30. Spinal Anesthesia Flashcards
cervical vertebrae
7
thoracic
12
lumbar
5
sacrum
5
coccyx
4
spinal tissue encounter order
skin
supraspinous
interspinal
ligamentum flavum
dura matter
subarachnoid space
adult spinal cord end
L1-2
peds spinal cord end
L2-3
what does the dural sheath innervate
bladder
GU
conus medullaris
end of spinal cord
cauda equina
nerve fibers extending caudally from spinal cord
filum terminale
fibrous tissue that connects conus medullaris to periosteum of coccyx
faster blockade
smaller
myelinated
proximity to injection
easiest to hardest to block
autonomic>sensory>motor
spinal can be the primary anesthetic for which cases
lower abdominal
inguinal
urogenital
rectal
lower extremity
spinal: absolute CI
infection
lack of consent
coagulopathy
severe hypovolemia
incr ICP
aortic/mitral stenosis
sepsis
warfarin: neuraxial
normal PT/INR
or
discontinue for 1 wk
rivaroxaban: neuraxial
discontinue 72 hrs prior
apixaban: neuraxial
discontinue 72 hrs prior
NSAIDS: neuraxial
no need to delay
clopidogrel: neuraxial
discontinue 5-7 days prior
clopidogrel AKA
plavix
anticoags
warfarin
rivaroxaban
apixaban
anticoags
NSAIDS
clopidogrel
low-dose SC heparin: neuraxial
delay 4-6 hrs after 5000 units
systemic heparin: neuraxial
delay 4-6 hrs and correct PTT
wait 1 hr after neuraxial event to admin
low dose LMWH: neuraxial
delay 12 hrs from admin
high dose LMWH: neuraxial
delay 24 hrs from admin
when would lateral positioning for a spinal be beneficial?
hip fractures
spinal kit
spinal needle
3mL syringe w/18ga needle
5mL syringe
18g introducer
25g skin local needle
filter tube or needle
0.75% hyperbaric bupivacaine
lidocaine
needle holder
sterile drape
sterila paper towel
iodine w/sponges
gauze
***epi
cutting needle
better for calcified ligaments
pencil point
better tactility
less incidence of PDPH
standard spinal needle size
25g 3.5”
a longer needle means
longer time for CSF to return
tuffiers line
body of L4
sometimes L4-L5 interspace
what should you mark on spinal pt
superior aspect of inferior spinous process
inferior aspect of superior spinous process
what do you use to localize in spinal
25g needle
3mL syringe
1% lidocaine
where should you insert needle for spinal
inferior aspect of the interspaceq
os
bone
os shallow
midline but need to redirect cephalad
os deep
off midline
heme
blood
what happens when you pass through the dura
pop
barbotage
CSF swirl when you aspirate CSF into local
barbotage only occurs with
hyperbaric medication
what can happen if you inject air into spinal
pnemocephalis
paramedian spinal indications
severe arthritis
kyphoscoliosis
previous spinal surgery
thoracic epidural placement
how do you insert needle for paramedian spinal
15 degrees to midline
most dependent part of spine
T4
most non-dependent part of spine
L2-L4
does the spine have dependent parts when pt is laying in lateral decubitus?
no
which block is preferrential for sacral nerves
saddle block
what type of solution is used for saddle block
hyperbaric
what influences spread of local anesthetic
baricity
pt position
orifice orientation
medication temp
faster injection
pt height
CSF volume
higher medication temp
more spread
faster injection
more spread
taller patient
less spread
decr CSF volume
more spread
what causes decreased CSF volume?
gravid uterus
ascites
tumor
engorged epidural veins
kyphosis/lordosis
advanced age (**intrinsic)
how long after injection of spinal does spread stop?
20-25 mins
sympathetic blockade travels the most
cephalad
sensory blockade is
2 levels caudal to sympathetic level
motor blockade is
2 levels caudal to sensory level
sympathetic blockade is tested by
temperature
sensory blockade is tested by
pain
light touch
T4
nipples
T10
umbilicus
typical surgeries that require spinal
C section
lower limb
TURP
surgery:
esophagus
lung
upper abdomen
block up to T1
C section
block up to T4
lower abdominal surgery
block up to T6
lower limb surgery
block up to L1-2
cardiac accelerator fibers
T1-T4
lumbar spinal will result in sympa or parasympa flow
uninhibited parasympathetic flow
spinal SE: CV
hypotension
- N/V
- dizzy
- dyspnea
variable HR
spinal CV: treatment
fluids
direct alpha antagonist
beta-antagonist
what pts dont tolerate fluid well
poor pulmonary status
ESRD
CHF
spinal SE: respiratory
decr coughing
minimize respiratory complications from spinal
proper positioning
supportive airway measures
what should you check if pt says they cant breathe?
SpO2 - 100%
hand squeeze
alert/oriented
spinal GI SE
peristaltic/contracted gut
decr hepatic BF
spinal GU SE
renal BF mx’d
urinary retention
spinal endocrine SE
neuroendocrine stress response
what causes neuroendocrine stress response
somatic and visceral afferents
what happens during neuroendocrine stress response
release of ACTH, corisol, epi, NE
activates RAAS
spinal complications
high neural block
cardiac arrest
urinary retention
meningitis/arachnoiditis
TNS
neurologic injury
pruritis
shivering
high spinal symptoms
unconsciousness
apnea
hypotension
total spinal
high spinal
cranial nerve blockade
seizures
treatment
supportive measures
ABC
typical pts who go into cardiac arrest during spinal
young
healthy
cardiac arrest spinal presentation
bradycardia
bradyarrythmias
hypotension
spinal cardiac arrest treatment
HR correction
BP correction
– fix preload/afterload
what causes urinary retention
afferent muscle block of sacral nerves inhibits bladder constriction
what makes urinary retention worse
narcotics
what treats urinary retention post-spinal
time
bethanechol (muscarinic)
prazosin (a1 blocker)
catheter
what pts are at a higher risk of meningitis/arachnoiditis
epidural or spinal catheters
TNS aka
transient radicular irritation
TNS symptoms
back pain radiating to legs w/o sensory or motor deificit
primary cause of TNS
hyperbaric lidocaine spinal
what % of pts get pruirius with a spinal
> 30% of pts who get neuraxial opioids
treatment for pruritius
naloxone
naltrexone
ondansatron
diphenhydramine
what % of pts get shivering?
55%
is shivering more prevalent in spinals or epidurals?
epidurals due to larger volume of injectate
what reduces shivering
neuraxial opioids
active warming
Spinal benefits compared to general
decr resp complications
decr cardiac complications
less PONV
earlier ambulation
decr DVT
lower infection
better analgesia
faster GI function recovery
cheaper
