Neuraxial Flashcards
1
Q
Name the 5 divisions of the spinal column. How many in each?
A
Cervical - 7
Thoracic - 12
Lumbar - 5
Sacrum - 5 fused
Coccyx - 4 fused
2
Q
What ligament covers the sacral hiatus? Why does this matter?
A
sacrococcygeal ligament
This is punctured during the caudal approach of the epidural space
3
Q
Order the 5 ligaments of the spinal column from posterior to anterior
A
Supraspinous
Interspinous
Flavum
Posterior longitudinal ligament
Anterior longitudinal ligament
4
Q
Which ligaments are punctured during a midline approach for an epidural ? How about Paramedian?
A
Midline - Supra + Inter + Flavum
Paramedian - Flavum
5
Q
Which two ligaments should never be punctured?
A
Posterior longitudinal ligament
Anterior longitudinal ligament
6
Q
List all structures during a subarachnoid block
A
- Skin
- Subq
- Muscle
- Supra
- Inter
- Flavum
(Epidural Space)
- Dura mater
(Subdural Space) - Arachnoid matter
(Subarachnoid space) - Pia matter
- Spinal cord
7
Q
What is Batson’s Plexus? Why does this matter?
A
Epidural Veins
Drains venous blood from the spinal cord
(during pregnancy these veins become engorged, causing increased risk of needle injury or cannulation)
8
Q
What is the Plica MEdiana Dorsalis?
A
Possible band of connective tissue between Flavum and dura matter. (unsure if it exists)
9
Q
Which Spinal root blocks the 1st digit (Thumb)?
A
C6
10
Q
Which Spinal root blocks the 2nd and 3rd digits?
A
C7
11
Q
Which spinal root blocks the Pubic Symphysis?
A
T12
12
Q
Which spinal root blocks the nipple line?
A
T4
13
Q
Which spinal root blocks the Anterior knee?
A
L4
14
Q
Which spinal root blocks the Xiphoid process?
A
T6
15
Q
Which spinal root blocks the 4th and 5th digits?
A
C8
16
Q
Which spinal root blocks the belly button?
A
T10
17
Q
Skin dermatomes photo
A
18
Q
Skin dermatomes photo
A
19
Q
What innervates face?
A
Trigeminal nerve (CN5)
20
Q
What is the site of action for spinal anesthesia?
A
Bathes the nerve roots - myelinated preganglionic fibers
Local anesthetics inhibit neural transmission
21
Q
What is the site of action for epidural anesthesia?
A
Locals must diffuse the dural cuff
Can also leak through the intervertebral foramen to enter the paravertebral area and cause multiple blocks
22
Q
Which factors affect the spread during a spinal block?
A
Baricity of the local
Patient position
Dose
Site of injection
Volume of CSF
Density of CSF
23
Q
Which factors do not affect the spread of a spinal block?
A
-Vasoconstrictor
-Weight
-Gender
-Orientation of bevel
-Speed of injection
-Increased intra-abdominal pressure
-Barbotage
24
Q
What is the primary determinant of spread for epidural?
A
Volume
25
Which type of fibers are blocked first? Second? Third?
Autonomic
Sensory
Motor
26
Why does it matter on the order of blockade?
autonomic is 2-6 dermatomes higher than sensory
Sensory is 2 dermatomes higher than motor
27
How is a differential blockade different with epidural anesthesia?
No autonomic block with epidural
Sensory block is 2-4 dermatomes higher than motor
28
Order of different nerve fibers?
1. Beta
2. C
3. Alpha - Gamma and Delta
4. Alpha - alpha and beta
29
Function of A Alpha nerves?
Heavy myelination
Skeletal muscle and motor proprioception
30
Function of A beta nerves?
Touch and pressure
Heavy myelination
31
Function of A gamma?
Skeletal muscle tone
Medium myelination
32
Function of A delta?
Fast pain
Temp
Touch
Medium myelination
33
Function of B fibers?
Preganglionic ANS fibers
Light myelination
34
Function of C sympathetic fibers?
Post ganglionic ANS fibers
NO myelination
35
Function of C dorsal root fibers?
