Regional- Spinal (subarachnoid) Neural Blockade Flashcards
what is the front of the spinal cord called?
Anterior
Ventral
what is the back of the spinal cord called
Posterior
Dorsal
what is the area where the spinal nerves exit called
Facet joint
cervical nerves exit where?
above the vertebrae
all other nerves exit where?
below the vertebrae
what is the 1st and 2nd cervical vertebrae
- Atlas
- Axis
Remember “t” comes before “x”
In a supine pt where are the high points of the spine
C3
L3

In the supine pt where are the low spots of the spine
T6
S2

the spinal cord extends from the ____ _____ to the Lumbar level ___ in the adult and ____ in the newborn
Foramen Magnum
L1 (adult)
L3 (newborn)
by what age should the newborns Spinal cord be at the adult level
2 yo
the cord terminates where?
conus medullaris
how many cervical vertebrae are there?
7
how many thoracic vertebrae are there?
12
how many lumbar vertebrae are there?
5
how many sacral vertebrae are there?
5
how many coccygeal vertebrae are there?
4
how many pairs of spinal nerves are there
31
where is the spinal cord the wideest
L2
where is the spinal cord the narrowest
C5
what is the nerve group in the lower dural sac L1- S5 termed
Cauda Equiuna (horses Tail)
what is the area between S4 and S5 termed and what do we use it for?
Sacral Hiatus
Caudal Block
is a caudal block grouped as a spinal or epidural?
Epidural
what is total CSF volume
100-150ml (go with 150mL)
how much CSF is in the subarachnoid
25-30mL (1/5)
How much CSF is produced daily?
500mL
what is normal CSF pressure?
10-20 cmH20
what are the layers of the spinal meninges form outer to inner?
Dura matter
Arachnoid matter
Pia matter
what 2 things absorb CSF
arachnoid villi
arachnoid granuloma
the subarachnoid space lies where?
between the arachnoid and pia matter
the principle site of actin for neuraxial blockade is where
the nerve root
where is CSF found
the subarachnoid space (b/t the arachnoid matter and pia matter)
the sacral coccygeal membrane is an extension of what?
ligamentum flavum
pic of the layers of the meninges

vasoconstrictors prolong duration of spinal block how? who’s law?
decreased absorption
ficks law
what are 10 factors that effect the distribution of the drug in a spinal
- Site
- Anatomical shape of spinal column
- Height
- Angilation of needle
- Volume of CSF
- LA (dnesity/specific gravity/baracity)
- Dose
- Volume
- Position of pt during injection
- position of pt after injection
so volume of CSF affects the distribution of spinal anesthesia.. what happens to speed with inccreased CSF? and Decreased CSF
Increased CSF = Decreased speed
Decreased CSF= Increased speed
what is the specific gravity of CSF
1.004 - 1.009
think of james bond 007 (and your in the middle)
SG of CSF is 1.004-1.009
what is isobaric?
Hyperbaric?
Hypobaric?
Iso- SG = CSF SG
Hyper SG > CSF SG (follows gravity)
Hypo SG
what % of the bodies blood is in the venous side? arterial side?
75% venous
25% arterial
with a spinal you get venodilation… what does that do to preload?
decreases it
although sympathetic preganglionic neurons send signals to smooth muscles of both arteries and veins, the predomiant action of sympathetic blockade d/t LA is what?
Venodilation
if the sympathetic outflow from T1- T4 is blocked by LA, unapposed vagus stimulation will produce what? and what is this reflex termed?
bradycardia
Bainbridge reflex
the best means for treating hypotension during spinal anesthesia is what
physiologic not pharmacologic
AKA give fluids
if pt is normovolemic and still has hypotension what is the best pressor
ephedrine
volume for initail treatment of hypotension is from balanced salt solutions that do NOT contain glucose. administer volume in increments of how much?
5 mL/kg
why would you not want to replace volume with glucose in the hypovolemic hypotensive pt
glucose is a diuretic and can worsen the hypovolemia
if apnea occurs with a high spinal it is often d/t hypoperfusion of the repiratory centers in the medulla secondary to severe hypotension. what should u do?
treat the pressure and usually it will fix it self
what are the 3 groups with the least reserve and at the highest risk for hemodynamic compromise with regional anesthesia?
peds
elderly
Very sick
what are 3 symptoms of cauda equina syndrome?
lower extremity weakness
bowel and bladder dysfunction
what are the 2 cutting needles used
QuinKe BadcocK
PitKin
“k” for th C sound in Cutting
Picture of cutting needles

