Neuraxial Anesthesia Flashcards
1
Q
General Facts about neuraxial anesthesia vs. GA
A
Neuraxial anesthesia can be an alternative to general anesthesia
Neuraxial anesthesia may be used simultaneously with general anesthesia or afterward for postoperative analgesia
2
Q
Neuraxial blocks can be performed as a ____ or ___.
A
single injection or with a catheter to allow intermittent boluses or continuous infusions
3
Q
Neuraxial blocks may reduce the incidence of ____.
A
- venous thrombosis and pulmonary embolism
- cardiac complications in high-risk patients
- bleeding and transfusion requirements
- vascular graft occlusion
- pneumonia
4
Q
Postoperative epidural analgesia may also significantly reduce both the need for _____.
A
mechanical ventilation and the time until extubation after major abdominal or thoracic surgery.
5
Q
Cesarean delivery is most commonly performed under ___.
A
spinal or epidural anesthesia
Regional anesthesia for cesarean delivery is associated with less maternal morbidity and mortality than general anesthesia d/t aspiration and failed intubation
6
Q
The primary site of action for neuraxial blockade is ____.
A
the nerve root
7
Q
Mechanism of action of spinal anesthesia
A
a relatively small volume of medication is injected into the subarachnoid space, mixes with cerebral spinal fluid, and provides a dense sensory and motor blockade
8
Q
Mechanism of action of epidural and caudal anesthesia
A
a relatively large volume of medication is injected into the epidural space, and provides a differentiated blockade to the middle of the nerve roots
9
Q
Differential blockade typically results in ____.
A
sympathetic blockade (judged by temperature sensitivity) that may be two segments or more cephalad than the sensory block (pain, light touch), which, in turn, is usually several segments more cephalad than the motor blockade.
10
Q
Blockade of the posterior nerve root fibers interrupts ____.
A
somatic and visceral sensation
11
Q
The physiological responses to neuraxial blockade result from _____.
A
decreased sympathetic tone or unopposed parasympathetic tone, or both
12
Q
List the divisions of the nervous system
A
1) Central and peripheral nervous systems
2) The peripheral nervous system is divided into the somatic and autonomic nervous systems
3) The autonomic nervous system is divided into the sympathetic and parasympathetic nervous systems
13
Q
The sympathetic outflow is also called the ____.
A
thoracolumbar outflow
14
Q
The sympathetic, or thoracolumbar, outflow arises from segments ___.
A
T1–L2 or segments T1–L3
15
Q
Most sympathetic preganglionic neurons synapse with ___.
A
postganglionic fibers in the paravertebral ganglia
16
Q
Sympathetic cardiac accelerator fibers arise from ____.
A
T1–T4
17
Q
The stellate ganglion is formed by the ____.
A
inferior cervical and first thoracic ganglia
*stellate ganglion is important as it relates to horners syndrome
18
Q
A massive sympathetic response would lead to ___.
A
tachycardia, dry mouth, bronchodilation and diaphoresis.
19
Q
Effects of sympathetic nervous system on body organs
A
Eye - The pupil dilation (mydriasis)
Heart - Increased heart rate
Secretions - Decreased salivary and bronchial secretions
Smooth Muscle - Bronchodilation, and decreased motility and tone of the stomach and intestines and relaxation of the bladder (detrusor muscle)
Pancreas – Increased blood glucose
20
Q
The sympathetic NS is ____ compared to the peripheral NS?
A
The sympathetic nervous system is anatomically and functionally more systemic in its effects when compared to the PNS
21
Q
Which nervous system is associated with the fight or flight response?
A
sympathetic
22
Q
The parasympathetic outflow is also called the ___.
A
craniosacral outflow
23
Q
The parasympathetic, or craniosacral, outflow arises from cranial nerves _____.
A
III, VII, IX, and X and sacral segments S2, S3, and S4
(3, 7, 9, 10)
24
Q
Cranial nerve III arises from the ___.
A
midbrain
25
Cranial nerve VII arises in the \_\_\_
pons
26
Cranial nerves IX and X arise from the \_\_\_\_.
medulla
27
The parasympathetic nervous system is ___ compared to the SNS.
anatomically and functionally **more selective and localized** in its effects
28
The parasympathetic nervous system functions primarily to \_\_\_\_\_.
conserve energy and maintain organ function (resting and digest)
29
A massive parasympathetic response would lead to \_\_\_\_.
salivation, wheezing, weeping, vomiting, urinating, defecating, and seizing.
