Spinal And Epidural Anesthesia Flashcards
How many total vertebra Numbers: Cervical Thoracic Lumbar Sacral Coccygeal
33 7 12 5 5 4
High vertebral curves
C5 and L3
Low vertebral curves
T5 and S2
Purpose of ligaments
Where supraspinous ligament runs from
Stabilizing vertebral body
C5 to sacrum
Where inter spinous ligament runs from
Entire length
Outside to in ligaments (5)
Supraspinous Interspinous Ligamentum flavum Posterior longitudinal ligament Anterior longitudinal ligament
Ligamentum flavum
Extends from where to where
Shaped like what and composed of what
Foramen magnum to sacral hiatus
Wedge shaped, elastin
Ligamentum flavum
Thickest where
What color
Landmark for what
Tough and fibrous in who
Mid line 3-5 mm at L3
Yellow
Epidural placement
Young pregnant women
Spinal meninges are continuous with what
Cranial meninges
Dura mater
_____ meningeal tissue
Begins where and ends where in adults and where in infants
Abuts the what
Thickest
Foramen magnum, ends caudally at S2/Dural sac (PSIS) S3 in babies
Arachnoid mater/ subdural space
Arachnoid mater
Principal physiologic ____ for ____ moving between epidural space and ___ ____
Abuts the ___ ___ giving rise to the subarachnoid space
Ends at ____.
It is ____ and ____
Barrier for drugs
Spinal cord
Pia mater
S2
Delicate and nonvascular
Subarachnoid space
Contains _____
Continuous with cranial ____ and provides vehicle for ___ in the spinal _____ to reach the ____
Houses what (2)
CSF
CSF, drugs, CSF, brain
Spinal nerve roots and rootlets
Spinal cord
Runs from ___ ___ to ___ ____ ends at level ___-___
___ pairs of spinal nerves
Each with ___ root (motor) and ____root (sensory)
___ are composed of _____
Foramen magnum to conus medullaris, L1-L2
31
Anterior, posterior
Roots, rootlets
Dural sac terminates at what level
What is role of filum terminale
S2
Anchors everything down
Dorsal/posterior (____) roots — _____
Ventral/anterior (_____/____) roots — _____
Sensory, dermatomes
Motor/autonomic, Myotome
_____ is the skin area innervated by a spinal nerve and its segment
The portion of the spinal cord that gives rise to all the rootlets of a signal spinal nerve is called a _____
Dermatome
Segment
Cutaneous distribution of spinal nerves
C6 \_\_\_ C7 \_\_\_ and \_\_\_ \_\_\_ C8 \_\_\_\_ and \_\_\_ \_\_\_ T4 \_\_\_\_ T6 \_\_\_\_ T8 \_\_\_\_ \_\_\_\_ T10 \_\_\_\_\_\_
Thumb 2nd and 3rd finger 4th and 5th finger Nippe Xiphoid Last rib Umbilicus
CSF
_____ cc in subarachnoid space
Volume replaced ___-___x per day
Produced ___ml/hr by ___ ____
Specific gravity ____-____
150
3-4
21, choroid plexus
1.004-1.008
Blood supply
Spinal cord supplied by ___ ___ spinal artery and __ ___ spinal arteries
___ branches come off of the ___ to supply these arteries
2 ____ arteries have better continuity of blood supply than the ___ spinal artery
1 anterior, 2 posterior
Radicular, aorta
Posterior, anterior
Neural blockade
Local anesthetic bathes the ___ ___ in that space
\_\_\_\_ block (spinal anesthesia) Local anesthetic is injected into \_\_\_ to directly bathe the nerve root, leads to rapid onset
Epidural anesthesia (outside of \_\_\_\_) Local anesthesia is injected into \_\_\_ or \_\_\_ space and diffused through the \_\_\_\_ cuff before bathing the nerve root. Slower onset
Nerve roots
Subarachnoid, CSF
Meninges, epidural, caudal, Dural
Physiology of neural blockade
Goal: blockade of ___ impulse, a stimulus that causes ___ or ___
Blocks all ___ regardless of fiber type
4 types:
__ and ___ function are also blocked
Nocioceptive, pain, injury
Impulses
Autonomic, sensory, proprioception, motor
Autonomic and motor
Physiology of neural blockade
Different nerve types have different ___ to local anesthetic
___ nerves highly sensitive with rapid onset of blockade
___ nerve intermediate sensitivity
__ nerves more resistant to LA and have slower onset
Sensitivities
Autonomic
Sensory
Motor
Physiology of neural blockade
Spinal blockade
- autonomic blockade ___-___ levels ___ sensory blockade
- motor blockade ___ ___ sensory blockade
Epidural blockade
- autonomic blockade __ level as sensory blockade
- motor blockade ___-___ levels ___ sensory blockade
