Neuroaxial Blocks, Epidurals & Spinals Flashcards
What terms match up? 1. Epidural 2. Spinal block 3. SAB (subarachnoid block) 4. Peridural 5. Intrathecal 6. Extradural 7. Caudal
1, 4, 6, 7 2, 3, 5
How many curvatures are there in the spine?
4
Anterior or posterior curve? 1. Cervical 2. Thoracic 3. Lumbar 4. Sacral
- Anterior 2. Posterior 3. Anterior 4. Posterior
How many vertebrae are in each category? 1. Cervical 2. Thoracic 3. Lumbar 4. Sacral 5. Coccygeal
- 7 2. 12 3. 5 4. 5 5. 4
What two types of vertebrae are fused in adults?
Sacral and coccygeal
What level does the spinal cord stop from? And what emerges from there?
L1 and the cauda equina emerges from there
What level is the line drawn from the lower borders of the scapula?
T7
What spinal level is the line is drawn between the iliac crests? And what is the name for this?
L4 - Tuffier’s Line
What is the line between the posterior superior iliac spines?
S2 - distal extent of the dural sac
What is the term for a baricity greater than the spinal fluid? Hyper or hypobaric?
Hyperbaric
What are the 6 common parts of a vertebrae? And how many of each?
1 vertebral body 2 pedicles 2 transverse processes 2 laminae 1 spinous process 4 articular processes

What is the function of the 2 pedicles on the vertebra?
Notched for nerve roots
What is the function of the transverse processes on the vertebra?
Muscle attachments
What is the function of the 4 articular processes on the vertebra?
Synovial joints or faucet joints. Enable the spine to bend, move and twist.
What spinous process are more horizontal: Lumbar, cervical or throacic?
Lumbar & cervical
What vertebrae laminae are more vertical in orientation?
The more caudal vertebra
What vertebrae have shorter and broader spinous processes?
Lumbar
What ligament joins the vertebral spines?
supraspinous ligament
What ligament extends from the occipital protuberance to the coccyx?
supraspinous ligament
What ligament is between the spinous processes?
Interspinous ligament
What ligament extends from the foramen magnum to the sacral hiatus and is thickest in the lumbar area?
Ligamentum flavum
What three ligaments do you transverse when you are placing an epidural?
Supraspinous ligament, transverse ligament, and ligmentum flavum.
When will you know that you are in the epidural space?
When you loose resistance after crossing the ligmentum flavum
The epidural space extends from what area to what area?
base of the skull to the sacrococcygeal membrane.
The epidural space contains what?
epidural veins, fat, lymphatics, arteries, and nerve roots
What is the distance from the surface of the skin to the epidural space?
2.5cm to 8cm
What spinal level does the spinal cord extend to in adults and what level in children?
Adults: L1 Children: L3
What is the term for the tapered end of the spinal cord?
Conus medullaris
What structure anchors the spinal cord to the coccyx?
Flium Terminale
What are the nerve roots called that originate from the conus medullaris? And how does the spinal needle affect these nerve roots?
Cauda equina (“horses tail”) The spinal needle pushes the nerve roots away
Label these 10 items


What are the three meninges from deep to superficial?
Pia mater, arachnoid mater, and dura mater
What meninges are thin?
Pia and arachnoid maters
What meninges are thick?
Dura mater
What meninge directly covers the spinal cord?
Pia mater
What meninge is spider web-like?
Arachnoid mater
What space contains the CSF?
Subarachonid space
What meninge is the outer layer that is the consistency of an egg membrane?
Dura mater
What area of the spinal cord is supplied by the anterior spinal artery? Is this artery single or paird? And where does this artery arise from?
Supplies the anterior 2/3 of the spinal cord.
Single.
Arises from the vertebral artery.
What does the posterior spinal artery supply blood to? Is this single or paired artery? What does this artery arise from?
posterior 1/3 of the cord
Paired
Arises from the cerebellar arteries
What is the artery in the spinal cord that aries from the aorta? What does it supply blood to? What level in the spine is this artery found?
Artery of Adamkiewicz
Major blood supply to the anterior lower 2/3 of the cord
Between T11 and L3
What is the term for the area between the radicular arteries on the spinal cord? What type of blood flow occurs in these areas? Why is this siginificant during low-flow states? Between which specific arteries does this occur?
