Exam II: Central Nerve Blocks Flashcards
Understanding of the ___ ___ of the vertebral body is necessary for consistent success in ___ in administration.
structural components, block
This is the best picture to appreciate needle advancement, but also note that___ connect the ___ ___ to the vertebral body and lamina connect the transverse process to the ___ process
pedicles, transverse process, spinous
Spinal needle___ ___ ___to aid evaluation of tip location within the subarachnoid space.
rotated 360 degrees
The spinal cord terminates at the level of___in most adults having continued from the base of the ___.
L2 , brain
This last portion of the cord is termed the ___ ___and is generally at the level of __.
conus medularis, L2
The___ of the cord is not abrupt but transitions into a collection of nerves called the ___.
termination, cauda equina
The importance of this structure is the lessened risk of ___ ___ injury when a needle is placed into the space, thus ___-____ blockade is ideally placed ___ this level.
direct cord, sub-arachnoid, below
The epidural space is ___to the dura and ___ to the ligamentum flavum is ___.
posterior, anterior, “potential”
Like the esophagus, it’s not an ___ supported structure like the trachea.
air-filled
Rather, it is a ___structure like an ___balloon.
collapsed, uninflated
This space contains: ___, ___, and ___where nerve roots pass ____.
[Epidural]
nerve, vessels, fat, outwardly
The epidural space is generally ___ deep to the skin and is widest at the ___ ___ and tapering to the narrow ___.
5cm, midline point, inwardly
Bordering the space are the ___ ___.
epidural veins
The three essential curvatures of the spine should be noted (3)
Lordosis, Kyphosis, Scoliosis
Lordosis, is:
the inward curving position noted naturally in the lumbar and cervical regions resulting in a posterior directed spine.
Kyphosis is:
the outward-curving position found in the thoracic region and when exaggerated results in the forward leaning position.
Kyphosis is:
the outward-curving position found in the thoracic region and when exaggerated results in the forward leaning position.
Scoliosis is:
a lateral transitioning development.
For lumbar placement, opposition of the ___ ___ allows the spinous processes to ___ for the widest point of access.
natural lordosis, “open”
Lumbar spinous processes are the least___deflected compared with ___ and cervical vertebrae.
downward, thoracic
Thus, ___ approaches are often uses for ___ ___ to avoid the steep spinous process approach.
paramedian, thoracic approaches
Consideration of the use of ___ ___ follows other anesthetic decision-making pathways.
central blockade
The use of a ____ should be used.
[Consideration of central blockade]
risk to benefit comparison
The ___ ___is not to be underestimated as a decision-making tool and the ___ ___ though easily normalized away through integration of electronic health records, should not be dismissed.
patient history, patient interview,
___ at the site of injection or near the CNS, coagulopathy or use of ___, neuromuscular disease (MS, MG, Increased ICP), ___ frailty, patient consent and ability to___both the block placement and procedure under blockade, and surgical requirements should be considered in the process.
Infection, anticoagulants, cardiac, tolerate
Specific cardiac diagnoses have special implications for ___.
SAB
___ and HOCM/ IHSS have ___ specific blood pressure regulation and a ___ can result in cardiac arrest with difficulty in resuscitation.
Aortic valve stenosis, SVR, sympathectomy
Various ___ have been applied to coagulation lab values for epidural and spinal blockade eligibility.
ranges
Some of these are loosely based on ___ values and ___ within an institution.
[Lab values]
historic, normalized
For example, some facilities use an activated clotting time, aspirin use, platelet count, and PT/PTT values in developing a ___ though no absolute standard is recognized.
contraindication
A significant matter for which anesthesia should be involved is the post-operative removal of ___ ___.
epidural catheters
Not only is there potential for ___ ___, but special techniques may be required for ___.
accidental retention, extraction
Additionally, the prevalence of post-operative ___ ___ warrants careful timing of removal such that previous and anticipated doses of anti-coagulants do not increase the risk of___ ___
VTE prophylaxis, epidural hematoma.
The key point is that a non-compressible hemorrhage is ___, ___, and ___.
difficult to resolve, slow to be recognized, potentially catastrophic
The reliance on the ___ pathways to independently mitigate any ___ ___warrants the careful consideration of whether to proceed in the presence of a perceived or ___of normal blood clotting.
coagulation, vessel damage, potential impairment
See the reference article on the consensus statement regarding each of the specific coagulation manipulating agents and their respective ___ times that impact nerve blocks; particularly ___ ___.