what are 3 non cutting needles for spinals
Greene
whitacre
sprotte
(Pecan also used not shown here)
picture of NON cutting

how should you inseert the needle with a cutting needle
Turn tip paralle to fibers
never caudal or cephalad
how long should a pt be off ASA before getting a spinal
no need to be off ASA for spinal!
Pts receiving heparin IV before sx should not receive spinal untill what?
normal aPTT documented
when using a spinal and intraop heparin will be used . how long post spinal should u wait until you should give heparin
1 hour
what is the magical number for INR with coumadin therapy to either place a spinal or remove a catheter?
pts receiving fibrinolytics or thrombolytic drug therapy should not receive neuraxial for how many days
10 days
Anterior dermatome: name landmark
C4
clavicle
Anterior dermatome: name landmark
T4-T5
Nipples
Anterior dermatome: name landmark
T6 (to T8)
Xiphoid
Anterior dermatome: name landmark
T8
Lower border of rib cage
Anterior dermatome: name landmark
T10
Umbilicus
Anterior dermatome: name landmark
L1
inguinal ligament
Anterior dermatome: name landmark
L2-L3
Knee and below
Anterior dermatome: name landmark
S2-S5
Perineal
Posterior dermatome: name landmark
C7
most prominant cerivial spinous process
Posterior dermatome: name landmark
T7
inferior boarder of scapula (lower tip)
Posterior dermatome: name landmark
L4
Iliac crest (superior)
Tuffier’s line
Intercristal line
Posterior dermatome: name landmark
S2
Posterior superior iliac spine
Name Indications for spinal anesthesia
- Full stomach
- Anatomic distortions of upper airway
- TURP
- OB
- Decreased Post op pain
- Continuous infusion
Name some ABSOLUTE contraindications to spinal
- Infection at site of injection
- Patient Refusal
- Severe Aortic stenosis
- Dematologic conditions
- Shock or severe hypovolemia
- Increased ICP
- Blood clotting abnormalites
name all the structures the needle passes through for a Subarachnoid block (midline) from posterior to interior
- Skin
- subcutaneous tissue
- SupraSpinous Ligament
- Intraspinous ligament
- Ligamentum Flavum
- (epidural space)- not a real space
- Dura matter
- arachnoid matter
the lateral approach for a SA block will not pass through what 2 structures just listed for the midline approach?
Supraspinous ligament
intraspinous ligament
how many vertebraes does the spinal column have
33
what is the purpose of the stylet in the spinal needle
gives structure
does NOT allow tracking of cells from skin into CSF
what is the most common complication of Spinal
back ache
what is the 2nd most common complication of spinal
headache
whendoes the spinal headache usually set up
12-72 hours later
what are some of the risk factors for spinal headache
Large needles
Cutting needles
Female
Young
OB
Bevel perpendicular
Complications w/ spinal: infection
what are some predisposing factors to infectio
advanced age
DM
Alcoholism
Cancer
AIDS
Complications w/ spinal: infection
what are the classic signs of infection
High fever
nuchal rigidity
Severe Headache
Complications w/ spinal: infection
what does the s/s of infection from spinal resemble
Meningitis
Complications w/ spinal: infection
what is the most common causative organism
staphylococcus aureus
Complications w/ spinal: infection
with a PDPH why do you get diplopia
d/t traction on cranial nerves
what are s/s of PDPH
- nausea (loss of appetite)
- Photophobia
- Changes in auditory acuity
- tinnitus
- Depression
- “feel miserable”
- tearful
- bed-ridden
- diplopia
- cranial nerve palsies
what causes a PDPH
decreased amount of CSF in SA space, causes medulla and brainstem to drop into the foramen magnum, stretching the menengies, vessels, and nerves
what is a fix for PDPH
Blood patch
what comfirms PDPH versus all other potential diagnosis
the postural element
what is conservative therapy for PDPH?
Caffeine (cerebral vasoconstriction)
Lying flat
Hydration