Watershed zones
Could be a lack of direct blood supply
Could be areas of ischemia
Between cervical radicular artery and thoracic radicular artery or between thoracic radicular artery and radicularis magma
What is another name for radicularis magma? And what does this artery supply blood to?
Artery of Adamkiewicz
The lower 2/3 of the spinal cord
Where is the CSF made?
Choroid plexus
Where is the CSF absorbed?
arachnoid villi
How much (mls) CSF is produced daily?
500cc
What is the total volume of the CSF?
120-150ml
How much of the CSF (mls) is in the spinal cord?
25-35mls
What is the pressure of the CSF when supine (horizontal)?
6-8mmHg
What is the specific gravity of the CSF?
1.004-1.009
What procedures (7) are neuroaxial blocks useful for?
lower abdominal, inguinal, urogenital, rectal and lower extremity, obstetric, acute/chronic pain
Can it be used in combination with general anesthesia?
Yes
Neuroaxial anesthesia (more or less):
- nausea/vomiting
- urinary retention
- narcotic requirement
- return to metal alertness
- ability to eat, void and ambulate
- patient safety
- postop analgesia
- less
- less
- less
- quicker
- quicker
- improved
- better
What are some debatable advantages of neuroaxial anesthesia?
safer
decreased blood loss
decreased thromboembolic events
decreased post-op ileus
increased cardiac stability
increased respiratory stability
Absolute, relative or controversia contraindications?
- uncooperative patient
- patient refusal
- prolonged operation
- increased ICP
- major blood loss
- Mild or moderate stenotic valve lesions
- maneuvers that compromise respiration
- sepsis, elevated WBC, fever,
- Severe hypovolemia
- progressive or unstable neurologic disease
- infection at the site of injection
- severe arotic or mitral stenosis
- demylinating lesions
- Difficult to discern effects or complications of the block
- acute upper respiratory infection
- Chronic back pain, headache
- Multiple back surgeries
- significant coagulopathy (prolonged INR/PT, Plt <80, severe hepatic dysfunction)
- severe spinal deformity
- heart blocks
- full stomach
- Patient age
- HIV
- difficult airway
- relative
- absolute
- controversial
- absolute
- controversial
- relative
- controversial
- relative
- absolute
- relative
- absolute
- absolute
- relative
- relative
- controversial
- relative
- relative
- absolute
- relative
- relative
- controversial
- relative
- relative
- controversial
Blockade physiology:
- Level of motor neuron block compared to sensory
- Level of autonomic nerve block compared to sensory
- 2 levels below
- 2 levels above
Blockade physiology:
Heavy, light or no mylenation:
- motor
- sensory
- autonomic
- heavy
- non-mylenated
- light mylenated
Blockade physiology:
Type of fiber:
- Autonomic
- Sensory
- Motor
- B
- C
- A
Blockade physiology:
Onset (first, second, last) to effect:
- Autonomic
- Sensory
- Motor
- First
- second
- Last
Blockade physiology:
Time to recovery (first, second, last):
- Autonomic
- Sensory
- Motor
- Last
- Second
- First
Spinal/Epidural Cardiovascular effects:
The height of the block affects vasomotor tone how: Increase or decrease?
- arterial vasodilation
- SVR
- Venous pooling
- Venous return
- Heart rate
- increased
- decreased
- increased
- decreased
- decreased
Term for the autonomic blockade: unnoposed parasympathetic (vagal) tone (vs. sympathetic tone)
sympathectomy
Spinal/Epidural Cardiovascular effects: What level do the sympathetic fibers arise from?
T5-L1
Spinal/Epidural Cardiovascular effects: What levels do the cardio acceleratory fibers arise from?
T1-T4
Spinal/Epidural Cardiovascular effects:
What is the effect of blocking the cardioaccelerator fibers?
What is this reflex called?
unopposed vagal tone and slowing of the heart rate
Bainbridge reflex
What are some pulmonary effects of spinal anesthesia?
