Spinal & Epidural Anesthesia Flashcards
_______ not completely fused in pediatric patient, can do caudal anesthesia (only on pediatric patient).
Sacral vertebrae
- Lower angle of scapula = ____
- Top of iliac crest = _____
- Place when feeling patient’s back (on hips come across to medial section of back)
- L1
- L4-L5
- Tuffier’s Line
When you have herniations, usually from?
*Want to get the widest space for the widest access for needle placement.
Intervertebral disk
Vertebral Curves in Supine Position:
- High?
- Low?
- C5 & L3
* T5 & S2
The building blocks of the spine are the individual bones called?
Vertebrae
Purpose is to stabilize vertebral body?
Ligaments
Ligaments:
1) Most anterior ligament that connects the apices of the spinous process.
2) Connects spinous process to spinous process, put needle through ligament here. Positioning very important.
3) Very thick ligament, just before epidural space.
1) Supraspinous
2) Interspinous
3) Ligamentum Flavum
Ligaments:
1) Located behind vertebral body.
2) Typically ligaments that sit above C7, occasionally inject steroids for neck pain.
1) Longitudinal
2) Ligamentum nuchae
Ligamentum Flavum:
- Extends from foramen magnum to?
- Tough, wedge shaped ligament, composed of?
- Thickest in _____ (3-5 mm @ ___ in adult).
- The so called yellow ligament
- Sacral hiatus
- Elastin
- Midline (L3)
Protective membranes?
Meninges (continuous with cranial meninges)
Spinal Meninges:
Thickest meningeal tissue. Begins at foramen magnum and ends caudally at S2.
*Abuts the ____ (subdural space)
Dura mater
*Arachnoid mater
Spinal Meninges:
Principal physiologic barrier for drugs moving btw the epidural space and the spinal cord?
*Abuts the ____, giving rise to the subarachnoid space.
Arachnoid Mater
*Pia mater
Spinal Meninges:
Contains CSF. Continuous with the cranial CSF and provides vehicle for drugs in the spinal CSF to reach the brain?
*Houses the spinal nerve _____ & _____.
Subarachnoid space
*roots and rootlets
Spinal Meninges:
Adheres to the spinal cord?
Pia mater
- In spinal we are depositing local anesthetic directly into ____ where nerve roots and rootlets are, onset is faster, will not need as much medication.
- In epidual anesthesia, giving med behind ______ in epidural space, has to go through dura, subdura and arachnoid space, onset much slower when compared to spinal (dosage will also have to be a little bit higher).
- CSF
* Ligamentum flavum
Spinal Cord: Foramen magnum to ______ (terminates at _____).
Termination of the _____ @ S2.
Conus medullaris
L1-L2
Dural sac
Dermatomes:
Portion of the spinal cord that gives rise to all the rootlets of a single spinal nerve is called a?
Segment
Is the skin area innervated by a spinal nerve and its segment
Dermatone
_____ is the skin area innervated.
Need to assess patient’s dermatomes to make sure level is blocked where it needs to be.
If _____ does not work, may need to go to plan B general anesthesia (would not do another spinal due to risk of local anesthetic toxicity)
Dermatome
Spinal block
Example of test question: Pinky is innervated by?
Patient starts losing sensation in pinky, we were trying to block at level of T4.
*At ____ patient will start losing feeling of respiration.
(Start wondering if block is migrating up, place patient sitting up/arm up. Make sure patient does not lose airway.)
C8
C4
CSF:
Volume - ____ in the subarachnoid space.
CSF volume replaced 3-4x/day.
Produce ____ cc/hr by the?
- 150 cc
- 21
- choroid plexus
CSF:
-Specific Gravity?
1.004-1.008
CSF replaces itself daily.
We think of specific gravity when we want to change the?
Baricity of local anesthetic
Blood supply of the spinal cord: (3)
1) Responsible for 2/3 of flow?
1) Anterior spinal artery
2) Posterior spinal arteries
3) Radicular artery
Physiology of Neural Blockade:
Local anesthetic bathes the ______ in that space.
