Regional Anesthesia Flashcards
(168 cards)
1
Q
The spinal cord extends from the foramen magnum to ___ in the adult and ranges from ____ cm, and to ___ in the newborn.
A
L1
42-45 cm
L3
2
Q
The spinal cord terminates at conus medullaris and the ________ extends down and anchors in the lower sacral region.
A
Filum terminale
3
Q
How many vertebrae?
How many pairs of spinal nerves?
A
33 vertebrae (7 cervical, 12 thoracic, 5 lumbar, 5 sacral, 4 coccygeal) 31 pairs of spinal nerves
4
Q
What is the nerve group in the lower dural sac (L1 to S5)?
A
Cauda equina
5
Q
List the structures traversed to arrive at the subarachnoid space.
A
- Skin
- Subcutaneous
- Supraspinous ligament (C7 to sacrum)
- Interspinous ligament
- Ligamentum flavum
- Epidural space
- Dura
- Arachnoid
- Subarachnoid space
6
Q
Which ligament binds the epidural space posteriorly? Anteriorly?
A
Ligamentum flavum
Dura
7
Q
Where is the ligamentum flavum the widest? Narrowest?
A
Wides at L2
Narrowest at C5
8
Q
List the 3 spinal meninges.
A
- Dura mater
- Arachnoid
- Pia mater
9
Q
Where is CSF found?
A
Subarachnoid space
Between the arachnoid and pia mater
10
Q
What is the principle site of action for neuraxial blockade?
A
Nerve root
LA act on nerve rootlets, nerve roots, and the spinal cord
11
Q
Factors with proven effects on distribution of drug include:
A
- Site of injection
- Anatomical shape of spinal column
- Patient height
- Angulation of needle
- Volume of CSF
- Characteristics of LA (baracity)
- Dose of LA
- Volume of LA
- Position of patient during injection
- Position of patient after injection
12
Q
Uptake of LA occurs by ____ down a concentration gradient.
A
Diffusion
Uptake is greatest where the concentration of LA is the greatest
13
Q
Elimination occurs by ______ via subarachnoid and epidural _______.
A
Vascular absorption
Blood vessels
14
Q
The predominant action of sympathetic blockade due to LAs is ________.
A
Venodilation
Reduces VR, SV, CO, BP
15
Q
What happens if sympathetic outflow from T1 to T4 is blocked by LAs?
A
Unopposed vagal stimulation
Bradycardia
16
Q
Bradycardia following spinal injection is a result of what 2 things?
A
- Blockade of cardioaccelerator fibers (T1-T4)
2. Bainbridge reflex (decreased VR)
17
Q
The best means for treating hypotension during spinal anesthesia is ________, not pharmacologic.
A
Physiologic
- Give IV fluids if not normovolemic (5 mL/kg)
- If normovolemic, give ephedrine or neo
18
Q
When giving a fluid bolus for hypotension following a spinal injection, why avoid glucose containing solutions?
A
Glucose can act as a diuretic - worsen the situation
19
Q
Explain why the patient may feel dyspneic under subarachnoid or epidural block.
A
As the sensory block reaches the level of T2-T4 - loss of perception of intercostal and abdominal wall movement
20
Q
Apnea, if it occurs, under subarachnoid or epidural block is due to what?
A
Hypoperfusion of the respiratory centers in the medulla
Secondary to severe hypotension
21
Q
Spinal or epidural: ability to control the spread of the anesthetic by controlling the specific gravity of the solution and the position of the patient.
A
Spinal
22
Q
With cut-bevel needles (Quinke)…the bevel should face what in the sitting position? Lateral position?
A
Sitting position - face either R or L
Lateral position - face up or down
(to minimize trauma to the dura)
23
Q
Anticoagulants and Neuraxial Anesthesia NSAIDS? Aspirin? Herbals? SubQ or minidose Heparin? IV Heparin? Chronic Warfarin? Ticlodipine? Clopidogrel? Abciximab? Eptifibatide and tirofiban? GPIIb/IIIa antagonists?
A
NSAIDS, Aspirin - OK Herbals - OK if alone SubQ or minidose Heparin - OK IV Heparin - NO, unless a normal PTT Chronic Warfarin - 4 days Ticlodipine - 14 days Clopidogrel - 7 days Abciximab - 24-48 hours Eptifibatide and tirofiban - 4-8 hours GPIIb/IIIa antagonists - 4 weeks
24
Q
When a central nerve block is used and intra-op anticoagulation is initiated, it is recommended that heparin dosing be held for a least ___ hour after placement of the neuraxial anesthetic.
