Spinal And Epidural Flashcards
1
Q
Cocaine, Procaine, Tetracine and Chloroprocaine are all ______.
A
Esters
1 “i” in the name
2
Q
Dibucaine, Lidocaine, Mepivacaine, Prilocaine … are all _____.
A
Amides
2 “i’s” in the name
3
Q
Local anesthetics are (strong/weak) / (bases/acids).
A
Weak Bases
4
Q
The chemical structure of LAs have a ______ ______ portion and an _____ ______ portion.
A
Aromatic lipophilic, Amine hydrophilic
5
Q
Amino Esters have a ______ chain in the middle.
A
C-O-C
6
Q
Amino Amides have a ______ chain in the middle.
A
NH
7
Q
What is pKa?
A
The pH at which 50% of LA is charged and 50% is uncharged.
8
Q
LA with a lower pKa value will have a _____ onset.
A
faster
9
Q
Both _______ and ________ molecules are present in LA (pKa).
A
charged and uncharged
10
Q
The _______ form is most _______ _______ and able to gain access to the axon.
A
Uncharged, lipid soluble
11
Q
Insert SLide 7 HERE
A
Here too
12
Q
MOA of LA:
A
BLock nerve conduction, impairs propagation of action potential in axons
< rate of rise of AP = threshold potential is not reached.
13
Q
LA MOA interact directly with receptors on the ___ channel.
A
Na+
14
Q
_____ determines speed of onset of neural blockade.
A
pKa
15
Q
Agents with a > degree of protein binding will __ _______ effect.
A
> duration
16
Q
LA _____ cross membranes.
A
Easily
17
Q
Lipid solubility is related to _______.
A
Potency.
18
Q
_____ / _______ fibers are more easily blocked than _____ / _______fibers.
A
Thin, thick
19
Q
Myelinated fibers procude block only at:
A
Node of Ranvier
20
Q
Sequence of clinical anesthesia of LAs:
A
ATP TP MVP
1st: autonomic block myelinated b fibers (and c?)
Skin temp and pain
2nd: Loss of touch and pressure sensation
3rd: Motor paralysis
Vibration
Proprioception
21
Q
A fibers ___ B fibers ___ C fibers
A
> , >, >
22
Q
How many types of A fibers?
A
4
23
Q
B fibers are:
A
Preganglionic autonomic fibers
24
Q
Metabolism is either _______ or _______.
A
ESTERS or AMIDES
25
Esters is readily cleaved by ______ ________. 1/2 life is:
plasma cholinesterase (1 min)
26
What is the degradation product of Ester metabolism?
P-aminobenzoic acid.
27
P-aminobenzoic acid has > rates of:
Patient allergic reactions
28
Amides is cleaved through __________ followed by __________.
N-dealkylation, hydrolysis.
29
1/2 life of AMIDES:
2-3 hours
30
Where does metabolism of amides primarily occur?
Liver. (Hepatic disease > reactions)
31
Baricity
Hypobaric (floats up)
Hyperbaric (sink down)
Isobaric (stay)
32
Different additives to LA will > ________.
Baricity
33
(4) Epinephrine added to LAs will:
Prolong duration of LA
> intensity of block
(< surgical bleeding?)
Assists in evaluation of test dose
34
When not to add epi to LAs?
And what other additive?
- Peripheral (fingers, toes, penis)
- Beir block
- Hx uncontrolled HTN, CAD, arrhythmia, > thyroid, uterus-placental insufficiency.
-Phenylephrine
35
Adding Na Bicarb to LAs does what 2 things?
> pH, this > non-ionized base
> rate of Diffusion across nerve membrane (> onset speed).
36
Add how munch of Na Bicarb equivalents with lidocaine?
Add how munch of Na Bicarb equivalents with bupivicaine?
1 mEq added to each 10 ml of lido
0.1 mEq added to each 10 ml of bupivi
37
Does Na Bicarb in combos with LAs sting?
