Neuraxial Anesthesia Flashcards
(231 cards)
1
Q
Spinal:
Onset
Spread
Nature or Block
Motor Block
Hypotension
A
Onset: 5 min, rapid, fast.
Spread: goes very high (numb in their hands means it is moving cephalad)
C-3,4,5 SOB (phrenic nerves).
Nature of Block: Dense block means that it knocks out motor and sensory. Not Segmental
Hypotension: (sympathectomy) and Bradycardia at T1-T4 (cardiac accelerator) more likely than epidural
2
Q
Epidural:
Onset
Spread
Nature or Block
Motor Block
Hypotension
A
Onset 10-15 min…? Speed up with bicarb…
Spread: requires more** volume** and slower onset.
Stays put in the epidural pace for the most part.
Nature of Block: Segmental means that they might be able to still move (ropivacaine = walking epidural).
Motor Block: minimal
Hypotension: less than spinal
3
Q
Spinal:
- Placement Level
- Dosing
- Concentration
- Toxicity?
- Gravity influence
- Manipulation
A
first attempt should be at L 3-4 and then move down with subsequent attempts down to L5-S1
Dose base: Spinal anesthesia the most will be 3 ml max. Concentrated and fixed
Concentration fixed
No toxicity
Baricity relates to gravity and is mostly involved in spinal
Positioning is used to move the spinal effect and make onset faster
4
Q
Epidural:
- Placement Level
- Dosing
- Concentration
- Toxicity?
- Gravity influence
- Manipulation
A
To start out at L3-4 but can be at any level with skill. (Slow down insertion at the Ligamentum Flavum)
Dosing: Volume Based: Can be up to a volume of 20 ml with lower concentrations. Can use a variety of concentrations but volume is what matters more.
Concentration: varies
Toxicity: Inadvertent IV administration is more likely with epidural due to the presence of veins on the side of the epidural space.
No baracity effect because there is no CSF in the epidural space. Instead, additional volume is given to move the effect of the epidural
1-2 ml PER SEGMENT. If you want to go five segments higher then you can give 10 ml
5
Q
7 benefits of Neuraxial Anesthesia
A
- Great mental alertness
- Less urinary retention
- Quicker to be able to eat, void, and ambulate
- Avoid unexpected overnight admission from complications of general anesthesia
- Quicker PACU discharge times* (Lido is faster than bupivicaine)
- Preemptive anesthesia
- Blunts stress response from surgery
6
Q
Neuraxial Anesthesia decrease these 6 side effects
A
Decreased
* Postoperative ileus
* Thromboembolic events
* PONV
* Respiratory Complications
* Bleeding
* Narcotic usage
7
Q
Absolute Contraindications to neuraxial Anesthesia
A
- INR >1.5
- PTL < 50,000 (trend it)
- Pt on anticoags or has a bleeding disorder
- if they are Septic don’t let the sepsis have an entry into their spine
- Dermal site infection
- Intraspinal mass
- Preload dependency (valvular and hypovolemia)
- Valvular disease! Hypotension caused by spinal will exacerbate low SVR due to sympathectomy. Hypotension in AS can cause tachycardia and spiral out of control with terrible hypotension
- AS or fixed cardiac Output < 1 cm
- MS
- Idiopathic hypertrophic subaortic Stenosis
- Increased inter-cranial pressure???
8
Q
What are 4 Relative Contraindications NeuroAxial Anesthesia?
A
- Deformities of spinal column
- Spinal stenosis, kyphoscoliosis, ankylosing spondylitis
- Paramedian approach - Preexisting disease of the spinal cord
- Exacerbate a progressive, degenerating disease
- Multiple Sclerosis, post polio syndrome - Chronic headache/backache
- Take a baseline headache assessment - Inability to perform SAB after 3 attempts
- User error
9
Q
How many pairs of spinal nerves and how many at each level?
A
31 PAIRS of spinal nerves
- 7 cervical (8 nerve pairs)
- 12 Thoracic (12 nerve pairs)
- 5 Lumbar (5 nerve pairs)
- 5 Sacrum (sacral Hiatus) ( 5 nerve pairs)
- 4 Coccyx vertebra (only one pair of nerves)
10
Q
The ——– ———- are bony prominences on either side of the ————— and aid in identifying it
A
sacral cornu, hiatus
11
Q
The ———- ———- provides an opening into the sacral canal, which is the caudal termination of the ———— ———–.
A
sacral hiatus, epidural space.
12
Q
When supine, what are the two spinal high points? What are the two spinal low points?
A
C3 and L3
T6 and S2
13
Q
What type of neuraxial anesthesia is bericity important?
A
Spinal
14
Q
If you give a hypobaric spinal to T6, what might happen if the patient is sat up?
A
Hypotension and Bradycardia due to blockage of cardiac accelerator T1-4
15
Q
Characterize the Lumbar spinous process:
A
Relatively straight posterior/horizontal orientation
16
Q
Characterize the Thoracic spinous process:
A
pointing caudally/or oblique orientation
17
Q
——– ——— and ——— ———– are located at the lateral aspect of the epidural space
A
Adipose tissue and blood vessels
18
Q
What is the order in which the needle passes in Epidural access?
What ligaments are anterior to the spinal cord?
A
Supraspinous, Intraspinous, and then Ligamentum Flavum
(Anterior and Posterior Longitudinal Ligament are on the anterior side of the spinal cord)
19
Q
80% of the population has a distance of _____ to _____cm from the skin to the Ligamentum Flavum.
50% of the population measures at ____ cm from the skin to the Ligamentum Flavum.
A
4 to 6 cm
4 cm
20
Q
——– (for boards) is the end of spinal cord for adults
——– is the end for pediatrics
———is where the Dural sack ends
A
L1
L3
S2
21
Q
———— is the end of the Dural sack.
Filum terminal (interna) starts at———
Cauda equina starts at what in 60% of people?
What is inside the dural sack after L4?
