Neuraxial Blocks - Torabi PP Flashcards
1
Q
What vertebral level corresponds with this landmark: Spine of Scapula
A
T3
2
Q
What vertebral level corresponds with this landmark: Posterior Superior Iliac Spine
A
S2
3
Q
What vertebral level corresponds with this landmark: Superior Aspect of Iliac Crest
A
L4
4
Q
What vertebral level corresponds with this landmark: Vertebra Prominens
A
C7
5
Q
What vertebral level corresponds with this landmark: Inferior Angle of Scapula
A
T7
6
Q
What vertebral level corresponds with this landmark: Rib margin 10cm from the midline
A
L1
7
Q
How many vertebrae are there?
A
33
8
Q
How many cervical vertebrae?
A
7
9
Q
How many thoracic vertebrae?
A
12
10
Q
How many lumbar vertebrae?
A
5
11
Q
How many sacral vertebrae?
A
5 -fused
12
Q
How many coccygeal vertebrae?
A
4-fused
13
Q
Another name for facet joint?
A
Zygapophyseal Joint
14
Q
What is the intercristal line?
A
AKA Tuffers Line
A horizontal line drawn across the superior aspects of the iliac crests correlates with the L4 vertebra.
15
Q
The interspace above the intercristal line correlates with?
A
L3-L4
16
Q
The interspace below the intercristal line correlates with?
A
L4-L5
17
Q
In infants, up to 1 year, the intercristal line correlates with the?
A
L5-S1 interspace
18
Q
What is the Sacral Hiatus?
What vertebrae does it coincide with?
A
- Coincides with S5
- Covered by sacrococcygeal ligament
- Provides entry point to epidural space, useful in pediatrics
19
Q
What is the sacral cornua
A
bony nodules that flank the sacral hiatus
20
Q
Where is the conus medullaris located in adults and infants?
A
Adult: L1-L2
Infant: L3
21
Q
What and Where is the cauda equina?
A
Bundle of spinal nerves extending from the conus medullaris to the dural sac.
Nerve and Nerve Roots from L2-S5 nerve pairs and coccygeal nerve
22
Q
Where does the subarachnoid space terminate? What vertebrae?
A
dural sac
Adult: S2
Infant S3
23
Q
What anchors the spinal cord to the coccyx?
A
Filum Terminale
24
Q
What two points is the Filum Terminale fixed at?
A
- conus medullaris
- coccyx
25
Describe the location of the supraspinous ligament
Runs most of the length of the spine and joins the tips of the spinous processes
26
Describe the location of the Interspinous Ligament
Travels adjacent to and joins the spinous processes
27
Describe the location of the Ligamentum Flavum
2 Flava run the length of the spinal canal
Form the dorsolateral margins of the epidural space
28
Where is the ligamentum flavum thickest?
Lumbar region
29
Piercing the ligamentum flavum contributes to losing resistance when the needle enters the ____?
Epidural Space
30
Describe the location of the posterior longitudinal ligament?
Travels along the posterior surface of the vertebral bodies
31
Describe the location of the anterior longitudinal ligament
It attaches to the anterior surface (tummy side) of the vertebral bodies and extends the entire length of the spine.
It also attaches the annulus fibrosus of the intervertebral discs
32
During the midline approach, the needle [passes through how many and which ligaments?
passes through 3
Supraspinous Ligament
Interspinous Ligament
Ligamentum Flavum
33
During the paramedian or Taylor approach, how many ligaments does the needle pass, and which ligaments?
1 ligament: Ligamentum Flavum
34
With either approach, midline or paramedian, the needle should NEVER pass through which ligaments?
Anterior or Posterior Longitudinal Ligaments
35
When is the paramedian approach useful?
When the interspinous ligament is calcified or when the patient cannot flex their spine
36
What position can the paramedian approach be performed in?