“hold”, central blocks.
Complications that may arise from ___, ____, or ___parallel the anticipated impairment of the neurologically controlled systems.
CNS infection, hematoma, direct injury
___, ____, ___; changes in bowel or bladder function; or severe pain in the back warrant immediate evaluation.
Altered pain, temperature, motor function
A “total” spinal occurs when injected medications block nerves high into the ___or even ___levels.
thoracic, cervical
Blockade of sympathetic stimulation results in ___; bradycardia, hypotension, vascular collapse, and apnea accompany the loss of motor function of the ____ extremities.
unimpeded parasympathetic response, lower and upper
Loss of consciousness should be expected; presumably related to ___ ___.
cerebral hypoperfusion
Loss of consciousness should be expected; presumably related to ___ ___.
cerebral hypoperfusion
___, ___, and ___support should follow quickly with consideration of ___ response if the obstetric setting.
[Complications]
Airway support, oxygen, and hemodynamic, fetal
What are 6 adverse physiological responses for neuraxial anesthesia?
Urinary retention, high block, total spinal anesthesia, cardiac arrest, anterior spinal artery syndrome, and Horner syndrome.
Complications related to needle/catheter placement: B___, dural puncture/leak, postural puncture headache, diplopia, t___, neural injury, nerve root damage, spinal cord damage, caudal equine syndrome, bleeding, infra spinal/epidural hematoma, misplacement, ___/inadequate anesthesia, s___ block, inadvertent intravascular injection catheter shearing/retention.
Backache, tinnitus, no effect, subdural
What is a “Spinal headache”?
Post-Dural puncture headache/PDPH
PDPH occurs when ___ ___occurs and ___ ___ is inadequate resulting in CSF leakage.
dural puncture, dural closure
When ___ ___supersedes production, the “stretching” of the ____ results in a headache
CSF leakage, meninges
Classic symptoms include a worsening of the headache in ___position; when ____, the CSF pressure increases relieving the ____.
[PDPH]
the upright, supine, stretching
Incidence is ___ of spinals.
[PDPH]
1-2%
Incidence is ___ of spinals.
[PDPH]
1-2%
Conservative treatment involves (4)…
[PDPH]
rest, supine position, caffeine (oral or IV), and hydration.
If unsuccessful, an ___ ___ __ is performed resolving most cases (90%).
[PDPH]
epidural blood patch
Rarely is a ___ ___necessary, but can be used.
[PDPH]
second patch
If unsuccessful, more ____and/ or____pathologies must be considered.
[PDPH]
serious, permanent
____ volume of blood is used to “patch” the dura.
[PDPH]
20ml
Cutting needles mimic ____ in that they have beveled edge.
[Subarachnoid/spinal placement]
hypodermic
A ____ inside the needle reduces the likelihood of coring of tissue during____.
[Subarachnoid/spinal placement]
stylet, insertion
___-___ needles are popular and have a ___ shaped tip that are designed to separate without cutting tissues
[Subarachnoid/spinal placement]
Non-cutting, cone
Generally, ____ gauge needles are used to reduce the chance of a ___ ___from dural holes.
[Subarachnoid/spinal placement]
small, CSF leak
Baricity reflects the response of the ___ to the native ___.
[Baricity]
injectate, CSF
____ indicates in “sinks” whereas ___ stays in the same location and ____ floats.
[Baricity]
Hyperbaric, isobaric, hypobaric
Commonly, a hyperbaric solution is used and achieved by use of Dextrose ___ and is often found ____ with the LA.
[Baricity]
7.5%, pre-mixed
Selecting the baricity has application when the ___, ___, ___ are considered.
[Baricity]
position of the patient, surgical site, and toleration of the procedure
For example, a left hip fracture patient may not tolerate lying on the ___ ___ for a spinal.
[Baricity]
left hip
A ___ spinal might be used to affect the left hip while lying on the right.
[Baricity]
hypobaric
What are 6 most important factors affecting the dermatomal spread of spinal anesthesia?
Baracity of anesthetic solution, position of the patient, during injection, immediately after injection, drug dosage, site of injection.
