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Concepts 1 > Neuraxial Anesthesia > Flashcards

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

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2
Q

Neuraxial blocks can be performed as a ____ or ___.

A

single injection or with a catheter to allow intermittent boluses or continuous infusions

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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
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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.

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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

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6
Q

The primary site of action for neuraxial blockade is ____.

A

the nerve root

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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

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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

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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.

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10
Q

Blockade of the posterior nerve root fibers interrupts ____.

A

­somatic and visceral sensation

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11
Q

The physiological responses to neuraxial blockade result from _____.

A

decreased sympathetic tone or unopposed parasympathetic tone, or both

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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

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13
Q

The sympathetic outflow is also called the ____.

A

thoracolumbar outflow

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14
Q

The sympathetic, or thoracolumbar, outflow arises from segments ___.

A

T1–L2 or segments T1–L3

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15
Q

Most sympathetic preganglionic neurons synapse with ___.

A

postganglionic fibers in the paravertebral ganglia

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16
Q

Sympathetic cardiac accelerator fibers arise from ____.

A

T1–T4

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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

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18
Q

A massive sympathetic response would lead to ___.

A

tachycardia, dry mouth, bronchodilation and diaphoresis.

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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

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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

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21
Q

Which nervous system is associated with the fight or flight response?

A

sympathetic

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22
Q

The parasympathetic outflow is also called the ___.

A

craniosacral outflow

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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)

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24
Q

Cranial nerve III arises from the ___.

A

midbrain

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25
Q

Cranial nerve VII arises in the ___

A

pons

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26
Q

Cranial nerves IX and X arise from the ____.

A

medulla

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27
Q

The parasympathetic nervous system is ___ compared to the SNS.

A

anatomically and functionally more selective and localized in its effects

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28
Q

The parasympathetic nervous system functions primarily to _____.

A

conserve energy and maintain organ function (resting and digest)

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29
Q

A massive parasympathetic response would lead to ____.

A

salivation, wheezing, weeping, vomiting, urinating, defecating, and seizing.

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30
Q

Effects of the parasympathetic NS on the body organs

A

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)

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31
Q

Neuraxial anesthesia will likely result in varying degrees of ____.

A

hypotension and bradycardia

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32
Q

How does hypotension occur with neuraxial anesthesia?

A

­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

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33
Q

How does bradycardia occur with neuraxial anesthesia?

A

­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

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34
Q

Treatment of hypotension and bradycardia related to neuraxial anesthesia

A

­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
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35
Q

the diaphragm is innervated by the ____.

A

­phrenic nerve (C 3, 4, 5)

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36
Q

Pulmonary effects of neuraxial anesthesia

A

­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

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37
Q

Postoperative thoracic epidural analgesia in high-risk patients can ___.

A

­improve pulmonary outcome by decreasing the incidence of pneumonia and respiratory failure, improving oxygenation, and decreasing the duration of mechanical ventilatory support

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38
Q

Gastrointestinal effects of neuraxial anesthesia

A

­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

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39
Q

GU Effects of Neuraxial Anesthesia

A

­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

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40
Q

Metabolic and Endocrine Effects of Neuraxial Anesthesia

A

­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

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41
Q

Neuraxial blocks may be used ____.

A

alone or in conjunction with general anesthesia for many procedures below the neck.

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42
Q

As a primary anesthetic, neuraxial blocks have proved most useful in ____.

A

lower abdominal, inguinal, urogenital, rectal, and lower extremity surgery.

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43
Q

Which type of neuraxial anesthesia would you use for a breast surgery?

Need for GA?

A

Epidural

Yes, needs GA

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44
Q

Which type of neuraxial anesthesia would you use for a thoracic surgery?

Need for GA?

A

Epidural

Yes, needs GA

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45
Q

Which type of neuraxial anesthesia would you use for a major abdominal surgery?

Need for GA?

A

Epidural

Yes, needs GA

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46
Q

Which type of neuraxial anesthesia would you use for a hip replacement surgery?

Need for GA?

A

Spinal or epidural

No, you do not need GA

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47
Q

Which type of neuraxial anesthesia would you use for a knee replacement surgery?

Need for GA?

A

Spinal

No, you do not need GA

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48
Q

What are the abdolute contraindications to neuraxial anesthesia?

A

Infection at the injection site

Lack of consent

Coagulopathy

Severe hypovolemia

Increased ICP

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49
Q

What are the relative contraindications to neuraxial anesthesia?