A
1 hour
25
Indwelling catheters should be removed ___ hours after the last heparin dose and the patient's heparin status is known.
2-4 hours
26
Heparinization can occur ___ hour after catheter removal.
1 hour
27
Neuraxial block may be administered IF the perioperative INR is less than what?
INR < 1.5
28
Indwelling catheters should be removed at a minimum of ____ hours after last LMWH dose is given.
10-12 hours
29
Initiate any subsequent LMWH dosing a minimum of ___ hours after the catheter has been removed.
2 hours
30
```
Dermatomes Anterior
C4
T4
T6
T8
T10
L1
L2-L3
S2-S5
```
```
C4 - clavicle
T4 - nipples
T6 - xiphoid
T8 - lower border of ribcage
T10 - umbilicus
L1 - inguinal ligament
L2-L3 - knee and below
S2-S5 - perineal
```
31
```
Dermatomes Posterior
C7
T7
L4
S2
```
C7 - most prominent cervical spinous process
T7 - inferior border of scapula
L4 - superior iliac crest
S2 - posterior superior iliac spine
32
Absolute Contraindications of Spinal Anesthesia
```
Patient refusal or uncooperative
Lack of skill of provider
Operation > DOA of spinal
Infection at the site of injection
Severe hypovolemia
Increased ICP, brain tumor
Spinal cord disease
Abnormal coagulation
```
Abruptio placentae
Severe aortic stenosis
Severe mitral stenosis
IHSS
33
Relative Contraindications of Spinal Anesthesia
```
Surgical procedure above umbilicus
Deformity of spinal column
Chronic headache or backache
Neurologic defect
3 failed attempts
Extreme patient age
Mobitz type I, II, and CHB w/o PM
```
Controversial: prior back surgery, complicated surgery
34
Cardiac disease, whether myocardial, valvular, or ischemic, is considered a major contraindication to spinal anesthesia if sensory levels of ____ or above are required.
T6
35
Spinal anesthesia is indicated in patients with even severe cardiac disease if only ____ levels of anesthesia are required.
Perineal
36
The lateral approach to a neuraxial block will not pass through which 2 structures?
1. Supraspinous ligament
| 2. Interspinous ligament
37
Complications of Spinal Anesthesia
Infection (fever, nuchal rigidity, severe headaches)
Backache
Headache - PDPH
Failed block
38
What is the common infectious agent seen with spinal meningitis?
Alpha hemolytic steptococci
39
What is the most common causative organism in epidural abscess?
Staphylococcus aureus
40
Hematomas with neurologic deficits are best diagnosed with?
MRI
41
What is the most common complication of spinal block?
Backache
42
What is the second most common complication of spinal block?
Headache
43
PDPH
Frequency?
Location?
Aggravated by what position?
0.2-24% Highest incidence in obstetrics
Bifrontal and occipital
Aggravated in upright position
44
Describe what is happening with a PDPH.
Decrease in the amount of CSF
Causes the medulla and brainstem to drop into the foramen magnum - stretching the meninges, vessels, and nerves
CN palsy d/t decreased blood supply to nerves
45
Epidural Blood Patch
How many mL for injection?
First blood patch resolves ____ of headaches.
May repeat after how many hours?
10-30 mL of aseptically-drawn blood
1st - 89-95%
May repeat in 24 hours
46
In the supine position, the highest point of the spinal column lies at the level of which vertebrae? Where is the lowest point?
Highest point - L3
| Lowest point - T6
47
The largest space in the spinal canal is found where?
| The epidural space is largest at what level?
L5-S1
| L2-L3
48
What is the major inhibitory NT in the spinal cord?
Glycine
49
Is the hydrostatic pressure in the subarachnoid space positive or negative?
Positive (5-15 mmHg)
| fluid should leak out of a needle when its tip is placed in this space
50
Does the epidural space have a negative or positive pressure?
What does the epidural space contain?
Negative
| Loose connective tissue, adipose tissue, nerve roots, blood vessels, lymphatics
51
A line drawn between the L and R iliac crest crosses the spine of what lumbar vertebra?
L4
52
As the needle is being inserted for subarachnoid block, you feel a pop. What has occurred?