Slow pain
Temp
Touch
NO myelination
36
What are cardiovascular effects of a neuraxial anesthesia ?
Vasodilates - Venous more than arterial
Reduction on venous return, CO, BP
Bradycardia by blockage of T1-T4 cardioaccelerator fivers
Unloading of cardiac mechanoreceptors (Bezold Jarisch Reflex)
Unloading of stretch receptors in the SA node
37
What are respiratory effects of a neuraxial anesthesia ?
-Accessory muscle is reduced
-intercostals (decreased inspiration and expiration)
-Abdominal muscles (Ability to cough and clear secretions)
-Apnea is from brainstem hypoperfusion, not phrenic nerve block
-Careful in COPD
38
What are the neuroendocrine effects of a neuraxial anesthesia ?
-Blocks stress response
Reduces catecholamines, renin, angiotensin, glucose, thyroid stimulating hormone, and growth hormone
39
What are GI effects of a neuraxial anesthesia ?
Neuraxial blocks sympathetic tone which increases parasympathetic tone in the gut
-Increases peristalsis, relaxes sphincters
40
What are liver and kidney effects of a neuraxial anesthesia ?
As long as systemic BP is maintained, there is NO effect
41
What are risks with coagulopathy and neuraxial anesthesia ? Labs?
Spinal or epidural hematoma
Plt < 100,000
PT, aPTT and or bleeding time twice the normal value
42
Which valve lesions are contraindicated with neuraxial anesthesia?
Aortic Stenosis
Mitral Stenosis
Hypertrophic Cardiomyopathy
43
What is the risk of neuraxial anesthesia and increased ICP ?
Sudden change in CSF can cause brain herniation
44
Relationship between neuraxial anesthesia and MS?
Should be okay but use lower dose and warn the patient their symptoms might be exacerbated
45
Specific gravity of CSF?
1.002-1.009
46
What is baricity? How does it affect local?
Describes the density of the local
-Isobaric is similar to CSF
-Hyperbaric is more dense than CSF
-Hypobaric is less dense than CSF
47
What solution is usually hyperbaric? What will happen?
Dextrose is usually hyperbaric
The solution will sink
48
What solution is usually hypobaric? What will happen?
Water (hypO)
The solution will rise
49
What solution is usually isobaric? What will happen?
Saline
Solution will remain in place
50
What solution is an exception?
Procaine 10% in water
This will be hyperbaric because there are so many molecules
51
What is a saddle block?
If the patient stays sitting with a hyperbaric solution
Solution sinks and coats the sacral nerve roots
52
If you lay a patient down with a hyperbaric solution, what will happen?
The solution will settle and pool in the sacrum and thoracic kyphosis
53
Hyperbaric photo
54
Hypobaric photo
55
Where will hypobaric solution settle?
Highest point in the spinal canal
Do not give to sitting up patient. It will rise to the head
56
What is the name of the cutting needle?
Cutting - Quincke
57
What is the name of the non cutting needles?
Pencil - Sprotte
Pencil - Whitacre
Rounded -Green
58
Pros and Cons of cutting?
Pros - less force
Cons - Less tactile, easily deflected, more likely to injure cauda equina, higher risk of PDPH
59
Pros and Cons of non cutting
Pros - More tactile, less likely to deflect, less likely to injure cauda equina, lower risk of PDPH
Cons- Need more force
60
Three different types of epidural needles ?
Crawford - 0 degrees
Hustead - 15 degrees
Tuohy - 30 degrees
Alphabetical order
61
Dosage for adult and child caudal anesthetic
62
What are absolute contraindications to caudal anesthesia?
Spina bifida
Meningitis
Meningomyelocele of sacrum
63
What are relative contraindications to caudal anesthesia?
Pilonidal cyst
Abnormal landmarks
Hydrocephalus
Intracranial tumor
Progressive degenerative neuropathy
64
MOA of neuraxial opioids ?
Inhibit afferent pain the substantia gelatinosa (lamina 2) of the dorsal horn
Decreased cAMP
Decreased Ca in presynaptic
Increased K in postsynaptic
Epidural opioids diffuse systemically
65
Do neuraxial opioids cause sympathectomy, skeletal muscle weakness, or change in proprioception?
