The human spine consists of how many vertebrae; 33 (7
cervical, 12 thoracic, 5 lumbar, 5 fused sacral, 4 fused coxxygeal)
Which end of the LA is the lipophilic side; benzene ring
Which end of the LA I the hydrophilic side; amine end
The chain of the LA connecting the benzene ring and the
amine determines whether the LA is; an ester or an amide
Ester LA have more; adverse rxns
The vertebrae serve to; protect the spinal cord, support and
transmit body weight
Who discovered LA; augustus Bier – 1898, cocaine
What is the level of the larynx in an adult; C3-4
The vertebrae unit consists of what; the body, 2 pedicles,
paired laminae, transverse process, spinous process
Where does the conus medularis end; L1-L2
What level is the cauda equine; L1-S5
The vertebrae’s transverse processes are created by; joining
of the pedicles and laminae
The posterior spinous process is formed by; the fusion of
the laminae
Why is the lumbar area the safest site for introducing a
spinal needle; provides the largest aperture (space btwn processes) and least
neural tissue
The cervical and thoracic vertebrae have spinous processes
that angle acutely in a; caudad direction
In the lumbar region, the vertebrae are larger and the
spinous processes become; shorter and broader
The vertebral bodies are separated by a ; fibrocartilaginous
intervertebral disc
Transverse processes on both sides of the pedicles allows
for; muscular attachments and control of movement
The spaces between the foramen are called ____ and provide;
intervertebral foramina provide safe passage for spinal nerves
The articular surfaces of the facet joints are covered by;
hyaline cartilage which permits a gliding motion between vertebrae
Facet joints are innervated by branches from; closely
associated spinal nerves
When facet joints become injured…;the associated spinal
nerves may also be affected leading to pain along dermatomes or muscle spasm
The sacrum is tightly wedged btwn ; 2 iliac crests
The lamina of the last sacral vertebrae is; incomplete and
bridged only by ligaments..known as sacral hiatus
Coccyx become fused at age; 25-30 yrs
Are there any pedicles or spinous processes on coccyx?; no
The sacrum contains 2 sacral cornu (bony protuberances)
which; protect the sacral hiatus
Where can you do a spinal on the pediatric population?;
sacral hiatus à
causal anesthesia
There are more than ___ pairs of muscles and ligaments in
the back; 35
What are the 3 ligaments in the back; supraspinous ligament,
interspinous ligament, ligamentum flavum (yellow)
Which ligament in the back is pain felt; ligamentum flavum
The supraspinous ligament is a strong cordlike ligament
that; connects the apices of the spinous processes
The supraspinous ligament is thick and serves as a major
ligament in the; cervical and upper thoracic regions
The supraspinous ligament consists of ___ layers; 3
The interspinous ligament is ____ in the lumbar area; thin
The ________ is the strongest of the posterior ligaments;
ligamentum flava
Describe the ligamenta flava; paired, flat, thicker in the
lumbar area than cervical area bc responsible for maintenance of upright
posture
Ligamenta flava color comes from; high content of elastic
tissue
Spinal cord extends from ; medulla oblongata to L2
Spinal cord tapers to; conus medullaris
Where is the spinal cord in newborns; spinal cord is lower
in newborns (L3) and pulled up as child ages
The spinal cord is enveloped by the same 3 membranes that
line the cranium called; meninges
What are meninges; nonnervous support tissue that provide
protective covering from foramen magnum to base of cauda equine
Meninge layers are; dura mater, arachnoid mater and pia
mater
Pop during spinal is associated with entering the; arachnoid
mater
Which layer is in direct contact with the outer surface of
the spinal cord
As the roots exit the canal via the intervertebral foramina
the dura blends into the root at a junction called; dural cuff or root sleeve
The epidural space is a _______space and is continuous from;
potential space continuous from base of cranium to the base of the sacral
sulcus
The epidural space contains; veins, fat, lymphatics,
segmental arteries, nerve roots
Fat in the epidural space is; physiolgicaly fluid acting as
a pad and lubricant for the movement of neural structures within the canal