30
Effects of the parasympathetic NS on the body organs
**Eye** - The pupil constricts (miosis)
**Heart** - Decreased heart rate
**Secretions** - Increased salivary and bronchial secretions
**Smooth Muscle** - Bronchoconstriction, gall bladder contraction, increased motility and tone of the stomach and intestines and contraction of the bladder (detrusor muscle)
31
Neuraxial anesthesia will likely result in varying degrees of \_\_\_\_.
hypotension and bradycardia
32
How does hypotension occur with neuraxial anesthesia?
Vasomotor tone is primarily determined by sympathetic fibers arising from **T5 to L1**, innervating arterial and venous smooth muscle.
Vasodilation of veins decreases preload and often decreases cardiac output
Arterial vasodilation decreases compensatory vasoconstriction
In general, a more cephalad (towaards the head) blockade results in increased hemodynamic instability
33
How does bradycardia occur with neuraxial anesthesia?
A high sympathetic block may also block the sympathetic cardiac accelerator fibers that arise at **T1 to T4**
Unopposed vagal tone may explain the sudden cardiac arrest sometimes seen with spinal anesthesia
34
Treatment of hypotension and bradycardia related to neuraxial anesthesia
Pharmacologic interventions
* A **bolus of intravenous fluid** (5–10 mL/kg) in patients with appropriate cardiac and renal function
* **Ephedrine is the first line therapy**; glycopyrrolate or atropine can be used for symptomatic bradycardia
Positioning interventions
* Autotransfusion by placing the patient in the **head-down position**
* Left uterine displacement in the third trimester of pregnancy helps to minimize physical obstruction to venous return
35
the diaphragm is innervated by the \_\_\_\_.
phrenic nerve (C 3, 4, 5)
36
Pulmonary effects of neuraxial anesthesia
Overall, pulmonary function is not impacted by neuraxial anesthesia
However, patients with severe chronic lung disease may rely on the intercostal and abdominal muscles to actively inspire or exhale, therefore high levels of neural blockade will impair these muscles
37
Postoperative thoracic epidural analgesia in high-risk patients can \_\_\_.
improve pulmonary outcome by decreasing the incidence of pneumonia and respiratory failure, improving oxygenation, and decreasing the duration of mechanical ventilatory support
38
Gastrointestinal effects of neuraxial anesthesia
Unopposed vagal stimulation results in a small contracted gut and increase peristalsis, which can be helpful during intestinal surgery
Postoperative epidural analgesia decreases systemic opioid requirements, which can expedite the return of GI functioning
Hepatic blood flow is decreased from neuraxial and general anesthesia
39
GU Effects of Neuraxial Anesthesia
Renal blood flow is maintained by autoregulation
Bladder function is controlled by the sympathetic and parasympathetic nervous system, therefor patients are at risk for urinary retention
Patients without urinary catheters should receive judicious amounts of intravenous fluids, short acting medications neuraxially and assessed for bladder distention
40
Metabolic and Endocrine Effects of Neuraxial Anesthesia
Neuraxial blockade can partially suppress (during major invasive abdominal or thoracic surgery) or totally block (during lower extremity surgery) the **neuroendocrine stress response**
To maximize this blunting of the neuroendocrine stress response, neuraxial block **should precede incision and continue postoperatively**
41
Neuraxial blocks may be used \_\_\_\_.
alone or in conjunction with general anesthesia for many procedures below the neck.
42
As a primary anesthetic, neuraxial blocks have proved most useful in \_\_\_\_.
lower abdominal, inguinal, urogenital, rectal, and lower extremity surgery.
43
Which type of neuraxial anesthesia would you use for a breast surgery?
Need for GA?
Epidural
Yes, needs GA
44
Which type of neuraxial anesthesia would you use for a thoracic surgery?
Need for GA?
Epidural
Yes, needs GA
45
Which type of neuraxial anesthesia would you use for a major abdominal surgery?
Need for GA?
Epidural
Yes, needs GA
46
Which type of neuraxial anesthesia would you use for a hip replacement surgery?