A
  • Sepsis
  • Uncooperative patient
  • Preexisting neurological deficits
  • Stenotic heart valves
  • LV outflow obstruction
  • Severe spinal deformity
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50
Q

When bleeding occurs in the closed space of the spinal canal, the expanding hematoma can cause ___.

A

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

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51
Q

The decision to use neuraxial anesthesia in patients who either have been or will be receiving antithrombotic medication must ___.

A

weigh the benefit of the neuraxial anesthetic against the risk of spinal epidural hematoma

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52
Q

For patients on Warfarin, what are the requirements to place an epidural catheter/remove one?

A

Must be 4 to 5 days from their last dose and verify normal INR

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53
Q

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?

A

Must be 4 to 6 hours after holding gtt and verify normal aPTT

Can restart gtt one hour after

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54
Q

For patients on subcutaneous low dose thromboprophylaxis Heparin, what are the requirements to place an epidural catheter/remove one?

A

must be placed 4 to 6 hours after last dose or verify normal aPTT

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55
Q

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?

A

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
Q

Argatroban is a ____. When can you place an epidural if a patient is on this drug?

A

Thrombin inhibitor

Avoid neuraxial techniques if a patient is on this medication

57
Q

Which drugs are ok to continue using during the placement/removal of an epidural catheter?

A
  • Aspirin
  • NSAIDs
  • Herbal medications (ginko, garlic, ginseng)
58
Q

Neuraxial blocks must be performed only in a facility in which ____.

A

all the equipment and drugs needed for intubation, resuscitation, and general anesthesia are immediately available

59
Q

Regional anesthesia can be facilitated by ___.

A

patient education, preparation and adequate premedication

60
Q

If using sedation during neuraxial blocks, you may need ___.

A

Supplemental oxygen via a face mask or nasal cannula may be required to avoid hypoxemia

61
Q

Monitoring requirements for labor analgesia include ___.

A

blood pressure and pulse oximetry

62
Q

Monitoring for blocks in surgical anesthesia is ___.

A

the same as that in general anesthesia

63
Q

What can help facilitate locating spinous processes when difficult to palpate?

A

Ultrasound

64
Q

___ is the most prominent cervical process.

A

C7

65
Q

___ is at the same level as the inferior angle of the scapulae.

A

T7

66
Q

___ is where the spinal cord ends.

A

L1-L2

67
Q

____ is the highest points of both iliac crests and is also known as ___.

A

L4

Tuffier’s line

68
Q

____ is the largest vertebral interspace.

A

L4-L5

69
Q

___ is between the posterior superior iliac spine.

A

S2

70
Q

Spinous processes are palpated to identify ___.

A

midline

71
Q

What is the needle position for cervical and lumbar spine?

A

cervical and lumbar spine are nearly horizontal thus the needle is directed with only a slight cephalad angle

72
Q

What is the needle position for thoracic spine?

A

­the thoracic spine slant in a caudal direction therefor the needle must be angled significantly more cephalad

73
Q

What is the preferred position for placing an epidural catheter?

A

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
Q

What is an alternative position to use for placing an epidural catheter?

A

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
Q

Steps for Spinal Anesthesia: Midline approach

A
  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
Q

Paramedian approach

A

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
Q

List the principal dermatomes from the clavicle to the level of the nipples

A
  • 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
Q

List the principal dermatomes from the umbilicus to the perineum

A
  • 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
Q

With knowledge of the sensory dermatomes, the extent of sensory block can be assessed by ___.

A

a blunted needle or a piece of ice

80
Q

Characteristics of Spinal Needles

A

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
Q

Examples of Spinal Needles

A

­The Quincke is an example of a cutting-tipped needle

­The Whitacre is an example of a pencil point needle

82
Q

The most important factors influencing the level of spinal block are ____.

A
  • baricity of the local anesthetic solution
  • position of the patient during and immediately after injection
  • drug dosage
  • site of injection
83
Q

What is baracity?

What factors influence the baricity?

A

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
Q

Spread of anesthetic solution in a head-down position

A

­a hyperbaric solution spreads cephalad, and a hypobaric anesthetic solution moves caudad

85
Q

Spread of anesthetic solution in a head-up position

A

­a hyperbaric solution moves caudad and a hypobaric solution moves cephalad

86
Q

Spread of anesthetic solution in a lateral position

A

­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
Q

An isobaric solution tends to ____.