A
S2
L1 or end of spinal cord
L1
Cauda Equina, CSF, Fillam Turminal
22
Q
The _______ _______ is contained within a dural sac filled with cerebrospinal fluid.
A
cauda equina
23
Q
What originates from the intercostal and lumbar arteries?
What spinal artery originates from the vertebral artery?
What spinal artery originates from the inferior cerebellar artery?
A
Segmental spinal arteries (medullary arteries)
Anterior Spinal Artery
Two posterior spinal Arteries
24
Q
Dural sack ends at_____
A
S2
25
Pia Mater adheres to the ------ -------.
Subarachnoid Space: CSF is in between -------- and --------- --------.
-------------is delicate and avascular.
-------------is the outermost layer that is thick.
What layer is highly vascularized?
spinal cord
Pia and Arachnoid Mater
Arachnoid Mater
Dura Mater
Pia Mater is highly vascularized
26
At what rate is CSF produced?
The entire CSF is replaced?
How much CSF does an adult have at a given time?
How much CSF is made daily?
20-25 ml/hr
every 6 hr
100 - 160 ml
500 ml made daily
27
Dermatome levels become more ----------- as they descend -----------.
oblique
caudally
28
T10 = ________
T 4 = ________
C 6 = ________
C 6, 7, 8 = ________
T10 = umbilical
T 4 = nipples (c-section desired level) fundal pressure to get baby out
C 6 = Thumb
C 6, 7, 8 Hand (so if you are getting hand numbness, you are getting close to cardiac accelerators)
29
What is Tuffier’s Line and what is another name for it?
* Intercristal Line is a horizontal line drawn across the highest points of both the iliac crests
* intercristal line most often intersects the body of L4 in men or body of L5 in women. Also called Jacoby’s Line
30
Spinal nerves in subarachnoid space is covered by thin ------ ------
Where does the dura layer end?
The ------ ------ is the terminal end of the spinal cord located at ------.
Spinal nerves in subarachnoid space is covered by a thin **pia layer**
Where does the dura layer end? Caudally, the spinal dura ends at the level of **S2** where becomes a thin cord-like extension
The _____ ________ is the terminal end of the spinal cord **Conus medullaris
It is located at L1**
31
-----------intensifys the block but does not affect onset or duration.
----------- Intensifies AND also prolong the block.
------------ only extend the duration of the block.
_________intensify block but does not affect onset or duration. **Opioids, Makes the block more dense**
_________ Intensifies AND also prolong the block.
**Alpha – 2 agonist like Clonidine or Dexmedetomidine**
_________ only extend the duration of the block. **Vasopressors like epi and Neo constrict blood flow**
32
Spinal Med Dose:
Morphine: _________
Fentanyl: __________
Sufentanil: ___________
Spinal Meds
Morphine 100-400 mcg (24 hrs)
Fentanyl 10-25 mcg
Sufentanil 2.5-10 mcg
33
Epidural Med Dose:
Morphine: _________
Fentanyl: __________
Sufentanil: ___________
Epidural
Morphine 3-5 mg (24 hr duration)
Fentanyl 50-100 mcg
Sufentanil 10-25 mcg
34
Is Morphine Hydrophilic or Lipophilic?
Slow or fast in onset in the subarachnoid space.
Morphine will spread rostral and go to the _______.
Is Morphine Hydrophilic or lipophilic?
**Hydrophilic**
Slow or fast in onset in the subarachnoid space.
**Slow**
Morphing will spread rostral and go to the _______.
**Brain**
35
Morphine has ---------- respiratory depression.
---------- is a reversal agent that lasts shorter than morphine.
Morphine has **Delayed** respiratory depression.
**Narcan** is a reversal agent that lasts shorter than morphine.
36
------------ drugs (morphine) have a slow onset and
greater cephalad spread than -----------drugs (Fentanyl/Sufentanil)
Hydrophilic, lipophilic
37
treatment/meds for neuraxial opioid induce itching
Benadryl, Naloxone and buprenex
38
Fentanyl and sufentanal are ---------- agents while Morphine is -------------.
lipophilic, hydrophilic
39
A side effect of Sufentanyl is ______________
muscle rigidity
40
Because Fent and Sufentanyl is lipophilic respiratory depression occurs ------------.
early on (and so much on the floor)
41
What are 3 troublesome signs of opioids that lead to poor satisfaction
Puritis, NV , and Urinary retention
42
What drugs are used in prophylaxis of Puritis
Ondansetron 4 mg IV
Nubain 2.5 - 5 mg IV
(also minimizing morphine to <300mcg)
43
Treatment for opioid-induced puritis?
Benadryl 25 - 50 mg IV
Naloxone 0.1 mg IV (best)
buprenex
44
----------- nature of some opiods causes cephalad spread
Hydrophilic (morphine)
45
Intrathecal morphine require ----------- monitoring
Apnea
(Respiratory (EKG), Pulse oximetry, Alarms)
46
At what dose of spinal morphine can you expect to see NO N/V?
<100 mcg
47
What is a dose of "epi wash"?
0.2 - 0.3 mg
48
Ondansetron 8 mg can be used for NV and interesting prevents ------------.
prevents hypotension
49
Used in combination: Fentanyl/Sufentanil + Morphine has a very high incidence of -----------
N/V
50
A side effect of neuraxial Opioids is Urinary Retention which occurs in _____ to _____ % of people.
30-40%
(Often detected in PACU and US used to detect retention)
51
- Vasoconstrictors added to tetracaine cause --------- in duration
- Vasoconstrictors added to Lidocaine or Bupivacaine cause ------------------- in duration
- profound increase
- no change or variable increase
"However,
lidocaine spinal anesthesia can be prolonged by epinephrine
when measured by both two-dermatome regression in
the lower thoracic dermatomes and by occurrence of pain
at the operative site for procedures carried out at the level
of the lumbosacral dermatomes. Similarly, bupivacaine
spinal duration may be increased, but because of the
already long duration, epinephrine is not generally added to
bupivacaine." pg 1427
52
Alpha 2 agonists will do what to a block?
