exam 1 Flashcards
(279 cards)
1
Q
what type of gating is LA for the sodium channel
A
voltage-gated
2
Q
normally, sodium ________ a cell, the cell becomes more _____________, and _________________ occurs
A
sodium enters
cell positive
depolarization occurs
LAs block this! They block impulse propagation!
3
Q
ligand gated involves a ___________ messenger (neurotransmitter) such as ____
A
second messenger
Ach
4
Q
LAs are _____-dependent
A
dose
larger amount of LA blocks a respectively larger number of channels
5
Q
true or false
nerve fibers can be sensory, motor, or both
A
true
6
Q
how are nerve fibers blocked? in order of:
A
size
myelination variables
7
Q
what is blocked FIRST, small or large nerve fibers
A
small fibers (B or C)
8
Q
what is blocked FIRST, myelinated or unmyelinated
A
unmyelinated
9
Q
what type of fibers do LAs work fastest
A
B fibers
10
Q
LAs have a _____________/____________ threshold
A
functional/minimal
11
Q
true or false
for LAs, until a minimum dose is met, there will be NO effect
A
true
12
Q
true or false
LAs are:
concentration-dependent
dose-dependent
volume-dependent
in order to have an effect
A
true
13
Q
AFFERENT neurons are also known as
A
somatosensory
14
Q
EFFERENT neurons are also known as
A
motor
15
Q
what types of nerves are afferent, efferent, and autonomic
A
SOMATIC portion of the PNS
16
Q
what do autonomic neurons do
A
sensory
motor
autonomic functions: signal brain and spinal cord to control visceral elements (hemodynamics, digestion)
17
Q
spinal nerves that travel to the thoracic and abdominal compartments
A
intercostal nerves
18
Q
outside the spinal cord, spinal nerves =
A
peripheral nerves
19
Q
what is the functional unit of the nerve
(individual fiber of nerve)
A
axon
20
Q
what type of cells surround the axon
A
schwann (in layers)
21
Q
myelin sheaths surround the _______
A
axon
22
Q
interspersed among the axon at spaces that are NOT myelinated
A
nodes of ranvier
23
Q
where is a primary site for LAs action
A
nodes of ranvier
24
Q
“Axon intervals”: voltage gated sodium channels that propagate the nerve conduction
A
nodes of ranvier
25
true or false, smallest to largest:
fiber/axon < fascicles (bundles of axons) < fibers (afferent/efferent) < peripheral nerve
true
26
resting membrane nerve potential
-60 to -90 mV
27
3 states of sodium channel
1) activated/open
2) inactivated/closed
3) resting/closed
28
where can LAs NOT act
resting/closed
29
state of sodium channel also known as "refractory period"
inactivated/closed
30
what are the largest and fastest fibers
A (especially A alpha)
31
order of ease of blockade (which occur first, then last)
B fibers, C fibers, then A delta, then A alpha
32
Recovery or “Wearing Off” of Blockade
A-alpha, then A-delta, then C fibers, then B fibers
33
sensory/afferent = ______lateral aspect of the cord
dorso
(from the body)
34
motor/efferent = _______lateral aspect of the cord
ventro
(to the body)
35
These 2 roots converge to form a spinal nerve before dividing into dorsal and ventral rami which innervate anterior and posterior structures
dorsal root
ventral root
36
subarachnoid/spinal space
_________ dose
smaller
37
epidural space
_________ dose
larger
38
how many pairs of spinal nerves
31 pairs
39
how many bones
33
40
cervical NERVES
8*
41
cervical nerves lie ______ the named vertebral body
EXCEPT for ____, which is _________
ABOVE
(except for the 8th, which is below the vertebral body)
42
cervical VERTEBRAE
7
43
thoracic NERVES
12
44
thoracic VERTEBRAE
12
45
lumbar VERTEBRAE
5
46
lumbar NERVES
5
47
sacral VERTEBRAE
5
48
sacral NERVES
5
49
coccygeal NERVE
1
50
coccygeal VERTEBRAE
4*
51
cervical spinous processes are pointed _________
caudad (toward the feet)
52
lumbar spinous processes are pointed _________
straight
53
landmark:
cricoid cartilage
C6
54
landmark:
most prominent cervical level called “vertebral prominens”
C7
55
landmark:
superior angle of the scapula and sternal notch
T2
56
landmark:
plane of Ludwig; carina; angle of Louis
T4
57
landmark:
inferior angle of the scapulae
T7
58
landmark:
xiphoid process
T9
59
landmark:
umbilicus
T10
60
landmark:
superior iliac crest
L4
61
what goes farther, sensation or motor?