The dura has been penetrated
53
The clinical progression of differential nerve block by LAs, from first blocked to last blocked, is...
Autonomic fibers
Sensory fibers
Motor fibers
54
What is the order of nerve fiber blockage during a spinal and epidural?
B fibers
Preganglionic sympathetic efferents
C and A-delta fibers
Postganglionic sympathetic neurons
Pain + temp + touch
A-gamma
A-beta
A-alpha *most difficult to block
55
What level of spinal block would be appropriate for a patient with kidney pain?
T10-L1
56
What level of spinal block would be appropriate for a TURP?
T10
57
What level of spinal block would be appropriate for lower abdominal surgery?
T6
58
What level of spinal block would be appropriate for upper abdominal surgery?
T4
59
The surgical procedure requires a tourniquet on the LE. What is the min sensory level required for cutaneous anesthesia in this case?
T8
60
What is the specific gravity of CSF?
1.003-1.008
61
What factor most influences the level of block achieved with a hyperbaric spinal?
Position
62
Which LA produces the most profound motor block?
Tetracaine
63
What is the DOA of lidocaine used for spinal anesthesia w/ and w/o epinephrine?
W/ epinephrine - 60-90 min
| W/o epinephrine - 45-60 min
64
You should assess subarachnoid block after how many minutes?
5 min
65
Subarachnoid block usually reaches its highest level ____ minutes after spinal injection.
20 min
66
Describe the differential block with epidural anesthesia.
Sympathetic is at the same level as sensory block
| Motor block is 4 segments lower
67
The half-life of a LA is longer when injected intrathecally or epidurally?
Intrathecally
68
Which is more voluminous...the epidural space or the subarachnoid space?
Subarachnoid space
69
Epidural space extends from the base of the skull to the _______.
Sacrococcygeal membrane
70
For an epidural block, ____ mL of LA should be given per segment to be blocked.
1-2 mL
71
Which fibers are more sensitive to LA block?
Large, myelinated fibers
| Large myelinated > smaller myelinated > unmyelinated
72
Why are large, myelinated fibers the last to be blocked if they are the most sensitive?
Small diameter nerve fibers are found close to the nerve root surface
73
Is the sensory and motor block quality better with a spinal or epidural?
Spinal
74
Distance from skin to epidural space
Average adult
Obese
Thin
Average adult - 4-6 cm
Obese - 8 cm
Thin - 3 cm
75
What is the most sensitive indicator of initial onset of sensory block?
Alcohol swab to assess loss of temp sensation
76
What is the most accurate assessment of overall sensory block?
Pinprick
77
A lumbar epidural injection is associated with greater cranial than caudal spread of LA. There may be a delay in onset in L5 to S1 segments due to what?
Large size of the nerve roots
78
A mid-thoracic epidural is associated with uniform spread of LA: however, the upper thoracic and lower cervical segments are resistant to block because of what?
Large size of the nerve roots and the large # of nerve fibers w/in them
79
Why do you perform a test dose after placement of the epidural catheter?
To detect both subarachnoid and intravascular injection
80
Caudal Epidural Block
Needle insertion through the...
Should you be able to aspirate anything?
Test dose?
What volume is required to get a sensory block at T10-T12?
What size needle should be used?
Sacrococcygeal membrane
CSF, air, or blood should NOT be aspirated
Yes administer a test dose (5 mL of preservative-free saline, no midline bulge should be palpable + 0.5 mcg/kg of Epi)
L2 - 15-20 mL
T10-T12 - 25-35 mL
22-G needle or larger
81
Are there higher or lower plasma levels of LA after caudal administration compared to lumbar epidural?
Higher
82
What is the most common complaint of a caudal epidural block?
Injection site pain
83
What is the most frequent problem of a caudal epidural block?
Ineffective block
84
Caudal Epidural Block
| Dosing for Children
0.5-1 mL/kg
0.125% to 0.25% Bupivacaine
1% Lidocaine
85
An epidural is administered. What is the first sign it is working?
Sensory analgesia - pinprick
86
What LA produces the most profound sensory block if administered epidurally?
Bupivacaine
87
What is the DOA of lidocaine used for epidural anesthesia w/ and w/o epinephrine?
W/ epinephrine - 120-180 min
| W/o epinephrine - 80-120 min
88
What is the onset time of lidocaine for epidural anesthesia?
5-15 min
89
How long should you wait after an epidural test dose?
