Master Deck Flashcards
What is the outermost layer surrounding the spinal cord?
Dura mater
The dural sac terminates at what level?
S2
What are the cardioaccelerator nerve fibers? (Select 4)
T1 - T4
What is the absolute contraindication of spinal anesthesia?
Patient refusal
Sensory blockade of which level is necessary for upper abdominal surgery?
T4
For isobaric solution, what is the most important factor in determining the spread of the local anesthetic in subarachnoid block?
- Dose
- Concentration
- Volume
- Baricity
Dose
Chloroprocaine is (Select 2)
- metabolized by the Liver
- (–) enantiomer of racemic procaine
- an ester local anesthetic
- short acting local anesthetic
- an ester local anesthetic
- short acting local anesthetic
The blood in the venous sytem represents what amount of the total blood volume?
75%
The effects of Bezold-Jarisch reflex are manifested as (Select 3)
- bradycardia.
- hypotension.
- coronary dilation.
- tachycardia.
- vasoconstriction.
- hyperventilation.
bradycardia.
hypotension.
coronary dilation.
The diaphragm is innervated by?
C3 - C5
The incidence of cauda equina syndrome is linked to high dose of which local anesthetic?
Lidocaine
The patient allergic to para-aminobenzoic acid will most likely develop hypersensitivity to?
- Tetracaine
- Benzocaine
- Cocaine
- Bupivacaine
- Lidocaine
- Ropivacaine
Tetracaine
Benzocaine
Cocaine
Which local anesthetic has high affinity to cardiac toxicity?
Bupivacaine
Two mL of hyperbaric bupivacaine 0.75% concentration is equivalent to how many mg?
15mg
What is the dermatome level for the umbilical area?
T10
What needle offers the better control for an epidural
Winged Tuohy
At what interval & how long are VS monitored after a spinal?
Q3mins for 15-20mins
At what interval & how long are VS monitored after an epidural?
Q5mins for 20-30mins
The spread of a spinal block is?
What about the spread of an epidural?
- Higher than expected
- As expected & can be controlled with LA volume
The nature of a spinal block is ____ & it is ____ for an epidural?
- Dense
- Segmental
Which neuraxial block is more likely to cause hypotension?
Spinal (SAB)
What are the onset times for a spinal & epidural?
- Spinal= 5mins
- Epidural= 10-15mins
What is the max dose for a spinal?
3cc
What is the max dose for an epidural?
~20cc
What is the max dose for an epidural?
~20cc
The LA concentration for a spinal is what?
Fixed
Which neuraxial is influenced by gravity?
Spinal
Which neuraxial is more likely to cause LA toxicity?
Epidural d/t more veins
How many mL dose each segment hold in an epidural?
1-2mL
Spinal anesthesia is usually performed for procedures involving what?
- Lower abdomen
- perineum
- lower extremities
What is the preferred neuraxial for C-sections?
Spinal
What are the absolute contraindications for an SAB?
- Coagulopathy
- Sepsis
- Pt refusal
- Dermal site infection
- Hypovolemia
- Spinal cord disorders
- Valvular heart disease
With what aortic stenosis area (cm²) is a spinal contraindicated?
What about MS?
- AS= <1.0 cm²
- MS= <1.0 cm²
What neuraxial approach should be used with spinal column deformities?
Perimedian approach
At what dermatome level should one start for a thoracic epidural?
T7 & then can go up
How many spinal nerves are there?
31 pairs
- 8 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 1 coccyx
How many cervical spinal nerve pairs are there?
8 pairs
What helps locate the sacral hiatus?
The sacral cornu to either side
What is the needle approach with thoracic neuraxial?
Cephalad
Where are adipose tissue & blood vessels located in the epidural space?
Laterally
What is the average lumbar distance from skin to ligamentum Flavum?
4-6cm
In most adults the spinal cord ends at ____ & at ____ for children?
- L1
- L3
The dural sac terminates at what location?
S2
What conditions cause low CSF?
- Obesity
- Pregnancy
- ascites
- increased abdominal pressure
LA anesthetic selection depends on?
- Type of surgery
- Length of surgery
- Surgeon
Which LA is not mixed with Epinephrine?
Ropivicaine
What class of medications are used as neuraxial adjuncts?
- Opioids
- Alpha-2 agonists
- Vasopressors
How do vasopressors affect neuraxial anesthesia?
The extend the duration only
How do alpha-2 agonists affect neuraxial anesthesia?
Improve density, duration & analgesia
How do opioid adjuncts affect neuraxial anesthesia?
Intensify the block/density
- Do not extend the duration
What are the spinal doses for
- Morphine
- Fentanyl
- Sufentanil
- Morphine: 100 - 400 mcg
- Fentanyl: 10 - 25 mcg
- Sufentanil: 2.5 - 10 mcg
What are the epidural doses for
- Morphine
- Fentanyl
- Sufentanil
- Morphine: 3 - 5 mg
- Fentanyl: 50 - 100 mcg
- Sufentanil: 10 - 25 mcg
Fentanyl & Sufentanil cause early respiratory depression due to being?