No. Helps to prevent sting.
38
Fentanyl (opioid) added to LAs will ___ ________ of block
> strength
39
Fentanyl added to LA will work on ____ receptors.
Mu (in spinal cord, dorsal horn)
40
Fentanyl added to LAs are ________ together.
Synergistic
41
How to minimize LA systemic toxicity:
- Aspiration prior to injection
- Use of epi for test dose
- Use of small incremental volumes. (5ccs q 5 mins)
- Use of proper technique
42
Allergic reactions with LAs are common or rare.
Rare
43
Amides Allergic reaction:
Methyl-paraben (preservative)
And PABA
44
Ester allergic reactions with LAs:
Sulfonamides or Thiazides diuretics.
45
Progression of CNS toxicity:
Lightheadedness-Tinnitus-Visual-numbness of tongue and lip
Then progress to
Muscle twitching-LOC-seizure-coma
46
What LA is more toxic?
Bupivacaine > Lidocaine > Mepiv > Prilo > Pro
| Reversed would be greatest convulsive threshold
47
What is a strong indicator of convulsive threshold?
PaCO2
48
Tx of LA CNS toxicity:
```
O2
Seizure activity
-Midazolam 1-2 mg
-Thiopental 50-200mg
-Propofol
```
49
LA Cardiovascular Toxicity:
< contractility
< conduction
Loss of peripheral vasomotor tone
CV collapse (bupivicaine or etidocaine)
50
What LA has the greatest CV collapse dose threshold?
Lido>Etidocaine>Bupivacaine
51
Tx CV toxicity:
```
O2
Vasopressin and inotropes
ACLS
To v-tach with cardioversion
Long resuscitation times (40 mins).
```
52
Research suggests that post op morbidity and mortality is ___ when neuraxial blockage is used.
<
| Neuraxial is beneficial
53
7 Reduced Incidences of with LAs:
- Thrombosis
- PE
- Cardiac complications
- Vascular graft occlusion
- Resp depression and Pnx
- Blood loss and transfusion
- Earlier return of GI function
54
Other names for Spinal Blocks:
Subarachanoid blocks
| Intrathecal block
55
Indications for spinal:
Surgery of lower abd
Surgery of lower extremities
Surgery on perineum
56
Things in a good pre op exam:
- Note Baseline neuromuscular deficits
- Bacteremia - abscess
- Current meds (can’t do with anticoags)
- Cardiac disease
57
Aortic stenosis with LAs
Fixed CO
| < Cardiac coronary BF (no pressure for BF)
58
Aortic stenosis os a relative or absolute contraindication for a spinal?
Relative
59
Slide 42 Here
Research for current
42
60
Must diagnose and surgically decompress a Spinal hematoma with in _____ for best outcome.
8 hours
61
Symptoms of spinal or epidural hematoma:
- New onset weakness to lower limbs
- New onset back pain
- New onset bowel or bladder dysfunction
62
Risk of spinal neurological injury
1 - 4.2 : 10,000
63
Risk of epidural neurological injury:
0 - 7.6 : 10,000
64
Minimum Cutaneous levels for spinal:
```
Lower extremities
Hip
Vagina/ uterus
Bladder / prostate
Testis / ovaries
Lower abd
Nipple
Xifoid
Bellybutton
Pinky
```
```
Lower extremities. T12
Hip. T10
Vagina/ uterus T10
Bladder / prostate T10
Testis / ovaries T8
Lower abd T6
Nipple. T4
Xifoid T6T7
Bellybutton T10
Pinky C8-T1
```
65
Where are the cardiac accelerators?
T1-T4 Bradycardia results with blockage
66
Where would a block affect a patients breathing?
C3C4C5
67
How many cervical vertebra?
7
68
How many cervical nerve roots?
8
69
How many thoracic vertebral?
12
70
How many Lumbar vertebra?
5
71
How many sacral vertebra?
5
72
How many coccygeal vertebra?