sensation (dermatomes)
62
true or false
there is OVERLAP in nerve function
true
63
plexus:
cervical
C1-C4
64
plexus:
brachial
C5-T1
65
plexus:
lumbar
T12-L4
66
plexus:
sacral
L4-S4
67
the brachial plexus is located between the __________ and ________ scalene muscles
anterior
middle
68
Triceps
Supination
Extension of wrist
Extension of other fingers
ABduction of thumb
radial
69
Follows the track of the brachial artery (lying MEDIAL to it)
Pronates
Flexion of wrist + elbow
Flexion of fingers and thumb
ABduction of thumb
mediaN
70
Formed from C8-T1
Follows the brachial artery following the posterior aspect of the medial epicondyle
Flexion of wrist, ring, and pinky finger
Flexion of thumb
ADduction of fingers + thumb
ulnar
71
nerve:
Formed from L2-L4
femoral
72
nerve:
Formed from L4-S3
tibial
73
nerve:
Formed from L4-S2
common peroneal
74
nerve:
Formed from tibial + common peroneal
Extension of hip
Flexion of knee
Plantarflexion of ankle
Dorsiflexion of ankle
All movements of the toes
sciatic
75
why block a plexus, instead of an individual nerve (2)
* In case there is an anomaly
* Convenience (they are very close together)
76
binds to the lipid side with carbon OXYGEN
ester
77
Metabolism: plasma/pseudocholinesterases
Caution with: pseudo cholinesterase deficiency; risk of toxicity due to SLOWER metabolism!
ester
78
Less stable; shorter ½ life; shorter acting
More easily hydrolyzed/broken apart
ester
79
Allergies are MORE likely
* Metabolites para-amino benzoic acid (PABA); causes reaction
ester
80
binds to the lipid side with carbon NITROGEN + HYDROGEN
amide
81
Metabolism: P450 enzymes (liver)
Caution with: liver disease, protein binding issue, enzyme inducing issue!
amide
82
More stable; longer ½ life; longer acting
Less likely to be hydrolyzed/broken apart
amide
83
Some allergies can still occur, rarer
* Due to preservatives such as methylparaben in the LA
amide
84
most common LAs for allergies:
amide
prilocaine
85
most common LAs for allergies:
ester
procaine
86
what is the longest acting ester
tetracaine
87
_________ are more lipophilic and protein bound of the LAs
longer acting
amides
88
lipophilic portion (ring)
aromatic ring
89
linker region (classifies LA)
ester or amide
90
lipophilic region of LA
hydrocarbon chain
91
ionizable/hydrophilic region of the LA
tertiary amine
92
when does metabolism of LAs occur
during "uptake"
once the non-intravascular injected LA gets into circulation/plasma/bloodstream
93
what is the exception, the only one that does NOT get metabolized by pseudocholinesterase for esters
cocaine (metabolized in the liver)
94
An LA can have a long clinical effect until it gets into the bloodstream
DECREASES toxicity!