Nerve roots
Physiology of Neural Blockade:
1) Local anesthetic is injected into CSF?
2) Local anesthetic is injected into epidural or caudal space?
1) Sub-arachnoid Block (Spinal Anesthesia)
2) Epidural Anesthesia
Physiology of Neural Blockade:
*Overall Goal
1) _____ - interrupts transmission of painful stimuli
2) _____ - skeletal muscle tone
1) Sensory blockade
2) Motor Blockade
In pediatric patient’s a ________ is like an epidural block, block sensory but get some motor.
Caudal Block
Neural Blockade of Subarachnoid Block (SAB) and Epidural Block:
1) Principal site is the?
2) _____ can occur at any point AND all points along the ______ extending from the site of drug administration to the interior of the cord.
1) Nerve root
2) Blockade
neural pathways
Subarachnoid block (spinal block) more profound response from _______ than epidural block.
Autonomic Nervous System
*If aiming for T10 block (umbilicus). At T10 will get autonomic block up to about T4.
Not just getting block at L4, getting some below and some above.
Will lose some of autonomic response - _____ or ____ (this is expected, this is not a complication). Make sure patient gets good ____, may want ____, phenylephrine or ephedrine at bedside.
- bradycardia or hypotension
- pre-hydration
- fluid
Physiology of Centroneuraxial Blockade:
Blocks all impulses regardless of fiber type: (4)
Nociceptive
Motor
Proprioceptive
Autonomic
Physiology of Centroneuraxial Blockade:
*The Purpose is blockade of ____ impulses.
(this impulse is a stimulus that causes pain or injury)
*However, ____ and ____ are also blocked!
- Nociceptive impulses
* Autonomic and Motor
Autonomic and motor is an ______, we don’t mean for this to happen, but can’t prevent it.
Ancillary Block
Benefits of Neuroaxial Anesthesia:
1) Decreased _______ response to surgery and anesthesia when compared with general anesthesia.
2) Avoids?
3) Decreased incidence of post-op ______.
1) metabolic stress
2) airway instrumentation
3) nausea (as long as they are well hydrated)
Benefits of Neuroaxial Anesthesia (continued):
1) Less intra-operative _____ (good thing for patients with lots of coexisting diseases).
2) Post-op?
3) Allows patient to remain awake during?
1) sedation
2) pain relief
3) C-section
Disadvantages of Neuroaxial Anesthesia:
1) _____
2) Slower case start if challenging placement
3) _____ depends on experience
4) _____
(Patients talk about BP issues, what happened to their mother, etc.)
1) Hypotension
3) Failure rate
4) Urban legends
Considerations for choosing a regional technique: (4)
1) Anatomy
2) Age
3) Pregnancy
4) Pathophysiology
Considerations for choosing a regional technique:
1) Anatomy: do they have scoliosis, contractures, ____ - may make impossible to do
2) Age: ____ at extreme ages
3) Pregnancy: reduced volume in _____, compression of vena cava (problems with CO, decreased venous return. Never let them _____, lye on ____ so uterus is tipped, no compression of vena cava.
4) Physiology: _____ - may not want to do spinal
(consider epidural due to slower onset, will tolerate anesthesia better)
1) BMI of 45
2) dose requirements diminish
3) epidural space
lye flat
hip
4) Valvular disorders
Indications of SAB/Epidural:
*Sensory level of anesthesia required vs. adverse physiological effects of regional anesthesia
*Need to consider: (3)
1) Length of procedure
2) Post-op analgesia needs
3) Co-existing diseases
Indications of SAB/Epidural:
*Sensory level of anesthesia required vs. adverse physiological effects of regional anesthesia
____ using thoracic muscles to help push air out (leaning forward to breathe), if blocking T4, think your blocking T6 will not spontaneously ventilate very well. Using those accessory muscles to breathe.
COPD patient
You can ____ an epidural because your leaving the catheter in (can not do this with spinal, taking needle out). Patient needs _____ need to insert at the same time with spinal, can add later with epidural.
- Re-dose
- Post-op pain relief