Need for GA?
Spinal or epidural
No, you do not need GA
47
Which type of neuraxial anesthesia would you use for a knee replacement surgery?
Need for GA?
Spinal
No, you do not need GA
48
What are the abdolute contraindications to neuraxial anesthesia?
Infection at the injection site
**Lack of consent**
Coagulopathy
Severe hypovolemia
Increased ICP
49
What are the relative contraindications to neuraxial anesthesia?
* Sepsis
* Uncooperative patient
* Preexisting neurological deficits
* Stenotic heart valves
* LV outflow obstruction
* Severe spinal deformity
50
When bleeding occurs in the closed space of the spinal canal, the expanding hematoma can cause \_\_\_.
pressure on the spinal cord or cauda equina, which in turn may lead to spinal cord ischemia and infarction, with potential for severe neurologic injury or paraplegia
51
The decision to use neuraxial anesthesia in patients who either have been or will be receiving antithrombotic medication must \_\_\_.
weigh the benefit of the neuraxial anesthetic against the risk of spinal epidural hematoma
52
For patients on Warfarin, what are the requirements to place an epidural catheter/remove one?
Must be 4 to 5 days from their last dose and verify normal INR
53
For patients on IV Heparin, what are the requirements to place an epidural catheter/remove one?
After placement/removal, when can you restart the drip?
Must be 4 to 6 hours after holding gtt and verify normal aPTT
Can restart gtt one hour after
54
For patients on subcutaneous low dose thromboprophylaxis Heparin, what are the requirements to place an epidural catheter/remove one?
must be placed 4 to 6 hours after last dose or verify normal aPTT
55
For patients on Clopidogrel (Platelet P2Y12 receptor blocker), what are the requirements to place an epidural catheter/remove one?
After placement/removal, when can you give the next dose?
Must be placed or removed **5 to 7 days after last dose**
Timing for giving the next dose after placement/removal:
* Without loading dose: immediate
* With loading dose: wait 6 hours after
56
Argatroban is a \_\_\_\_. When can you place an epidural if a patient is on this drug?
Thrombin inhibitor
Avoid neuraxial techniques if a patient is on this medication
57
Which drugs are ok to continue using during the placement/removal of an epidural catheter?
* Aspirin
* NSAIDs
* Herbal medications (ginko, garlic, ginseng)
58
Neuraxial blocks must be performed only in a facility in which \_\_\_\_.
all the equipment and drugs needed for intubation, resuscitation, and general anesthesia are immediately available
59
Regional anesthesia can be facilitated by \_\_\_.
patient education, preparation and adequate premedication
60
If using sedation during neuraxial blocks, you may need \_\_\_.
Supplemental oxygen via a face mask or nasal cannula may be required to avoid hypoxemia
61
Monitoring requirements for labor analgesia include \_\_\_.
blood pressure and pulse oximetry
62
Monitoring for blocks in surgical anesthesia is \_\_\_.
the same as that in general anesthesia
63
What can help facilitate locating spinous processes when difficult to palpate?
Ultrasound
64
\_\_\_ is the most prominent cervical process.
C7
65
\_\_\_ is at the same level as the inferior angle of the scapulae.
T7
66
\_\_\_ is where the spinal cord ends.
L1-L2
67
\_\_\_\_ is the highest points of both iliac crests and is also known as \_\_\_.
L4
Tuffier’s line
68
\_\_\_\_ is the largest vertebral interspace.
L4-L5
69
\_\_\_ is between the posterior superior iliac spine.
S2
70
Spinous processes are palpated to identify \_\_\_.
midline
71
What is the needle position for cervical and lumbar spine?
cervical and lumbar spine are nearly horizontal thus the needle is directed with only a slight cephalad angle
72
What is the needle position for thoracic spine?
the thoracic spine slant in a caudal direction therefor the needle must be angled significantly more cephalad
73
What is the preferred position for placing an epidural catheter?
**Sitting position \******preferred*****\***
The anatomic midline is easier to identify when the patient is sitting with their arms resting on a bedside table and flexing their spine (like an angry cat)
Flexion of the spine maximizes the space between spinous processes and pushes the spine closer to the skin
74
What is an alternative position to use for placing an epidural catheter?