2-6, above
2 below
Same
2-4 below
Benefits of neuroaxial anesthesia
- decreased incidence of ___, cardiac ___, and ____
- decreased lower extremity vascular ___ ___ due to vasodilation and increased blood flow ___ blockade
- decreased incidence of ____
DVT, morbidity, death
Graft occlusion, below
Pneumonia
Benefits of neuroaxial anesthesia
- decreased ___ response
- avoids ____ manipulation
- decreased incidence of ____
- intra and postop ___ relief
Stress
Airway
PONV
Pain
Disadvantages of neuroaxial anesthesia
- ___
- delayed ____ start
- failure rate depends on _____
- not a ____ anesthetic
Hypotension
Case
Experience
Benign
7 considerations for choosing a technique
Anatomy Age Pregnancy Patho/comorbidities Sensory level required vs adverse physiologic effects Length of procedure Post op analgesic needs
Indications for SAB/Epidural
Anesthesia
- sole ___
- combined ____-___ blockade
- combined _____/____ used in major ____ procedures and lower ___ ____ cases
Anesthetic
Spinal-epidural
GA/regional
Abdominal, extremity vascular
Indications for SAB/epidural
Analgesia
____ and in ___ and ____
Postop and in labor and delivery
Contraindications
One absolute:
Semi absolute ____
____ at injection site
___ defects/____ therapy
Patient refusal
Increased ICP
Infection
Clotting, anticoagulant
Contraindications
Severe _____ or ____
CNS ___/____
Inability to remain ____ for block
_____
______
Hemorrhage or hypovolemia
Disease/meningitis
Still
Bacteremia
Septicemia
Contraindications
____ lesions with fixed __ ___ (severe ___/___ and ___ cardiomyopathy)
Difficult _____
Full ____
______ neuropathies
Valvular, stroke volume, AS/MS, hypertrophic
Airway
Stomach
Peripheral
Cardiovascular changes
Loss of ____ activity results in vasodilation ___ blockade, decreasing SVR ___-___%, decreased ___, therefore CO ___-___%
___ dilation greater than ___ dilation
Sympathetic, below,
15-20,
preload,
10-15
Venous, arterial
Cardiovascular changes
If blocked is at or cephalad to __-__ level the cardiac accelerators are blocked resulting in ___
Results in profound ____
Treatment includes: 3
T1-T4, bradycardia
Hypotension
Vasopressors, volume load (15 ml/kg), vagolytics to treat bradycardia
Pulmonary changes
Low levels of blocked- minimal effect of ___/___/___/___ space
As block ascends, _____ muscle paralysis occurs, a perception of ineffective breathing and decrease ability to ___ develops
No direct ___ effects except those related to positioning unless high block (___-___, ___ nerve)
With profound hypotension, may see ___ of central respiratory centers which causes respiratory ___
MV, TV, RR, Dead
Accessory, protect
Respiratory, C3-5, phrenic
Ischemia, arrest
GI/Renal effects
Nausea vomiting effects ___%
_____ due to unopposed ___ activity
Flow to liver ___ dependent, maintenance of MAP-___untoward liver effects
Renal blood flow has ____ effect
_____ dysfunction, urinary ____. Avoid excessive ____ if no foley
20
Hyperperistalsis, parasympathetic
BP, no
Minimal
Bladder, retention, IVF
Metabolic/endocrine effects
Blocks ___ response to surgery
____ release may be blocked from the ___ ___
____ secretion is delayed
____ due to altered ____ with vasodilation
Stress
Catecholamine, adrenal medulla
Cortisol
Shivering, thermoregulation
Neuro effects
___ maintained unless MAP less than ___
Manifested by ___/___ and if sufficiently decreased, ___ and ___
Decreased signals to ____ ___ system leads to ___
CBF, 60
N/V, apnea and hypoxia
Reticular activating system, drowsiness
Lateral decubitus
___ to the ___. ___ flexed to the ___
Sitting
Low ___
____ block
Improved ___ anatomy
Forehead to the knees, thighs flexed to abdomen
Lumbar, sacral, midline
Pre-procedure set up
Monitors: 3
____
___ delivery
Fluids ____-___ ml
Equipment for ___ management and resuscitation available
Emergency ___ drawn
Consider___ prior to procedure, identify ____
Pulse ox, ekg, BP
Suction
Oxygen
500-1000
Airway
Meds
Sedation, landmarks
Median approach
Most ___, needle placed ___, ___ to spinous processes, aiming slightly ____
Common, midline, perpendicular, cephalad
Paramedian approach