Glyco is great for gently increasing _____ and does not cross ____.
Intensifies and prolongs
HR, BBB
53
What is the spinal dose of Clonidine?
What is the spinal dose of Dexmedetomidine?
15-45 mcg
3 mcg
54
Epi and Neo wash dose?
Epi: 0.2 - 0.3 mg
Neo: 2 - 5 mcg
55
What are the 4 factors affecting the uptake?
1. Concentration of LA,
2. Surface area of neural tissue,
3. Lipid content,
4. Blood flow of the nerve
56
What type of block is segmental?
What type of block is never segmental?
What type of block is differential?
Epidural
Spinal
Both spinal and epidural
57
- What fibers are peripheral in a nerve bundle and affected first by LA?
- What fibers are affected 2nd?
- What fibers are affected 3rd?
- What fibers are affected last?
B- Fibers or sympathetic
C fibers (unmyelinated), Sensory: Pain, Temp, touch
A-delta, Pain, cold temp, touch
A- Gamma, Beta, alpha: Proprioception and motor, touch, pressure, Tone
58
Sympathetic/Autonomic level is how many segments are higher or lower than sensory?
2-6 levels higher
59
Sensory level is how many segments higher or lower than motor?
sensory is 2 levels higher than Motor
60
All LA are eliminated by ------------?
**Reuptake**
Vascular reabsorption (vessels in pia mater)
61
------------ drugs have slower reuptake because they have a --------- affinity for epidural fat.
Lipophilic drugs
high affinity
62
Why does Bupivacaine last longer than Lidocaine?
It is more Lipophilic.
63
---------- is the most reliable determinant of local anesthetic spread.
Dose (or concentration X volume)
64
Hyperbaric local anesthetic injections are primarily influenced by ________.
baricity
65
---------- is defined as the relationship between the densities of local anesthetics and the density of CSF.
Baricity
66
what is CSF or a pregnant woman and a normal 70kg, 30 year old male
1.00033 (pregnant)
1.00067 (men)
67
What is added to LA to increase SG
What is added to LA to decrease SG
Dextrose
Water
68
Dosing of Hyperbaric SAD in Non OB Pts
T4: _____
T10: _____
Sacral: ______
T4: 2 ml
T10: 1.5 ml
Sacral: 1 ml
69
How do you control the dermatome spread in spinal anesthesia, and how long do you have to affect the spread?
Positioning within the first 5 min.
70
The estimated ED50 of hyperbaric bupivacaine with or without opioid ranged from ___ mg to ___ mg. The calculated ED95 ranged from ___ mg to ___ mg.
4.7 mg to 9.8 mg
8.8 mg to 15 mg.
71
What type of LA is associated with “high spinal” complications with incorrect positioning and dosing
Hyperbaric
72
What is the only spinal preparation of LA available for intrabdominal procedures, safely (T4 level)
Hyperbaric
73
With a isobaric LA it is difficult to get a level above ______ regardless of dose.
T10
74
What type of LA is longer lasting and more hemodynamically stable?
Isobaric
75
what type of LA is good hemodynamics and positioning for hip fractures*
Hypobaric
76
The less CSF you have the more concentrated the LA will be in the CSF. therefor you can give -------
Peak of block, or height of block, will be higher when you have _____CSF.
What two conditions have low CSF?
You can give less LA
Less CSF
Pregnancy and obesity have low CSF volume
77
The older the Pt the _____________ LA you need.
Give 4 reasons why?
Less LA needed
- With advanced age, neural nerves are vulnerable to LA
- The number of myelinated nerves decreased
- Conduction velocity in motor nerves decreased
- CSF volume decreases, and specific gravity increases
78
In what 3 ways does age change the affects of spinal anesthesia
Faster onset
Higher level of blockade
Longer lasting anesthesia
79
In pregnancy, the spread will go what direction due to pressure
Also, because of more or less CSF?
higher
low CSF
80
In most studies, injection site higher than what level can caused neural damage
L3
81
Even though you are doing a regional approach, make sure you also prepare what?
General set up
82
What situations may need someone to transition to general from neuaxial?
- Ineffective block (One-sided blocks, not high enough, patchy, no block at all)
- LAST (Interlipid 20% 1.5 ml/kg and gtt at 0.25 ml/kg for 10 min)
- block that is too high
- anaphylaxis (esters with PABA)
- CV collapse
- a case that has gone longer than expected
83
What are 3 important components to mention to patients when gaining informed consent for neuraxial anesthesia?
HA
Hematoma
Hypotension
84
what level is necessary for Peri-anal/anal surgery (“saddle block”)
S2-S5
85
What level is necessary for Foot/Ankle surgery
L2
86
What level is necessary for Thigh/ lower leg/knee
L1
87
What level is necessary for Vaginal delivery/uterine/hip procedure/tourniquet/TURP
T10
88
What level is necessary for Scrotum procedures?
Penis Procedures?
Testicular procedure*?
S3
S2
T8 *Testicles are embryonically derived from the same level as the kidneys for pain transmission (T10-L1)
89
What level is necessary for Urologic/gynecologic/lower abdominal procedures
T6
90
What level is needed for Cesarean section/Upper abdominal** procedures
T4
** Sometimes may require concomitant general anesthesia due to vagal stimulation from abdominal traction
91
A 20 G needle that comes in the spinal pack is used for what?
to draw up the 1% Lidoc
92
A pink 20 G needle connected to the 3 ml syringe in the spinal pack is used for what?
to draw up 1% Lido, not for infiltration, switch to smaller needle
(use the filter)
93
5ml is the ______ syringe in a spinal kit is used for.
Spinal access
94
What type of needles used in spinal access have an increased likelihood of causing post-dural puncture headache
Cutting needles- Quincke and Pitkin
95
With what type of needle do you feel the pop associated with accessing the epidural space better and has fewer headaches associated with them?