Sitting, lateral, or prone
37
The paramedian approach involves inserting the needle:
15 degrees off the midline or
1cm lateral and 1 cm inferior to the interspace
38
Name the borders of the epidural space: cranial, caudal, anterior, posterior, lateral
Cranial: Foramen Magnum
Caudaul: Sacrococcygeal Ligament
Anterior: Posterior Longitudinal Ligament
Posterior: Ligamentum Flavum, Vertebral Lamina
Lateral: Vertebral Pedicles
39
Epidural fat acts as a sink for lipophilic drugs, reducing their bioavailability. List these drugs in order of bioavailability in the epidural space: fentanyl, morphine, bupivacaine, lidocaine
Bupivacaine > Lidocaine and Fentanyl > Morphine
40
The group of epidural veins that drain venous blood from the spinal cord is called?
Batson's Plexus
41
What regions do the epidural veins pass through within the epidural space
anterior and lateral regions
42
Conditions such as obesity and pregnancy increase or decrease the epidural space?
Decrease. Increases in intraabdominal pressure cause engorgement of Batson's plexus. Associated with an increased risk of needle injury or cannulation during neuraxial techniques.
43
Inadvertent local anesthetic injection into the subdural space will cause?
If using epidural dosing: A high spinal
If using spinal dosing: A failed spinal
44
The subarachnoid space lies deep to the arachnoid mater. Name a few things it contains:
CSF, Nerve Roots, Rootlets, and the spinal cord
45
What is the target area when performing a spinal anesthetic?
Subarachnoid Space
46
The adult spinal cord extends from where to where? And in Children?
The medulla oblongata through L1 – L2
Children L3
47
What is the primary function of the cauda equina?
To send and receive messages between the lower limbs and the pelvic organs, which consist of the bladder, the rectum, and internal genital organs.
48
What regional anesthesia factors increase the risk of cauda equina syndrome?
5% Lidocaine, Spinal Microcatheters
49
S/S of cauda equina syndrome
severe back and butt pain that radiates to legs
50
When does Cauda Equina syndrome usually develop, and how long does it persist?
Develops within 6-36 hours and persists 1-7 days
51
What position is caudal anesthesia done in? What landmark do you palpate for?
Lateral or prone position
Palpate scaral hiatus and sacral cornua
52
Absolute contraindications for caudal anesthesia
Spina bifida
meningomyelocele of the sacrum
meningitis
53
Incidence of local anesthetic-induced seizures occurs more frequently following what kind of neuraxial anesthesia?
Caudal epidural
54
Indications and Advantages of Neuraxial blockade
-Indicated for acute and chronic pain, surgery, labor analgesia/anesthesia
-Less nausea, vomiting, urinary retention
-Decreased opioid consumption
-Greater mental alertness
-Blunt stress response to surgery
-Decrease intraoperative blood loss
-Lower thromboembolic events, ileus
-Increase patency of vascular grafts
-Improved respiratory function
55
In the adult, the Dura sack ends at what vertebrae? In the infant?
S2-adult
S3-infant
56
How much CSF is produced every day, what produces it?
500 mL produced every day/25 mLs per hour.
Produced by the choroid plexus in the lateral third and fourth ventricle.
57
How much CSF is in circulation?
125–150 mL
58
how much CSF in the subarachnoid space from T11 and down?
30–80 mL (T – 11 downward)
59
After CSF is produced in the lateral ventricles, where does it flow next?
Through the Foramina of Munro to the third ventricle.
60
in the third ventricle where does CSF flow next?
Through the aqueduct of Sylvius to the fourth ventricle
61
From the fourth ventricle, where does CSF next?
passes through the foramina
of Magendie and Luschka of the fourth ventricle to reach the subarachnoid space of
the brain
62
About how long does a spinal last that doesn't have epinephrine added?
~2 hours
63
What are some procedures you'd want a high (T4-T8) thoracic anesthetic coverage
Thoracotomy, pectus repair, thoracic, aortic aneurysm repair
64
What are some procedures that you'd want mid thoracic / upper abdominal coverage (T6-T9) from an epidural?
Upper abdominal surgery such as: esophagectomy, gastrectomy, pancreatectomy, hepatic resection
65
What are some procedures youd want lower thoracic/lower abdominal (T7-T10) coverage for a thoracic epidural?
Lower abdominal surgery such as: abdominal aortic aneurysm repair. Colectomy, abdominal peroneal resection
66
when performing a spinal for a C-section. What dermatome level do we want the spinal to reach?
