Spinals and epidurals (exam 4) Flashcards
(134 cards)
1
Q
The lamina of S5 is ________ and bridged _____
A
incomplete and bridged only by ligaments
2
Q
Sacral hiatus correlates with
A
s5
3
Q
Conus medullaris spinal level (adult and infant)
A
Adult: L1-L2
Infant: L3
4
Q
Dural sac spinal level adult and peds
A
adult: S2
Infant: S3
5
Q
Cauda Equina area
A
Bundle of spinal nerves from clonus to dural sac
6
Q
Two fixation points of filum terminale
A
conus medullaris and Coccyx
7
Q
Supra spinous ligament role
A
Joins tips of spinous processes (posterior)
8
Q
Interspinous ligament location
A
adjacent to spinous process
9
Q
Ligamentaum flavum is thickest in the
A
Lumbar region
10
Q
CSF circulates between
A
pia and arachnoid mater layers
11
Q
Nerves responsible for touch (3)
A
-A beta
-A delta
-C dorsal root
12
Q
Nerves responsible for temperature (2)
A
-A delta
-C dorsal root
13
Q
Sensory, Visceral and Somatic/pain afferents are transmitted through the
A
posterior (dorsal) root
14
Q
Autonomic and motor nerve efferents are transmitted through the
A
anterior (ventral) root
15
Q
Vertebra prominence is at
A
C7
16
Q
Spine of scapula is at
A
T3
17
Q
Inferior angle of scapula is at
A
T7
18
Q
Rib margin is at
A
10 cm from midline L1
19
Q
Superior aspect of illiac crest is at
A
L4
20
Q
Posterior Superior illiac spine is at
A
S2
21
Q
Intercristal or Tuffier line is
A
S1 at the level of posterior illiac crest
apex L4?
22
Q
cauda equina nerve bundle
A
roots L2-S5 pairs and coccygeal nerve
23
Q
Dural sac is the
A
termination of the subarachnoid space
24
Q
Best place for a block
A
lower = lowest incidence of injuring spinal cord by direct needle trauma
25
Midline approach - go thourgh:
supraspinous ligament --> interspinous ligament --> ligamentum flavum
26
Taylor's approach is the technique for locating
the L5-S1 space
26
Midline approach: average depth from skin to epidural space is
3-5 cm (in adult)
27
Taylor's approach aka
paramedian approach
28
Taylors Approach needle insertion direction:
Upward and medially
29
Caudal anesthesia location
up to a T10 sensory block
30
Caudal anesthesia is common in
pediatrics
31
Caudal anesthesia uses (5)
1. circumcision
2. hypospadias
3. anal
4. inguinal herniorrhapthy
5. Low thoracic surgery
32
Caudal block landmarks:
Posterior iliac spine
Sacral hiatus
33
In caudal anesthesia, you should not
use air for LOR (loss of resistance)
34
When using chlorohexadine for an epidural
wait full 30 seconds to dry because chlorohex is nuerotoxic
35
Spinal needle with highest incidence of spinal HA
cutting needle
36
Average thread of an epidural catheter into epidural space
3-5
37
If you go too deep with an epidural, it may
enter an epidural vein or exit through intervertebral foramen
blood black = vein
38
Pros of cutting tip needle
Requires less force
39
Cons of cutting needle
Higher risk of PDPH
40
Pros of non-cutting tip needle
Less likely to injure cauda equina
41
1st digit (thumb) spinal nerve root correlation
C6
42
2-3 digits (pointer, middle) spinal nerve root correlation
C7
43
4-5 digits (ring, pinky) spinal nerve root correlation
C8
44
Xiphoid process spinal nerve root correlation
T6
45
Umbilicus spinal nerve root correlation
T10
46
Pubic symphysis nerve root correlation
T12
47
Anterior knee nerve root correlation
L4
48
Vaginal delivery sensory level block required at
T10
49
Lower extremity surgical block level
L1-L3
50
C section surgical block level
T4
51
THA (total hip arthroplasty) surgical block level
T10
52
TURP surgical block level
T10
53
Upper abdominal surgical block level
T4
54
Cystectomy block level
T4
55
Thoracic T2-T6 (upper thoracic) dosing
(local anesthetic)
5-10 mL
56
T6-L1 (lower thoracic) surgical dosing
(local anesthetic)
10-20 mL
57
L2-L5 (lower extremity) surgical dosing
(local anesthetic)
20 mL
58
General trend for local anesthetic dosing
lower in spine = higher dose
59
sacral LA dosing
12-15 mL
60
Do not exceed this dose for LA in peds
2.5 mg/kg
61
Baracity is
analogous to specific gravity
62
Baracity changes with
fever
63
Hyperbaric
goes down canal (more dense sinks)
i.e. dextrose
64
hypobaric
goes up canal (less dense floats)
i.e water
65
Isobaric
doesn't sink or float (stay in same spot)
i.e. saline
66
How do neuroaxial opioids work
Inhibit afferent pain transmission in substantia gelatinosa by decreasing cAMP, Ca conductance and increasing K conductance.