3-5 min
If intravascularly, increase in HR 20 bpm will occur w/in 30-60 sec
If intrathecally, s/s may not appear for 3-5 min
90
How far should an epidural catheter be safely threaded into the epidural space?
3-5 cm
91
The extent of caudal anesthesia is largely determined by what?
Volume of LA injected
92
Caudal anesthesia injection is made at the sacral hiatus. What landmarks are palpated to locate the sacral hiatus?
5 cm above the tip of the coccyx
Directly beneath the uppermost limit of the natal cleft
2 sacral cornua lie on either side of the sacral hiatus
93
The sacrococcygeal ligament is an extension of what structure?
Ligamentum flavum
94
Which nerve is most superior in the brachial bundle?
Median
95
Which nerve is outside the brachial bundle? This nerve leaves the fascial sheath early in the axilla and lies w/in the coracobrachialis muscle?
Musculocutaneous
96
Which 5 nerves form the brachial plexus?
C5-C8, T1
97
Axillary block provides anesthesia for surgery on the...
Forearm
Wrist
*NOT for shoulder and upper arm surgery
Subcut injection in combo for coverage of the intercostobrachial nerve and medial brachial cutaneous nerve
98
How many mL do you use for an axillary block?
40 mL
99
Innervation of Arm and Hand
| Root Supply
Pinky + Ring finger - C8
Middle + Pointer finger - C7
Thumb - C6
100
Innervation of Arm and Hand
| Nerve Supply
Thumb side of forearm - Musculocutaneous
Pinky side of forearm - Median antebrachial cutaneous
Middle of back side of forearm - Radial
Armpit - Intercostobrachial
Back Side of Hand
Pinky + Ring finger - Ulnar
Middle + Pointer finger + thumb - Radial
Finger tips - Median
Palm Side of Hand
Pinky + Ring finger - Ulnar
Middle + Pointer finger + thumb - Median
Side of thumb - Radial
101
Ulnar Block at the Elbow
Where is the insertion point?
How much LA do you inject?
Between the medial condyle of the humerus and the olecranon process of the ulna
4 mL
102
Median Block at the Elbow
Where is the insertion point?
How much LA do you inject?
Draw a line from the medial to lateral condyles of the humerus on anterior surface
Insert B-bevel needle slightly medial to the brachial artery
4 mL
103
Radial Block at the Elbow
Where is the insertion point?
How much LA do you inject?
Locate brachioradialis muscle and biceps brachii muscle insertion
4 mL
104
Ulnar Block at the Wrist
Where is the insertion point?
How much LA do you inject?
Insert B-bevel needle slightly adjacent to ulnar artery
3 mL
*Block of dorsal branch requires a lidocaine wheal around the ulnar portion of the wrist
105
Median Block at the Wrist
Where is the insertion point?
How much LA do you inject?
Insert B-bevel between long palmar muscle and the radial flexor muscle, medial to ulnar pulse
22-G
3 mL
106
Radial Block at the Wrist
Where is the insertion point?
How much LA do you inject?
Inject subcut ring of LA from radial flexor muscle to the dorsal surface of the ulnar styloid
*Avoid continuous ring when done with ulnar block - circulation to the hand could be compromised
6 mL
107
```
Femoral Nerve - 3 in 1 Block
(aka lumbar plexus block)
Provide anesthesia for...
What is the insertion point?
How much LA do you inject?
What 3 nerves are blocked?
```
Anterior thigh, knee, and a small part of the medial foot
2 cm lateral to the femoral pulse
2 cm inferior to a line draw b/t the pubic symphysis and the anterior superior iliac spine (2 cm distal to the inguinal ligament)
PNS with a 2'' 22-G stimulating needle and look for quadriceps twitch or patellar snap
30 mL
*Femoral, Obturator, Lateral Femoral Cutaneous
108
Sciatic Nerve Block
Sciatic nerve is composed of what nerve roots?
Sciatic nerve supplies what areas?
Site of injection for anterior approach?
How much LA do you inject?
L4-5, S1-3
Sensory fibers: posterior hip capsule, knee, distal to the knee (except anteriomedial - saphenous)
Motor fibers: hamstrings, muscles distal to knee
Inguinal ligament divided into 3rds, at the junction of the medial and middle 3rd a perpendicular line is drawn that intersects the greater trochanter line at a right angle
PNS with a 4 inch, 21-G stimulating needle and look for motor response in the distal ankle, foot, or toes
20 mL
109
What 2 major nerves supply the leg?