Indicated in patients who can’t ___
Spinal needle placed ____ cm ____ and slightly ___ to the center of the selected interspace
Flex
1.5, laterally, caudal
Midline approach
Layers transversed \_\_\_\_ \_\_\_\_\_ \_\_\_\_ \_\_\_\_ \_\_\_\_ \_\_\_\_ \_\_\_\_ \_\_\_\_ \_\_\_\_ (\_\_\_\_ \_\_\_) \_\_\_ \_\_\_ \_\_\_ \_\_\_ (\_\_\_\_ \_\_\_) \_\_\_ \_\_\_ \_\_\_ \_\_\_ If reached last 2, too far
Skin SQ tissue Supraspinous ligament Interspinous ligament Ligamentum flavum Epidural space Dura mater Arachnoid mater Subarachnoid space Pia mater Spinal cord
Paramedian approach
Misses the ___ and ___ ligaments
Unable to use ___ ___ as guide
Useful in ___ epidurals or pts with narrow ___ openings
Supraspinous and inter spinous
Spinous process
Thoracic, vertebral
Pencil point needle (___/___)
- designed to spread fibers and reduce ___ ___ ___
- yield a distinct ___ as pencil point penetrates the ___
- offers increased ___ strength to minimize bending or breakage
Sprotte, Whitacre
Post Dural headache
Pop, dura
Tip
Cutting needle (_____)
Dural ___ less likely to be noticed due to ___ tip
Increased risk of __ ___ ___
Introducer may not be ___
Bevel must be facing ___/___ in sitting position and ___/___ in lateral position to reduce headache risk
Quincke
Pop, sharper
Postdural puncture headache
Necessary
Left/right, up/down
SAB
- An atomic landmark is identified, ___ ___ ___ palpated and ___ is identified
- A __ ___ is established and a prep solution applied with ___ basic sponges, applied in what fashion
- A drape is applied, using a ___ ___ wipe the ___ from the injection site
- A skin wheel is raised with ___ml of ___ ___ with a ___G needle
Superior iliac crest, L4
Sterile field, 3
Sterile gauze, iodine
2, 1% lidocaine, 25
SAB
- A ___G introducer is passed through skin ___, angled cephalad, stopping in the ___ ___
- A ___G needle is inserted into introducer, stopping at ___ space where presence of ____ determined
Layers further than epidural:
17, wheal
Ligamentum flavum
25, arachnoid, CSF
Dura, arachnoid, subarachnoid space
SAB
- CSF is ___ and ___ ___ are identified as a change in ___ and ____ as the local anesthetic and CSF mix
- The dose is slowly injected, ___ after installation
- All needles are removed and patient is ___
Aspirated, mixing lines, baricity, temperature
Aspirating
Positioned
Midline approach
Palpated ___ ___ of upper vertebra to make sure midline
Increased resistance as pass through the ___ ___ then loss of resistance as pass through ___ to ___ ___
Remove ___ and confirm free flow of CSF (rotate ___ degrees ___times)
Aspirate CSF ___ and ___ med admin
Transverse processes
Ligamentum flavum, dura, subarachnoid space
Stylet, 90, 4
Before and after
Paramedian approach
Identify ___ edge of ___ ___ process
Skin wheel ___ cm ___ and ___ cm ___ to that point
Needle aimed __-__ degrees __ and slightly ___
If lamina contacted needle and walked off in a __ and __ direction
After ___ obtained ___ technique as midline
Caudad, superior spinous
1, lateral, 1 caudad
10-15, medial, cephalad
Medial and cephalad
CSF, same
Density
Specific gravity
The weight in grams of 1 cc of solution at a certain temp
The ratio of the density of a solution to the density of water at a constant temperature
Baricity
What substances are referring to in SAB
CSF specific gravity
The density of a solution to the density of another substance
CSF and LA
1.004- 1.008 (heavier than water)
Specific gravity of LA can be altered by adding ___, ___ or ___
_baric and ___baric produce reliable blocks
Dextrose, water, CSF
Isobaric and hyperbaric
Hyperbaric solution
Specific gravity:
Mix the local anesthetic with ___ and allows LA to ___ into ___ areas
Greater than 1.11
Dextrose, settle, dependent
Hypobaric solution
Specific gravity:
Mix LA with what
Will go where
Isobaric solution
Specific gravity
How you mix it
Factors affecting spread of LA
Top 3 affecting spinal and not epidural
3 others that affect both
Baricity of LA,
position of patient,
concentration and volume injected
Level of injection,
rate of injection (barbotage),
direction of needle and bevel
Which solution used in hip surgery