4
73
Needle approach in ______ T12 - L5
Flat
74
Needle approach is _______ thoracic T1-T12
Angled
75
3 major ligaments involved with the spine:
SLIDE 51
- Supraspinous ligament (Posterior) (links all together on top)
- Interspinous ligament (in between)
- Ligamentum flavum (anterior portion) (closest to LA epidural space)
76
What intralaminar ligament is the most dense/thickest?
Ligamentum flavum
77
Where does the spinal cord end at birth and 2yrs and adult?
L3
L1
L1
78
What is the name of the end of the spinal cord?
Conus medularis
79
Name of the nerves that hang at end of spinal cord?
Cauda equina
80
Spinal needles are placed below ___ to not hit the spinal cord.
L2
| Needle passes through cauda equina
81
3 meninges that surround the spinal cord:
- Dura mater (outside) (tough fibrous)
- Arachnoid (between dura and pia)
- Pia mater (NO needle STOP before)
82
What meninge holds the CSF?
Arachnoid
83
What is between ligamentum flavum and Dura?
Epidural space
84
Difference between spinal and epidural?
Can give epidural slower and controlled, spinal is one does in and out.
85
What is the total volume of CSF
140 mls
86
CSF fills the ________ space
Subarachnoid space
87
Volume of CSF in spinal canal is?
30-80 mls (rest is in the brain/ventricles)
88
How much CSF is made every day?
500mls
20.8mls/hr
89
CSF is replaced how many times a day?
3
90
specific gravity of CSF:
1.004-1.009
91
What produces CSF?
Corae plexus
| Arachnoid villi or grandulations absorb CSF
92
Factor that affect level of spinal block:
Drug Dose / Drug Volume
Turbulence of CSF
- Rapid injection
- Barbotage
- Coughing
- > pt movement
> intra abd Pressure (pregnancy, obese, ascities, abd tumors)
Spinal curvatures
Baricity of LA
93
Spinals are placed between _______and __________.
Pia and arachnoid
94
What do you do with does with > abd situations?
< dose
95
What is the most common LA solution?
Hyperbaric
96
What is added in hyperbaric solutions?
Glucose (dextrose)
97
What is often added to hypobaric LA solutions?
Water
98
Does positioning matter with isobaric solutions?
No
99
> dose of a __________ solution will > _________ of LA not ________ of LA.
Isobaric, duration, spread
100
______ is a cutting type needle.
Quickie
| Turn bevel sideways
101
Other name for Pencil point needle?
Whitacre
| Sport
102
What type of needle is used for epidurals?
Touhy (curved up)
103
Benefits of pencil point needle:
< HA
Drag < contaminates in to subarachnoid space.
Better fill (feel pop more)
104
What are the identifying marks in sitting position?
```
Below L1-L2
Iliac crests (L4) (tuviers line)
```
105
What is often the solution used of LA in sitting position?
Hyperbaric
106
What solution is often used in prone position?
Hypobaric
| Rectum, perineum, anus procedures
107
Midline approach
Needle advanced through skin at same plane as ________ ________ with slight _________ angulation.
Spinous process, cephalad
108
When is Paramedian approach useful?
Pts who cant maximally flex or intraspinous ligaments are ossified.
109
Paramedian approach needle is placed ...
1-1.5cm lateral to midline
110
Contamination of spinal kit and antiseptic solution can cause....
Neurotoxicity
111
Infiltrate skin with __ ________ with a ___ gauge needle
1% lidocaine, 25 gauge
112
A sudden “pop” is felt as the needle is advances past the ______ ligament.
Ligamentum flavum (pull stylet out, wait for free flow CSF drain)
113
What to do if paresthesia (pain) occurs?
Stop, wait for it to go away (take stylet out to see if your in the right spot)
Do not continue to push with paresthesia
114
Aspiration of CSF confirms...
Free flow.
115
Re-aspiration of CSF at end of injection confirms...
Needle tip is still in subarachnoid space.
116
How long does the fixation of a LA take?