This procedure can also be performed in the **lateral decubitus position** where patients flex their knees flexed and against their abdomen or chest, assuming a “fetal position.”
The lateral decubitus position can be technically more challenging but often utilized for hip fractures
75
Steps for Spinal Anesthesia: Midline approach
1. The anesthesia professional should cover their hair and wear a mask
2. The patient is positioned, spine is palpated, and insertion site is identified (nail imprint or marker)
3. The site is cleaned with a sterile solution, hands are washed, and once dry, sterile gloves are applied, and a sterile drape is applied
4. A skin wheel is made at the insertion site with local anesthesia using a small (25-gauge) needle
5. Replace smaller needle with a longer needle for deeper local anesthetic infiltration
6. Insert the introducer slightly above the caudad spinous process with a 10 degree cephalad angle
7. Using a midline approach, the procedural (spinal) needle is passed through 1) skin, 2) subcutaneous tissue, 3) supraspinous ligament, 4) interspinous ligament, 5) ligamentum flavum, 6) epidural space, 7) dura mater, 8) arachnoid mater
8. Remove the stylet and CSF should be appreciated dripping.
9. Once the needle is in the subarachnoid space, fix it in position and attach syringe securely
10. Gently aspirate CSF to confirm needle is still in space, inject LA slowly (0.5 ml/s)
11. Complete the injection, aspirate a small volume to confirm that the needle remained in space while the local anesthetic was deposited
12. This CSF is then reinjected and the needle, syringe, and introducer removed together
13. Pay strict attention to the hemodynamic status (support blood pressure and heart rate)
14. Assess a level by temperature sensation (ETOH swab/laryngoscope handle) or pin prick (spinal needle stylet)
76
Paramedian approach
The paramedian approach can bypass heavily calcified ligaments and be helpful with thoracic epidurals and/or patients who have difficulty with positioning
After identifying the correct level for neuraxial anesthesia placement, palpate the spinous process
The needle should be inserted 1 cm lateral to this point and directed toward the middle of the interspace
The ligamentum flavum is usually the first resistance identified
77
List the principal dermatomes from the clavicle to the level of the nipples
* C5- clavicles
* C5, 6, 7- lateral parts of upper limbs
* C8, T1- medial side of upper limbs
* C6- Thumb
* C6, 7, 8- Hand
* C8- Ring and little fingers
* T4- level of the nipples
78
List the principal dermatomes from the umbilicus to the perineum
* T10- level of umbilicus
* T12- Inguinal or groin regions
* L1, 2, 3, 4- Anterior and inner surfaces of lower limbs
* L4, 5, S1- Foot
* L4- Medial side of great toe
* S1, 2, L5- Posterior and outer surfaces of lower limbs
* S1- Lateral margin of foot and little toe
* S2, 3, 4- perineum
79
With knowledge of the sensory dermatomes, the extent of sensory block can be assessed by \_\_\_.
a blunted needle or a piece of ice
80
Characteristics of Spinal Needles
All spinal needles have a tightly fitting stylet, but may differ in size length, and bevel and tip designs
Spinal needles are categorized as sharp (cutting)-tipped or blunt-tipped
In general, the smaller the gauge needle (along with use of a blunt-tipped needle), the lower will be the incidence of headache
81
Examples of Spinal Needles
The Quincke is an example of a cutting-tipped needle
The Whitacre is an example of a pencil point needle
82
The most important factors influencing the level of spinal block are \_\_\_\_.
* baricity of the local anesthetic solution
* position of the patient during and immediately after injection
* drug dosage
* site of injection
83
What is baracity?
What factors influence the baricity?
Baricity is used in anesthesia to determine the manner in which a particular drug will spread in the intrathecal space.
Migration of the local anesthetic solution depends on its density relative to CSF (CSF has a specific gravity of 1.003).
A hyperbaric solution of local anesthetic is denser (heavier) than CSF, whereas a hypobaric solution is less dense (lighter) than CSF.
