Other Blocks (eye, airway, etc) Flashcards
Caudal blocks are limited to what population and why?
Pediatrics
anatomical structures are less reliable in adults
caudal blocks are functionally similar to what other block?
epidural blocks
caudal blocks are approached through what space
sacral hiatus
What are the target levels of anesthesia for caudal blocks
- lower extremities
- distal colon
- urologic
What is responsible for the increased failure rate associated with caudal blocks
inadvertent extravasation of LA into other compartments
Identification of landmarks for caudal block
note the distal end of the coccyx, the sacral cornua on the lateral margins, and the sacral hiatus in the center
(this means nothing to me, going to try and find a better explanation)
What gauge needle for caudal block
22g
For caudal block what angle do you advance your needle and in what direction
advance at 45-degree angle cephalad until a pop and loss of resistance is achieved
At what point during caudal block can injection of LA occur
after pop and loss of resistance
Benefits of topical for eye procedures
- you don’t have to get a needle stabbed in your eye
- fast onset
What LA is of used for topical for eye procedures
2% lidocaine
Sub-Tenon block
- depositing LA outside of the cone/posterior compartment and around the sclera
- less-invasive block that can produce akinesia is sufficient volume is used
For a sub-tenon block achieving akinesia is dependent on what
volume
name of the fascial layer that encapsulates the sclera and produces the “container” for the sub-tenon block
tenon capsule
What volume is used to fill the tenon capsule
3-5ml
For a peri-bulbar block where is LA injected
into the tissue around the eye
With a peri-bulbar block is there an increased or decreased chance of fully covering all extraocular muscles
decreased
(vs. retrobulbar, I think? v unclear)
What volume is used for a peri-bulbar block
5-8ml
Peri-bulbar block approach
(going to try and find better explanation for this from a different source)
- inferior lateral to advance through the conjunctiva
- “4-5 o’clock” position for the right eye
- “7-8 o’clock” for the left eye
What direction is used for a peri-bulbar block- cephalad or caudad?
caudal direction until the mid-point of the globe is reached, then injection is given
the caudal direction during a peri-bulbar block reduces the chances of what?
increased chance for?
- reduces the likelihood of globe and posterior compartment trauma
- increases the chance of failed akinesia on first injection
true/false: you can only perform peri-bulbar blocks with an inferior lateral injection
false: combining superior lateral and inferior lateral injections “may produce desirable affect”
injection of LA into the compartment directly posterior to the globe of the eye
retrobulbar block
what cranial nerves are blocked/targeted for retrobulbar blocks
CN III, IV, V, VI, VII
What LA and volume are used for a Retrobulbar block
2-4ml of 1-2% preservative-free lidocaine after topical skin cleansing
What would be v kind of you to give before an eye block
anxiolytic
What length needle is used for retrobulbar blocks
1” blunt tip needle
maximum needle depth for retrobulbar block
1” depth
Describe the needle angle/approach for retrobulbar blocks
initially downward, then parallel to the globe and only directed superiorly after passing the midpoint of the globe
how should the patient be instructed to direct their gaze during an eye block
straight ahead or towards the needle to ensure the optic nerve isn’t in the path of the needle
Complications associated with eye blocks
- seizures (injection in optic nerve sheath)
- hemorrhagic injury to posterior vasculature
- globe injury
- significant vagal stimulation
What complication should be anticipated and prepared for, for any eye block
vagal stimulation bradycardia
who must be present during eye blocks
a clinician competent in decompression of the eye
true/false: monitoring during eye blocks isn’t necessary
false duh
is venous injection during eye blocks a serious complication?
no- intravascular injection isn’t dangerous, but the block won’t be effective
airway blocks are primarily used for what
awake fiberoptic intubations without sedation
controls sensation to the posterior tongue, pharynx, portions of the soft palate, and the epiglottis
glossopharyngeal CN IX
How is the glossopharyngeal nerve blocked
- blocked through bilateral injection of LA at the base of each tonsilar pillar
- atomized LA into the oral cavity and posterior pharynx
What LA and how much volume is used for glossopharyngeal blocks
2ml 1-2% lidocaine (bilaterally)
innervates the larynx and posterior epiglottis and controls the cricothyroid muscle
superior laryngeal nerve- derived from the Vagus
What is the landmark used for superior laryngeal block
hyoid bone
where is LA injected for a SLN block in relation to the hyoid bone
inject 2ml laterally and inferiorly to the most lateral portion
controls sensation below the vocal cords and muscles of the larynx except for the cricothyroid muscle
RLN
How is the RLN blocked
trans-tracheal injection through the cricothyroid membrane
after puncturing the cricothyroid membrane what is done to confirm placement before LA injection
aspirate for air
what LA and how much volume is used in a RLN block
2-3ml of 4% lidocaine
what response to trans-tracheal injection of LA is beneficial to help the spread
cough
why is there a high risk of toxicity with nebulizing LA to the airway
the tracheal site has the fastest uptake
What adjunct drugs should be considered before airway blocks
- antisilalogogue
- aspiration prophylaxis
- anxiolysis and amnesia
two nerves lie on either side of the finger more to the __ side
ventral
volume used for digital block
2ml
how long will a lidocaine digital block last
1-3hrs
bupivacaine digital block will last as long as?
12hrs
should you add epi to a digital block
no d/t risk of vascular ischemia
where is LA injected for a digital block
single injection along the flexor sheath identified by the “callous” in the palm of the hand
or
bilateral injections of 2 mL for each nerve on the ventral part of the finger
Volume used for caudal block
1 ml/kg
is caudal block typically used as sole anesthetic?
No, more of an adjunct
depth of needle for retrobulbar block before directing upward and medially
(note with block video he uploaded)
at least half