slow uptake
95
true or false
we want to SLOW the UPTAKE process
true
example: epi
96
where are plasma/pseudo cholinesterases found
OUTSIDE the NMJ
(in the plasma)
97
what is Ach metabolized by
acetylcholinesterase drugs (inside the NMJ)
98
what is the best LA group for true allergic patients
preservative-free amide LA
99
what 2 LAs are common culprits of methemoglobinemia
benzocaine (hurricane spray)
prilocaine
100
signs of methemoglobinemia (3)
tachypnea
low PO2 "blue blood"
LEFT shift (inability of Hgb to carry oxygen)
presents like a PE
101
treatment for methemoglobinemia
methylene blue (1-2 mg/kg IV)
102
the pH at which ½ of the drug is unionized and ionized
pKa
103
If a pH solution (patient) is ________ than the pKa of the drug, then the LA becomes more ionized/hydrophilic, and is LESS able to enter the nerve and have its effect
LOWER
104
with infections, the LA onset is _________ and _______ dense
slower and less dense
105
another term for lipid-solubility in LAs
alkalization
106
what 3 things are associated with lipid philicity
binds better to tissue
longer duration
higher potency
107
_________________ is what allows sodium channel to close
hydrophilicity
108
When a drug has a HIGH pKA, it becomes more _____________ to enter the nerve for action
high pKa= more DIFFICULT
109
a HIGH pKa = more ___________/____________
ionized/hydrophilic
this can be exaggerated when pH is lower or with additives that make the pH lower
110
LAs enter the nerve, ______________________________, ionized portion binds
equilibration of non-ionized and ionized portion = pKa equal
111
3 factors of duration/longevity of action of LAs
1) starting dose
2) tissue distribution (lipid solubility)
3) drug metabolism = delay of uptake
112
true or false
the larger the dose of LA, the longer the duration
true
113
increased blood flow is ____________ related to duration of action
inversely
opposite
114
systemic absorption of LA can be affected by 3 things
site of injection (vessel rich vs vessel poor)
dose
properties (pKa, pH, lipophilicity, protein binding)
115
HIGH protein binding (adherence to tissue) ___________ uptake*
decreases uptake (makes it last longer!)
free drug is more quickly used up
116
what represents the duration of clinical utility
uptake of LA
117
what organ removes a large portion of LA (especially lidocaine)
lungs
118
after injection into tissue, it is how long the LA stays in the tissue (around the nerve) before it gets absorbed into circulation/plasma and taken away for metabolism
clinical duration of action
119
Rates of Uptake from Fastest to Slowest*
(shortest to longest duration)
IV (inadvertent) > tracheal > intercostal > caudal/sacrum > epidural > brachial plexus > femoral = tied with sciatic
120
what LA disables pseudo/plasmacholinesterase
dibucaine
121
the higher the dibucaine number, the __________
better
example: dibucaine 80; 80% of enzyme (plasmacholinesterase) is inhibited
122
what drugs are affected by plasma cholinesterases (4)
remifentanil
esmolol
Sch
esters
123
toxicity with LAs is due to ______________ of inhibitory neurons
depression
124
signs of LAST (5)
SNS symptoms:
ringing in ears
circumoral numbness
tongue numbness
seizures, hyperexcitation
resp arrest, cardiac collapse
(DECREASED conductance)
125
LAST can cause smooth muscle _______________
relaxation
126
which type of LAs are associated with cardiac toxicity (3)
high-protein binding
longer acting drugs
bupivacaine
127
.25% is _____mg/ml
2.5
128
toxicity of LAs occur __-__ minutes from time of injection
1!!-5 min
this is often due to it being intravascular (IV)
129
how can you prevent toxicity of LAs (7)
* Frequent aspiration
* Avoidance of excessive dosing
* Use of ultrasound
* Test-dosing for epidurals
* Incremental dosing
stay below MAX dose
use less lipophilic drugs
130
A form of toxicity in the INTRATHECAL space; nerve roots
permanent
loss of function
intractable pain
cauda equina syndrome
131
causes of cauda equina syndrome or TNS (3)
LAs in prolonged exposure
Mechanical processes such as infection, compression/hematoma, or structural changes
Subarachnoid catheters (particularly with lidocaine, high concentration 5%)
132
Resolvable within a few weeks
loss of function
intractable pain
transient neurologic symptoms (TNS)
133
“Sympathectomy”
LAST
134
LAs are additive**
if giving 2, you need to 1/2 it
135
what is the most lipophilic LA
bupivacaine
136
4 drugs and 1 thing to do for LAST treatment
benzos (best option)
propofol (10%)
20% lipid solution/chelating agent
paralytic
oxygenation/ventilation/control airway
137
CARDIAC treatment for LAST
smaller doses of epi
100 mcg
138
what is the best method to sustain a patient for LAST
cardiac bypass
139