T4 – nipple line
67
what dermatome gives cutaneous innervation to the first digit a.k.a. thumb
C6
68
What spinal nerve root gives cutaneous innervation to the second and third digits?
C7
69
What spinal nerve root gives cutaneous innervation of the fourth and fifth digits
C8
70
What spinal nerve root gives cutaneous innervation across the nipple line?
T4
71
What spinal nerve root gives cutaneous innervation at the xiphoid process?
T6
72
What spinal nerve root gives cutaneous innervation at the umbilicus?
T 10
73
What spinal nerve root gives cutaneous innervation at the pubic symphysis?
T12
74
What spinal nerve root gives cutaneous innervation at the anterior knee?
L4
75
what three nerve roots keep the diaphragm alive?
C3 four and five
76
At what dermatome level are all cardio accelerator fibers blocked?
C8
77
list the order of blockade from a spinal
Autonomic (B-fibers)
Temperature (C- Fibers)
Pain (A-Delta)
Touch (A -beta)
Deep pressure (A-beta)
Motor (A-alpha)
78
what are three things you can use to test your sensation/sensory block?
Cold spray, ice cubes, alcohol pad
79
What are three things you can use to test your sensory/pain block?
Broken end of tongue blade, stylet of epidural, needle, or blunt needle tip, nerve stimulator.
Test normal area first (upper arm) then test from mid thigh and move upwards 2-3levels until they feel pain. This is the deramtome you chart.
80
What are two ways to test your motor block?
Ask the patient to lift their leg or ask the patient to step on the gas
81
what is the site of action of an epidural?
Defuses through the Dural Cuff migrating to nerve roots
82
Spinal and Epidural Differences
Epidural:
-higher dose volumes (10-20mL)
-Slower onset (10-30min)
-does NOT cause significant autonomic/sympathetic response
-multiple dosing possible
-can be given at various points along the backbone
Spinal: lower volume (1.5-2mL)
Faster onset (2-5min)
DOES cause significant sympathetic response
-Single dose only
-Can only be given at specific points along backbone
83
What is the site of action of a spinal?
Myelinated pre-ganglionic fibers of spinal nerve roots
84
What gauge is the Tuohy needle used in an epidural?
17G
85
The primary determinant of spread in an epidural is?
the volume injected
86
do you expect an autonomic/sympathetic blockade in epidurals?
NO, unless you position the patient flat and dose them too high for a C-section.
87
When you administer a spinal, how many levels higher can your sympathetic/autonomic block (b-fibers and c-fibers) travel?
2-6! levels higher than sensory
88
When you administer a spinal, how many levels higher can your sensory (pain - A-delta, A-beta, and A-gamma)) block travel?
2 levels higher than motor
89
What is baricity?
Ratio of the density of the local anesthetic solution to the density of CSF
90
What is the standard local anesthetic solution that comes in the spinal kits?
Bupivacaine 0.75% (7.5mg/mL) in 8.25% dextrose within a 2mL ampule
91
Caution must be used when using a hypobaric local anesthetic solution because?
It can rise, causing a more dispersed blockade
92
what are two ways via positioning, you can use baricity to your advantage when performing a spinal for a hemorrhoidectomy?
Hyperbaric solution: place patient in sitting position for 15 minutes, then turn prone
Hypobaric solution: jackknife or prone position
93
what is the main determinant of local anesthetic spread for a spinal?
Baricity
94
what are factors that significantly affect the spread of spinal anesthesia?
-Baricity of local anesthetic
-Patient position during and after block
-Dose
-Site of injection
95
What are factors that do not significantly affect the spread of spinal anesthesia?
Barbotage
Increased intra-abdominal pressure
Speed of injection
Orientation of needle bevel
Addition of vasoconstrictor
Weight
Gender
96
What is barbotage?
The aspiration of injected volume + CSF back into the syringe, followed by re-injection twice with 0.5mL INCREASES WITH EACH ASPIRATED VOLUME.
[the technique of repeatedly withdrawing and re-injecting cerebrospinal fluid (CSF) and local anesthetic solution during the injection process]
97
What are absolute contraindications to neuraxial anesthesia?
