spinals and epidurals Flashcards
what is the advantage of a pencil point needle?
better feel, less trauma
the stylet prevents the introduction of dermal cells, but can lead to ____ ____ ____ ____
dermoid spinal cord tumor
what are the absolute contraindications to spinal?
patient refusal, lack of cooperation, uncorrected coagulopathies, infection at the site of block, increased ICP, indeterminate neurological disease
what three factors affect distribution?
barcity, position, dose
what factors affect uptake and spread from subarachnoid space?
concentration of LA in CSF, surface area of nerve tissue exposed, lipid content of nerve tissue, blood flow to nerve tissue
drugs in dextrose are hypo iso or hyperbaric?
hyper
T/F Physiologic changes with a spinal include venodilation and arterial dilation
true
sympathectomy is dependent on block ____
height
physiologic changes related to a spinal and the GI system come from sympathetic innervation at what levels?
T6-L2
GI effects of spinal = ____ secretions, sphincters ___ and bowel ____
increased secretions, sphincters relax, bowel constricts
the iliac crest which spinal level?
L4-L5
if you contact bone while doing a spinal what should you do
withdraw needle and stylet to skin and redirect. [moving introducer inside can cut and tough ligaments wont allow the needle to move well inside]
which approach is good for calcified intraspinous ligament or difficult positioning
paramedian
paramedian approach - angle the needle ___ and ____
medially and cephalad
what are some causes of neurologic injury
needle introduction to nerve or cord, spinal cord ischemia, bacterial contamination, hematoma
what causes caudal equina syndrome
microcatheters, 5% lido, repeated dosing
what are causes of arachnoiditis?
infection, myelograms from oil based dyes, blood, neuro irritant, surgical interventions, intrathecal steroids, trauma
what are the causes of meningitis?
bacterial or aseptic, use strict sterile technique
PDPH has up to a ___% incidence
25
PDPH is worse when head __, relief when ____
up, supine
PDPH may take up to ___ weeks to resolve
1-6
epidural blood patch is 1st effective in up to ___% OB and __% non-OB.
2nd effective up to ___%
90
what are risk factors for spinal hematoma?
anticoagulation, increased age, female, hx of GI bleed, length of therapy
epidurals - can use adult levels after age __
8
vasomotor tone is controlled by __-___
T5-L1
[decreased venous return, subsequent decreased CO]
where are cardiac sympathetic fibers?
T1-T4
[profound hypotension and bradycardia]
respiratory arrest with an epidural is usually due to?
sympathectomy and brain and brainstem ischemia
what is the key factor affecting spread for an epidural?
volume
lumbar gets more spread ____ than ____
cephalad than caudal
how to dose epidurals :
<5’2 use?
>5’2 use?
<5’2 use 1ml per level
>5’2 increase by 0.1ml for each 2 inches
why do you decrease the dose for pregnancy and obesity?
epidural vein engorgement and increased adipose tissue
the hanging drop technique is most commonly used for ____ epidurals
thoracic
for a caudal block, the sacral ____ is ID’d by the sacral ___
hiatus, cornu
for a caudal block, insert the needle at ___ degree angle, and a distinct pop or snap is felt when through _____
45
sacrococcygeal membrane
what is the test dose for an epidural
3ml of 1.5% lido with 15mcg epi
what should you do if you have a unilateral block?
pull catheter back, unaffected side down, redose, replace
what should you do if you have an inadequate block?
raise head and redose with higher concentration. add fentanyl or give 50mcg
what should you do if the epidural is questionable and you need to go to the OR
in OR remove catheter, do CSE with new catheter placement
what should you do with a dissipating block? (requires more or doesn’t last)
check for intravascular placement, rebels with higher concentration and increase rate, add opiod.
what happens if you inject epidural into the SA space?
fast high spinal
what happens if you give an epidural dose subdural?
delayed response 10-15min. get ready for high spinal
what are the s/s for meningitis
non-positional headache, fever, lethargy, confusion, and classic nuchal rigidity
what’s the tx for meningitis?
emergent abx therapy, head CT, LP, neuro consult
what condition is thought to be from adherence of tissue pulling?
arachnoiditis
how far in advance do aspirin and NSAID’s have to be d/c’d
they dont
how far in advance does plavix need to be d/c’d?
7 days
how far in advance does warfarin have to be d/c’d?
4-5 days
apex says 5
you want the INR to be
1.5
for IV heparin: delay until __h after block, remove catheter ___-___h after last dose
1, 2-4
LMWH (ardeparin, dalteparin, enoxaparin, tinzaparin, danaparoid) PRE-OP guidelines?
block 10-12h after last dose; high dose delay 24h.
LMWH post-op guidelines
once daily dose: 6-8h post op, remove catheter 10-12hr after last dose and wait 2h until next dose
herbal drugs = d/c ___ days before surgery
5-7
order the 5 ligaments form skin to sc
surpaspinous, interspinous, ligamentum falvum, posterior longitudinal, anterior longitudinal
T/F With both the midline and paramedian approach, the needle should NEVER pass thru the anterior or posterior longitudinal ligaments
TRUE
T/F Inadvertent injection of LA into the subdural space will cause a high spinal if using epidural dosing or a failed spinal if using spinal dosing.
TRUE
(APEX) LA in the epidural space must first diffuse thru the ___ before they can block the nerve roots
dural cuff
(APEX) in the subarachnoid space, the primary site of LA action is on the _____
myelinated pre-ganglionic fibers of the spinal nerve roots.
(APEX) what are the factors that significantly affect spread for a spinal
baricity, patient position before/after, dose, site of injection, volume of CSF, density of CSF
(APEX) T/F The factors that do not significantly affect spread of a spinal include barbotage, increased intrabdominal pressure, speed of injection, orientation of bevel, addition of vasoconstrictor, weight, gender.
TRUE
(APEX) T/F Apnea after a spinal is usually the result of phrenic nerve paralysis or high concentrations of LA in the CSF?
FALSE. It is usually the result of cerebral hypo perfusion.
(APEX) Spinal affect on GI system: inhibition of sympathetic outflow causes sphincters to ___ and ____ peristalsis
relax, peristalsis
T/F in the setting of a spinal, as long as SBO is maintained, hepatic and renal blood flow and function are unchanged.
TRUE.
(APEX) whats the deal with MS and neuraxials?
epidural anesthesia is safe but intrathecal technique may exacerbate symptoms
a ____ solution will sink, a ____ solution will rise
hyperbaric sinks, hypobaric rises
dextrose ___ baricity, water ___ baricity
increase, reduce
(APEX) procaine 10% in water is an exception.. is it hyper, hypo, or isobaric?
hyperbaric
which 2 needs are cutting tips
quincke and pitkin
which 4 needles are non-cutting
pencil points = sprotte, whitacre, pencan.
rounded bevel tips = greene
T/F the pencil point tips require less force.
false they actually require more force.
which needle type is more easily deflected/
cutting tip (quincke, pitkin)
(APEX) what two things about the tuohy needle minimize the risk of dural puncture?
30 degree curvature and blunt tip
T/F you should never withdraw the epidural catheter thru the needle
TRUE. this can shear the catheter leaving fragments inside the patient.
(APEX) what factors increase the risk of caudal equina syndrome
5% lido and spinal micro catheters