- accessory muscle
- intercostal nerve
- perception of breathing
- vital capacity
- effect of phrenic nerve
- cough
- loss of
- paralysis
- loss - can be scary
- small decrease
- Rarely paralyzed - apnea may result from brainstem hypoperfusion
- Impaired - problem with pts with COPD
Effects of spinal anesthesia:
GI:
- vagal tone
- peristalsis
- sphincters
- unopposed
- increased
- relaxed
Effects fo spinal anesthesia:
- thermoregulation
- CNS
- stress response
- decreased
- depression (some)
- decreased (some)
Immediate complications of spinal anesthesia: Total spinal
How does this happen?
inadvertent dural injections with epidural placement
Immediate complications of spinal anesthesia: Total spinal
Onset fast or slow?
Fast
Immediate complications of spinal anesthesia: Total spinal
What levels does it get to?
cervical levels
Immediate complications of spinal anesthesia: Total spinal
What are symptoms? (2 neuro, 2 cardiac, 1 GI, 2 resp)
agitation, unconsciousness, nausea, hypotension, bradycardia, respiratory insufficiency, apnea
Immediate complications of spinal anesthesia: Total spinal
What is treatment? (Actions and meds)
ABC’s
Ephedrine, phenylepherine, fluids, move rapidly to epinephrine (300-500mcg)
Immediate complications of spinal anesthesia: Cardiac arrest
What is an early symptom?
profound bradycardia
Immediate complications of spinal anesthesia: Cardiac arrest
What patient population is most at risk?
young, healthy people
Immediate complications of spinal anesthesia: Cardiac arrest
What type of block does it arise from?
high sympathetic block
Immediate complications of spinal anesthesia: Cardiac arrest
Why does it occur?
vagal responses to decreased preload
Immediate complications of spinal anesthesia: Cardiac arrest
What type of treatment is necessary?
Rapid, agressive treatment of bradycardia and hypotension (epinepherine 300-500mcg)
Immediate complications of spinal anesthesia: GI complications
Incidence of nausea and vomiting
25%
about 100% for c-section
Immediate complications of spinal anesthesia: GI complications
unopposed vagal tone, increased peristalsis, relaxed sphincters
Immediate complications of spinal anesthesia: GI complications
What is a good antiemetic that is not usually used for an antiemetic?
atropine
Immediate complications of spinal anesthesia: intravenous injection/local toxicity
What should you do prior to injection?
Aspirate
Immediate complications of spinal anesthesia: intravenous injection/local toxicity
What should you do prior to giving the entire epidural injection?
Give a test dose
Immediate complications of spinal anesthesia: intravenous injection/local toxicity
Lidocaine toxicity will manifest how?
CNS toxiticy (tingling, strange taste - copper pennies/metalic, visual disturbances, ringing in the ears)
Immediate complications of spinal anesthesia: intravenous injection/local toxicity
Marcaine (bupivicaine) toxicity will manifest how? How do you treat?
Cardiac toxicity (ventricular arrhythmias)
Treat with lipid rescue - because lipid soluable
Immediate complications of spinal anesthesia: intravenous injection/local toxicity
What is the med dose and % for lipid rescue? what is the bolus rate? How often do you repeat the boluses? Until what dose is reached?
What is the infusion rate? Continue until when? When would you increase the infusion? What would you increase the infusion to?
What is the maximum dose?
intralipid 20%
Bolus: 1.5ml/kg over 1 min
Repeat boluses every 3-5 minutes
until 3ml/kg
Infusion: 0.25ml/kg/min
continue until hemodynamic stability has been restored
Increase rate if BP drops - to 0.5ml/kg/min
Maximum dose: 8ml/kg
Delayed complications of spinal anesthesia:
What is the most common complication of SAB?
Post dural puncture headache (PDPH)
Delayed complications of spinal anesthesia:
What is the cause of PDPH?
Leakage of CSF through dural hole - CSF pressure falls and brainstem drops into the foramen magnum
Delayed complications of spinal anesthesia: PDPH
What needle gauge do you want to use?
high gauge - small needle
17g touhy - 80%
29g sprotte - 1%
Delayed complications of spinal anesthesia: PDPH
What direction do you want the bevel?
Keep parallel to fibers to avoid cutting - bevel to the side
Delayed complications of spinal anesthesia: PDPH
What patient population has the highest incidence?
