Spinal & Epidural Anesthesia Flashcards by Pootie Poo

____ provides alternatives to General anesthesia

Neuraxial anesthesia

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Also used as postoperative analgesia

REGIONAL ANESTHESIA NEURAXIAL ANESTHESIA CENTRAL BLOCKS

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Principal site of action in SPINAL AND EPIDURAL ANESTHESIA

nerve root

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Blockade of neural transmission in the ____
interrupts somatic and visceral sensation

posterior nerve root fibers

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blockade in the ____ prevent efferent motor and autonomic outflow

anterior nerve roots fibers

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Somatic blockade:
• Interrupts ___ transmission of painful stimuli
• Abolish the ___ impulses responsible for skeletal muscle tone

• Interrupts afferent transmission of painful stimuli

• Abolish the efferent impulses responsible for skeletal muscle tone

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Interruption of efferent autonomic transmission at the spinal nerve roots produces sympathetic blockade

AUTONOMIC BLOCKADE

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Cardiovascular manifestations in autonomic blockade:

• Profound hypotension treated with ___

• Extreme bradycardia treated with ___

• Profound hypotension treated with alpha adrenergics
• Extreme bradycardia treated with atropine

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Cardiovascular manifestations in autonomic blockade:

GI manifestation: ____

Active peristalsis

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Loss of autonomic bladder control results in ____

urinary retention

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CONTRAINDICATIONS TO NEURAXIAL BLOCKADE:
absolute

Infection at the site of injection
Patient refusal (e.g. procedure)
Coagulopathy or other bleeding diathesis (bleeding
disorder)
Severe hypovolemia (e.g. trauma)
Increased intracranial pressure
Severe aortic stenosis
Severe mitral stenosis

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CONTRAINDICATIONS TO NEURAXIAL BLOCKADE:

relative

Sepsis
Uncooperative patient
preexisting neurological deficits
demyelinating lesions
stenotic valvular heart lesions
left ventricular outflow obstruction (hypertrophic obstruction cardiomyopathy)
severe spinal deformity

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CONTRAINDICATIONS TO NEURAXIAL BLOCKADE:

controversial

prior back surg at site of injection
complicated surgery
prolonged operation
major blood loss
maneuvers that compromise respiration

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Spinal and Epidural anesthesia fall under the category of ____

REGIONAL Anesthesia

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Spinal Anesthesia
● Injecting agent into the _____

Epidural Anesthesia
● Injecting agent into the _____

Spinal Anesthesia
● Injecting agent into the SUBARACHNOID SPACE

Epidural Anesthesia
● Injecting agent into the EPIDURAL SPACE

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Meninges

Dura Mater

Arachnoid membrane

Pia

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> fibroelastic membrane
prevents displacement of an epidural catheter into the fluid-filled subarachnoid space

Dura Mater

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> adherent to the inner surface of the dura

> major pharmacologic barrier preventing movement of drug from the epidural to the subarachnoid space

Arachnoid membrane

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major pharmacologic barrier preventing movement of drug from the epidural to the subarachnoid space

Arachnoid membrane

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> innermost layer
highly vascular
inner border of the subarachnoid space

Pia mater

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> inner border of the subarachnoid space

Pia mater

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Landmarks:

__ – most prominent vertebrae

__ – first palpable spinous process

__ level of iliac crest

__ - PSIS

__ – tip of the scapula

• C2 – first palpable spinous process
• C7 – most prominent vertebrae
• T7 – tip of the scapula
• L4 – level of iliac crest
• S2 - PSIS

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first palpable spinous process

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most prominent vertebrae

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tip of the scapula

level of iliac crest

Posterior superior iliac spine landmark

generally used for surgical procedures involving the lower abdominal area, perineum, and lower extremities.

Spinal anesthesia

Used for abdomen and lower extremities

Epidural anesthesia

- Control of labor pain - Supplement anesthetic for thoracic and upper abdominal procedures

Epidural anesthesia

supplement anesthetic for thoracic and upper abdominal procedures

Epidural anesthesia

Agent injected into the subarachnoid space

Spinal Anesthesia

Spinal Anesthesia agent is injected into the ____

subarachnoid space

Spread by CSF which bathes the spinal cord and nerve roots

Spinal Anesthesia

Patient Positioning for spinal anesthesia

● Lateral Decubitus ● Sitting ● Jack-knife or Prone

➢ Patient lies on his side with back and legs flexed ➢ More comfortable for the ill and frail

Lateral Decubitus

➢ Encourages flexion and recognition of midline ➢ Patient bends his back to a “C” shape

Sitting position

In sitting position: Lumbar CSF is __ in this position, the dural sac is __, thus providing a larger target for the spinal needle.

Lumbar CSF is elevated in this position, the dural sac is distended, thus providing a larger target for the spinal needle.