(bring axon membrane to lower potential/hyperpolarize/more negative)
67
Neuraxial opioids create no (3):
1. Sympathectomy
2. Skeletal muscle weakness
3. Change in proprioception
68
Which stays in the CSF for longer: Hydrophillic opioids or Lipophillic opiods
Hydrophillic opioids stay in for a longer periods of time
69
Resp depression in Lipophillic opioids
early AND late
?
70
Resp depression in lipophillic opioids
early only (less than 6 hrs)
71
4 primary side effects of neuraxial opoids
1. Pruritis*
2. Resp depression
3. Urinary retention
4. N & V
72
6 factors that increase the risk of resp. depression
1. Increase dose of LA
2. co administration of sedatives
3. Lower lipid solubility
4. advanced age
5. opioid naive
6. Increased intrathoracic pressure
73
Spinal site of action
Subarachnoid space myelinated preganglionic fibers of roots
74
epidural site of action
dural cuff to nerve roots
intervertebral foramen to paravertebral area
75
Increased intra abdominal pressure (couging, labor) - does it significantly alter anesthetic spread?
No
76
For spread of epidural, caudad=
cervical
77
For spread of epidural, cephalad =
lumbar
78
Factors that affect spread of spinals:
1. Patient position
2. Baricity of LA
3. Dose
4. LA volume (most important drug - related)
5. Level of injection
79
For a sensory block,
2 dermatomal levels above motor
80
For an autonomic block, you should block
2-6 dermatomal levels above sensory
81
For a sensory block, your blockade is always _____ above ____
2 dermatomal levels above motor
82
Autonomic block is ____ above ___
2-6 dermatomal levels above sensory
83
Nerve fibers blocked
B-preganglionic ANS fibers
84
Factors that affect the spread of epidurals
1. LA volume (most important drug related)
2. level of injection (most important procedure related factor)
3. dose
85
Dermatome differential blockade
Autonomic --> sensory --> motor
Dermatome high to liow
autonomic is always higher than sensory, sensory is always higher than motor
86
Spinal sensory block level
2 dermatomes above motor
87
Spinal autonomic block level
2-6 dermatomes above sensory
88
Epidural sensory and ANS block
2-4 dermatomes above motor
89
When testing effectiveness of block, test in this order:
1. Temp
2. Pain (pin prick)
3. light touch
90
Motor monitoring/ Bromage scale
0 = no motor
1 = pt cannot raise extended leg but can move knees and fe
2 - cannot raise extended leg or move the knee but can move feet
3= complete motor block
91
Density =
ratio of mass of substance relative to its volume
92
Baricity is
density of LA solution relative to CSF
93
If spinal is hypobaric, what should you do and why
Do not keep patient in sitting position because it goes to brain
94
What maintains arterial and venous tone in autonomic blockade
Preganglionic B fibers
95
What are blocked first by neuroaxial anesthesia
Preganglionic B fibers
96
Autonomic blockade =
Decreased sympathetic tone:
1. vasodilation
2. decrease venous return
3. decrease CO
4.Increase venous capacitance (venous pooling)
5. Hypotension
6. Bradycardia
97
Main mechanism of bradycardia and asystole in autonomic blockade
Bezold- Jarisch relfex
98
Bradycardia mechanism (what is blocked?)
T1-T4 cardio accelerator fiber block
99
Even with a high T4 thoracic level dermatome spread of local anesthetic, what does not change?