What patient population has the lowest incidence?
pregnant, young females - 20%
elderly males - <5%
Delayed complications of spinal anesthesia: PDPH
What is the hallmark symptom? What are the characterisitics? What is the onset time?
POSITIONAL HEADACHE
headache behind the eyes moving posteriorly to occiput and extending to the neck and shoulders.
Throbbing or constant and associated with photophobia and nausea
Onset: 12-72 hours following the procedure
Delayed complications of spinal anesthesia: PDPH
What are the 5 interventions to treat a PDPH?
Recumbant positioning
analgesics
fluid
caffeine
blood patch
Delayed complications of spinal anesthesia: PDPH
How much blood is needed for a blood patch?
15-20 mLs
Delayed complications of spinal anesthesia: PDPH
What level do you put the blood patch?
One level below the leak
Delayed complications of spinal anesthesia: PDPH
How long does relief take with a blood patch?
Immediate
Delayed complications of spinal anesthesia: GI
Is there increased or decreased peristalsis with a sympathetic blockade? What if the patient has a bowel obstruction?
Increased peristalsis
Contraindicated in a bowel obstruction
Delayed complications of spinal anesthesia: Urinary
What complication can happen in the urinary tract?
Urinary retention
Delayed complications of spinal anesthesia: Endocrine
What happens with the stress response?
Blunted
Delayed complications of spinal anesthesia: Bachache
What causes backache? How can you treat this?
Profound skeletal muscle relaxation with SAB, positioning in litotomy may cause ligament strain
Treat with reassurance, rest - (or resume reasonable activities of daily leaving), heat, and mild analgesics.
Delayed complications of spinal anesthesia: paralysis
What is the incidence of paralysis - frequent or rare? What is the etiology (three categories)?
Rare
Direct: needle trauma, surgical positioning
Toxic: chemical (betadine/chlorahexidine), virus, bacteria
Ischemic: hematoma (in watershed zones)
Transient neurological symptoms:
What are some transient neurological symptoms of spinal anesthesia? What is the etiology? How long do symptoms last? What are risk factors?
pain or dysthesia in the buttocks, thighs, or lower limbs
radicular irritation
Symptoms usually resolve in 1 week
Risk factors: lidocaine, lithotomy, obesity
What is cauda equina syndrome?
Neurotoxicity
Cauda Equina Syndrome: What are possible factors?
Multiple attempts, parathesia, microcatheters, 5% lidocaine
Cauda Equina Syndrome: What are symptoms?
Bowel and bladder dysfunction, paresis fo the legs, patchy sensory deficits
Menningitis and arachnoiditis: How does this occur? List 4
- Contamination of equipment - virtually elimated with disposables
- insertion technique,
- catheter (coring of epidermis - use stylet in needles),
- glass particles (use filtered needle)
Epidural hematoma: What increases the risk of epidural hematoma?
use of LMWH
Epidural hematoma: What happens to the spinal cord with an epidural hematoma?
Mass effect - direct pressure and ischemia of the spinal cord
Epidural hematoma: What are symptoms of an epidural hematoma?
Sharp back and leg pain - progression of numbness and motor weakness. With or without sphincter dysfunction
Epidural hematoma: What diagnostic technique needs to be done immediately?
CT or MRI
Epidural hematoma: What is the treatment of an epidural hematoma? and how soon does it need to be done?
Evacuation within 6 hours?
Epidural abscess: What are the symptoms of an epidural abscess?
back pain with fever following epidural anesthesia
Epidural abscess: What is the treatment for an epidural abscess?
Antibiotics and surgical decompression
Epidural abscess: What can you do to prevent an epidural abscess?
Sterile technique and remove the catheter after 96 hours
What is the invisible line called that goes above the iliac crests? What vertebrae does this intersect?
Tuffier’s line
L4
When inserting a neuroaxial block, what does the dominant hand do? What does the nondominant hand do?
Dominant: drives the needle
Non-dominant: braces against the back
When do you aspiriate when injecting for a spinal?
What are you looking for when you aspiriate?
Aspirate at the beginning, mid and post (personal preference)
“swirl” of the CSF - to make sure it got into the CSF
What is the paramedian technique?
Approaching the spinal column 1 inch from midline