20 mins
117
Closely monitor VS for how long after LA is injected?
At least 1 min until pt is deemed stable.
118
___ fibers are more easily blocked than _______ sensory and motor fibers.
C, larger
119
The level of the autonomic blockade should be ...
The highest point of the spinal bc it is the easiest blocked.
120
_________ level, then _______ levels about 2 spinal levels below that, then _______ block 2 spinal level below that.
Sympathetic, sensory, motor
| Top to bottom
121
Autonomic block __ Sensory block __ Motor.
>, >
122
CV is _________ to the degree of sympathetic block achieved.
Hypotension.
Dilation
< SVR
> risk w/ hypovolemic pts
123
Lower block ___ hypotension
| Higher block ___ hypotension.
<
| >
124
HR change with LA in most pts.
No significant change
125
Bradycardia does occurs with LAs __ % of the time
10-15%
126
> risk of bradycardia with LAs occurs with...
> sensory levels
| Cardio block @ T1-T4
127
Tx of CV response
```
Fluid load 500-1000cc
O2 mask
Vasopressin
Atropine
Epinephrine
CPR
```
128
CV effects _____ be anticipated with steps takes to minimize _____ and _____.
Should, hypotension and bradycardia.
129
Significant
HTN
130
Careful with pts who have chronic lung disease with LA, they don’t have ________ ________ if blocked. Difficult ______ing.
Accessory muscles, coughing.(use suction) (limited reserve)
131
4 most important factors affecting level of LA.
Baricity
Position
Dose
Site of injection
```
Even more than:
Pregnancy
Volume
Age
Spine shape
```
132
Young ________ _________ are > rush of dural puncture HA.
Pregnant females
133
Common side effects of spinal anesthesia:
Nausea
Urinary retention
Hypoventilation
Backache
134
The epidural space is _____ ____at midline.
5-6mm wide
135
There is a more narrow margin of error at the ____________ region epidural space.
Mid-thoracic (it Is only 5-6mm wide)
136
Depth of epidural space is __________.
3-9 cm
137
Epidural onset is ________ and intensity is ________.
Slower, less
138
A segmental type block is...
At pt cash still get up and walk around.
Selective blockade.
139
Epidural position:
Lateral or sitting
140
Epidural can be titrated to deliver ________ or _________.
Analgesia or anesthesia (dose amount)
141
Epidural take _____ volumes of LA to achieve anesthesia and they take _______.
Large, longer
142
Needle should alway enter the epidural space in the ______ regardless of approach.
Midline (space is wider there)
143
Use wither the __________ technique or the __________ technique to locate the epidural space.
Loss of resistance, hanging drop.
144
What kind of needle for epidural?
Long 25 gauge needle
145
Thoracic epidural requires ____ dose of LA
Less
146
Insert needle in a more _________ direction in thoracic epidural placement.
Cephalad
147
Epidural test dose include what dose and med?
1:200,000 epi.
If in epidural vein, HR > 20-30%
148
1: 200,000 —> 1,000,000/200,000 = 5 mcg/mL
1: 10,000 —> 1,000,000/10,000 = 100 mcg/ml
Conversion SLIDE 104
149
Factors effects level of epidural blockade:
```
Volume of LA
Age
Pregnancy
Speed of injection
Position
Spread of epidural blockade
```
150
__ ml of NA bicarb for each __ mls of LA
1 ml, 10mls
151
Sympathetic nervous system blockade has a ______ onset with a _______ incidence of abrupt hypotension.
Slower, decreased.
152
Post dural puncture headache occurs _______.
1-2%
| Backache 35-40%
153
Variations of epidurals:
```
Single shot
Continuous
Combined spinal/epidural
Combined epidural/general
Caudal anesthesia (< dose peds)
```
154
Touey
Is bent up so you can move cath up.
Slide 113
155
Spinal sympathetic block can result in __ preload, __ CO, __ BP
Decreased, decreased, decreased