The distance to the epidural space varies with____ and is
loosely correlated with______; vertebral level – correlated with patient weight
The distance from the skin to the lumbar epidural space
using midline approach varies from; 2.5 to 8 cm – average of 5 cm
The epidural space is abundant with ______that are located
in the lateral portion of the epidural space; epidural veins
Epidural veins are_____veins that drain blood from SC and
linings of cord; valveless
When are you likely to hit an epidural vein; if you stray
away from midline while performing an epidural
In __________ pts, the epidural veins becomes engorged or
swollen d/t ; pregnant women or obese pts d/t incr intraabdominal pressure
causing venous congestion
___ curves to the normal spine; 4
In scoliosis, the most common abnormal curve is; lateral
curvature of spine (right or left)
Kyphosis is; an excessive posterior curvature or hump in
thoracic region
Lordosis is; an abnormal anterior convexity of the spine as
result of obesity or pregnancy as body attempts to restore center of gravity
What are absolute CI to regional; patient refusal,
coagulation deficiencies, infection at site
What is a relative CI to regional; patient age – neonates benefit
from regional d/t impairment of ventilator regulation
What level are the cardiac accelerators; T1-T4
What level is a total spinal; C3 – respiratory arrest,
hypotension
What are immediate complications of regional; hypotension,
hypoxia/hypercarbia, total sympathetic block, nausea, intravascular injection,
ineffective cough, hematoma
What are delayed complications of regional; PDPH, wet tap,
urinary retention, infection, paraplegia, persistent backache
How is a PDPH treated; blood patch (20-30 cc), propofol and
fentanyl, fluids
What are other names for spinals; intrathecal, subarachnoid
block, neuraxial anesthesia
What is the definition of spinal anesthesia; the reversible
chemical blockade of neuronal transmission produced by injection of LA into
cerebral spinal fluid contained within subarachnoid space of central neuraxis
The primary intent of spinals are to; render the patient
insensitive to surgical stimulation while producing a minimum physiologic
alteration
The temporary chemical interruption of sensory, autonomic
and motor nerve fiber transmission takes place in; anterior and posterior nerve
roots as they pass through CSF on course to periphery
Where is sympathetic block in relation to sensory and motor
block; sympathetic block is 2 levels above sensory and 4 levels above motor
What are some advantages of spinal anesthesia; ideal for
lower abdomen procedures, minimal systemic uptake and tox, less blood loss,
better on CV system, better muscle relaxation than NMBD
What are disadvantages of spinal anesthesia; undesired
physiologic results of blocking autonomic and motor nerves at level of SC
What are examples of cutting needles; Quincke 22 g
What are examples of pencil point non cutting needles;
whitacre and sprotte 24 g – needs introducer 18-20 g
All spinal needles have ______ that are removed when you
think you are in the intrathecal space; stylets
Sprotte needle is used for; those at risk for PDPH, young
women and men (<60yrs)
Sympathectomy gives rise to ______ and can be decreased by;
hypotension, giving 1 L crystalloid prior to spinal
What monitors are usually required for spinal; pulse ox and
BP – EKG usually not needed
Sitting position for spinals is good for; OB, urology, hip
and knee replacements
Lateral position for spinals is good for spread to; right or
left sided extremity
Why should the patient arch the back during a spinal; to
maximize the space btwn the spinous processes
What are the two approaches when performing a spinal;
midline and paramedical (15 deg to right or left)
The line formed between the superior aspects of the iliac
crest is called; tuffier’s line – L3-L4
Betadine releases; 1% free iodine
Parturient or urology usually requires what type of block;
saddle block (hyperbaric)
What is the grip called when you hold the spinal needle
steady while injecting LA; bromage grip
Does the paramedial approach go btwn the spinous processes?;
no
What is the taylor approach; going btwn the L5 interspace
(largest interlaminar space)
Once the LA is injected into the CSF, the distribution of
