much fluid does spinal catheter hold?
0.25ml
what was cauda equina syndrome related to?
microcatheters and hyperbaric lidocaine
why is PDPH less with spinal catheter?
creates inflammation thought to plug the hole
how to trouble shoot one sided block?
withdraw catheter one cm, put unaffected side in down position and re-dose
what may be happening if getting parathesia with epidural placement?
could be in a root and not midline. if consistent parathesia pull out and start again
where is an open ligamentum flavum most often seen?
between L1-L2
what body response can make PDPH worse?
dilation of intracranila vessels to compensate for lost space
S/S PDPH?
N/V, headache, feeling miserable, diplopia, photosensitive, extreme headache when sitting up
when does PDPH prsent?
within 1-2 days, but can take up to 5 days
how quickly will PDPH resolve without any tx?
usually 5-7days
how to treat PDPH?
conservative first, bedrest, prone position, abd binder, IV fluids 3L/day
caffeine sodium benzoate IV vasoconstrictor
how does international calssification of headache disorders define PDPH?
onset within 15min of moving to the supine position with at least 1 of the following symptoms:
headache, neck stiffness, tinnitus, photophobia or nausea
differential dx for PDPH?
migraine, HTN, subarachnoid hemorrhage, meningitis, lactation headache, pneumocephalus (has postural component), brain tumor, sinusitis
If caffeine and conservative measures for PDPH fail what do you do?
epidural blood patch
how do you do an epidural blood patch?
aseptically draw up 10-20ml pt blood
inject blood into epidural space 1 level lower than original puncture.
need to inject 10-20cc, but 15 is optimum.
common complaints with epidural blood patch?
pressure, back ache, hip fullness
how effective our epidural blood patches?
get rid of 85-90% of PDPH on first try
when can you repeat epidural blood patch?
in 24hours
another symptom you may see with epidural blood patch?
bradycardia
relative contraindications for epidural?
spinal pathology
chronic headahce/backaches
atempts failed after 3x
epidural contraindications?
1 pt refusall, or uncooperative pt
infection or derm issues
spetic shock
high rapid blood loss case
severe hypotension/hypvolemia
increase ICP
clotting issue
severe AS or mitral stenosis (cant tolerate drop in BP)