A

­remain at the level of injection

88
Q

How does drug dosage and site of injection impact the level of anesthesia?

A

­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
Q

Additional factors influencing the level of a spinal block include ___.

A

patient height, age, intraabdominal pressure, direction of the bevel on injection and natural spinal anatomy

90
Q

With spinal anesthesia, hyperbaric solutions tend to move ____.

A

to the most dependent area of the spine (normally T4–T8 in the supine position

91
Q

With normal spinal anatomy, the apex of the thoracolumbar curvature is ___.

A

T4, which should limit the cephalad spread of a local anesthetic solution *prevents a high spinal*

92
Q

Spinal Anesthesia Agents

A

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
Q

General facts for epidural anesthesia

Where is it performed? Use? Etc.

A

­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
Q

Onset of epidural anesthesia

A

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
Q

A segmental block is characterized by ____.

A

­a well-defined band of anesthesia at certain nerve roots; leaving nerve roots above and below unblocked

96
Q

Facts about the epidural needle

A

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
Q

How far should you advance the Tuohy needle?

A
  1. Average adult: 4-6 cm
  2. Obese adult: up to 8 cm
  3. Thin adult: 3 cm
98
Q

Epidural Catheter Placement: Midline Approach

A
  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
Q

What does an epidural test dose check for?

A

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
Q

What would be a positive response to a test dose?

A

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
Q

Factors Affecting Level of Block

A

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
Q

Epidural anesthetic agents

A

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
Q

Previous chloroprocaine formulations with preservatives produced

A

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
Q

What is the route for neuraxial opioids?

A

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
Q

Spinal opioid analgesia is mediated primarily by ____.

A

Mu-2 receptors

106
Q

Side effects of neuraxial opioids

A

Same side effects as systemic opioids with increased frequency of pruritus and urinary retention

107
Q

A hydrophillic opioid = ___.

A

morphine

108
Q

Describe the route of morphine for intrathecal placement

A

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
Q

Describe the route of morphine for an epidural

A

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
Q

For epidural anesthesia, a sudden loss of resistance (to injection of air or saline) indicates that ___.

A

the needle has passed through the ligamentum flavum and enters the epidural space.

111
Q

For spinal anesthesia, the needle is advanced through ___.

A

the epidural space and penetrates the dura, as signaled by freely flowing CSF

112
Q

Resistance will increase as ____.

A

the needle transects the supraspinous and interspinous ligaments

113
Q

What if the needle contacts bone?

A

­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
Q

What happens as the needle penetrates the ligamentum flavum?

A

an obvious increase in resistance is encountered, and a pop is appreciated

115
Q

Persistent paresthesias or pain with injection of drugs should ___.

A

prompt the clinician to withdraw and redirect the needle.

116
Q

What are the advantages/disadvantages of a single shot spinal?

A

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
Q

What are the advantages/disadvantages of an epidural?

A

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
Q

What are the advantages/disadvantages of a combined spinal epidural?

A

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
Q

What are the advantages/disadvantages of a continuous spinal?

A

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
Q

Caudal Anesthesia

A

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
Q

Complications of Neuraxial Anesthesia

A

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
Q

Postdural Puncture Headache

A

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
Q

Symptoms of PDPH

A

headache, nausea, vomiting, neck stiffness, visual changes

124
Q

Patient risk factors include ____.

A

female, pregnancy, younger age, low BMI

125
Q

Procedural risk factors of PDPH include ___.

A

cutting needle and needle size

126
Q

Treatment of PDPH = ___.

A

bed rest, drug therapy and an epidural blood patch

127
Q

What is a high spinal?

A

A high spinal is the effect of neuraxial medications exhibiting effects in the upper portion of the spinal column and/or brain stem

128
Q

Symptoms of a high spinal

A

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
Q

Treatment of a high spinal

A

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
Q

Diagnosis of a spinal-epidural hematoma

A

­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
Q

Structures transected during injection

A

Skin, SQ tissue, supraspinous ligament, intraspinous ligament, ligamentum flavum, epidural space

132
Q

Potential Hot Spot

A

Pictures on Slide #5

133
Q

What occurs if a patient develops an epidural hematoma?

A

emergency surgery for evacuation

134
Q

Markings on Touhy Needle

A

brown and silver makings are 1cm each

135
Q

Blockade of anterior nerve root fibers interrupts ___.

A

efferent motor and autonomic outflow

Concepts 1 (10 decks)

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