`patient refusal
`Coagulopathy or bleeding
`Increased intracranial pressure
`Severe aortic or mitral stenosis
`Ischemic hypertrophic subaortic stenosis
`Severe hypovolemia
`Infection at site of injection
98
relative contraindications to neuraxial anesthesia
`Pre-existing neurological complications
`Peripheral neuropathy
`Sepsis
`Hypertrophic obstructive cardiomyopathy
`Uncooperative patient
`Severe spinal deformity
`Demyelinating lesions
99
what are some controversial contraindications to neuraxial anesthesia?
` prior back surgery
` prolonged operation
` major blood loss
` complicated surgery
` maneuvers that compromise respiration
100
what coag lab values would indicate neuraxial anesthesia should be avoided?
Platelets less than 100,000
PT, aPTT, and bleeding time > than 2x normal values
101
What is normal PT values
11.3-14s
102
What is normal PTT values
25-35s
103
Normal Bleeding time
3-7min
104
When used alone do herbal supplements appear to increase the risk of spinal hematoma?
No, but when combined with an anticoagulant risk increases
105
What three herbal supplements should be stopped prior to expected neuraxial anesthesia? (If taking high doses or concurrently with anticoagulants)
Ginkgo (stop 36 hours)
Garlic (stop 7 days)
Ginseng (stop 34hrs)
106
How many days before a block placement should warfarin be held
Five days
107
What anticoagulant class of agents are absolute contraindications to Neuraxial anesthesia?
Thrombolytic agents such as TPA, streptokinase, Alteplase, urokinase
108
An epidural catheter can be removed if the INR is less than?
1.5
109
What are the neuraxial anesthetic considerations for patients on unfractionated heparin?
You can proceed with neuraxial if:
1. Patient has a normal clotting mechanism.
2. Patient is not on other blood thinning drug drugs.
Hold heparin 2 to 4 hours before block.
Hold for one hour after block
After indwelling catheter has been removed hold 2 to 4 hours
110
What are the neuraxial anesthetic considerations for patients on LMW heparin?
If on a once-daily prophylactic dose hold for 12 hours
If on a therapeutic dose twice daily, hold for 24 hours
Before removing indwelling catheter hold 12 hours
After indwelling catheter has been removed hold two hours
111
Do you need to hold neuraxial anesthesia if patient is taking NSAIDs?
No, as long as patient has a normal clotting mechanism and isn't on any other blood thinning agents
112
How many days before neuraxial block placement should Clopidogrel be held?
Seven days
113
What are three types of neuraxial infections?
Septic/aseptic meningitis
Epidural abscess
Arachnoiditis
114
How many days before neuraxial block placement should NSAIDs and Aspirin be held?
none, if pt has normal clotting mechanism and not on other blood thinning agents
115
What are some risk factors that increase the risk of infection during neuraxial anesthesia?
Breaking aseptic technique
Psoriasis
Diabetes
HIV, immunosuppression
Steroid therapy
Herpes
116
What are "must do's" for aseptic technique
Wash hands for 20 seconds
Surgical cap for provider and patient
Mask which covers both nose and mouth
No ID tags in field
Sterile prep and drape
117
Systemic effects of neuraxial anesthesia
`Vasodilate arterial and Venus vessels (hypotension, bradycardia)
`Accessory muscle function is decreased
`Impairment of intercostal muscle(impaired ability to cough)
`Loss of proprioceptive input from chest (dyspnea)
`Reduces sensory input to the reticular activating system(drowsiness)
`Inhibits afferent pathways(decreased stress response)
118
Intraoperative risks of neuraxial anesthesia?
Inability to obtain adequate anesthesia
Paresthesia
Hypotension
Dyspnea
High or total spinal
Nausea and vomiting
Allergic reactions
119
What patient population is more likely to have an unexpected cardiac arrest following neuraxial anesthesia?
Young healthy patients due to increased basal vagel tone
120
Sub arachnoid block, cardiac arrest can occur______ minutes after insertion
20-60min
121
Strategies to prevent and treat spinal anesthesia-induced hypotension (SIH)
Crystalloid/collide Solutions 15mL/kg, or 500-1000mL, 15 min before procedure
Vasopressors
Positioning
5 – HT3 antagonists (zofran)
122
Post operative risks of neuraxial anesthesia?