84
Spread of anesthetic solution in a head-down position
a hyperbaric solution spreads cephalad, and a hypobaric anesthetic solution moves caudad
85
Spread of anesthetic solution in a head-up position
a hyperbaric solution moves caudad and a hypobaric solution moves cephalad
86
Spread of anesthetic solution in a lateral position
a hyperbaric spinal solution will have a greater effect on the dependent (down) side, whereas a hypobaric solution will achieve a higher level on the nondependent (up) side
87
An isobaric solution tends to \_\_\_\_.
remain at the level of injection
88
How does drug dosage and site of injection impact the level of anesthesia?
In general, the larger the dosage or more cephalad the site of injection, the more cephalad the level of anesthesia that will be obtained
89
Additional factors influencing the level of a spinal block include \_\_\_.
patient height, age, intraabdominal pressure, direction of the bevel on injection and natural spinal anatomy
90
With spinal anesthesia, hyperbaric solutions tend to move \_\_\_\_.
to the most dependent area of the spine (normally T4–T8 in the supine position
91
With normal spinal anatomy, the apex of the thoracolumbar curvature is \_\_\_.
T4, which should limit the cephalad spread of a local anesthetic solution \**prevents a high spinal*\*
92
Spinal Anesthesia Agents
There are a variety of types and concentrations of local anesthetics used for spinal anesthesia. Examples: 3% chloroprocaine, 2% lidocaine, 0.5% bupivacaine.
**\*Only preservative-free local anesthetic solutions are used**
Vasoconstrictors (α-adrenergic agonists, epinephrine) and opioids enhance the quality and/or prolong the duration of spinal anesthesia.
Vasoconstrictor Examples: epinephrine, phenylephrine
Opioid Examples: fentanyl, morphine
93
General facts for epidural anesthesia
Where is it performed? Use? Etc.
An epidural block can be performed at the lumbar, thoracic, or cervical level
Epidural techniques are used for surgical anesthesia, obstetric analgesia, postoperative pain control, and chronic pain management
Epidurals can be used as a single shot technique or with a catheter that allows intermittent boluses or continuous infusion, or both
The motor block can range from none to complete
94
Onset of epidural anesthesia
Epidural anesthesia is slower in onset (10–20 min), may not be as dense as spinal anesthesia and offers a segmental block
This can be advantageous as an epidural can provide analgesia without motor block
Slower onset is also good for patients with AS who could not tolerate a spinal
95
A segmental block is characterized by \_\_\_\_.
a well-defined band of anesthesia at certain nerve roots; leaving nerve roots above and below unblocked
96
Facts about the epidural needle
The standard epidural needle (Tuohy needle) is typically 16 to 18 gauge and has a blunt bevel with a gentle curve of 15° to 30° at the tip.
The blunt, curved tip helps to push away the dura after passing through the ligamentum flavum (instead of penetrating it)
97
How far should you advance the Tuohy needle?
1. Average adult: 4-6 cm
2. Obese adult: up to 8 cm
3. Thin adult: 3 cm
98
Epidural Catheter Placement: Midline Approach
1. Insert epidural needle into the interspinous ligament (has a “gritty” feel, like inserting a needle into a bag of sand)
2. Advance slowly until the ligamentum flavum is contacted (identified by a feel of increased resistance).
3. Attach glass syringe of 2–3 ml of saline and 0.1–0.3 ml of air epidural needle and press plunger
4. Once the ligamentum flavum is identified, advance needle slowly with nondominant hand while dominant hand maintains constant pressure on the syringe plunger.
5. Advance catheter only 3–5 cm into the epidural space (minimizes the risk of entering a vein, puncturing dura)
6. Confirm the length of catheter in the epidural space at the hub of the needle
7. Withdraw needle slowly with one hand stabilizing the catheter with the other
8. Again, confirm length of catheter in the epidural space at the skin
99
What does an epidural test dose check for?
Intravascular or intrathecal placement check
Aspirate and confirm the absence of blood
An epidural test dose is performed to confirm the epidural catheter is not intravascular or intrathecal
3 ml of LA solution (1.5% lidocaine) with 5 mcg/ml of epinephrine (1:200,000) are injected into the epidural catheter
100
What would be a positive response to a test dose?