8 other factors are considered affecting the dermatomal spread of spinal anesthesia: age, CSF, c___, drug volume, i____, needle direction, patient height, p___
curvature of the spine, intraabdominal pressure, pregnancy
The two approaches to the sub-arachnoid space are the ___ and ____approach.
midline and paramedian
Midline offers the benefit of ___ ___ to consider and simply approaches the structures ___.
fewer angles, directly
Additionally, the midline approach offers the ___portion of the epidural space versus the ____.
widest, paramedian
Commonly, the___ are connected resulting in identification of L4.
iliac crests
Between this and the L2, spinous processes are visualized to form an ___ line.
intersecting
Following skin preparation and draping, ____ between the selected spinous processes, ___ lidocaine is injected for topical sensation.
midway, 1%
Then an introducer needle is placed ____ or slightly ___ followed by insertion of the spinal needle through the ____.
horizontally, cephalad, introducer
Generally, ligaments are recognized by a ____, or ____ (friction) changes as the needle advances.
pop, tension
It is acceptable to frequently check the needle by removing the ____for identification of the ___.
stylet, CSF
Following the absence of___ or ___, the LA is injected into the CSF and both the spinal and ____ needles are removed.
blood or paresthesia, introducer
The effect of spinal block on vascular tone (sympathetic blockade) is noticed in ___ and ____.
[Side effects: subarachnoid block]
loss of vascular tone/ SVR and subsequent hypotension
This (sympathetic blockade) can be more pronounced in patients with ___ ___or in conditions of___ ___.
[Side effects: subarachnoid block]
underlying disease, volume depletion
This “sympathectomy” occurs within ____ of injection and can be mitigated with small doses of ____ and ___ ___ pre-treatment in eligible patients.
[Side effects: subarachnoid block]
minutes, vasopressors, volume challenge
When dermatome levels reach the ___ level, cardioaccelerator nerves are blocked resulting in prominent (unopposed) ___stimulation and ____.
[Side effects: subarachnoid block]
T1- T4, parasympathetic, bradycardia
Under certain conditions, the sudden loss of ___ coupled with loss of heart rate can result in profound ___ and ____.
[Side effects: subarachnoid block]
SVR, hypotension and loss of consciousness
If the anesthetic is associated with obstetrics, concern for ___ ___ is warranted.
[Side effects: subarachnoid block]
fetal circulation
While neosynephrine is often recommended for hypotension, reflex bradycardia may result in ____ ___ with a high-level spinal (___ ___).
[Side effects: subarachnoid block]
cardiac asystole, baroreceptor response
Prudence in managing ___and ___ ___ simultaneously is recommended.
[Side effects: subarachnoid block]
SVR, heart rate
A recognition of dermatome levels is helpful in developing ___, ___, and ___.
[Dermatone Level Evaluation]
dosing calculations, documentation, and adequacy of coverage for analgesia
Many charts exist to assist in memorization of the ___and the ___ landmarks.
[Dermatone Level Evaluation]
levels, surface
Access anesthesiology references in the Hadzic’s textbook of regional anesthesia are generally very practical.
[Dermatone Level Evaluation]
I think this just a tip**
In addition to these charts, several ____ are well known corresponding markers for dermatome levels.
[Dermatone Level Evaluation]
landmarks
___ is the most prominent cervical spinous process, the ____ is at T7, T10 is at the ____, and ___ is at the level of the superior aspect of the iliac crests.
[Dermatone Level Evaluation]
C7, base of the scapulae, umbilicus, L4
For both spinal and epidural, a “___” or ___be identified by having a level of sympathetic blockade with loss of temperature superior to an area of sensory blockade with loss of sense of touch and pain superior to a motor blockade with inability to generate skeletal muscle control.
[Dermatone Level Evaluation]
“differential block”, difference of effect can
As a general rule, these differentiations are a couple of ____apart (1-3).
[Dermatone Level Evaluation]
segments
As the ___ wanes, so does these levels.
[Dermatone Level Evaluation
blockade
Spinal dosing is influenced by the desired ____ of anesthesia and the ____ to be anesthetized.
[Dosing]
length, dermatome level
In a dose dependent fashion, more ____ of LA results in a ___ and higher___of blockade.
[Spinal Dosing]
milligrams, longer block, level
Blockade height can be manipulated by adjusting ___ and ___ at insertion.
[Spinal Dosing]
baricity and position
Most important factors: (6)
B____
D___
D___
A____
S___
P____
[Factors affecting the dermatomal spread of spinal anesthesia]
Baracity of anesthetic solution
Drug Dosage
During Injection
After Injection (immediately)
Site of Injection
Position of the patient
Other factors:
Patient ___, Intraabdominal ____, Pregnancy, CSF, ____ of the spine, Age, Needle direction, Drug volume
[Factors affecting the dermatomal spread of spinal anesthesia]
Height, pressure, Curvature
Epidurals offer ____ blockade anesthesia with several unique characteristics that must be weighed in the ___ decision making process.