For perineal procedures position

Jack-knife or Prone

For Jack-knife or Prone position there is __ flexion, the __ dural sac, and the __ CSF pressure

Limited flexion, the contracted dural sac, and the low CSF pressure

Spinal needles gauge

Gauge 22-25

Free flow of CSF confirms correct placement

Induction technique

Needle is secured by holding the hub between the thumb and the index finger

“pencil like manner” in Induction technique

In midline approach— Needle inserted at the ____ of the selected interspace, easily identified by visual inspection and palpation

top margin of the lower spinous process

In midline approaches — Needle is progressively advanced with a slight ____

cephalad orientation

In midline approaches: The patient should NOT BE HEAVILY SEDATED because successful spinal and epidural anesthesia requires patient participation to maintain good position, evaluate block height, and indicate to the anesthesiologist about paresthesias if the needle contacts neural elements. T/F?

True

The presence of __ confirms that the needle encountered a cauda equina nerve root in the subarachnoid space and the needle tip is in __ position

The presence of CSF confirms that the needle encountered a cauda equina nerve root in the subarachnoid space and the needle tip is in good position.

__ insertion is prone to bleeding since one can encounter a lot of vasculatures

Paramedian

Paramedian insertion surpasses the suprasinous and interspinous ligament and the _____ will be the first resistance encountered

ligamentum flavum

widest approach/insertion but inaccessible from midline

LUMBOSACRAL Taylor (L5-S1 interspace)

Layers traversed by the Spinal Needle:

1. Skin 2. Subcutaneous tissue 3. Supraspinous ligament 4. Interspinous ligament 5. Ligamentum flavum 6. Epidural Space 7. Dura 8. Subarachnoid space

FACTORS FOR DISTRIBUTION OF ANESTHETIC: Distribution of local anesthetic solution in CSF is influenced by

Baricity of the solution Contour of the spinal canal Position of the patient Dose, volume and concentration Patient characteristics

RATIO OF local anesthetic solution’s density relative to the density of CSF

Baricity

In hyperbaric solutions (>1.007) - principal advantage is the ability to achieve ____ of anesthesia

greater cephalad spread

HYPERBARIC SOLUTIONS (>1.007) GRAVITATES TOWARD THE ____ PORTION HEAD DOWN POSITION FOR ____

GRAVITATES TOWARD THE DEPENDENT PORTION HEAD DOWN POSITION FOR CEPHALAD SPREAD

Reserved for patients undergoing perineal procedures in jackknife position

HYPOBARIC SOLUTIONS (<0.997)

Distribution not affected by gravity, not influenced by patient position

ISOBARIC SOLUTIONS

For perineal or lower extremity procedures, lower part of the trunk (hip arthroplasty, inguinal hernia repair)

ISOBARIC SOLUTIONS

__ does not influence the long acting anesthesia

Epinephrine

Opioids and Other Analgesics — Effect is mediated at the dorsal horn of the spinal cord where opioids mimic the effect of endogenous __

enkephalins

Side effects and complications in Opioids and Other Analgesics

• Hypotension • Bradycardia • Post spinal headache • Nausea • Urinary Retention • Backache • Neurologic sequelae • Hypoventilation

• Injection of local anesthetic into the epidural space

Epidural Anesthesia

• Anesthesia occurs more slowly (30 mins -1hour) and develops in a segmental manner • Major site of action: spinal nerve roots

Epidural Anesthesia

Major site of action in epidural anesthesia:

spinal nerve roots

Epidural Kit gauge

LARGER GAUGES • 17- or 18-gauge needle which permits passage of a 19- or 20- gauge catheter

Layers Traversed by Epidural Needle

1. Skin 2. Subcutaneous tissue 3. Supraspinous ligament 4. Interspinous process 5. Ligamentum flavum

In Lumbar and Low Thoracic areas&approaches — Both __ and __ approaches are used

Both midline and paramedian approaches are used

____ approach is more popular due to: - Simpler anatomy and easier orientation - Passage of needle through less sensitive structures

Midline approach

Generally uses a paramedian approach

Thoracic

LOSS OF RESISTANCE TECHNIQUE: A syringe containing ____ is attached to the needle

air/saline or both

A small drop of saline is placed at the hub of the epidural needle The drop is retracted into the needle by the negative pressure in the epidural space

HANGING DROP TECHNIQUE

Things To Remember With Epidural Placement: Thread the catheter __cm

3-5 cm

Adjuvants: To prolong the duration

EPINEPHRINE

Adjuvants

Epinephrine Opioids Sodium bicarbonate

Because local anesthetics are weak bases, they exist largely in the ionic form, adding sodium bicarbonate favors the non-ionized form of local anesthetic and favors _____ onset of anesthesia

faster

Local anesthetics used for epidural anesthesia

- chloroprocaine - lidocaine - bupovacaine - ropivacaine

Side Effects of local anesthetics used for epidural anesthesia

• Backache • Postdural puncture headache • Hearing loss • Systemic toxicity • Total spinal • Neurologic injury • Spinal Hematoma

Table spinal vs. epidural

Slide 50

As you pass ligamentum flavum, the resistance will increase. T/F?

True