Hypobaric
4 decisions to consider when dosing SAB
Surgical site
Length of procedure
Body size (height and width)
Physiology
Duration of spinal block
___ of local anesthetic ___ determines duration
Done by ___ absorption via ___ and ___ blood vessels
Metabolized in ___
___ can prolong length of block
Rate, elimination
Vascular, subarachnoid, epidural
Vasoconstrictors
Epidural placement
___ ___ technique with __ needle, ___ facing opening
___ of ___ technique, __ or ___ filled glass syringe
Continuous catheter, touhy, laterally
Loss, resistance, air, saline
Epidural insertion sites: 3
Thoracic, lumbar, caudal
Epidural space
Widest point is ___, ___ mm
Contains ___ and __ ___
Closed space
Medication and catheter deposited into ___ space
L2, 5
Fat and blood vessels
Potential
Epidural
Ligamentum flavum depth from skin is __ cm, 80% of pts between __-__ cm
___-__mm thick at midline in lumbar region
4
3.5-6
5-6
Epidural placement
LOR technique
Steady ___ on ___ compress __ __ while advancing needle, when epidural space entered __ is gone and fluid is easily injected
Note needle __ when this happens
Advance __-__ cm, ___-__ is pregnant
Pressure, plunger, air bubble
Resistance
Depth
2-3
4-6
Caudal block
Involved delivery into __ space via injection through ___ ___
Acces via ___ ligament and __ ___
__ or __g needle and syringe
Epidural, sacral hiatus
Sacrococcygeal ligament and sacral hiatus
22 or 23
Landmarks in caudal anesthesia: 3
Sacral Cornu
Posterior illiac spines S2
Sacral hiatus
Caudal anesthesia
Identify __ __ and __
Needle is introduced in a slightly ___ direction through __ at a __ degree angle
The needle advanced until a __ felt as going through __ membrane
Needle is then __ to a __ degree angle and advanced __-__ __ to make sure bevel is in caudal epidural space
Sacral hiatus and PSIS
Cranial, 60
Pop, sacrococcygeal
Drop, 20, 2-3 mm
Caudal anesthesia
___ to confirm absence of ___ and __
Make sure no ___ injection with other hand
There should be very little ___ to injection
Aspirate, blood and CSF
SQ
Resistance
Caudal anesthesia uses: 4
Peds post op pain control
Hypospadias
Inguinal hernia repair
Perineal and sacral area procedures
Limitations to caudal anesthesia
Variable anatomy in ___, best in pts in what age group
High risk of injection into a ___ ___
Difficulty maintaining ___ should a catheter be used
Adults, less than 7 years old
Venous plexus
Sterility
Spread of epidural
While injecting test dose will notice what if in vascular space or what in subarachnoid space
The quality and extent of epidural dependent on ___ and __ of LA
For induction use ___-___ ml per segment
Rise in heart rate from epi, can’t feel legs if in subarachnoid
Volume and concentration
1.25-1.6
Post dural puncture headache
__-__% incidence
Due to decrease in ___ pressure with compensatory cerebral ___. Causes brain stem to ___ which stretches __ and pulls on ___
Fronts-occipital postural headache occurs within what range of anesthesia
Treatment: 7
1-4
Intracranial, vasodilation, sag, meninges, tentorium
One day to one week
Bed rest, hydration, NSAIDS, abdominal binder, epidural saline injection, caffeine, epidural blood patch
PDPH
Increased incidence in
\_\_\_ \_\_ patients \_\_\_ needle size \_\_\_ population \_\_\_ for LOR \_\_\_ tip needles \_\_ to meninges \_\_\_ attempts
Young female Larger Pregnant Air Cutting, perpendicular Multiple
Procedure for epidural blood patch
__-__ ml
Aseptic epidural injection of autologous blood into ___ level, at same level or more ___
__% effective
If more than __ attempts than other causes need to be ruled out
Side effects: 2
10-20
Epidural, caudad
Greater than 90
2
Backache and radicular pain (pain radiating to lower extremity)
Epidural hematoma
Primary cause is what
Presents with __ or __ ___ weakness
Consult ___ right away if suspected, __-__ hours before permanent injury
Greater than __ hours makes odds of decompression less successful
Hold LMWH __-__ hours before placement and hold __-__ hours after. Heparin can be given __-__ post.
Coagulation defect
Numbness or lower extremity weakness
Neurosurgery, 6-8
8
10-12, 10-12
1-2