anesthetic molecules is dependent upon; chemical and physical characteristics
of soln in relation to chemical and physical characteristics of pts CSF and SA
space
Approx. ____ ml of CSF is produced by ______ each day; 500
ml by choroid plexuses of cerebral ventricles
How many cc of CSF is in the spinal canal; 30-80 ml
Density of CSF compared to water is known as ; specific
gravity
What is the SG of CSF; 1.004-1.009 – vary depending upon
variations in temp and location of fluid within SA space
The SG of CSF taken from ____ is greater than_______; lumbar
greater than ventricles in brain
Glucose and protein in the CSF d/t incr age does what to SG
of CSF; increases it
What does jaundice and liver problems do to CSF SG; decrease
What do hyperglycemia and uremia do to SG of CSF; increases –
influence distribution of LA but is beyond our control
Baricity refers to; the resting position of 2 fluids with
differing SG when fluids are mixed in the spinal canal
Hyperbaric soln has SG of; >1.015 – saddle or pudendal
blocks
Hypobaric soln has SG of; < 0.999
What are the most important factors that affect the spread
of LA in the CSF; total dose of LA, site of injection, baricity of Rx, position
of patient
What anatomic mark is T4; nipples
What anatomic mark is T6; xyphoid
What anatomic mark is T10; umbilicus
The duration of the spinal is based on; LA used and total
dose used
Which LA are highly protein bound and what does this cause;
tetracaine, bupivicaine, ropivicaine – long duration of action
What are less protein bound LA; lidocaine, mepivicaine
What does epi do to LA; prolongs duration d/t
vasoconstriction
The effect of added epi on prolongation of anesthesia is
greatest with what LA; tetracaine, less with lidocaine, minimal with bupivicaine
What opioids can be injected into a spinal; 10-25 mcg
fentanyl, 10 mcg sufenta, 250 mcg duramorph (morphine)
Increasing the total dose of spinal anesthetic will; incr
duration and affect sensory level achieved
Is duration of sensory and motor blockade for LA
predictable?; yes
Increasing dose of hyperbaric bupivacaine from 10 mg to 15 mg prolongs
duration of sensory block by; 50% and increases maximum sensory level achieved
The site of injection can be a ______ predictor of final
level of sensory anesthesia achieved; poor
For determination of sensory level achieved the medication
must become; fixed on nerve roots and spinal cord
After a spinal begin to assess ______ after repositioning
the patient; level and quality of the block
The spinal anesthesia level is generally fixed in ___ min; 5
min
How often should level be checked after spinal is fixed;
every 15 min
The degree of physiologic changes experienced during spinal
anesthesia is closely related to; extent of central nervous system exposed to
LA agent
The distribution of spinal anesthesia is most easily
measured by determining the; dermatome level of the block
What is a dermatome; a delineated area of skin innervated by
spinal cord segment
Correlating spinal nerve exits where in comparison to
vertebrae; underneath vertebrae
The primary objective of the SAB is to block the ____ fibers
located in the _____; afferent, dorsal roots
Sympathetic innervation of GI tract is from; T5-L2 via
prevertebral ganglia
Spinal does what to GIT; unopposed parasympathetic activity
causes constriction of bowel, incr peristalsis and incr shitting
Dose of lidocaine without epi in
mg/kg; 4.5 mg/kg
Dose of lido with epi in mg/kg; 7 mg/kg
Dose of bupivacaine with and without epi in mg/kg; 2.5 mg/kg
without epi, 3 mg/kg with epi
Dose of ropivicaine max; 200 mg
Dose of ropivicaine in mg/kg; no epi 5 mg/kg – no dose for
with epi
Dose of mepivicaine max in mg; 400 mg
Dose of mepivicaine in mg/kg; 7 mg/kg without epi – no dose
for with epi
Max dose of bupivacaine in mg; 175 mg without epi
By blocking the afferent fibers located in the dorsal roots,
__________ fibers also located in dorsal roots are also blocked; proprioceptive
and sympathetic fibers
Motor and sympathetic fibers are also blocked as they pass
through the _______;ventral root
Blocking of motor and sympathetic fibers allows for
profound_________; muscle relaxation and blocks tourniquet pain
The block of all fibers, regardless of size, location, and
morphology is rapid and causes a; differential block (3 types: sensory, motor,