Non-cutting needles or Pencil-Point needles
- Sprotte, Whitacre, Pencan, Greene, Gertie Marx
- A “click” or “pop” can be sensed with a pencil point needle
- Pencil-point carry significantly less risk of PDPH.
- Pencil-point needles are associated with less than a 1% risk of PDPH and a failure rate of about 5%.
96
What can you do if the flow of CSF out of the spinal catheter is slow?
Rotate the needle
97
How much might you want to asspirate when doing 2nd Barbatage?
3 ml
(a volume larger than the LA being administered so you know you are not just pulling the LA you just injected back out and actually getting some CSF as well) (or push half the dose or 1 ml of LA and pull back 2 ml and see the swirl if hyperbaric)
98
When removing a spinal needle how should it be done
Pull the introducer and needle at the same time
99
After removing the spinal needle, what do you do next?
* place the pt supine or in cervical flexion
* evaluate BP and HR
* Assess dermatome levels with something cold
* reposition to prevent high spinal block
* Within 5 min your block is set
100
After removing the spinal needle, what do you do next?
place the pt supine or in cervical flexion
evaluate BP and HR
Assess dermatome levels with something cold
reposition to prevent high spinal block
Within 5 min your block is set
101
what procedure would benefit from a lateral spinal insertion
Hip replacements
102
What are 3 positioning needs of a lateral spinal insertion
- Needs to be Parallel to the Edge of the Bed
- Legs Flexed up to Abdomen
- Forehead Flexed down towards Knees
103
What are the Layers Traversed During the Median Spinal approach
Skin
Subcutaneous fat
Supraspinous ligament
Interspinous ligament
Ligamentum flavum
Dura Mater
Subdural space
Arachnoid Mater
Subarachnoid space
104
As the ligamentum flavum a “pop” and then also the dura are transversed - where are you now?
subdural space
105
In spinal insertion, Once you are in the subarachnoid space, what do you do next
Remove the stylet and look for CSF drip
106
Once you have confirmed placement in the subarachnoid space by CSF what do you do next?
- If CSF +, steady the needle with your non-dominant hand against the patients back
- Carefully attach the syringe to the needle
- Gently aspirate CSF back into the syringe
107
With the Paramedian approach, what differences should you expect?
Since you are lateral the spinal needle will be inserted further than with the midline approach
108
How many degrees laterally should you adjust your needle in a paramedian approach?
10-15 degrees
109
Layers Traverse During Paramedian approach
Skin
Subcutaneous fat
Ligamentum flavum
Dura Mater
Subdural space
Arachnoid Mater
Subarachnoid space
110
The spinal needle is already deeply inserted, and it feels as if it is in the right place but there is no CSF. What should you do?
- Rotate the needle 90 degrees and wait for 10 to 15 seconds; repeat if necessary
- Insert the stylet and remove it.
- Try to aspirate at different rotating angles.
- If no CSF can be aspirated, you have directed the needle too laterally.
- Withdraw the needle, check the position of the patient ,and try again
111
What if there is blood in the spinal needle?
- There may be some blood from the epidural space; usually, it clears when a few drops of CSF are allowed to drip
- However, if the blood CONTINUES to drip, the position of the needle must be changed.
- Most probably, it is in an epidural vein if continuous
112
Bupivacaine is to what as Succ is to Anectine
Marcaine
113
The spinal needle causes pain in the leg. What is this called and what do you do?
- Paresthesia: refers to a burning or prickling sensation that is usually felt in the hands, arms, legs, or feet, but can also occur in other parts of the body
- Do not inject anything
- Withdraw the needle and redirect it more medially
114
The risk of spinal hematoma is increased in patients with -------------------
spinal stenosis
115
What should you do if the needle hits bone?
- Reposition the patient
- Change the needle — the tip of the needle is damaged from contact with bone
- Try a different interspace or paramedian technique
- Remember that the risk of spinal hematoma is increased in patients with spinal stenosis
- Therefore, if you are not able to find the subarachnoid space, change the anesthesia method and do not stubbornly persist with further attempts at lumbar puncture
116
The needle hits bone early in the procedure. What do you do?
- Needle is contacting the spinous process
- Point the needle slightly CAUDAD
117
The needle hits bone late in the procedure. What do you do?
- Needle is contacting the lamina
- Point the needle slightly CEPHALAD
118
A pt who has a spinal is complaining of difficulty breathing. What other complication can you expect to also have? why
Hypotention and Bradycardia
difficulty breathing means C-3,4,5 are affected and therefore T1-4 must also have already been affected.
119
What 5 unexpected events occur with the cephalic spread of spinal anesthesia?
Spread of local anesthesia extending into high cervical and cranial nerves can lead to:
1. **Apnea** (Diaphragm innervated by C3, C4, and C5)Probably a result of severe hypotension and medullary hypotension
2. **Unconsciousness** (Depressed RAS) radicular activating system
3. **upper peralysis**: Loss of ability to move upper extremities
4. **Severe hypotension and bradycardia**
5. **Inability to PHONATE** (EARLY SYMPTOM) indicates cervical nerves being affected
120
If a pt can still --------, the block probably isn't high enough to require -------. Instead what should you do?
* Phonate
* intubation
* Support the patient with vasopressors for hypotension, and oxygen/CPAP
121
if a hyperbaric solution is traveling too cranial what should you do
position the pt with the head up
122
What 5 things cause a high spinal?
1. **Excessive dosing** of local anesthetics
2. Failure to reduce doses in selected patients (elderly, obese, and very short)
3. **Rapid injection** of LA in SAB (do that barbatage thing)
4. **Improper positioning** after placement of SAB
5. Unrecognized **intrathecal placement of epidural** catheter
123
What meningeal layer has the most pain receptors
Dura Mater
124
what is your first line of defence when you have a total of high spinal?
General
125
What are some steps to prevent a high neuraxial anesthesia?
If with epidural:
Careful dosing of LA (Frequent dermatome assessment)
Early recognition of inadvertent intrathecal catheter placement
- Adequate assessment of the epidural “test dose”
- Slow, incremental dosing epidural
Awareness of patient’s position after SAB is placed
126
If you patient is experiencing Dyspnea, what does this mean and what position is helpful? When might you need to intubate?
