Spinal Anesthesia (Exam I) Flashcards
What type of neuraxial technique would exhibit a more rapid onset?
Spinal blocks
What type of neuraxial technique would exhibit a slower onset?
Epidural blocks
What type of block tends to extend cephalad?
Spinal blocks
The spread of epidural blocks can be controlled via the ______ of the local anesthetic.
volume
Which type of neuraxial block is more dense? Which is more segmental?
Spinal = Dense
Epidural = Segmental
Which type of neuraxial block will produce a dense neuromuscular blockade?
Spinal blocks
T/F. Epidural blocks tend to produce hypotension more than spinal blocks?
False. Spinal blocks tend to produce greater hypotension.
Spinal blocks are ____ based, whilst epidural blocks are _____ based.
dose; volume
Where should spinal blocks be placed? (especially if you’re a beginner)
L3 - L4
Differentiate the duration of action of spinal blocks vs epidural blocks.
Spinal blocks = limited and fixed duration
Epidural = variable duration due to catheter in place and infusion delivery.
Which neuraxial technique is more prone to local anesthetic toxicity?
Why?
- Epidural blocks
- Possibility for LA to infiltrate vasculature and flood the circulation.
Which neuraxial technique exhibits baracity?
What does this mean?
- Spinal blocks
- This means that the LA is influenced by gravity.
What factors affect the dermatome spread of a spinal block?
- Position changes
- Baricity
- Dose
Epidural dermatome spread is incremental based on _______.
volume
Epidural spread is ____ mls per segment.
1 - 2
Which neuraxial technique is the preferred technique for Cesarean delivery?
Spinal block
What other names exist for spinal blocks?
- Subarachnoid block
- Intrathecal block
What types of surgical procedures indicate the use of spinal block?
- Lower abdomen
- Perineum
- Lower extremities
What are absolute contraindications to spinal block?
- Coagulopathy (ex. known disorder)
- Sepsis
- Patient refusal
- Dermal site infection
- Hypovolemia
- Intraspinal mass
- Severe Valvular disease
What are the relative contraindications to neuraxial anesthesia?
- Spinal column deformities (ex. kyphosis)
- Preexisting spinal cord disease (ex. MS)
- Chronic Headache/backache
- Inability to place block after 3 attempts
How many attempts does one have to place a neuraxial block?
Three attempts typically
The superior aspects of the iliac crests line up with what spinal segment?
L4
The inferior aspects of the scapula line up with what spinal segment?
T7
How many vertebrae are there?
- 8 Cervical
- 12 Thoracic
- 5 Lumbar
- 5 Sacral
- 1 Coccyx
What type of neuraxial technique is used with a sacral approach?
Epidural
How is the sacral hiatus identified?
Via the sacral cornua on either side of the hiatus.
Which spinal nerves are our cardioaccelerators?
T1 - T4
What are the high points of the spine when the patient lays in the supine position?
High points = C3 and L3
What are the low points of the spine when the patient lays in the supine position?
Low points = T6 and S2
When blood is encountered during a neuraxial needle insertion, the most likely cause is that the needle is _________.
lateral
(needle should be dead center medial)
What ligament is indicated by “c” in the picture below?
Supraspinous ligament
What ligament is indicated by “b” in the picture below?
Interspinous ligament
What ligament is indicated by “a” in the picture below?
Ligamentum Flavum
What is the distance from the skin to the ligamentum flavum?
4 cm in 50% of patients
4-6 cm in 80% of patients
Where is the ligamentum flavum thinnest?
Cervical interlaminal spaces
Is the ligamentum flavum thickest near the rostral lamina or the caudad lamina?
Caudad Lamina
Where does the spinal cord typically end in adults?
L1 (60% of patients)
Where does the spinal cord typically end in kids?
L3
Where should a beginner SRNA stick for neuraxial access?
L3 - L4 interlaminar space
Where does the dural sac terminate?
What is in the dural sac after the termination of the spinal cord?
- S2
- Cauda Equina
List the spinal meninges from outermost to innermost.
Dura mater
Arachnoid mater
Pia mater
Which of the spinal meninges is avascular?
Arachnoid mater
Which of the spinal meninges is composed of a thin layer of connective tissue with interspersed collagen?
Pia mater
How much CSF do adults have?
100 - 160 mL
At what rate is CSF produced?
20 - 25 mL/hr
The entire CSF volume is replaced roughly every ____ hours.
6
What dermatome is at the level of the umbilicus?
T10
What dermatome is at the level of the nipples?
T4
What dermatome is associated with the thumb?
Why is this dermatome pertinent in the monitoring of neuraxial anesthesia?
- C6
- Thumb being numb could be indicative of impending C3-C6 involvement (diaphragmatic innervation)
What is Tuffier’s line?
What does it indicate?
- Imaginary line between iliac crests.
- Indicates L4 (or L4-L5 interlaminar space)
How much should the second dose of lidocaine 5% be in a spinal neuraxial technique?
Trick question. Spinal’s are one dose only.
What common dose of bupivacaine is used in spinal anesthesia?
Bupivacaine 0.75% in 8.5% dextrose
What common dose of Lidocaine is used in spinal anesthesia?
Lidocaine 5% in 7.5% dextrose
What common dose of Tetracaine is used in spinal anesthesia?
1% in 5% dextrose
What type of anesthetic is indicated below?
Ester
What type of anesthetic is indicated below?
Amide
What is the benefit of neuraxial pharmacologic adjuncts?
- Postoperative analgesia
- Extended duration
- Improved block density