NO
66
Opioid intrathecal and epidural dosage guise
67
How does lipophilicity affect rostral spread in the subarachnoid space?
Hydrophilic drugs stay in subarachnoid space and travel towards brain (rostral spread)
Hydrophilic drugs diffuse out and enter systemic circulation
68
Rank opioids from most lipophilic to most hydrophilic
Most lipophilic
Sufentanil
Fentanyl
Meperidine
Hydromorphone
Morphine
69
Lipophilic or hydrophilic ; Which stays in the CSF longer?
Hydrophilic
70
Lipophilic or hydrophilic ; Which has more CSF spread?
Hydrophilic has extensive spread
More rostral spread (towards brain)
Wide band of analgesia
71
Lipophilic and hydrophilic ; Site of action?
Both are rexed laminae 2+3
but lipophilic also has systemic effects
72
Lipophilic or hydrophilic ; Which has faster onset?
Lipophilic (5-10 minutes)
Hydrophilic (30-60 minutes)
73
Lipophilic or hydrophilic ; Which has longer duration?
Hydrophilic (6-24 hours)
Lipophilic (2-4 hours)
74
Lipophilic or hydrophilic ; Higher incidence of PONV and Pruritus ?
Hydrophilic for both
75
Lipophilic or hydrophilic ; Respiratory depression?
Both can be early on (<6 hours)
Hydrophilic can also be late (>6 hours)
76
Four most common side effects of neuraxial opioids?
1. Pruritus (most common)
2. Respiratory depression
3. Urinary retention
4. N/V
77
Which local reduces efficacy of epidural opioids?
2-Chloroprocaine
78
Which epidural opioids can reactivate herpes?
Morphine 2-5 days later
Spreads to trigeminal nucleus
79
Pathophysiology of post dural headaches?
1. CSF leaks from subarachnoid space
2. CSF pressure is lost, cerebral vessels dilate
3.Brainstem sags into the foramen magnum which stretches meninges and pulls on the tentorium
80
Presentation of post dural headaches?
Fronto-occipital headache
N/V
Tinnitus
Diplopia
Photophobia
Sitting makes it worse, laying makes it better
81
Higher risk for PDPH?
Young
Female
Pregnant
Cutting needle
Large needle
Using air for LOR with epidural
Needle is perpendicular to long axis
82
What has no effect on PDPH?
Early ambulation
Continuous spinal catheter
83
How to treat PDPH?
Best rest
Hydration
NSAIDS
Caffeine
Blood patch
NOT OPIOIDS
84
How is a blood patch preformed ?
90% success rate
Sterile technique 10-20 mL of venous blood are aspirated and injected into the epidural and subarachnoid space
When pressure is felt by the patient, it is complete
Blood compresses the space and acts as a plug
85
Most common side effects of a blood patch ?
Back ache and radicular pain
86
What is the primary risk of neuraxial anesthesia in the anticoagulated patient? How does it present?
Epidural hematoma during initial block and the removal of the catheter
Presents - weakness, numbness, low back pain, bowel and bladder dysfunction
Treatment - surgical decompression
87
Where does the spinal cord end in an adult? Subarachnoid space?
Adult - Ends at L1-L2 (conus medullaris)
Ends at S2 - (dural sac)
88
Where does the spinal cord end in an infant? Subarachnoid space?
Ends at L3 (conus medullaris)
Ends at S3 (dural sac)
89
What is the cause of cauda equina syndrome?
Neurotoxicity of high concentrations of local anesthetic
5% lidocaine and spinal microcatheters make it worse (because it exposes a small region to high amounts)
90
How does cauda equina present?
Bowel and bladder dysfunction, sensory deficits, weakness, paralysis
Treatment is supportive
91
What is the cause of transient neurologic symptoms? What factors increase the risk?
patient positioning, stretching of the sciatic nerve, myofascial strain, and muscle spasms
Lidocaine, lithotomy, knee scope, ambulatory surgery
92
How does transient neurologic symptoms present?
Severe back and butt pain, down both legs
Develops 6-26 hours after and lasts for 1-7 days
Treatment - NSAIDS, opioids, trigger point injections
93
What is the most common organism responsible for post spina bacterial meningitis?