1. Femoral - distal to the knee becomes saphenous
| 2. Sciatic - bifurcates into the common peroneal (superficial and deep) and tibial (sural)
110
Ankle block anesthetizes what 5 nerves?
1. Posterior tibial
2. Sural
3. Saphenous
4. Deep peroneal
5. Superficial peroneal
5 mL per nerve - 25 mL total
111
Tibial Nerve
Fibers L4-S3
Largest division of the sciatic trunk
Sensation to skin of heel and medial side the sole of the foot
112
Superficial Peroneal Nerve
Sensation to dorsum of foot and adjacent sides of the 1-5 toes
113
Saphenous Nerve
Fibers L3-L4
Largest sensory branch of the femoral nerve
Skin on medial side of the leg, ankle, and foot
114
Sural Nerve
Branch of the posterior tibial nerve
| Sensation to posterior lateral aspect of lower calf and lateral side of foot and 5th toe
115
Deep Peroneal Nerve
Runs in the anterior compartment of leg
Enters ankle b/t flexor hallicus longus and extensor digitorum longus tendons
Innervates toe extensors, provides sensation to the medial half of the dorsal foot (esp. 1st and 2nd toes)
116
Cervical Plexus Block
| Technique?
Block C2-C4 (C1 is a motor nerve only)
Draw a line from the tip of the mastoid process to the anterior tubercle of the transverse process of C6
Use 22-G
Direct needle slightly caudal until contact is made with each transverse process
3-5 mL per level
117
Complications of Cervical Plexus Block
Block of phrenic nerve (hiccups)
Block of recurrent laryngeal nerve (hoarseness)
Horner's syndrome
Accidental subarachnoid or epidural injection
4 mL per level
118
```
Interscalene Block
Appropriate for what type of surgery?
What nerve is frequently not blocked?
Technique?
Complications?
```
Target the trunks
Shoulder surgery
Ulnar nerve is frequently missed
Roll fingers off SCM muscle posteriorly, intersection at C6, b/t the anterior and middle scalene muscles
23-G needle perpendicular to floor (45 deg caudad, posterior, medial)
20-40 mL
Vertebral artery puncture, phrenic nerve block
119
Where is the brachial plexus most compact?
Supraclavicular block
| 3 trunks
120
What is the homogenous block of the brachial plexus (ulnar nerve is covered)?
Supraclavicular block
121
Supraclavicular Block
Insertion site? mL?
What is a risk?
2 cm from mid-point of clavicle
40 mL
Pneumothorax
122
Infraclavicular Block
2.5 cm below the clavicle
40 mL
Pneumothorax
123
Which upper extremity block requires a special position of the upper arm?
Axillary Block
124
Movement in Response to Stimulation
| Radial Nerve
Extension at elbow
Supination of forearm
Extension of wrist and fingers
125
Movement in Response to Stimulation
| Median Nerve
Pronation of the forearm
Flexion of wrist
Opposition of the middle, forefinger, and thumb
Flexion of the lateral 3 fingers
126
Movement in Response to Stimulation
| Ulnar Nerve
Flexion of wrist
Adduction of all fingers
Opposition of medial 2 fingers towards thumb
Flexion of medial 2 fingers
127
Movement in Response to Stimulation
| Musculocutaneous Nerve
Flexion at elbow
128
Tips on Digital Nerve Blocks
Do NOT use Epi
Max volume of 2 mL on each side of digit
Tourniquet limit of 15 min - do NOT use if Raynaud's or PVD
129
What is the main contraindication to finger/limb blocks?
Infection proximal to site of injection
130
Intercostal Nerve Blocks
Primary rami T1-T11
2-5 mL
Needle 15-20 deg angle cephalad
131
What is the most common complication of a retrobulbar block?
Intra-arterial injection
132
Bier Block
40-50 mL of 0.5% Lidocaine
Tourniquet time should NOT exceed 2 hrs
Do NOT deflate unless it has been 25 min
Avoid vasoconstrictors
133
What is the most common complication of an ilioinguinal and iliohypogastric nerve block?
Patient discomfort
134
What 2 nerves are derived from the posterior cord of the brachial plexus?
1. Radial
| 2. Axillary
135
What 2 nerves are derived from the lateral cord of the brachial plexus?
1. Musculocutaneous
| 2. Median
136
What 2 nerves are derived from the medial cord of the brachial plexus?