What can exacerbate severity of LAST (5)
seizure threshold (HIGH PaCO2)
high PaCO2, hypoventilation
acidosis
hypoxia
hyperkalemia
140
what is the best treatment for LAST
respiratory
hyperventilation
141
true or false
toxicity is NOT a “large dose”
true
often, it is a higher % concentration
142
how are LAs discussed (2)
% concentration
volume
143
g/____ml
100ml
144
LA additives:
steroids (1)
duration/improve blockade
145
LA additives:
alpha 2 agonist (2)
clonidine + dex
less pain (potency)
duration/improve blockade
(neurodepressive)
146
LA additives:
opioids (3)
lessen pain (potency)
pontentiation/cumulative effect
speed of onset (efficacy)
does NOT affect density or duration
synergistic with LAs
147
LA additives:
sodium bicarb (2)
lessen pain (potency)
speed of onset (efficacy)
148
LA additives:
epi (3)
safety
lessens pain (potency)
duration
149
which is more prominent, alpha 2 agonists or epi
alpha 2 agonists
150
Has a unique metabolite; o-toluidine; this is a pre-cursor for methemoglobin
prilocaine
151
permanently non-ionized (lipophilic ALWAYS; rapid onset)
has the ability to cause methemoglobinemia
secondary amine
BENZOcaine
152
o Not used anymore
o Historically was used regularly for sub-arachnoid block (spinal)
reports of neurotoxicity
5% lidocaine
153
Has a particular propensity to cause cardiac effects (high affinity) more than other LAs
Has a LONG duration of action, highly lipid-soluble
BUPIVacaine
154
Behaves similarly to bupivacaine with respect to onset/time/duration
However, it has less cardiotoxic effects and generally has less pronounced motor block potency
Second generation
Safer
ROPIVacaine
155
EMLA cream
eutectic mixture (LOWER boiling point)
_____________+______________
lidocaine + prilocaine
156
how far in advance does EMLA cream need to be applied
1 hour
157
o A sustained release LA
o Designated for infiltration, this LA is found to have prolonged duration of action, presumably due to DELAYED uptake!
LONGEST DURATION of action (24-48 hours)
good for ortho/joint surgery
liposomal BUPIVacaine (EXPAREL)
158
what can LAs be used for (5)
nerve blockade
inhibition of vent dysrhythmias
reduction in CBF (high ICP)
pain
blunt resp stimulation
159
CAUTION to LAs for cardiac patients
heart block/conduction delay (can cause cardiac standstill)
beta blockers
calcium channel blockers
160
how do we pick which LA to use (2)
onset/duration
safety factor
161
If you need a LARGE volume of a certain medicine, you need to ____________ the % concentration, so you do not reach the max dose
DECREASE
162
_______ axis of the needle
LONG
163
_______ axis of the structure
SHORT
164
reasons for regional anesthesia (4)
postop pain control
opioid reduction or elimination
avoidance of general anesthesia and airway manipulation
reduction in side effects of GAs (cardiac, lung, PONV)
165
what are the 2 ABSOLUTE contraindications to regional
patient refusal
coagulopathy
(depending on severity of block and severity of lab value)
166
what are the 4 RELATIVE contraindications to regional
infection
tolerance for pain (AMS)
risk vs benefit
risk for LAST
167
infection: pH of the tissue is _________ the pKa
BELOW (more ionized)
168
what is a patient at HIGH risk for PTX and regional is CONTRAindicated
COPD patient, at home with 4L O2, 50% CPAP at night
169
what is the best type of skin prep
chloroprep
170
how much lidocaine should be used for a skin wheel
0.5 to 1ml
1%
30g needle
171
what type of system is used for a nerve stimulator
2-lead
positive: connected to EKG sticker
negative: nerve
172
what type of needle is used with a 2-lead system
block/blunt/B needle
conical/rounded in shape
(does NOT have shearing action)
173
true or false:
block needles only have electrical stimuli at the tip
true
174
by adjusting the power/milliamp stimulation (turning it DOWN) you make it more ______________
sensitive
175
how much milliamp do you want
.3 to .5 mA
176
when do you want to inject LA
right after losing muscle movement
177
true or false
ultrasound beam lies ONLY DIRECTLY UNDER the probe
true
178
cross section = ________ axis
short
179
longitudinal = _______ axis
long
180
what do you want to use first _________ axis
short axis
181
with short axis, you can see ________/________ or _________
left/right or WIDTH
182
with long axis, you can see ________
depth
must be "in-plane"
183
what is the ONLY upper approach that does NOT have risk of PTX
axillary
184
paralysis of half the diaphragm
ipsilateral (SAME SIDE)
185
ipsilateral (SAME SIDE) hemiparesis is related to what nerve
phrenic
186
temporary, only occur during the duration of the block
uptake of LA into the head and neck may result in sympathetic blockade to nerves affecting facial structures (PNS symptoms!)