**Associated with high dermatome blocks**
Intercostal muscle and abdominal muscle wall blockade
In respiratory compromised patient, might a contraindication for neuraxial blockade.
**CPAP***
Can be extremely bothersome requiring heavy sedation “Can’t catch their breath” or unable to take deep breaths
Usually doesn’t lead to intubation unless become **Aphonic**
**Reverse trendelburg** is indicated and maybe helpful in the 1st 5 minutes
127
Postdural Puncture Headache (PPHD) is caused by what?
- **Failure of a dura puncture site to properly “seal over**” once breeched by a needle (cutting needle worse than pencil needle)
- Continuous **LEAK of CSF** causes an overall reduction in CSF volume
- This reduction in volume cause“renting” (collapse) and stretch on the dura
- Dura has large amount of pain afferent fibers that generate a headache (frontal or occipital)
128
What position is associated with PPHD
**UPRIGHT POSTURE** exacerbates the dura stretch producing a profound and debilitating headache (Postural) Differential diagnosis
Positional headache!
129
Are old people at higher or lower risk of PPHD. What about women?
Elderly = lower risk
Women = higher risk
130
What 4 things are some modifiable risk factors with PPHD
1. **Size of needle** (larger needle = more risks) 18-19 G for epidural (blunt and needs to fit the catheter inside so dont tap with this) vs 25 G needle for a spinal
2. **History** of previous post-dural headache
3. **Multiple dural punctures**. (Go a level lower to re-puncture)
4. **Needle design** (pencil point vs cutting)
131
What problem occures with the eye that is associated with PPHA
**Diplopia**
CN VI: Traction causes failure of the affected eye to abduct
132
___________ leads to cranial nerve traction which causes what
**Low CSF volume**
Traction causes failure of the affected eye to abduct - diplopia (CN VI)
133
Auditory simptoms of PPHA cause what symptom and affects what nerve?
- tinnitus (CN VIII)
134
--------- can occure due cerebral vasospasm caused by cerebral hypotension from dural puncture
Seizures
135
If a patinet is complaining of a PPHA what are 6 treatments?
1. **Supine** position relieves HA but does not hasten resolution
2. **NSAIDs, narcotics** useful for mild HA
3. Methylxanthine derivatives (**caffeine**) for mild HA
Caution for elderly and those who can not tolerate CNS/cardiac stimulation
- CAFFEINE: 300–500mg of oral or intravenous caffeine once or twice daily
4. Blood patch
6. Bedrest
136
What is a Blood Patch and how does it work?
How much volume of blood is taken from the pt?
*** Blood will clot and occlude the perforation, preventing further CSF leak**
* With the patient in the lateral position, the epidural space is located with a Tuohy needle at the level of the dural puncture or an intervertebral space lower (look at the chart to ensure the correct history of location of the tap)
* Access the EPIDURAL SPACE while the pt is in sitting position
* **20 ml** blood is then taken from the patient’s arm via fresh IV stick
(may be painful for pt but keep the pt still untill all blood has been given)
137
What are the 6 side effects of loss of autonomic Tone?
What fibers carry sympathetic stimulus?
1. Arterial and Venous dilation
2. Decrease in venous return
3. Decrease in cardiac output
4. Increase in venous capacitance (venous pooling)
5. HYPOTENSION
6. Bradycardia: (inhibition of Bainbridge reflex), SA Node atrial stretching, Bezold-Jarisch reflex, and T1-T4 cardioaccelerator block (4 mechanisms)
**Perganglionic B fibers** maintain arterial and venous tone
138
Explain the Bezold-Jarisch Reflex
The Bezold-Jarisch reflex responds to noxious ventricular stimuli sensed by chemoreceptors and mechanoreceptors within the left ventricular wall by inducing the triad of **hypotension, bradycardia, and coronary artery dilatation**. (apnea)
The activated receptors communicate along unmyelinated vagal afferent type C fibers. These fibers reflexively increase parasympathetic tone. Because it invokes bradycardia, the Bezold-Jarisch reflex is thought of as a **cardioprotective reflex**. This reflex has been implicated in the physiologic response to a range of cardiovascular conditions such as myocardial ischemia or infarction, thrombolysis, or revascularization and syncope. Natriuretic peptide receptors stimulated by endogenous ANP or BNP may modulate the Bezold-Jarisch reflex. Thus, the Bezold-Jarisch reflex may be less pronounced in patients with cardiac hypertrophy or atrial fibrillation.!
139
What age population is more likely to see profound hypotension in spinal anesthesia?
Young adults
140
At what time does this profound hypotension occur after spinal anesthesia?
20-60 min after spinal placement
141
Unopposed parasympathetic tone to the cardioaccelerator fibers (T1-T4) can result in profound ____________, ___________, and ______________.
bradycardia, hypotension, and sudden cardiac arrest.
142
What type of procedures is Sudden Cardiac Death and spinal anesthesia associated with
Associated with large blood loss and orthopedic cement placement
143
__________ is when fluids are given around 30 m in before procedure. (1L isotonic solution)
____________ is when fluids are given while the spinal is being placed and on a pressure bag to infuse quickly
**Preload:** give fluids around 30 m in before procedure. 1L isotonic solution
**Co-Loading:** give it while the spinal is being placed and on a pressure bag to infuse quickly
144
Your Pt is hypotensive,
Give what if not normovolemic;
If normovolemic then what is more effective.
IV fluids
ephedrine
145
Why no glucose in the IV solution?
Will eventualy risk dehyrating your patient and could cause hypotention
146
When you do a spinal anticipate a drop in BP and HR so have what two meds ready?
neo and ephedrine
147
If severe hypertension occurs from ephedrine or phenylephrine, it must be managed with what 3 meds?
vasodilators, narcotics, and anxioloytics
148
,Typically with respiratory changes and spinal anesthesia is inhalation or exhalation more affected?