1. Median
| 2. Ulnar
137
How is the function of the median nerve assessed?
Checking for normal sensation on the palmar surface of the index finger
138
How is the function of the ulnar nerve assessed?
Checking for normal sensation on the palmar surface of the 5th finger
139
Damage to what nerve causes an inability to adduct the thumb?
Median nerve
140
Damage to what nerve causes an inability to abduct the thumb?
Radial nerve
141
Describe the anatomic relationships of the median, ulnar, and radial nerves to the axillary artery.
Median - anterior, superior
Ulnar - medial, posterior, inferior
Radial - lateral, posterior
142
Which nerve is damaged by an IV needle in the antecubital space?
Median
143
Which nerve is most commonly blocked with transarterial approach to an axillary block?
Radial
144
What nerve innervates the medial aspect of the upper arm? Medial aspect of forearm?
Medial upper arm - medial cutaneous nerve + intercostobrachial nerve
Medial forearm - medial cutaneous nerve
145
Which nerve innervates the lateral aspect of the forearm?
Musculocutaneous --- branches into lateral cutaneous nerve of the forearm
146
What approach to the brachial plexus is associated with the greatest risk for pneumo? Least risk?
Greatest - Supraclavicular
| Least - Axillary
147
What is thoracic outlet syndrome?
Compression of the brachial plexus and subclavian artery at the thoracic outlet b/t the first rib and the clavicle OR b/t the scalene muscles
148
What single nerve block is best for ACL repair?
Femoral nerve block
149
What 2 nerves are blocked in a popliteal block?
1. Tibial
2. Common peroneal
Located in the upper margin of the popliteal fossa
Both branches of the sciatic nerve
Used for foot and ankle surgery
150
Of the 5 sensory nerves to the ankle and foot, which 3 lie most superficial?
1. Superficial peroneal
2. Saphenous
3. Sural
*All start with "S" and are superficial!
Posterior tibial nerve is the most difficult to block
151
What nerve causes flexion of the foot? Extension?
Flexion - medial and lateral plantar nerves (tibial nerve)
| Extension - peroneal nerve
152
What nerve may be blocked by injection of agent at the base of the tonsillar pillars? What is in close proximity to injection?
CN 9 - Glossopharyngeal
| Carotid artery
153
Explain the transtracheal block technique.
Lidocaine 4% 4 mL 22-G
Through the cricothyroid membrane
Blocks recurrent laryngeal nerve
154
Is an IV regional technique absolutely contraindicated in a patient with sickle cell anemia?
Relative contraindication
155
What cutaneous sensory level should be reached with a central block to provide adequate analgesia for cystoscopic procedures?
T10
156
What cutaneous sensory level should be reached with a central block to provide adequate analgesia for vaginal and uterine surgery?
T8-T10
157
Why would hyperventilation help in the setting of local anesthetic toxicity?
Hypocapnia - constriction of cerebral vessels - decreased delivery to brain
Alkalosis and hypokalemia - hyperpolarization of nerve membranes
158
What is the most common complication of spinal anesthesia?
Backache
| Then PDPH
159
The likelihood of PDPH is increased by what 5 factors?
1. Younger
2. Females
3. Larger needle sizes
4. Pregnant
5. Multiple punctures
160
What is the incidence of PDPH with the dura is punctured with a 16-G? 17-18-G epidural needle in young? OB population?
16 G - 18%
17-18 G epidural needle in young - 50%
17-18 G epidural needle in OB - 70-80%
161
Diplopia following a spinal anesthetic results from paralysis of what nerve?
Traction on the abducens nerve (CN VI)
162
What is the cause of respiratory arrest after administration of spinal anesthesia?
Ischemia of the brainstem medullary respiratory centers secondary to profound hypotension
163
What position is ideal with a high spinal anesthetic?
Head down position to facilitate VR
| Head up position worsens hemodynamics
164
What is the most common complication of interscalene block?
Phrenic nerve block
165
Which nerve fibers mediate tourniquet pain?
C and A-delta fibers
166
Which regional technique is associated with the greatest incidence of needle-induced nerve injury?
Axillary block
167
What are the 3 s/s of cauda equina syndrome?
1. Urinary and fecal incontinence
2. Partial paralysis of the LE
3. Diminished sensations of the perineum
168
What is the first symptom of an epidural hematoma?
Back pain