Lipophilic
What is a very common side effect of neuraxial anesthesia?
Pruritis
Neuraxial pruritis can be?
- Treated with:
- Prophylaxis:
- Treat: benadryl 25-50 mg IV, Naloxone 0.1 mg IV, Buprenex
- Prophylaxis: Minimize morphine dose <300mcg, Zofran 4 - 8 mg, Nubain 2.5 - 5 mg
What med can help prevent neuraxial hypotension?
Zofran 4 - 8 mg
What happenz to a SAB when Tetrcaine is mixed with a vasoconstrictor?
Profound increase in length of block
What med is given to prevent the 5 & Dime reflex?
Robenol (Glycopyrrolate)
What is the neuraxial adjunct dose for precedex?
3 mcg
What is the neuraxial adjunct dose for Clonidine?
15 - 45 mcg
What is the neuraxial adjunct dose for epinephrine?
0.2 - 0.3 mg
What is the neuraxial adjunct dose for phenylephrine?
2 - 5 mg
What factors affect LA uptake into neural space?
- LA concentration in CSF
- Surface area of neural tissue
- Lipid content of the nerve
- Blood flow to the nerve
List the affected nerves for a SAB in order first to last?
1) B-fibers
2) C-fibers
3) A-delta fibers
4) A-alpha, A-beta & A-gamma
C-fibers transmit ____ information & B-fibers transmit ____information?
- Sensory
- Sympathetic
Blocking C & A-delta fibers will result in the loss of?
Pain & temperature senses
What fibers are used for motor tone?
A-gamma
Proprioception & motor function is controlled by what fibers?
A-alpha
The sympathetic level is ____ levels higher/lower than the sensory?
- 2 - 6 levels
- higher
The sensory level is ___ levels higher/lower than the motor level?
- 2 levels
- higher
How are LA’s eliminated from the SAB?
Via vascular reabsorption
What drug factors are the most important affecting LA distribution & block height?
Dose & Baracity
What patient factors are the most important affecting LA distribution & block height?
- CSF Volume
- Advanced age
- Pregnancy
What procedure factors are the most important affecting LA distribution & block height?
- Pt position
- Epidural injection post spinal (EVE)
What type of LA is best suited for C-sections or hysterectomy?
Hyperbaric LA
What is the best LA type for prone cases?
Hypobaric
What are the doses of Hyperbaric SAB in Non-Obstetric patients?
- @ T4
- @ T10
- @ sacral
- T4= 2 mL
- T10= 1.5 mL
- Sacral= 1 mL
What is barbotage?
Aspirating CSF & seeing the “swirl” mixing into the LA
What is the Bezoid-Jarisch reflex?
The body tries to normalize cardiac function –> bradycardia
What can be given to inhibit the Bezoid-Jarisch reflex?
Zofran 4 - 8 mg IV
What fibers maintain arterial & venous tone?
Preganglionic B-fibers
What fluids are the best option for preloading?
Warmed Isotonic solutions
Why are glucose containing solutions avoided in neuraxial anesthesia?
Glucose leads to increased u/o, which can lead to more hypotension
What is the best option for normovolemic hypotension?
Ephedrine
GI sympathetic outflow originates at what dermatomes?
T6 - L1
A Pt complains of nausea after neuraxial anesthesia, what is most likely going to happen & how can it be averted?
- Hypotension
- Treat with ~ 1cc Neo
What VS monitoring is definitely needed for a spinal?
BP & SpO2
What is the dose for intralipid rescue?
1.5 mL/kg bolus –> 0.25 mL/kg drip
What dermatome correlates with the testicles?
S2
Vaginal delivery or a TURP require a block up to which dermatomes?
T10
What two needles increase the chances of a spinal headache?
Quincke & Pitkin (they are cutting needles)
What is the quickest way to determine if the fluid coming out of the spinal needle is CSF?
The fluid will be warm
How is a Pt positioned while performing a lateral spinal?
- Legs flexed up to abdomen
- Forehead flexed down towards knees
What solution will result in a swirl?
Hyperbaric solutions
When is a paramedian approach needed?
For a Pt with scoliosis or someone with rods.
What will be bypassed in a spinal with a paramedian approach?
- The supraspinous ligament &
- The interspinous ligament
The spinal needle is in the right place but you get no CSF, what do you do?
- rotate needle 90° & wait 10-15 sec
- insert stylet & remove it
- try aspirating
- withdraw needle & try again
There is blood in your spinal needle, what do you do?
- check if it clears up after a few drops of CSF
- reposition the needle if blood continues to drip
During a spinal the Pt complains of pain in the leg, what do you do?