Exhalation
149
What three things remain unchanged in respiratory when spinal anesthesia is being given?
Vt, RR and ABG
150
If a pt becomes concerned that their breathing might be weaker what should you do?
Check pt and monitors. Add oxygen and give reassurance. Give a smidge of Versed if they are really nervous about the decreased ability to exhale forcefully. Explain that the sensation is normal and they are breathing just fine.
151
In terms of respiratory changes, small decrease in ___________ may occurs due to loss of ____________.
Vital Capacity, forced expiratory capacity
152
What population should you be cautious when high thoracic blockade is in use? And why?
COPD
these pts often use accessory expiratory muscles to exhale
153
N/V is often secondary and proceeds what? What so you give?
Hypotension and bradycardia
Neo or ephedrin
154
GI sympathetic outflow originates where
T6-L1
"Neuraxial blockade from T6 to L1 disrupts splanchnic sympathetic
innervation to the gastrointestinal tract, resulting
in a contracted gut and hyperperistalsis. Nausea and
vomiting may be associated with neuraxial block in as
much as 20% of patients and they are primarily related
to gastrointestinal hyperperistalsis caused by unopposed parasympathetic (vagal) activity. Atropine is effective in
treating nausea"
155
Neuraxial anesthesia for abdominal surgery reduces post op incidence of what GI condition
ileus
156
Is there an increased or decreased GI blood flow during neuraxial anesthesia?
increased
157
Sympathetic block above what level affects bladder control?
T10
158
When you add opioids to a spinal what effect does it have on the urinary tract?
Decresed detrusor contraction and increased bladder capacitance.
(urinary retention)
159
Why do pts shiver with spinal anesthesia?
What drug is used to treat this?
What tool helps manage this?
* Impairment of central thermoregulation and or redistribution of blood flow due to vasodilation in peripheries.
* Zofran
* Bearhugger
160
What are 3 important components to mention to patients when gaining informed consent for neuraxial anesthesia?
HA
Hematoma
Hypotension
161
Transient Neurologic Symptoms is associated with what LA and is characterized how?
How long does it take to resolve?
*Associated with Lidocaine, but not dose dependent, per Miller pg 1442
* characterized by severe radicular **buttock/leg pain** that develops after an uneventful block resolves.
* not associated with any neurologic deficits, just pain!
* **Resolves within a week** in 90% of cases
162
Red flags of Cauda Equina Syndrome
Symptoms (Red flags)
* Bowel/Bladder dysfunction
* Paraplegia (late sign)
* Back pain
* Saddle anesthesia
* Sexual dysfunction
163
What LA is Cauda Equina Syndrome assosiated with
* associationbetween the small-bore catheters in the SAB and the development of cauda equina syndrome
* Case reports single lidocaine 5% SAB
164
Can Cauda Equina Syndrome lead to paraplegia
Yes
Cauda Equina Syndrome is a serious neurologic complication that can be permanent
"The rate of cauda equina syndrome is approximately
0.1/10,000 and invariably results in permanent neurologic
deficit. The lumbosacral roots of the spinal cord
may be particularly vulnerable to direct exposure to large
doses of local anesthetic, whether it is administered as a
single injection of relatively highly concentrated local
anesthetic (e.g., 5% lidocaine)"
165
What nerves are assosiated with Cauda Equina Syndrome?
“Cauda” L1-S4 + coccygeal nerves
166
If Compression (disc, hematoma, etc) is a factor, then what need to happen?
immediate laminectomy < 6 hrs
167
Auditory, Facial, and Ocular Complications of neuraxial anesthesia
**Transient hearing loss**
Changes in CSF pressure
**Horner’s syndrome**
Ptosis, anhydrosis, and miosis
High sympathetic blockade spread to the cervical sympathetic ganglia
**Trigeminal nerve palsy (ganglion bathed in CSF)**
V1 Ophthalmic
V2 Maxillary
V3 Mandibular
168
Risk factors for Epidural/spinal abscess
* Untreated Bacteremia
* **immune depression (HIV, etc)**
* multiple needle attempts
* catheter long duration
169
Meningitis has a mortality of what %
Meningitis 30% mortality
170
What is Arachnoiditis and what causes it?
**Inflammation of meninges** associated with the:
* Nonapproved administration of drug into intrathecal or epidural space (medical error)* or contamination
* Using non-preservative free solutions
* Betadine contamination (wipe off)
* ensure that chlorhexidine has fully dried before puncture
Leads to extensive sclerosis of arachnoid membranes and constriction of vascular supply
171
What 3 things is hematoma mostly associated with?
* Preexisting abnormalities in clotting hemostasis
* Traumatic or difficult needle placement
* Indwelling catheters and long-term anticoagulation
172
In the context of neuraxial hematoma, cord ischemia can be reversed within what time frame?
"Cord ischemia reversible if laminectomy is performed in **< 8 hours**
Bleeding within the vertebral canal can cause ischemic
compression of the spinal cord and lead to permanent
neurologic deficit if not recognized and evacuated expeditiously."
173
what is a major symptom of neuraxial hematoma?
Pain is a major symptom!!
"Radicular backpain, prolonged blockade longer than the expected duration
of the neuraxial technique, and bladder or bowel
dysfunction are features commonly associated with a
space-occupying lesion within the vertebral canal and
should prompt magnetic resonance imaging on an urgent
basis."
174
Systemic Toxicity is most common in what type of neuraxial anesthesia
More common with epidural anesthesia
175
5 major benefits of EPIDURAL over Spinal
* **Predictable** dermatome spread
* **Slower onset** of autonomic blockade, Slower onset of hypotension, Dose vasopressors more effectively (10-15 min onset without additives)
* **Unlimited Duration** "Top up" dose
* Use **varying concentrations** of local anesthetic for analgesia or surgical anesthesia (sensory analgesia)
* Can maintain the ability to ambulate and void if epidural is placed **above T10** (**segmental** blockade) Ropivicaine
176
3 disadvantages of Epidurals
* Longer time to perform the technique
* Slower onset
* Less dense block than spinal
177
Would an epidural be indicated for a upper extremity surgery?