[Epidural placement]
central, anesthesia
*Ability to create ____blockade without motor blockade.
[Epidural placement]
sensory
*Ability to titrate more or less dosage to change of ___ and ____.
[Epidural placement]
spread medication and clinical effect
*Ability to provide prolonged effect through ___ or ___dosing
[Epidural placement]
continuous or intermittent
*Less dense of a motor block than ____
[Epidural placement]
SAB
*Larger needle placement, increases risk of ____from inadvertent vessel injury
[Epidural placement]
bleeding
*Larger needle increases risk of ___ if inadvertent subarachnoid puncture
[Epidural placement]
PDPH
Clinical effect is achieved through both the action on ____ as they pass through the epidural space and diffusion into the CSF where action is on the ____.
[Epidural placement]
spinal roots, spinal cord
The ____ process is slower than with SAB injection directly into the CSF.
[Epidural placement]
diffusion
Access to the epidural space is by a special needle that is both ___ and ___.
[Epidural placement]
blunted and curved
The blunting decreases the likelihood of ___ puncture; the needle should pass through the ___, stop in the ___ space, and remain shallow to/ proximal to the ___.
[Epidural placement]
dural, ligamentum flavum, epidural potential, dura
The curvature also protects the dura by avoiding a ___ on the ___end.
[Epidural placement]
piercing tip, distal
Additionally, the curvature directs the ___; generally, ___ for advancement.
[Epidural placement]
catheter, cephalad
The larger gauge ___ facilitates the placement of the ___through the needle once it arrives in the ___ space; generally advancing the catheter 2-5cm past the needle tip.
[Epidural placement]
(18-16g), catheter, epidural
Identification of the epidural space requires a unique process with one of two techniques, either ___ or ___.
[Epidural placement]
loss of resistance or hanging drop
The ___ technique is the most common and easier to learn.
[Epidural placement]
loss of resistance
Once the epidural needle is advanced into ___, the stylet in the ___ needle is removed and a glass syringe attached. [Epidural placement: Loss of resistance technique]
interspinous ligament, Tuohy
The property of the syringe is such that the plunger is “___” within the barrel and feels “___”.
[Epidural placement: Loss of resistance technique]
“loose”, “spongy”
The needle is___advanced with careful bracing against the patient with ___ or ___ compressions of the plunger.
[Epidural placement: Loss of resistance technique]
slowly , constant, frequent
Because the ___ will not allow injection, the plunger bounces back to compression.
[Epidural placement: Loss of resistance technique]
ligament
Only after entering the ___ space (or vessel), will the loss of resistance be achieved where the plunger ___.
[Epidural placement: Loss of resistance technique]
epidural, advances
This (loss of resistance) signifies needle ___.
[Epidural placement]
entry
The hanging drop again begins with the needle tip in ___ as soft tissue superficially ___ injection.
[Epidural placement: Hanging Drop]
ligament, accepts
Once the needle is in ligament, the ___ is removed and ___ is added to the hub of the needle to be maintained by ___.
[Epidural placement: Hanging Drop]
stylet, saline, surface tension
As the needle advances, the potential space, with its ____ pressure, will draw the saline into the needle.
[Epidural placement: Hanging Drop]
subatmospheric
Thus placement is confirmed when the saline drop ___ into the needle. [Epidural placement: Hanging Drop]
withdraws
Anecdotally, caution must be used with this technique as it requires ___ and ___.
[Epidural placement: Hanging Drop]
extraordinary attention and needle control
Further, any occlusion of the needle will ___ the drop from having access to the space and its negative pressure property which exposes the patient to ___.
[Epidural placement: Hanging Drop]
prevent, inadvertent dural puncture
*If a dural puncture occurs, ___ of the needle is warranted immediately. Some practitioners have considered placement of a ____ to “seal” the hole and allows ___block dosing as a temporary measure. Since sub-arachnoid catheters have fallen out of favor due to TNS and cauda equina syndrome, this practice is not recommended.
[Special precautions with epidural needles]
removal, sub-arachnoid catheter, spinal
*Catheters should not be ____from the needle. If the catheter must be ____, the needle should be removed ___ and then the catheter.
[Special precautions with epidural needles]
withdrawn,, withdrawn, first
*Test dosing: The use of ____ (historically ___with ___epinephrine) is used to rule out intravascular and subarachnoid catheter placement.