Streptococcus (Found in mouth so wear mask)
Reaches CSF because of failure of sterile technique and bacteria already in blood at time of SAB
94
Best way to prepare skin for neuraxial anesthesia?
Chlorhexidine + alcohol
**Chlorhexidine is toxic so wait for it to dry
95
Mnemonic for brachial plexus
Reach - Roots - 5
To - Trunks -3
Drink - Divisions - 6
Cold - Cords - 3
Beer - Branches - 5
96
What makes up the trunks of the brachial plexus?
Superior C5 + 6
Middle C7
Inferior C8 + T1
97
What are the three cords? What makes them up?
Lateral C5-C7
Posterior C5 - T1
Medial C8+T1
98
What are the 5 branches?
Musculocutaneous C5-7
Axillary C5-C6
Median C5-T1
Radial C5-T1
Ulnar C8-T1
99
Where do the brachial plexus roots turn into trunks?
Just beyond the lateral border of the scalene muscles
100
Where do the brachial plexus trunks turn into divisions?
Underneath the clavicle and over the first rib
101
Where do the brachial plexus divisions turn into cords?
Under the pectoralis minor muscle
102
Where do the brachial plexus cords turn into terminal branches?
In the axilla
103
Sensory innervation of the upper extremity
104
In addition to the brachial plexus, which nerve must be blocked to tolerate a upper tourniquet ?
Intercostobrachial (arises from T2)
5mL injected for a field blocker
105
Which procedures is an ISB good for? Not good for ?
Shoulder, upper arm, clavicle
Not good for anything below elbow (spares C8-T1) roots
106
Which approach usually results in phrenic nerve blockade?
ISB
**Issue with respiratory disease
107
Which approach usually results in Horner syndrome?
ISB - blocking the stellate ganglion at C7
-ptosis
Miosis
anhidrosis
****Indicates successful block
108
Discuss the relationship between shoulder arthroscopy, ISB, and hypotensive bradycardia episodes.
The bezold-jarish reflex is the proposed mechanism
Venous pooling in LE reduces venous return
Unloaded ventricle + SNS stimulation+ Epi uptake
109
What is targeted for a supraclavicular block? What is this good for? Bad for?
Targets trunks and divisions.
Good for upper arm, elbow, wrist, and hand
Bad for shoulder
110
Greatest risk for a supraclavicular block?
Pneumothorax
Can use the first rib as a blocker
111
What does a infraclavicular block target? Good for? Bad for?
Targets the cords below clavicle
Good for upper arm, elbow, wrist, hand
**Favored over supraclavicular with patients that have respiratory complications (avoids phrenic nerve)
Not good for shoulder
112
Is the axillary nerve blocked during an axillary block?
No
113
What is an axillary block good for? What does it miss?
Good for forearm and hand
Does not cover the skim of the medial upper arm (intercostobrachial nerve)
Skin of the deltoid (axillary nerve)
114
How is the radial nerve blocked?
Derives from the posterior cord
Injected 3-5mL between biceps and brachioradialis
115
How is the ulnar nerve blocked?
Elbow flexed at 90 degrees and 3-5 mL is injected between olecranon and medial epicondyle of the humerus
***Too much volume can compress and cause ischemia
116
How do you block the median nerve at the wrist?
5mL between flexor carpi radialis tendon and flexor palmaris longus tendon
117
How is a bier block performed?
1, Apply double tourniquet
2. Place 22g PIV distally
3. Elevate extremity to allow passive exsanguination
4. Wrap Esmarch bandage
5.Inflate DISTAL cuff
6. Inflate proximal cuff
7. Deflate distal cuff
8. Remove Esmarch bandage
9. Inject large volume of lidocaine local -50mL
10. Increase pressure to 250 (min 100)
118
Notes about a Bier block?
Do not use bupivacaine due to risk of cardiac issues
Do not use epi or anything with preservatives
Can use toradol
TWO HOURS MAX INLFATION TIME
119
When does tourniquet pain start? How to treat?
Starts as early as 25 minutes
Since Proximal cuff is inflated, must inflate the distal cuff first to prevent local going systemically
Inflate distal
Deflate proximal
120
Most significant risk of a Bier block?