Can an epidural be used at the same time as General?
Is there such thing as PCA for epidural?
Yes! Upper and lower extremity surgery
Can be used as a sole anesthetic or adjunct to GETA (big lung surgery)
Post-op as a continuous infusion with or without patient-controlled epidural analgesia. (Limited by staff training of epidural pumps) (also helps with limiting narc use)
178
If you can not avoid the tatoo what should you do?
Use the tatto site for Epidural Anethesia without nicking of the skin
179
The Epidural Space extends from where to where?
Extends from the base of the skull to the **sacral hiatus**
180
Why is inadvertant venous puncture more likley in pregnant women?
Engorged Veins in the epidural space
181
What 6 things are inside the epidural space?
It is a space filled with the
1. fat
2. areolar tissue (Areolar connective tissue is the type of tissue which connects and surrounds different organs in the human body)
3. lymphatics
4. veins (engorgement of the epidural veins from caval compression)
5. nerve roots
6. blood vessels
182
Off-midline needle insertion is more likely to result in what undesired outcome?
blood vessel puncture
183
Density of epidural veins increases ---------------.
Laterally
184
Epidural Veins have one way valves and form a plexus draining blood from the cord and its linings. T/F
False
Epidural veins are **valveless** and form a plexus draining blood from the cord and its linings.
(Veins become engorged in the pregnant and obese)
185
Injection of what two substances opens up the potential space of the epidural space
liquid or air
186
In the upper thoracic region, what epidural approach is more difficult and why?
In the upper thoracic region, a **midline approach** to the epidural space is more difficult because of the **angulation of the spinous processes**
* Needle pointing cephalad
* A paramedian approach
187
The safest point of entry into the epidural space is
below the level of the spinal cord (ends at L1 in 60% adults and L3 in pediatrics)
188
LA a weak -------- with a pKa -------- than physiologic.
Typically, the closer the pka is to physiologic the faster the -----------.
Bases, higher
onset.
189
Bupivicaine has a pKa of 8.1 while Lidocaine has a pKa of 7.9. what can you infer about the onset of the two drugs
Lidocaine will have a faster onset.
190
An important factor in surgincal anesthesia using epidural anesthesia is to ensure you chose the LA that will cover the durration of the surgical procedure. T/F
True!
Ideal LA for surgican anesthesia
* fast onset
* long durration
* adequate concentration
191
What LA is faster than Lidocain in epidural and why?
3% chloroprocaine is faster than Lidocine becase the concentration is higher. Even though pKa is higher and farther from physiologic.
3% chloroprocaine is used for emergency C-sections due to fast onset.
192
What will increase diffusion through the dura and arachnoid layers
the addition of NaHCO3
193
What is the order of uptake of LA based on regional techniques
IV
Tracheal
Intercostal
Caudal
Paracervical
epidural
brachial
Sciatic
Subcutanious
194
Describe the mechanism of action of Epidural Anestheia?
LA is injected into the epidural space via needle or catheter where the drug **diffuses through the dural sheath of spinal nerves, roots, rootlets, and CSF **where nerve transmission is altered.
195
What determines block spread in an epidural?
* **Site of injection**
* **Volume and dose of LA**
"The level of injection is the most important procedurerelated factor that affects epidural block height. "
"The volume and total mass of injectate are the most important drug-related factors that affect block height after the administration of local anesthetic in the epidural space. As a general principle, 1 to 2 mL of solution should be injected
per segment to be blocked."
196
Are epidurals affected by position?
Generally, no
"The sitting and supine positions do not affect epidural block height.
However, the head-down tilt position does increase cephalad
spread in obstetric patients."
197
Increasing WHAT speeds the onset of LA
Concentration of LA
198
How does Age affect the spread of LA in epidurals
"Age can influence epidural block height. There appears
to be a stronger correlation with age and **block height (spread)** in thoracic epidurals, with one study suggesting that **40% less volume is required in the elderly**"
199
what conditions have increase abdominal pressure and what effect does this have on the volume of LA used
Pregnancy
Coughing, valsalva
Obesity
Lower CSF = Lower Dose
200
Does Pt height influence the dose of LA given in an epidural?
* "As with spinal anesthesia, it appears that only the **extremes of patient height** influence local anesthetic spread in the LA."
* So typicaly no unless you a deling with a giant vs a dwarf
201
Thoracic epidural injection produces ------------- spread of anesthetic solution.
Lumbar injection produces a ----------- spread.
Caudal injection predominantly results in ---------- and ------------ anesthesia.
Thoracic injection produces **symmetrical** spread of anesthetic solution
* A reduced volume of local anesthetic solution should be used at this level because of the potential for higher block and resultant hemodynamic instability
Lumbar injection produces a **preferential cephalad spread** due to the narrowing of the epidural space at the lumbosacral junction
* The larger diameter of the L5-S1 nerve roots may delay the onset or result in patchy anesthesia.
Caudal injection predominantly results in **sacral and low lumbar anesthesia**
202
What determines dermatome spread in epidurals?
**Volume**
A larger volume will block a greater number of segments
203
As you go down the spinal cord the volume of LA goes up or down. On average what volume do you give per segment to increase the spread.
**Epidural space volume increases down the spinal cord** as the cord occupies less space.
* Cervical/Thoracic 0.7-1 ml per segment
* Lumbar 1-1.5 ml segment
**Overall take-home message: 1-2 ml per segment**
For example, to achieve a T4 sensory level from an L4-5 injection, approximately 12–24 mL of local anesthetic should be administered (incremental dosing)
204
When injecting LA into Epidural space how should you give the LA?
By using this technique, what 4 things do you avoid
**Incremental Dosing with 5 ml fractions** avoids:
* Accidental “High spinal”
* Hypotension from rapid autonomic blockade (cardiac arrest)
* Local Anesthetic toxicity (LAST)
* If epi is added, can be used IV marker and indicate if you accidentaly gave it in the vein and LAST is avoided
205
What Epidural additive is used to prolong LA?