horner's syndrome
187
3 symptoms of horner's syndrome
1) drooping of eye (ptosis)
2) pupil CONSTRICTION (miosis)
3) ABSENCE of sweat (anhidrosis)
188
true or false
horner's syndrome is temporary
true
189
5 complications of UPPER regional blocks
1) PTX
2) ipsilateral hemiparesis
3) horner's syndrome
4) hemorrhage
5) accidental vascular (IV) injection
190
what approaches have a HIGH risk of hemorrhage (non-compressible)
infraclavicular, central
191
what approach has LOW risk of hemorrhage
axillary
192
cervical blockade can cause 5 issues
vertebral artery injection
sub-arachnoid injection
phrenic nerve paralysis (temp)
IV injection
vagus/recurrent laryngeal nerve blockade
193
what nerve roots are associated with cervical
C2, C3, C4
194
interscalene blocks:
________
trunks
think InTer ("IT")
195
SUPRAclavicular blocks:
___________
divisions
196
INFRAclavicular block:
_______
cords
197
axillary block:
_________
branches
198
what nerve roots are involved in brachial plexus
C5, C6, C7, C8, T1
199
What are the “distal” plexus approaches
INFRAclavicular
axillary
200
what is the only block that provides coverage to the shoulder
INTERscalene
201
what is the landmark for interscalene
cricoid cartilage (C6)
202
what 2 muscles is the interscalene block between
anterior and middle scalene
203
which block has the HIGHEST risk for PTX
SUPRAclavicular
204
what is a UPPER block that is challenging and painful
INFRAclavicular
205
for axillary block:
which nerve is most SUPERFICIAL
median
206
for axillary block:
which nerve is most DEEP
radial
207
for axillary block:
which nerve is on TRICEPS side
ulnar
208
for axillary block:
which nerve is on BICEPS side
musculocutaneous
209
which block can use landmark technique,
less precise,
involves intentional puncture of artery
axillary "transarterial"
2 puncture sites
210
how many mL for intercostal block
3-5 ml per site
211
how deep of injection (inferior edge of rib)
for INTERCOSTAL block
2-3 mm
212
which block is ONLY MIXED, not a sole anesthetic
trasversus abdominis plane (TAP)
213
true or false
TAP block does NOT affect ambulation
true
214
into what fascial plane do you inject for TAP block
transversus abdominus (fascial plane BEFORE reaching that muscle)
215
what nerves are blocked in TAP
T9-L1
216
what are the 3 muscles involved with TAP block
external oblique
internal oblique
transversus abdominis
217
which block does NOT use ultrasound or landmarks
bier block
IV regional
218
how long must tourniquet be inflated with bier block
AT LEAST 20 min
219
who is CONTRAindicated from using bier block (3)
dialysis patients
mastectomy patients
trauma patients
220
____mL of preservative-free, epi-free lidocaine is used
what ___%
50 ml
0.5%
221
what 2 things occur with tourniquet release
HYPOthermia
HYPOtension
222
how many mLs per level for PARAVERTEBRAL block
duration?
how many cm depth?