LAST
Tourniquet must be inflated for a minimum of 20 minutes
20-40 minutes can deflate but then must reinflate
40 minutes - deflate
121
Where does the lumbar plexus arise from?
L1-L4 with occasional T12 and gives rise to 6 nerves
122
Mnemonic for lumbar plexus?
I Invariably Get Lazy On Fridays
Iliohypogastric
Ilioinguinal
Genitofemoral
Lateral femoral cutaneous
Obturator
Femoral
123
Which nerve roots give rise to each nerve in the lumbar plexus?
124
Lower block table
125
Lumbar sensory innervation
126
What nerves are blocked during the psoas compartment block? What is another name for this block?
Lateral femoral cutaneous n
Femoral n
Obturator n
Also called the lumbar plexus block
127
When is the lumbar plexus block useful?
When neuraxial is contraindicated or one extremity is preferred
128
What are the borders of the femoral triangle?
S = Sartorius muscle
A = Adductor longus muscle
IL = Inguinal ligament
129
Going from medial to lateral, what are the structures inside the triangle?
V = Vein
A = Artery
N = Nerve
130
How many branches does the femoral nerve have? What are they?
Two
-Anterior branch innervates the ventral surface of the thigh and sartorius muscle
-Posterior branch innervates quadriceps, knee joint, and medial ligament
-Posterior branch gives rise to the saphenous nerve
131
What does the saphenous nerve innervate?
Sensory - medial aspect of the knee to the medial malleolus
Motor - NONE
Good when combined with popliteal or ankle block
132
Where does the sciatic nerve arise from?
L4-L5 and S1-S3
Divides io tibial nerve and peroneal nerve
133
Where is a popliteal block performed?
Sciatic nerve in the proximal popliteal fossa
134
5 nerves innervate the foot. How can you tell if they are sensory or sensory + motor
3 sensory start with just S
2 Mixed sensory and motor do not start with S
Femoral = Saphenous
Sciatic =
1.Deep peroneal
2. Superficial peroneal
3. Sural
4. Posterior tibial
135
Ankle innervation
136
Where is the Sural N blocked?
137
Where is the Deep Peroneal N blocked?
138
Where is the superficial peroneal n blocked?
139
Where is the saphenous nerve blocked?
140
At the level of the ankle, which nerve is not next to a vascular structure ?
Superficial peroneal nerve
141
What's the difference between PECS1 and PECS2 block?
PECS1 - inject between pec major and minor
PECS2 - inject between pec major and minor THEN between pec minor and serratus anterior
142
Where do intercostals arise from?
Ventral rami of the thoracic spine nerves T1-T11
Each nerve travels beneath the rib
143
Describe the distribution of anesthesia paravertebral block
Only covers one dermatome level
Must be performed at each level desired
144
What are the boundaries of the paravertebral space?
Anterior - Parietal pleura
Medial - Vertebral body and intravertebral foramen
Posterior - Transverse process and superior costotransverse ligament
145
Indications for a paravertebral block?
Thoracic
Breast
Chloey
Herniorrhaphy
Appendectomy
Rib fractures
Flail Chest
Blunt Trauma
Vertebral fractures
Herpes zoster
146
What is an erector spinae block?
Targets dorsal and ventral rami of the thoracolumbar nerves. Can have significant craniocaudal spread
147
What is the triangle of Petit?
Helps with TAP block
Posterior border - Latissimus dorsi
Anterior border - External oblique
Inferior border - Iliac crest
Inside the triangle - internal oblique
148
Goal of TAP block?
Place block between internal oblique and transverse abdominis muscles
These nerves from T6-L1 innervate the IO and TA muscles
149
Indications for a rectus sheath block?
Needs midline incision
Umbilical hernia repair
C Section
Laparoscopic tubal ligation
150
Describe the thoracolumbar fascia
151
Where is the thoracolumbar fascia block injected?
QL1- LA injected lateral to the QLM
QL2 - LA injected posterior to the QLM
QL3 - LA injected anterior to the QLM
152
Dosage for adult and child caudal anesthetic