[Special precautions with epidural needles]
3ml of lidocaine, 1.5%, 1:200,000
If the catheter is in a vessel, the ____ will cause an acute increase in heart rate and blood pressure. If the catheter is ___, then the dose will produce a rapid onset and dense spinal block.
[Special precautions with epidural needles]
epinephrine, subarachnoid
*Cather tip placement should ideally be at the center of the ___ region being anesthetized as this ____ the concentration of LA in that area.
[Special precautions with epidural needles]
dermatome, increases
*___ effects spread. A higher ____ agent with less volume can have a greater density with less spread, while a lower ____ agent with more volume will have a more diffuse, but less intense blockade.
[Special precautions with epidural needles]
Volume, concentration, concentration
A guide is to consider ___ml per level of spread. So for T-10 to S 5, you would need ___mls of volume.
[Special precautions with epidural needles]
1ml, 12 mls
Thus volume affects ___and concentration affects the ___affected.
[Special precautions with epidural needles]
spread, types fibers
*Re-dosing of a catheter does not require an additional___dose, but should always be ___first.
[Special precautions with epidural needles]
test, aspirated
*___ effects density, for laboring women, clinical effect might be ___ if they are positioned to one side.
[Special precautions with epidural needles]
Gravity, less
*Epidural dosing of ___ is similar to intravenous
[Special precautions with epidural needles]
opioids
Using this guide (Morgan and Mikhail text ), ___ml per level (___ with advanced age or during pregnancy for labor) can be administered.
[Special precautions with epidural needles]
1-2 ml, less
Following delivery (in labor epidurals) or surgery, ___ of the catheter is warranted unless sustained post-op ___ is desired.
[Catheter removal]
removal, analgesia
At the desired time, careful removal of the catheter is achieved by simply withdrawing the ___noting the complete ___removal in the ___.
[Catheter removal]
catheter, catheter, documentation
In the event the catheter is stuck, positioning of the patient into___position may open the spaces sufficiently to withdraw the catheter.
[Catheter removal]
placement
Retained catheters warrants neurologic follow up due to risk of ___ and ___irritation of the CNS structures.
[Catheter removal]
sepsis, mechanical
It is critical to remember that ___rules apply to catheter ___ just as they do to catheter insertion.
[Catheter removal]
anticoagulation, removal
For both___ and ___placement, strict adherence to sterility is essential.
[Sterility]
SAB and Epidural
At minimum, ___ preparation of the site, a sterile ___, and ___ should be used.
[Sterility]
sterile, drape, gloves
It is recommended that a ___, ___, ___ also be used.
[Sterility]
mask, hat, and eyewear
Anticipation of needs should accompany insertion such that the ___ prior to gloves being donned and ___ precedes site preparation.
[Sterility]
kit is opened, palpation of landmarks
___, while included in many commercially available kits, has begun to fall out of favor due to potential and advertised risk associated with introduction of ___into the CNS.
[Sterility]
Betadine, betadine
While ___ with ___(chloraprep) solution is also toxic within the CNS, it is more widely accepted as the preferred skin preparation for ___ ___ blocks.
[Sterility]
chlorhexidine, alcohol, central neuraxial
More commonly associated with ___ anesthesia, the caudal block is functionally the same as an ___block.
[Caudal blocks]
pediatric, epidural
Dosing and management are similar as the epidural, however the name is derived from the ___ to the space through the ___ ___(caudal location of insertion).
[Caudal blocks]
approach, sacral hiatus
The anatomical structures are___ reliable in adults thus reducing its ___ and limitations to the procedure also relate to the target level of anesthesia; that is the most ___, ___, and ___ procedures.
[Caudal blocks]
less, efficacy, distal colon, urologic, and lower extremity
Finally, the potential for inadvertent ___ of the LA into other compartments has resulted in an ___ ___ rate for this block as compared to other techniques and approaches.
[Caudal blocks]
extravasation, increase failure
Identification of landmarks is completed by noting the ___, the ___ on as lateral margins and the ___ in the center.
[Caudal blocks]
distal end of the coccyx, sacral cornua, sacral hiatus
A small gauge (___) needle is advanced at a ___degree angle ___ until a pop and loss of resistance is achieved (with saline).
[Caudal blocks]
22ga, 45, cephalad
At this point, injection may occur. ___ ml/kg are administered.
[Caudal blocks]
0.5-1