An increase of heart rate of 30 beats/min, in 30 seconds lasting 30 seconds might suggest intravascular placement
An immediate and profound motor block (or signs of toxicity e.g. circumoral numbness) might suggest intrathecal placement
101
Factors Affecting Level of Block
**1) Drug volume**: In adults, 1 to 2 mL of local anesthetic per segment to be blocked is a generally accepted guideline. For example, to achieve a T4 sensory level from an L4–L5 injection would require about 12 to 24 mL
2) **Patient height and size**: Patient height affects the extent of cephalad spread. (shorter patients may require only 1 mL of local anesthetic per segment to be blocked, whereas taller patients generally require 2 mL per segment)
3) **Age**: The size and compliance of the epidural space decreases with age, therefore less volume is needed
4) **Additives**: Additives to the local anesthetic, particularly opioids, tend to have a greater effect on the quality of epidural anesthesia than on the duration of the block
102
Epidural anesthetic agents
Commonly used **short- to intermediate-acting agents** for surgical anesthesia include **chloroprocaine, lidocaine, and mepivacaine**. Longer acting agents include bupivacaine and ropivacaine.
Following the initial 1 to 2 mL per segment bolus (in fractionated doses), repeat doses delivered through an epidural catheter are done either as a smaller bolus (one-third of initial does) or continuous infusion
103
Previous chloroprocaine formulations with preservatives produced
cauda equine syndrome when accidentally injected in a large volume intrathecally
the syndrome causes compression of the spinal nerve roots and there is risk of paralysis if it goes uncorrected
104
What is the route for neuraxial opioids?
After an opioid such as morphine (Duramorph®) is injected into the intrathecal or epidural space, it diffuses into the substantia gelatinosa (Rexed’s lamina II) and unites with opioid receptors on the nerve terminal of the primary pain afferent.
The release of substance P is reduced, and, hence, the transmission of impulses through the substantia gelatinosa is inhibited.
This is spinal analgesia. Mu-1, mu-2, kappa, and delta receptors mediate spinal analgesia.
105
Spinal opioid analgesia is mediated primarily by \_\_\_\_.
Mu-2 receptors
106
Side effects of neuraxial opioids
Same side effects as systemic opioids with increased frequency of pruritus and urinary retention
107
A hydrophillic opioid = \_\_\_.
morphine
108
Describe the route of morphine for intrathecal placement
After intrathecal (spinal) placement, morphine diffuses out of the intrathecal space slowly. Onset of analgesia is slow and duration of analgesia is prolonged. Early depression of ventilation does not occur because uptake by systemic circulation is minimal, but rostral spread of significant quantities of morphine in CSF causes late (6-12 hours) depression of ventilation (morphine trapped in CSF circulates to brainstem).
109
Describe the route of morphine for an epidural
After epidural placement of morphine, onset of analgesia is slow and duration of analgesia is prolonged. Because systemic uptake is greater when morphine is injected into the epidural space, early depression of ventilation (within two hours) may occur, although early depression of ventilation is unlikely with morphine. Late depression of ventilation, again due to rostral spread in CSF, occurs.
110
For epidural anesthesia, a sudden loss of resistance (to injection of air or saline) indicates that \_\_\_.
the needle has passed through the ligamentum flavum and enters the epidural space.
111
For spinal anesthesia, the needle is advanced through \_\_\_.
the epidural space and penetrates the dura, as signaled by freely flowing CSF
112
Resistance will increase as \_\_\_\_.
the needle transects the supraspinous and interspinous ligaments
113
What if the needle contacts bone?
If this occurs superficially, the needle is likely contacting a lower spinous process
If this occurs deeper, a midline needle might be contacting the upper spinous process, alternatively, and off midline needle might be contacting a lamina
In both scenarios, the needle should be redirected
114
What happens as the needle penetrates the ligamentum flavum?
an obvious increase in resistance is encountered, and a pop is appreciated
115
Persistent paresthesias or pain with injection of drugs should \_\_\_.
prompt the clinician to withdraw and redirect the needle.
116
What are the advantages/disadvantages of a single shot spinal?
Advantages = rapid onset of block, reliably symmetrical block (including sacral roots), low doses of local anesthetic and opioids, technically easy
Disadvantages = Limited duration of action, limited ability to extend block, & requires a dural puncture
117
What are the advantages/disadvantages of an epidural?