sympathetic)
When a LA interrupts nerve transmission of autonomic nerves
but not sensory nerves or motor nerves bc of variation in susceptibility the a
__________ is said to occur; differential block
Autonomic blocks occur quickly bc of; small size of nerve
fibers
Hemodynamic effects associated with sympathectomy is;
hypotension and vasodilation
Autonomic block is d/t what fibers; B fibers
Autonomic fibers form ____ of preganglionic sympathetic
nervous system; white rami
Describe autonomic fibers; small (1-3 microns), myelinated,
easiest to block with LA
Blocking cardioaccelerators causes what; hypotension and
bradycardia
Describe C fibers; unmyelinated, post-ganglionic autonomic
fibers that control dull pain, temperature and touch
Describe A-delta fibers; myelinated and control sharp pain,
heat and cold (use cold alcohol wipe to eval this)
When alcohol is wiped across a blocked area where light
touch and temp are diminished, the pt will report sensation as; wet but warm or
neutral
Once a line of demarcation is identified in block level,
future evals should concentrate on; the more cephalad dermatomes
Same fibers that control temp also control; pain
Ab and Ag fibers are; touch, pressure, initial motor
impairment
The level of loss of temperature discrimination correlates
well with; eventual level of sensory loss
What happens when A-alpha fibers are blocked; profound motor
block and loss of proprioception
What is the neural blockade sequence; sympathetic blockade
with peripheral vasodilation and incr skin temp, loss of temp sensation and
light touch, loss of touch, pressure and initial motor, loss of motor and
proprioception
Once LA has been diluted to degree its SG approximates CSF;
no further changes in level of block will occur à fixed point- remaining LA will circulate in CSF but
does not alter level
Saddle block is at what level; S2-S5
This level has little effect on autonomic nervous system
thus there is little or no vasodilation; saddle block S2-S5
Saddle block is limited to which regions; perineum,
perianal, external genitalia
Low spinal will block which nerves; sacral nerves S1-5 and
lower lumbar roots L1-L5
What is the level of a low spinal; T10
What is a low spinal adequate for; vaginal delivery,
cystoscopy, TURP – not adequate for inguinal herniorrhapy – adequate for lower
vascular surgery and ortho procedures not requiring a tourniquet
Which level is known as a high spinal; T4
High spinal allows for what type of surgery;
upper-abdominal, lower extremity tho, inguinal herniorrhapy, ureter and renal
pelvic, appendectomy, ovarian cystectomy, c-section, vaginal, abdominal
hysterectomy, knee and hip replacement
Little finger is what level; C8
What is a total spinal; block higher than T2
What happens during a total spinal; sensory loss in 2 min,
severe hypotension, total motor block, respiratory arrest
Will preservative free opioids injected intrathecally
produce surgical anesthesia? What will it do; no but will significantly reduce
requirements for other agents
Do opioids injected intrathecally produce sympathectomy,
skeletal muscle relaxation or loss of proprioception; no
Spinal anesthesia: Plavix should be stopped ____ prior to
surgery; 10 days
What do you check when someone is on Plavix; platelets –
does not effect PT or PTT
What do you check when someone is on Coumadin; PT
What do you check when someone is on heparin; PTT
What lab value is always checked before doing a spinal; INR
What are complications associated with spinals (group 1);
PDPH, urinary retention, paraplegia, cardiac arrest, auditory, ocular, facial,
inability to cough, apnea/phrenic nerve paralysis, pneumo, neurologic
What are more complications associated with spinals
(group2);traumatic puncture, paresthesia, hematoma, meningitis, abscess,
cranial nerve palsy, cauda equina syndrome, brain damage, herpes, GI,
musculoskeletal
Why does urinary retension occur; sympathetic fibers are
blocked and increased tone of internal urethral sphincter
Where does the phrenic nerve originate; C3-5
Why does the pt have an inability to cough during a spinal;
paralysis of intercostal muscles à
anxiety
What is anterior spinal artery syndrome; complication of
spinal anesthesia where artery that supplies SC during hypotension causes
flaccid paralysis with little or no sensory loss