5ml
4 hour
1 cm
223
what is a safe block for the back
erector spinae plane
224
you want to see the erector spinae MUSCLE in the _______ axis
LONG (like the needle)
225
erector spinae muscle:
TRANSVERSE PROCESS in the _______ axis
SHORT axis
226
lumbar plexus
L2, L3, L4
227
lateral femoral cutaneous nerve
L2, L3
228
obturator nerve
L2, L3, L4
229
what are 2 main nerves that come out of the lumbar plexus
obturator
LFCN
230
what is the drawback of the femoral nerve and LFCN block
canNOT ambulate
231
tibial nerve causes:
_________flexion
plantar
232
common peroneal nerve causes:
_________flexion
dorsi
233
foot drop occurs when injured
common peroneal nerve
234
femoral nerve block:
nerve is approached _____________ from the femoral artery
and ____________ the inguinal ligament/fascial layer
LATERAL
BELOW inguinal ligament
235
how many mLs for a femoral nerve block
20-30ml
236
what is the key target of the fascia iliaca block
lateral femoral cutaneous nerve
(femoral occurs by default)
237
2 other names for adductor canal block
saphenous nerve block
distal femoral block
238
true or false
adductor canal block does NOT affect the hip
true
239
true or false
which block is difficult to see the nerve (this is normal)
adductor canal block
240
what is the target of the adductor canal block
below/adjacent to the sartorious muscle
241
very few branches come off the ________ plexus
SACRAL
242
how many cm along the perpendicular line should the sciatic nerve block occur
5 cm
CAUDAD
243
where does the sciatic nerve divide:
____cm ABOVE the bend of the knee
10cm
244
true or false
you still ambulate with a popliteal block
true
245
which block requires the prone position
popliteal
246
nerves are _________ to vein/artery
LATERAL
247
tibial nerve is more ______________,
___________ to the vein and artery
MEDIAL
CLOSER to the vein/artery
248
common peroneal nerve is more ______________,
___________ to the vein and artery
LATERAL
FARTHER from the vein/artery
249
true or false
tibial nerve is LARGER
true
250
true or false
tibial and common peroneal nerves are VERY CLOSE together
true
251
5 nerves of the ankle
posterior tibial (PT)
saphenous
deep peroneal (DP)
superficial peroneal (SP)
sural
252
posterior to the PT artery
PT nerve
253
medial side, anterior to malleolus
saphenous
254
lateral to anterior tibial artery
DP
255
lateral, anterior to malleolus
superficial peroneal
256
lateral, posterior to malleolus
sural
257
true or false
ankle block is often LANDMARK guided
true
258
sural sensation
pinky toe
259
SP sensation
lateral/on the side
260
DP sensation
between first and second tarsal
261
PT and saph sensation
medial
262
How does complete anesthesia of the leg or knee occur
Femoral + sciatic nerve block
263
As long as you block ________ the site of surgery/pain, you are okay
ABOVE
264
Which nerve would NOT be covered with a popliteal block
saphenous
265
What nerve is covered by the Adductor Canal Block/saphenous Nerve Block
femoral
266
What 6 nerves will the sciatic cover
tibial
common peroneal
PT
DP
SP
sural
267
what is NOT covered by the interscalene block
ulnar nerve
and
sensory to the hand
268
what is NOT covered by the supraclavicular block
shoulder
269
what is NOT covered by the infraclavicular block
shoulder, upper arm
270
what is NOT covered by the axillary block
shoulder, upper arm, elbow
271
3 blocks for ANTERIOR KNEE
adductor
femoral
fascia iliaca
272
3 blocks for ANKLE
popliteal
sciatic
ankle
273
5 additives
1. sodium bicarbonate
2. epinephrine
3. opioids
4. alpha 2 agonist (clonidine)
5. steroids (dexamethasone)
274
adjusts the SENSITIVITY of the probe to the tissue
gain
275
increases the DISTANCE that the probe scans the tissue
depth
certain probes may DECREASING WIDTH of the scan as DEPTH INCREASES
276
C6
radial
277
C7
medial
278
C8
ulnar
279
what site has the highest risk of toxicity
tracheal (highest rate of uptake, besides IV)
