Regional Final Flashcards
the brachial plexus is formed by the _____
ventral rami of C5 - T1
The brachial plexus supplies the motor nerves of the _____ and the motor and sensory nerves of the ______
shoulder muscles
arm and hand
3 sections of the brachial plexus
trunks, cords, and nerves
nerves in Superior Trunk
C5-6
Nerves in Inferior Trunk
C8 - T1
the cords of the brachial plexus are positioned around the _____
axillary artery
the ____ cord starts in the anterior division of the inferior trunk
medial cord
the _____ cord starts in the combined anterior divisions from the superior and medial trunk
lateral cord
directly originates in the lateral cord and supplies motor function to the flexors of the upper arm and sensation to part of the forearm’s skin
musculocutaneous nerve
originates where fibers of the lateral and medial cords come together and innervates the motor unit of various flexors in the forearm and some hand muscles and gives sensation to the palm and parts of the fingers I-IV
median nerve
originates directly in the medial cord and innervates the motor unit of various flexors in the forearm, parts of the hand muscles and sensory parts of the back of the hand, palm and fingers I-IV
ulnar nerve
(2) originate in the medial cord and supply sensation to the medial side of the upper arm and forearm.
medial cutaneous
(forearm and arm)
originates in the posterior cord and partially innervates the motor unit of the shoulder girdle muscles and supplies sensation to the shoulder’s skin
axillary nerve
originates in the posterior cord and innervates the motor unit of all extensors in the arm and parts of the hand muscles, and supplies sensation to the dorsal side of the arm.
radial nerve
nerves inconsistently blocked during Interscalene
ulnar and medial cutaneous nerves
nerves inconsistently blocked during Supraclavicular
suprascapular and ulnar nerves
nerves inconsistently blocked during Infraclavicular
axillary, suprascapular, and medial cutaneous nerves
nerves inconsistently blocked during Axillary
axillary, suprascapular, and medial cutaneous nerves
Complications and side effects of Interscalene
- neuraxial anesthesia
- phrenic nerve block
- superior laryngeal nerve block
- Horner syndrome
- Bezold-Jarisch reflex
Complications and side effects of Supraclavicular
- pneumothorax
- phrenic nerve block
- Horner syndrome
complications and side effects of Infraclavicular
- pneumothorax
- Horner syndrome
(3) landmarks for the cervical plexus plexus block
mastoid process
lateral border of sternocleidomastoid
cricoid (C6)
(3) indications for a cervical plexus block
awake carotid
superficial cervical surgery
fractured clavicle
Most common complication of a cervical plexus block
CNS toxicity
(2) blocks for shoulder surgery
interscalene and supraclavicular
Interscalene block frequently spares the ____
ulnar nerve
LA with risks of cardiotoxicity
bupivacaine > ropivacaine > lidocaine
Which LA goes through the least hepatic clearance?
Chloroprocaine
(ester)
A 40-year-old man who is scheduled for repair of a tendon laceration of the left hand with supraclavicular block. Two hours of tourniquet inflation are required for completion of the procedure. The MOST appropriate NEXT step is an additional block of which of the following nerves?
intercostobrachial
Which LA delays ventricular repolarization
bupivacaine
Horner’s Syndrome
ptosis, miosis, and anhydrosis
(100% on interscalene)
which block should be used for an elbow athroplasty if the patient has COPD?
infraclavicular
True or False
epinephrine prolongs anesthesia and analgesia by 50% when added to mepivacaine
True
(4) things that can reduce the risk of seizure from regional anesthesia
- aspiration
- fractioned dosing with observation
- block selection
- test dose
True or False
Ropivacaine 1% and Bupivacaine 0.5% provide equivalent upper extremity anesthesia
True
in an adult, ____ mL of LA is adequate for a successful supraclavicular block
20 - 40 mL
mulitple injections may ______
increase the speed of onset and success rate
- higher risk of nerve injury
- no affect on injection pressure
- will not require an increase in volume
Endoneurium
connective tissue around each nerve fiber
Perineurium
surrounds a fascicle of nerve fibers
epineurium
surrounds groups of fascicles
the ratio of non-neural to neural tissue _____ distally
decreases
LA manifests its blockade from ______
proximal to distal
the 4 P’s in assessing blockade
push the arm
pull the forearm
pinch at the palmar base of index
pinch at the palmar base of pinky
vertebral artery travels cephalad from its origin in the subclavian artery at the _____ level
C6
nerves of the superficial cervical plexus
C3-C4
provide cutaneous innervation at the shoulder
suprascapular nerves
C5-C6
When is a suprascapular block used?
posterior shoulder pain
(due to an incomplete ISB)
Advantages of Ultrasound
- faster onset and longer blockade
- fewer needle passes
- less patient discomfort
infusion settings for brachial plexus blocks
- basal rate
- 5 - 10 mL/hour
- bolus volume
- 2 - 5 mL/hour
- lockout duration
- 20 - 60 minutes
concentration of 1:200,000
5 ug/mL
Advantages of using Epinephrine
- prolongs anethesia and analgesia
- acts as a marker of intravascular injection
- potentially limits toxicity
overall incidence of long-term nerve injury due to regional anesthesia
less than 0.4%
which block has a 100% risk of hemidiaphragmatic paresis (HDP)
interscalene block
