Exam 1- Neuraxial Principles (5/30/23) Flashcards
What are the two major components of regional anesthesia?
- Central Neuraxial Blocks
- Peripheral Nerve Blocks
What are the two components of Central Neuraxial Anesthesia?
Which one is harder to perform?
- Spinal Anesthesia
- Epidural Anesthesia (This one is harder to perform, it takes skills.)
Will you expect to see CSF during epidural blocks?
No. CSF should not be expected in epidural blocks.
CSF is expected in spinal blocks.
What ligaments (in order) will the needle pass through to get to the epidural space?
- Supraspinous Ligament
- Interspinous Ligament
- Ligamentum Flavum
Spinal Anesthesia is the injection of local anesthetic (LA) into the ____________ space.
- Subarachnoid
What are two other names for Spinal Anesthesia?
- Subarachnoid Block (SAB)
- Intrathecal Block
Are subarachnoid blocks used primarily as adjunct agents or as the sole anesthetic technique?
SABs can be used both as the primary anesthetic plan and also as adjuncts.
What procedures commonly require a SAB?
- C-section
- Lower extremity surgery
- Abdominal Surgery (Lower/Upper)
Differentiate the onset of action between a spinal block and an epidural block.
Spinal Block: Rapid Onset (5 min)
Epidural Block: Slow Onset (10-15 mins)
Describe the spread of LA between a spinal block and an epidural block.
Spinal Block: Higher than expected; may extend extracranially.
Epidural Block: As expected, can be controlled w/ volume of LA.
Which type of block tends to extend cephalad?
Spinal Block: Higher than expected; may extend extracranially.
Which type of block (spinal or epidural) is much more segmental in nature?
Epidural Block = Segmental
Which type of technique (spinal or epidural) will result in much greater motor neuron blockade?
Spinal Block = Dense motor block
Is hypotension more likely to occur between a spinal block or an epidural block?
- Spinal Block
For SAB, the _______ effect is usually 2 spinal segments cephalad of the sensory block.
- SNS
For SAB, the _______ effect is 2 spinal segments below the sensory block.
- Motor
What are your phrenic nerves?
- C3 nerve fiber
- C4 nerve fiber
- C5 nerve fiber
What LA discussed in class is used for a “walking” epidural.
- Ropivacaine
Ropivacaine provides a very segmental block
What are your cardiac accelerator nerves?
T1 - T4
What term was used in class to describe antagonized sympathetic nerve fibers secondary to local anesthetics?
- Sympathectomy
This usually results in hypotension and bradycardia.
Differentiate the duration of action between a spinal block vs an epidural block.
Spinal: Limited and fixed (one-shot)
Epidural: Unlimited (Catheter in place w/ LA infusion)
Differentiate the level of placement between a spinal block vs an epidural block.
Spinal Block: Start at L3-L4, L4-L5, L5-S1
Epidural Block: Any Level
Although an epidural can be performed at any level, residents will start at L3-L4.
How many attempts are permitted for a spinal/epidural block?
- Three
Differentiate the dosing between a spinal block vs an epidural block.
Spinal Block: Dose-base
Epidural Block: Volume-base
What is the max amount (volume) of LA for a spinal block vs epidural?
Spinal Block: 3 mL
Epidural Block: 20 mL
Differentiate the concentration of LA between a spinal block vs an epidural block.
Spinal Block: Concentrated and fixed
Epidural Block: Varies
Differentiate the LA Toxicity between a spinal block vs an epidural block.
Spinal: No
Epidural: Yes (Higher risk of LA entering the bloodstream due to bilateral veins on the spine.)
Which LA discussed in class is the most sensitive to the heart?
- Bupivacaine
What should be done during a Bier Block procedure if IV Bupivacaine is accidentally administered instead of Lidocaine?
- Leave the tourniquet in place and let the bupivacaine be absorbed.
- Do not deflate the cuff unless you want V-tach/ V-fib.
Differentiate how gravity influences a spinal block vs an epidural block.
Spinal Block: Yes, there will baricity
Epidural: No, unless the needle punctures the dura (“wet tap”).
Differentiate the manipulation of dermatome spread after dosing between a spinal block vs an epidural block.
Spinal: Positional Change depending on baricity (Iso, Hyper, Hypobaric)
Epidural: Incremental dermatome spread based on volume. 1-2 mL per segment.
Neuraxial anesthesia can reduce these 6 adverse events.
- Bleeding
- Narcotic usage
- Postop Illeus
- Thromboembolic events
- PONV
- Respiratory complications
What are the other benefits of Neuraxial Anesthesia?
- Great mental alertness
- Less urinary retention
- Quicker to eat, void, ambulate
- Quicker PACU discharge (use Lidocaine)
- Preemptive anesthesia
- Blunts stress response from surgery
What are the indications of spinal anesthesia?
- Surgical procedures involved with Lower abdomen, Perineum, and Lower extremities (Knees/Hips)
- Cesarean Delivery (for elective and stat cases only)
What anesthesia would be indicated if the surgeon needs the patient to be still?
- General Anesthesia
Important to communicate with surgeon about the plan of care.
What anesthesia would be indicated if there is an emergency Cesarean delivery?
- General Anesthesia (Rapid Sequence Induction)