What LA is it most and least effective?
Epi
most effective with lidocaine (from 60 - 90 min)
Less effective with bupivicaine (from 225 - 240 min)
206
What LA is used only for epidurals and has a very rapid onset?
How long does it last?
2-Chloroprocaine 3% (Ester)
Short-lived (metabolized by plasma cholinesterase)- redose every 45 mins
207
The epidural additive, -------------, can prolong sensory block to a greater extent than motor block, reduces the need for post op opiods, but has a variety of side effects including hypotension, bradycardia, dry mouth, and sedation. The
Clonidine
(15 - 45 mcg for spinal or epidural?)
"In spinal doses of 15 to 225 μg, clonidine prolongs the duration of sensory and motor blockade by approximately 1 hour and
improves analgesia, reducing morphine consumption by
up to 40%." Textbook says this dose is for spinal. no dose states for epidural.
208
-------------- synergistically enhances the analgesic
effects of epidural local anesthetics, without prolonging
motor block.
Opioids
209
If you want to speed onset of an epidural what would you add and how much?
**Bicarbonate** can speed the onset (More Nonionized form) weak base; pKa > physiologic pH
**1 MEQ for 10 ml LA**
210
List in order the LA from fastest epidural onset to longest
Chloroprocaine 3%
Lidocaine 2%
Mepivacaine 2%
Ropivacaine 0.75%
Bupivacaine 0.5%
211
What drug is associated with walking anesthesia?
Epidural Ropivicaine
212
What LA in an epidural space has the least motor effect?
Which LA has the most?
Ropivacaine - Least
Lidocaine - Most
(You may not want to give an ambulatory OB pt Lido or even high dose Ropivicaine in the fear that you may supress motor ability to push the baby out)
213
Explain "Top-Up" and its effect on an epidural
Repeated doses of drug: With “top-up” techniques, both motor and sensory blockade tend to become more intense with repeated doses
214
How long is the Tuphy needle?
Each mark = 1 cm
9 cm length - hub
10 cm - window
215
What are 3 common epidural needles?
which has the most curvature?
What does each marking on the needles mean and why is it important?
* **Tuohy:** most curvature (30 degrees) blunt tip, is less likely to puncture subarachnoid space. Usually, a 17- or 18- gauge needle
* **Hustead**: 15 degree curve
* **Crawford**: preferred when catheter placement is difficult or the angel is steep (thoracic epidural)
Each Needles has **1cm marking** used to identify how deep you are
216
What is the advantage of a coil reinforced catheter in an epidural? What is the drawback?
* Coil reinforced catheters (Stronger, less likely to shear when removed or placed)
* But a softer tips reduces inadvertent SAB placement
217
What is the benefit of a multi-oriface catheter for epidurals?
What is the drawback?
* Lower incidence of inadequate anesthesia (better distribution of local anesthesia spread)
* Higher incidence of inadvertent intravascular placement
218
How far in should you place the epidural Catheter in the epidural space?
Placed **3-5 cm** within the epidural space
219
Plastic Catheter Characteristics
* Easier to thread
* Inadvertent SAB puncture is a possibility
* Stiffer
* Less expensive
220
On an epidural catheter,
What does 3 thin close marks mean?
What does 4 thin close marks mean?
What does 3 thin marks mean? **15 cm**
What does 4 thin marks mean? **20 cm**
221
When the catheter is threaded to the tip of the needle, what numerical marker may you be at?
how much farther should you advance into the pt?
depends on needle length but maybe 11-12cm (a Tuohy needle is 9 cm + hub)
thread an additional 3 cm for a total around 14-15 cm
222
What ligament is just proximal to the epidural space and is 4-6 cm in most pts?
Ligamentum Flavum
223
In what type of neuraxial anesthesia do you do a test dose and, how and why do you do this?
* Epidural!
* You want to ensure you are not in a vein, or SAB
*** 3 mL of 1.5% lidocaine with epinephrine (1:200,000)**
224
How do you identify the epidural space durring Epidural insertion
Loss of resistance to air or liquid or both
(If using air only use 1-2 ml)
225
What 3 side effects will a pt first have if accidental IV LA occures?
Whar side effects do you see with a test dose given into a vein?
* Tinnitus
* Metallic taste
* Circumoral numbness
* A change of 20% or greater in heart rate after the test dose indicates a probable intravascular injection—replace the catheter
226
What happens if an epidural test dose goes into SAB space
* The intrathecal injection of lidocaine will produce a significant motor block consistent with spinal anesthesia in 3 mins
* A dense motor block within 5 min of a test dose should prompt a suspicion of a spinal block
227
Would an epidural be indicated for a upper extremity surgery?
Can an epidural be used at the same time as General?
Is there such thing as PCA for epidural?
Yes! Upper and lower extremity surgery
Can be used as a sole anesthetic or adjunct to GETA (big lung surgery)
Post-op as a continuous infusion with or without patient-controlled epidural analgesia. (Limited by staff training of epidural pumps)
228
What is the advantage of a coil reindorced catheter in an epidural? What is the drawback?
Coil reinforced catheters (Stronger, less likely to shear when removed or placed)
But a softer tips reduces inadvertent SAB placement
229
What s/s are you looking for in pediatric pts that indicate vascular injection in LA
Peaked P waves or changes in the T wave in children indicate a vascular injection
230
With a pregnent pt how do you give a test dose of Lido/epi for epidural?
Give the test dose to a pregnant patient **after a contraction is over** for a more accurate response to test dosing
231
You are giving a test dose of Lido with epi, but then remember that the patient takes a Beta blocker. What parameters will you use to guide your interpretation of the test dose?
A change in **systolic blood pressure of > 20 mm Hg** in patients on beta-blocking agents is more indicative of an intravascular injection
* (don't confuse this with the 20% increase in HR for normal pts)