Wet Tap: PDPH
Sepsis
Neurological problems
Backache
Hematoma
123
What is the definition of a high spinal?
Spread of local anesthetic block affecting the spinal nerves above T4. Effects will depend on the nerves involved. bradycardia and shortness of breath.
124
Intraoperative risks associated with spinal anesthesia
-inability to obtain adequate anesthesia
-paresthesia
-hypotension
-dyspnea
-high or total spinal
-N/V
-additional sedation
-allergic rxns
125
What is the definition of a total spinal?
Intracranial spread of local anesthetic, resulting in loss of consciousness
126
Cardiovascular effects of neuraxial anesthesia
`Decreased stroke volume via decreased venous return
`Decrease heart rate if cardio accelerator fibers T1 – T4 are blocked
`Bezold-Jarisch reflex: vagal afferent stimulation in response to noxious ventricular stimuli (aka drop in preload/ventricle pressure)
127
What dose of epinephrine can be added to local anesthetic to prolong duration of a subarachnoid block?
0.1–0.2 mg
128
What morphine dose can be added to enhance the quality of a subarachnoid block
0.1–0.25 mg
129
What fentanyl dose can be added to enhance the quality of a subarachnoid block?
10–25mcg
130
What pt variable do we consider when deciding how many mLs of local anesthetic to use during a spinal?
Height
5'6" ~1.6mL go from there lol
130
What morphine dose can be added to epidurals to prolong block duration and prolong analgesia?
2-5mg
131
What ocular and facial complication can occur if local anesthetic spread spreads to head and neck?
Horner syndrome (ptosis, miosis, and anhidrosis, enophthalmos)
132
What auditory complication can occur from postural puncture, leaks or large volumes of epidural injection?
Transient hearing loss and retinal hemorrhage by changes in CSF pressure
133
What is the site of action of opioids when added to neuraxial anesthesia?
Substantia gelatinosa, rexed lamina II
134
How do vasoconstrictors prolong the action of local anesthetics in neuraxial anesthesia?
Vasoconstriction keeps the local anesthetic in contact with nerve fibers longer
135
What baricity and % Bupivacaine is commonly used for subarachnoid block?
Bupivacaine 0.75% with Dextrose 8.25% which is hyperbaric
136
What is the duration of action of morphine in neuraxial anesthesia
6-24hours
137
What is the duration of action of fentanyl in neuraxial anesthesia
2-6hours
138
What is the epidural dose for fentanyl when added to lumbar epidural?
50-100mcg
dose should be reduced for thoracic
139
What is the average distance from skin to epidural space in an average adult?
4-6 cm
140
What is the average distance from skin to epidural space in an obese adult?
8 cm
141
What is the average distance from skin to epidural space in a thin adult?
3 cm
142
In what order, through what structures, does the needle pass during epidural placement?
Skin
Subcutaneous fat
Supraspinous ligament
Interspinous ligament
ligamentum flavum
Epidural space
143
What is Batson's plexus?
Venous plexus within the epidural space. Obesity and pregnancy make them more engorged.
144
What is the most common needle tip for spinal?
25G whitacre
145
What is the most common needle for epidurals?
17G Tuohy
146
For the Taylor Approach, for spinal anesthesia using a paramedial insertion - where is this performed
L5-S1
147
What is our test dose of lidocaine and epi for an epidural?
~3mL of 1.5% lido (15mg/mL) with 1:200,000 epi (5mcg/mL)
148
If an epidural catheter must be withdrawn while the needle remains in place. how do you remove?
Carefully withdraw both together
149
After loss of resistance, the epidural catheter should be inserted how many cm past the needle tip?
3 to 5 cm
150
Is epidural local anesthetic spread more or less in the elderly? *Torabi Red Item*
3 to 4 times greater in elderly limit local anesthetic volume amt to 0.5-1mL per segment
151
Is epidural local anesthetic spread more or less in the pregnant people? *Torabi Red Item*
3 to 4 times greater in elderly limit local anesthetic volume amt to 0.5-1mL per segment
152
How many mLs should be administered for each segment you're trying to block with an epidural?
1.25-1.5mL per segment.
example: if trying to block L2 and L3 (1.5mLx2)
153
Is epidural spread more or less in pregnancy?