Advantages = Can prolong the duration and extend block, relatively slow onset of anesthesia, may be used to provide postoperative anesthesia
Disadvantages = relatively slow onset of anesthesia, higher doses of local anesthetics and opiods than a spinal, high risk of PDPH with unintentional dural puncture, possibility of patchy or asymmetrical block, unreliable sacral block
118
What are the advantages/disadvantages of a combined spinal epidural?
Advantages = Rapid onset of block, reliably symmetric block (including sacral roots), can prolong the duration & extend block, option to titrate level of block, low doses of local anesthetic & opioids (spinal component), may be used to provide postoperative anesthesia
Disadvantages = may take longer than a single spinal shot, delayed confirmation of functional epidural catheter
119
What are the advantages/disadvantages of a continuous spinal?
Advantages = rapid onset of block, reliably symmetric block (including sacral roots), can prolong the duration and extend block, low doses of local anesthetics and opioids, option to titrate onset of block
Disadvantages = High incidence of PDPH with large dural puncture, possible higher risk of medication errors leading to a high spinal
120
Caudal Anesthesia
Caudal epidural anesthesia is a common regional technique in pediatric patients and often paired with general anesthesia for surgeries below the umbulicus
Caudal anesthesia involves needle or catheter penetration of the sacrococcygeal ligament covering the sacral hiatus that is created by the unfused S4 and S5 laminae
The hiatus may be felt as a groove or notch above the coccyx and between two bony prominences, the sacral cornu. The posterior superior iliac spines and the sacral hiatus define an equilateral triangle
121
Complications of Neuraxial Anesthesia
**Adverse or exaggerated physiological responses**: Urinary retention, High block, Total spinal anesthesia, Cardiac arrest, Horner syndrome
**Drug toxicity**: Systemic local anesthetic toxicity & Cauda equina syndrome
**Complications related to needle/catheter placement**
* Backache
* Dural puncture/leak (Postdural puncture headache)
* Neural injury
* Bleeding
* Intraspinal/epidural hematoma
* Misplacement (Inadequate anesthesia, Inadvertent intravascular block, Inadvertent intrathecal block & Infection)
122
Postdural Puncture Headache
Postdural Puncture Headache (PDPH) is a positional headache that usually occurs within 72 hours of dura puncture
Intracranial hypotension related to CSF leak may cause sagging of intracranial structures and stretch of sensory intracranial nerves, causing pain
123
Symptoms of PDPH
headache, nausea, vomiting, neck stiffness, visual changes
124
Patient risk factors include \_\_\_\_.
female, pregnancy, younger age, low BMI
125
Procedural risk factors of PDPH include \_\_\_.
cutting needle and needle size
126
Treatment of PDPH = \_\_\_.
bed rest, drug therapy and an epidural blood patch
127
What is a high spinal?
A high spinal is the effect of neuraxial medications exhibiting effects in the upper portion of the spinal column and/or brain stem
128
Symptoms of a high spinal
The signs and symptoms include a rapid ascending sympathetic, sensory, and motor block with associated bradycardia, hypotension, dyspnea, and difficulty with swallowing or phonation
Symptoms can progress to unconsciousness (due to brainstem hypoperfusion and/or brainstem anesthesia), and respiratory depression (secondary to respiratory muscle paralysis and brainstem hypoperfusion).
129
Treatment of a high spinal
Treatment depends on level of spinal and associated symptoms
* Bradycardia – epinephrine, ephedrine, glycopyrolate, atropine
* Hypotension – fluid bolus, vasopressors
* Dyspnea - reassurance
* Numbness of pinky finger
130
Diagnosis of a spinal-epidural hematoma
The diagnosis of spinal epidural hematoma is complicated by the concealed nature of the bleeding; thus, a high index of suspicion must be maintained. The most common presenting symptoms of neurologically significant SEH have been progressive motor and sensory block, and bowel or bladder dysfunction.
131
Structures transected during injection
Skin, SQ tissue, supraspinous ligament, intraspinous ligament, ligamentum flavum, epidural space
132
Potential Hot Spot
Pictures on Slide #5
133
What occurs if a patient develops an epidural hematoma?
emergency surgery for evacuation
134
Markings on Touhy Needle
brown and silver makings are 1cm each
135
Blockade of anterior nerve root fibers interrupts \_\_\_.
efferent motor and autonomic outflow
