centroneuraxial Flashcards
how many vertebrae in thoracic
12
how many vertebrae in cervical
7
how many vertebrae in lumbar
5
how many vertebrae in sacral
5
how many vertebrae in coccygeal
4
what are the high points?
L3-L4
what are the low points
T4
the spinal cord extends to __ in the adult and __ in the newborn
L1 adult
L3 newborn
the lateral approach DOES NOT pass through which two structures?
supraspinous and interspinous ligaments
the spinal cord is enlarged in two sections, one is called the cervical enlargement but actually forms the Brachial plexus (from __ to __), the other is the lumbosacral enlargement forms the lumbosacral plexus (from __ to __)
brachial plexus C5-T1
lumbosacral L2-S3
name the three meninges from outside in
dura
arachnoid
pia
dap
the distance from the skin to epidural space using a midline approach is __ to __ cm, with an average of 5 cm
2.5 - 8 cm
a 3.5” epidural needle is 8.9 cm long
the principal site of action for neuraxial block is the __
nerve root
scoliosis is a __ curvature
lateral
kyphosis is a __ curvature
excessive posterior
“hump” in thoracic region
lordosis is __ of the back due to obesity or pregancy
hollowing
what level for a c-section?
T4
belly button is at level
T10
inguinal is at level __
T12
what is the first fiber type to be blocked? what is its function? how big? myelinated? conduction velocity? sensitivity?
B, autonomic, to blockages.
what is the second fiber type to be blocked? what is its function? how big? myelinated? conduction velocity? sensitivity?
type C, pain, 0.4-12 microns, NO myelin, 0.5-2.3 m/s, ++++ sensitive
If I was on Hep “C” precautions “secondary” to a needle stick, even if it only penetrated 0.4-12 microns, I could have “NO” sex for 1/2 to 2.3 years and would have “++++” pain.
what is the third fiber type to be blocked? what is its function? how big? myelinated? conduction velocity? sensitivity?
type A, many functions, 2-20 microns, heavy myelin, 12-120 m/s, increasing sensitivity.
Three type A people I know do almost everything from age 2-20, even lifting heavy weights 12-120 pounds with increasing sensitivity
type A alpha
proprioception, motor
type A beta
touch, pressure
type A gamma
muscle spindles
type A delta
pain, temp
how to remember the type A fibers in order
I knew the car was motoring too fast, so I first touched then put pressure on the brakes, then muscled it as much as I could, but I crashed and now have a lot of pain and a fever.
what happens when you block B fibers?
venodilation and hypotension
your Blood pressure drops when you block your B fibers
what happens when you block your C and A-delta fibers?
loss of pain and temp
remember, if I get a needlestick and am on Hep C precautions, or if I wreck my car, it’s going to be very painful and my temp will go up
what happens when you block type A-gamma fibers
loss of muscle
remember, you’re muscling the brakes as much as you can to prevent a crash
what happens when you block type A-beta fibers
touch and pressure
remember, you first touch then apply pressure to the brake
what happens when you block type A-alpha fibers
loss of motor and proprioception
you “knew” the car was “motoring” too fast
where are your cardiac accelerator fibers?
T1-T4
profound bradycardia
Motor block occurs __ segments __ than sensory block
2-3 segments LOWER
sympathetic block occurs __ segments __ than sensory block
2-6 segments HIGHER
INR 1.2-1.5 = __
NO GO!!
Aspirin and NSAIDs
not a problem
heparin
need normal PTT, can heparinize 1 hour post catheter removal
coumadin
need INR less than 1.5 to perform or remove
report new lower limb weakness, sensory deficit, bladder/bowel dsfxn, back pain
IMMEDIATELY
need surgical decompression of hematoma!
most common complication?
second most common complication?
Backache 1
headache 2
etiology of post dural puncture headache
decreased CSF drops brain into foramen magnum, stretches meninges and vessels on top, leading to HA
treatment for PDPH as evidenced by bilateral FRONTAL pain from eyes posterior to occiput then caudad down neck
caffeine, fluids, bed rest, NSAIDs, epidural blood patch, DON’T LET THEM GO HOME!!
how to prevent PDPH
smallest pencil point needle, bevel sideways, straight in, avoid young or females, don’t dull needle on bone, use weak anesthetic, preferably tetra over bup
where would you give an epidural blood patch?
one level LOWer because blood will spread rostrally (cephalad)
tell me about the intercristal line
the plane across the top of the iliac crests, usually intersects L4-L5
taylor’s approach- _ cm medial and _ cm caudad to posterior superior iliac spine, angle medially and cephalad 55* toward L5 interspace
1
1
how much CSF do adults make each day?
500 ml
normal CSF pressure
10-20 cmH2O
how much CSF in the subarachnoid space, central canal, and brain at any given time?
how much in spinal canal only?
140 ml
30-80 ml
spec grav of CSF
1.004-1.009
HYPERbaric solutions have a spec grav __ than CSF and will thus sink to the lowest point
greater than
HYPObaric solutions have a spec grav __ than CSF and thus float or rise to the top
lower
how to make a HYPERbaric solution- dissolve in __, makes a baricity > 1
dextrose
how to make a HYPObaric solution- dissolve in __ water, makes a baricity < 1
sterile
how to make an isobaric solution
dissolve in CSF or NS
Highly protein bound drugs such as __ and __ last longer than those that aren’t like lidocaine
tetra and marcaine
distribution of local anesthetic in CSF is influenced by 4 things
baricity
concentration
position
contour
BeCause Position Counts
dysfunction of bowel or bladder, think
cauda equina
severe back pain think
transient neurological symptoms
n/v occurs due to unopposed parasympathetic activity and __
hyperperistalsis