More limit local anesthetic volume amount per segment
154
How would you manage a patchy epidural block or inadequate block?
Reposition the patient with the UNblocked side down (dependent) or by administration of a bolus more local anesthetic solution. or pull back catheter one cm if that doesnt work.
155
What tattoo pigment is associated with the highest incidence of reactions?
Red
156
What signs and symptoms might you see if you inadvertently injected your epidural anesthetic into vasculature?
Restlessness, dizziness, tinnitus, perioral paresthesia, difficulty speaking, seizures, loss of consciousness
157
When might you use an ultrasound for epidural placement?
scoliosis, obesity, diffcult insertion
158
What kind of probe would you use for ultrasound guided epidural
low frequency (2-5MHz)
Curved linear probe
159
Are spinal processes hyper or hypo echoic
Hyperechoic
-Bright-
160
What signs and symptoms might you see if you inadvertently injected your epidural anesthetic into the subarachnoid space (aka spinal)?
agitation, profound hypotension, bradycardia, dyspnea, inability to speak, LOC, T1-4 Blockade
161
What should you do if the epidural catheter tip breaks off during removal?
Inform patient, document in chart.
If pt asymptomatic - leave in
If symptomatic - order MRI and consult neurosurg
162
What are some complications of a Combined Spinal Epidural (CSE) block
`Failure to obtain a subarachnoid or epidural block
`Catheter migration
`Increased spinal level after epidural admin
`Metallic particles when spinal needle enters epidural needle
`PDPH
`Infection
`Neurologic Injury
163
What physiologically occurs that causes a post-dural puncture headache?
Decrease in CSF volume and pressure in subarachnoid space, meninges stretched.
164
What are some factors that increase the incidence of PDPH?
`Large, non-pencil point needle
`Cutting needle bevel direction (perpendicular) to long axis of meninges
`Multiple punctures
`Female
`Age less than 40
165
When does a PDPH usually occur? What are some S/S?
Within several hours to 1-2 days postop
Headache: mild to incapacitating. Positional, relieved when pt is lying down.
N/V
Appetite loss
Blurred vision, photophobia
Plugged ears sensation, loss of hearing acuity, tinnitus
Vertigo
Depression
166
What are two factors that do not effect the risk of PDPH
Early ambulation
Continuous spinal catheter, if placed after spinal block
167
Conservative treatments for PDPH
horizontal positioning
adequate hydration
oral analgesics
IV Caffeine (500mg)
Oral Caffeine (300mg)
Theophylline: 150mg q12hours
Sphenopalatine Ganglion Block (SPG)
168
What are the steps to performing a sphenopalatine ganglion block
1. Soak long cotton tupped applicator in 1-4% lidocaine or 0.5% bupivacaine
2. Place pt in sniffing position
3. Insert applicator into each nare toward middle turbinate
4. Stop when you hit the posterior wall of nasopharynx
5. Leave applicator in for 5-10min
169
What is the definitive tx for a PDPH? How does it work?
Epidural blood patch - performed 24 hrs AFTER the puncture
Works by helping clot formation to seal dura and increase CSF pressure
170
How quickly does an epidural blood patch work?
Relief is usually instantaneous
171
Can you repeat an epidural blood patch?
yes, may try again in 24 hours.
2 failed blood patches -> seek alt diagnosis
172
Where do you insert your needle for an epidural blood patch?
At the same level or 1 level below the level of the lowest initial needle insertion
173
Where do you obtain blood for a epidural blood patch?
20mL patient's venous blood from a PIV or 1 time AC blood draw
174
When do you stop injecting the blood in an epidural blood patch?
Proceed until pt senses pressure in back, butt, or legs (~12-15mL usually)
175
How long should the pt remain supine after an epidural blood patch?
30min-1hour after procedure
176
Describe the steps to performing a combined spinal epidural-single injection technique.
1. Insert the epiderul needle at the appropriate interspace.
2. Then usingthe epidural needle as a guide, insert the spinal needle through the epidural needle into the subarachnoid space and inject local anesthetic.
3. After injection, remove the spinal needle and thread epidural catheter into the epidural space via the epidural needle
4. Lastly, remove epidural needle and secure catheter.