a pneumothorax typically develops within _____ of the regional block
6 - 12 hours
(in the absence of positive pressure ventilation)
convulsant dose of unintended intravascular injection with lidocaine and bupivacaine
- 4 mg lidocaine
- 6 mg bupivacaine
which block as the highest incidence of seizures?
infraclavicular
the incidence of seizure after peripheral nerve block is ____ times more likely compared to an epidural
5x
which blocks have a risk of recurrent laryngeal nerve injury?
interscalene
supraclaviular
ischemia and damage are unlikely to occur during a tourniquet if flow is re-established within _____
6 hours
after tourniquet, up to _____ is necessary to return to normal metabolic status
40 minutes
Epidural or Spinal
can inject LA anywhere
epidural
spinal or epidural
better quality of block
spinal
spinal or epidural
longer procedure time
epidural
spinal or epidural
curvature is key
spinal
sacral hiatus
unfused opening between S4 and S5
C7 landmark
bony knob at base of neck
T7 - T8 landmark
lower limits of scapula
L2 landmark
terminal point of 12th ribs
L4 landmark
line across iliac crests
S2 landmark
posterior iliac crests
termination of spinal cord in adults and infants
L1 in adults
L3 in infants
Depth of epidural space
4 - 5 mm
(max of 6 mm at L2)
(5) complications to discuss with patient about neuroaxial anesthesia
- nerve damage
- bleeding
- infecction
- headache
- failed block
Perineal surgery should have a _____ anesthesia
spinal
contraindications to neuraxial anesthesia
- patient refusal
- infection
- coagulopathy or decreased platelets
- ICP
you should not attempt a spinal above ____
L3 - L4
pencil-point spinal needles
whitacre and sprotte
beveled spinal needle
Quincke
which type of spinal needle has a greater risk of post-dural puncture?
beveled
(quincke)
spinal approach for difficult cases
Taylor
(start 1 cm medial/caudal and advance cephalad)
level and duration of spinal are primarily determined by __(3)_\_
baricity
contour of spine
patient position
when to use hypobaric solutions
prone jackknife or those undergoing hip arthroplasty
which LA do vasopressors have a profound affect
Tetracaine
which LA decreases spinal and dural blood flow
bupivacaine
short duration LA
chloroprocaine
the use of vasoconstrictors with _____ is contraindicated
chloroprocaine
duration of lidocaine
60 - 90 minutes
duration of Bupivacaine
90 - 120 minutes
which longer-acting LA has a better sensory anesthesia?
bupivacaine
which longer-acting LA has a better motor blockade?
Tetracaine
opiates can be added to spinals and affect the _____
dorsal horn
Sensory level for Hemorrhoidectomy
S2 - S5
sensory level for Lower Extremity
L1 - L3
sensory level for Foot Surgery
L2 - L3
sensory level for Hip, TURP, and vaginal delivery
T10
sensory level of Lower Abdomen and Appendectomy
T6 - T7
sensory level of Upper Abdomen and C-section
T4
sympathetic block of spinals can exceed motor/sensory by ____ dermatomes
two
Anything above T5 inhibits SNS to the _____
GI tract
Hypotension occurs in 1/3 of spinal patients due to ____
decreased SVR
(also decreased venous return and cardiac output)
First line drug to treat Hypotension during a spinal
ephedrine
Treatment of bradycardia during spinal
volume
ephedrine
atropine
epinephrine
Treatment of Post-dural Puncture headache
bed rest, IVF, analgesia, and caffeine
(possibly a blood patch)
ideal needle size for spinals
24 - 25 G pencil-point
most common epidural needle
Tuohy
approach for lumbar epidurals
midline
approach for thoracic epidurals
paramedial
identification techniques for epidural space
loss of resistance or hanging drop
test dose for epidural
3 mL lidocaine with 1:200,000 epi
caudal blocks
epidural through sacrococcygeal ligament and sacral hiatus
sacral hiatus is absent in _____ of patients
10%
in epidurals, you can ____ concentration and _____ volume for a greater anesthetic spread
decrease concentration
increase volume
Lumbar epidurals tend to flow ____
cephalad
(due to negative intrathoracic pressure)
True or False
Baricity matters in epidurals
false
(negative intrathoracic pressure)
sodium bicarb and LA
favors non-ionized form which increases onset
systemic hypotension is more rare in _____
epidurals
major site of action for an epidural
nerve root
location of cardioaccelerator fibers
T1 - T4
neuraxial blocks results in a sympathectomy _____ dermatomes above the sensory block
2 - 6
(3) mechanisms effecting heart rate
- bainbridge reflex
- direct effect on SA node by atrial stretching
- T1 - T4 cardioaccelerator fibers
decreases HR
cardiovascular effects of Neuraxial anesthesia
decreased preload and HR
arterial and venous dilation
risk of headache after dural puncture
50%
(6) Risk factors for PDPH
- beveled needle
- larger needle
- female
- pregnancy
- younger
- history of headache
Block sensitivty
(first to last)
temp
SNS
pain
touch
motor (last to go)
benefits of central blocks
decrease MAC, produce sedation, and potentiate hypnotics
isobaric solutions offer _____ blocks than hyperbaric solutions
lower
(decreases the risk of cardiovascular compromise)
sacral level spinals will _______ than thoracic
last longer
higher blockers wear off _____ than lower blocks
faster
lumbar epidurals will generally anesthetize from _____
T6 - L4
decrease the anesthetic dose of epidurals by _____ if the upper thoracic dermatomes are anesthetized
30 - 50%
(increased risk of cephalad spread)
axillary block
(picture)