- Ask the Pt where the pain is
- Do not inject anything
- Withdraw the needle and direct more medially
During a spinal you continue to hit bone, what do you do?
- Reposition Pt
- Change needle if damaged
- Try a different interspace or paramedian approach
- Stop after 3 attempts
You hit a bony prominence early during a spinal, how do you direct your needle?
Direct it caudal
You hit a bony prominence late during a spinal, how do you direct your needle?
Direct it cephalad
What is an early symptom of a high spinal?
Inability to phonate
What are the causes of a high spinal?
- Excessive dose
- Failure to reduce dose in elderly, obese, & short ppl)
- Rapid injection
- Improper position after SAB
- unrecognized intrathecal placement of epidural catheter
Where would a PDPH headache located & what exacerbates it?
- Located in frontal & occipital lobes
- Upright position makes it worse
What possible S/S are associated with PDPH?
- Photophobia
- Diplopia (CN 5v1)
- Tinnitus (CN 8)
- seizures
What are the treatments for PDPH?
- Supine position
- NSAIDs, narcotics (fentanyl)
- Methylxanthine (caffeine) (caution in elderly sensitive to caffeine)
- Blood patch
What is the dose for caffeine PO or IV?
300 - 500 mg daily or BID
Describe a blood patch?
- The patch will be 1 level lower than the tap
- Need a fresh IV
- Pre-medicate Pt as injection of blood can be painful
- Place Pt in lateral position (for comfort)
- Once in epidural space get 20cc of blood from new IV
- Inject 20cc into epidural space
When do transient neurologic symptoms start after a spinal?
What are the S/S?
When does it resolve?
What med has a higher incidence?
- Develops after block resolves
- Severe radicular back pain
- 90% resolve within a week
- Higher incidence with 5% lidocaine
What are the S/S of cauda equina syndrome?
- Bowel/bladder dysfunction
- paraplegia (late sign)
- back pain
- saddle anesthesia
- sexual dysfunction
What are the S/S of Honer’s syndrome?
Ptosis, anhydrosis & Miosis
What 3 nerves are blocked during an awake intubation?
- Trigeminal (5₂)
- Glossopharyngeal (IX)
- Vagus (X)
How is CN 5₂ blocked?
With cocaine on a Q-tip into the nostrils for 5mins
How is CN 9 blocked
With a tongue depressor wrapped in 4x4 coated with lidocaine & have Pt suck on it for 5mins
How is the vagus nerve blocked for an awake intubation?
Inject lidocaine anteriorly and have Pt cough to spread the lidocaine.
What 3 things can cause arachnoiditis?
- nonapproved drugs into the intrathecal or epidural space
- using non-preservative free solutions
- betadine contamination
What are the S/S of spinal/epidural hematomas?
- Pain is a major sign
- Numbness/weakness
Which procedure has a higher incidence of systematic toxicity, spinal or epidural?
Epidural, hence the test dose
What’s the antibiotic of choice for prophylaxis?
- Cephalosporins
What would one change to decrease to the chances of a spinal/epidural abscess occuring?
Use CHG + alcohol instead of povidine-iodine
To maintain the ability to walk, where does an epidural have to be?
Has to be above T10
What are the disadvantage of epidurals?
- slower onset
- longer time to perform
- less dense block
For thoracic epidurals, one should adjust their needle approximately how many degrees cephalad?
35° - 55°
How does an increased pH affect epidurals?
The diffusion is increased
What are the 2 determinants of epidural block spread?
- Site of injection
- volume & dose of LA
What is the segmental dose for epidurals?
1-2 mL per segment
What can one ask the Pt during an epidural test dose to ensure placement?
- Do you have any ringing sensation?
- Do you have a metallic taste?
- Any oral numbness
What does adding Epi to an epidural result in?
Increased duration of the block
What is the phenylephrine dose for epidurals?
2 - 5 mg
Adding bicarb to an epidural will help with?
- Increases the rate of diffusion of the drug
- increases the speed of onset of the block
What is the downside of 2-chloroprocaine in epidurals?
What about the benefit?
- Downside is decreased efficacy of subsequent epidural opioids
- Must be re-dosed every 45mins
- Benefit of rapid onset
Which LA has the greatest motor function depression in epidurals?
What about the least?
- greatest: Lidocaine
- least: Ropivacaine
When is the Crawford needle preferred?
- In thoracic epidurals.
- Or difficult or steep angle placements
What is the downside to single opening epidural catheters?
Can cause spotty blocks
What is the test dose for epidurals?
3cc of 1.5% Lidocaine with Epi 1:200,000
What indicates a positive epidural test dose?
- 20% increase in HR
- Tinnitus, metallic taste, circumoral numbness
An epidural Pt complains of severe depressed motor function 5mins after the epidural, what is the cause?
The procedure resulted in a spinal block rather than an epidural
How much Bicarb is added to the LA for an epidural?
1 meq per 10 mL of LA