What does MPF stand for; methylparaben free
During spinals, how does cranial nerve palsy occur; ischemia
of CN 6 (abducens) following prolonged hypotension
How does asceptic/chemical meningitis occur during
spinal;wrong solution is injected into intrathecal space
What is cauda equina syndrome; persistent paralysis of nerves
of cauda equine with resultant lower extremity weakness and bowel/bladder
dysfunction d/t neurotoxic concentrations of LA (usually from epidural
catheters)
How can herpes simplex occur from spinals; d/t intrathecal
opioids reactivates HSV1 (cold sores)
Can spinals cause N/V; yes
What are some key points about PDPH; will resolve in 7 days
with no treatment, bedrest, analgesia, hydration, abdominal binder, IV
caffeine, epidural blood patch
How do you treat N/V associated with spinals; ephedrine
If the block rises high, the cardiac accelerators become
anesthetized and cause bradycardia this is known as the; Bainbridge reflex –
atropine or glyco is ineffective
What are some benefits epidurals have over G/A; return of GI
function faster, fewer pulmonary complications, decreased incidence of DVT/PE
What are some disadvantages of epidurals; risk of failure of
block higher compared to spinals, onset slower, risk for infection and
hematomas
In epidurals, LA spread _____ to the region of the dural
cuffs with ______ into the CSF and leakage through the intravertebral foramen into
paravertebral spaces; horizontally, diffusion
In epidurals, longitudinal spread is
preferentially______;cephalad
Dural cuffs or sleeves have a proliferation os _______ that
effectively reduce the thickness of the dura mater, permitting rapid diffusion
of anesthetics from epidural space
through dura into the CSF; arachnoid villi and granulations
Differences in physiochemical properties of the anesthetics,
such as _____, may account for differences in diffusion rates across the dura,
contributing to variances seen in sensory, motor and sympathetic blockade;
lipid solubility
Why are larger volumes required for epidural anesthesia;
because it is diffusion dependent
What is the epidural needle called; tuohy needle 16, 17 or
18 g
Is the tuohy needle a cutting needle; yes
What are other names of epidural needles and how do they
differ; hustead and Crawford – differ in angle of the tip
Epidural catheters should be designed to ; resist kinking,
compression and stretching and should be radiopaque
Epidural catheter should be advanced how far into epidural
space; 3-5 cm
Will you see a differential block with an epidural ; no
What sensation may the patient feel as you pass the catheter
into the epidural space; a funny bone sensation
Before an epidural catheter is used, what test dose must be
given; 3 ml of 2% MPF lidocaine with epi 1:200,000
After a test dose into an epidural catheter, what will you
see if the catheter is in a vessel or in the SA space; SA space – spinal anesthesia
will occur within 3 minutes, 20% rise in heart rate and BP within 30 seconds or
tinnitus, metallic taste in mouth, circumoral numbness, rushing sound in ears
What two factors are most important in determining the
extent of dermatomal blockage (epidural); dose and site of injection
T/F: small volumes of LA will spread across more segments in
the cervical area than in the thoracic and even less in lumbar and caudal
regions; true
The suggested dose of LA in an epidural is dependent upon;
location of tip of epidural catheter
Common practice is to insert the epidural needle at the
vertebral interspace such that the catheter tip falls near the ______ of the
spinal dermatomes of the proposed surgical incision; middle
An epidural catheter placed for labor or lower abdominal
anesthesia would be placed at; L2 to L3 interspace
An epidural catheter placed for upper abdominal surgery
would be placed at; T8-T10
An epidural catheter placed for thoracic surgery would be
placed at; T4-T5
The concentration of the LA generally affects the _____ of
the block, whereas the volume generally affects the _____ from the needle or
catheter tip throughout the epidural space; density, spread
Other factors thought to affect level of the blockade are;
height, weight, age, position during injection, pregnancy, speed of injection
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