cutaneous sensory distribution
(picture)

infraclavicular block
(picture)

interscalene block
(picture)

Supraclavicular block
(picture)

vertebral anatomy
(picture)

ligaments transversed during neuraxial anesthesia
supraspinous
interspinous
ligamentum flavum
subarachnoid space contains __(3)__
CSF, spinal cord, and conus medullaris
subarachnoid space extends down to ____
S2
filum terminale
extension of pia mater that attaches to the coccyx
____ roots are responsible for sensory blockade
dorsal
(posterior)
_____ roots are responsible for motor blockade
anterior
(ventral)
total CSF volume
100 - 150 mL
specific gravity of CSF
1.0003 - 1.0006
Tuffer’s line
highest points of both iliac crest
L4
HELLP syndrom
hemolysis, elevated liver enzymes, and low platelet count
1st stage of labor
dilation of the cervix and distention of lower uterine
mostly visceral
enter spinal cord at T10 - L1
2nd stage of labor
distension of pelvic floor, vagina, and perineum
mostly somatic
enter spinal cord at S2 - S4
benefits of epidural analgesia during labor
- pain relief and reduction of catecholamines
- extend duration of block to match labor
- blunts hemodynamic effects
- beneficial for patients with pre-eclampsia
reasons for parturients being anti-coagulated
- Protein S or C deficiency
- DVT prophylaxis
- Factor V Leiden
- artifical heart valves
- Lupus antibody
Pre-epidural checklist
- aspiration prophylaxis
- bicitra
- fluid bolus
- monitoring
- maternal and fetal HR
(2) Disadvantages of sitting during Epidural
- decreased uteroplacental blood flow
- orthostatic hypotension
Advantages of CSE
- rapid onset of intense analgesia
- very low failure rate
- minimal motor block (“walking epidural”)
CSE needle
Espocan (B. Braun)
usually a 27G spinal needle through Touhey
symptoms of Cauda Equina syndrome
- bowel and bladder dysfunction
- lower extremity weakness
- pain
- paresis of legs
potency of local anesthetics are related to _____
lipid solubility
duration of action of LA is affected by _____
protein binding
Ropivacaine is ____ less potent than Bupivacaine
40%
0.0625% bupivacaine = 0.1% ropivacaine
epidural and spinal dose of Morphine
- 5 - 5 mg
- 1 - 0.2 mg (spinal)
epidural and spinal dose of Fentanyl
50 - 100 ug
10 - 20 ug (spinal)
epidural and spinal dose of Sufentanil
10 - 20 ug
5 - 10 ug (spinal)
epidural dose of meperidine
25 mg
Ion trapping in Pegnancy
if the fetus is acidotic, then LA can ionize and will become trapped
Optimal spinal drug combination
12 mg Bupivacaine
15-35 ug Fentanyl
0.1 mg Morphine
optimal epidural drug combination
2% lidocaine
50 - 100 ug Fentanyl
3.75 mg Morphine
dosing in a cervical plexus should be ____ mL per level
3 - 5 mL
which type of LA has a greater risk of an allergic reaction?
esters
Prilocaine Toxicity
can lead to fetal methemoglobin when administered to pregnant patients
Rate of absorption by site
intercostal
paracervical
caudal
lumbar epidural
brachial plexus
subarachnoid
subcutaneous
onset of LA is determined by _____
pKa
LA Ranking of dose that causes CNS toxicity
bupivacaine < ropivacaine < lidocaine
term for white on an US
hyperechoic
Doppler flow color
blue away
red toward
(BART)
maneuvers to adjust US
pressure, alighnment, rotation, and tilt
(PART)

Supraclavicular







an infraclavicular block centers around the ______
axillary artery
supraclavicular block is near the ____ artery
subclavian
the interscalene block is between _____
middle and anterior scalene
axillary block involves the _____ of the brachial plexus
terminal branche
infraclavicular block involves the ____ of the brachial plexus
cords
supraclavicular block involves the _____ of the brachial plexus
trunk and divisions
interscalene block involves the _____ of the brachial plexus
roots