1. TV
2. RR
3. ABG
100
With a T4 high thoracic dermatomal spread, what does change?
Small decrease in vital capacity
^blockade of accessory muscles of respiration
101
With a T4 high thoracic dermatomal spread, dyspnea is
normal and very troublesome
102
In a spinal/epidural, apnea is cause by
Bran stem hypoperfusion, NOT phrenic paralysis, NOT hi concentration of LA in CSF
(in peripheral blocks, it is phrenic paralysis)
103
What innervates the parasympathetic GI system
vagus nerve
104
What transmits sensations of satiety, distension, nausea
parasypathetic AFFERENT
105
What signals tonic contractions, sphincter relaxation, peristalis and secretion
parasympathetic EFFERENT
106
Sympathetic innervation of GI tract stems from (nerve root)
T5-L2
107
sympathetic AFFERENT transmits
viceral pain
108
sympathetic EFFERENT:
1. inhibits peristalsis and gastric secretion
2. causes sphincter contraction and vasoconstriction
109
Nueroendocrine effects of spinal/epidural:
Decreases circulation levels of:
1. catecholamines
2. renin angiotensin
3. glucose
4. thyroid stress hormone
5. growth hormone (only negative)
110
Epidural/spinal abscess prevention
1. hand washhing
2. strict sterile technique (mask, gloves, hat
3. chlorohexidine and alcohol
111
Key treatment for epidural/spinal hematoma
Prompt diagnosis and intervention
112
Major symptom of epidural/spinal hematoma
Pain
113
Complications of neuraxial anesthesia
Horner's syndrome
114
Use of vasoconstrictors is a risk for
neurotoxicity
in anterior spinal artery syndrome
115
How to avoid spinal induced hypotension
1. vasopressors
2. 5-HT3 antagonists (zofran)
3. Bezold-jarisch relfex prevent
4. co-loading 15 mL/kg crystalloids
5. pelvic tilting
6. anticholinergics
116
Sudden cardiac arrest in neruaxial anesthesia is due to
unopposed tone to cardioaccelerator fibers T1-T4
117
Sudden cardiac arrest in in neuraxial is common in
young adults with high parasympathetic tone
118
Sudden cardiac arrest with neuraxial anesthesia is associated with
large blood loss and orthopedic cement placement
119
Post dural puncture HA treatment
1. Caffeine
2. bedrest
3. Nsaids/gaba
4. Sphenopalatine ganglion block
5. Epidural blood patch
120
If a block fails and there is no anesthesia
Repeat injectionI
121
If a block is patchy
do not repeat, switch technique
122
If a block is unilateral
position patient side down
123
Why is a full stomach contraindicated for spinals?
If failed, may need to switch to GA
124
Absolute contraindications of spinal
1. Coagulopathy
2. Sepsis
3. PT refusal/cooperation/competence/age/lack of informed consent
4. Dermal site infection
5. Hypovolemia
6. Preexisting spinal cord disorder
7. Vavlular heart disease
8. Increased ICP
9. Operation >duration LA
10. IHSS (idopathic subaortic stenosis)
11. Severe CHF
125
Epidural complications
1. post dural puncture HA
2. post spinal bacterial meningitis
3. spinal induced hypotension
4. cauda equina syndrome
5. transient neurologic symptoms
126
Contraindications of epidural
1. spina bifida
2.meningomyelocele of sacrum
3. meningitis
4. pilonidal cyst
5. hydrocephalus
6. intracranial tumor degenerative neuropathy
127
Transient neurologic symptom causes
1. stretching sciatic nerve
2. myofascial strain
3. muscle spasms
4. lidocaine
5. lithotomy position
6. ambulatory surgery
7. knee arthorscopy
128
Transient neurologic s/sx
Severe back and butt pain, 6-36 hrs, 1-7 days
129
transient neurologic symptom treatment
1. NSAIDs
2. opioid analgesic
3. trigger point injections
130
Cauda equina syndrome neurotoxicity is form
high concentrations of lidocaine
131
Cauda equina syndrome is more common when
microcatheters are used - focused on small area of cord, not enough spread
132
Low molecular weight heparin should be d/c'd
12 hours for prophylactic dosing
24 hours for therapeutic dosing
133
Theinopynidue derivative should be d/cs
7 days
