Anatomy
Which components are present inside of the muscle cone? SATA
A. CN 2
B. CN 3
C. CN 4
D. CN 6
E. Ophthalmic artery and vein
A
B
D
E
-- the trochlear nerve (CN4) is outside of the muscle cone
Match the gas type to the duration of the bubble
A. Sulfur hexachloride
B. Perfluoropropane
C. Silicone oil
1. long-term (months)
2. 6-8 weeks
3. 10-30 days
A. Sulfur hexachloride --- 10-30 days
B. Perfluoropropane --- 6-8 weeks
C. Silicone oil --- long-term (months)
Your patient has a history of scleral buckle. You know this means you cannot do what sort of block?
A. Retrobulbar Block
B. Peribulbar Block
C. Sub-tenon Block
D. Facial Nerve Block
C. Sub-tenon Block
Oh no! A patient with a literal ruptured eyeball comes into the ER. What are the main things you're thinking about for your anesthetic management? SATA
A. RSI GETA
B. hypoventilate to increase PaCO2
C. Defasciculating NDMR with Succ
D. arterial line prior to induction
A. RSI GETA (emergency likely with full stomach)
C. Defasciculating NDMR with Succ (helps to manage the increased IOP from succ for the RSI)
B. hypoventilate to increase PaCO2 --> increased PaCO2 will increase IOP
D. arterial line prior to induction --> not really necessary
Which CN is actually an outgrowth of the brain?
CN 2
Match each muscle to its function
A. Superior Rectus
B. Superior Oblique
C. Inferior Rectus
D. Inferior Oblique
1. Infraduction
2. Intorsion - Depression
3. Extorsion - Elevation
4. Supraduction
A. Superior Rectus ---- 4. Supraduction
B. Superior Oblique ----- 2. Intorsion - Depression
C. Inferior Rectus ----- 1. Infraduction
D. Inferior Oblique ---- 3. Extorsion - Elevation
Which of the following agents decreases IOP? SATA
A. Ketamine
B. Propofol
C. Midazolam
D. Etomidate
E. Rocuronium
B. Propofol
D. Etomidate
E. Rocuronium
Little effect at all:
C. Midazolam
A. Ketamine
Which block reliably creates akinesia of the eye?
A. Retrobulbar Block
B. Peribulbar Block
C. Sub-tenon Block
D. Facial Nerve Block
A. Retrobulbar
What type of anesthetic is most common for a vitrectomy?
general anesthesia either with an LMA or an ETT
Which ophthalmic medication may prolong succinylcholine duration of action?
Echothiophate
Tenon's capsule is a thin membrane surrounding the eyeball that allows _______ to enter the eye socket
Extraocular muscles and the optic nerve
you want your patient to dissociate during surgery since their eye will be open, so you give them ketamine to chill. Oops why is this a bad idea?
can cause nystagmus and then they cant operate on the moving eye and the surgeon will yell at you :/
You perform a retrobulbar block and your patient suddenly has a downward gaze. You don't freak out because you know this is a normal occurrence due to ______
The trochlear nerve is outside of the muscle cone, so it won't get blocked. The trochlear nerve is responsible for torsion and downward gaze
What are some anesthetic considerations with a keratoplasty?
A. No valsalva maneuvers
B. GETA with paralysis
C. Lateral positioning
D. systemic antibiotics
A. No valsalva maneuvers or coughing/bucking (procedure has open globe precautions)
abx eyedrops, not systemic
What is an advantage of performing peribulbar block for ophthalmic surgery?
A. Uses lower volume of LA
B. Produces rapid onset of anesthesia
C. Decreased risk of globe puncture
D. Reliable complete akinesia of eyeball
C. Decreased risk of globe puncture
The oculocardiac reflex has CN ____ as the afferent limb and CN ____ as the efferent limb of the reflex pathway
CN V (Ophthalmic) is afferent
CN X (Vagus) is efferent
How can Lidocaine help to minimize increases in IOP?
it can help to reduce coughing or bucking, which cause increased IOP
You want to paralyze the eyelid to avoid squinting during surgery. Which block will you expect to use?
A. Retrobulbar Block
B. Peribulbar Block
C. Sub-tenon Block
D. Facial Nerve Block
D. Facial nerve block
-- blocks the orbicularis oculi muscle
What type of block are you most likely to use with a trabeculectomy?
A. Retrobulbar Block
B. Peribulbar Block
C. Sub-tenon Block
D. Facial Nerve Block
C. Sub-tenon Block
Which patient is the BEST candidate for retrobulbar block for ophthalmic surgery
A. Patient with a ruptured globe
B. An outpatient
C. A patient with a full stomach
D. A patient with myopia
B. An outpatient
What happens if LA is injected into the optic nerve on accident?
A. Pain
B. CNS depression
C. Oculocardiac Reflex
D. Ptosis of the eye
B. CNS depression
CN 2 is covered by meninges with CSF. Injecting LA into it is essentially a high spinal. CNS Depression --> respiratory arrest
Which of the following are advantages of the peribulbar block? SATA
A. Ability to perform on an anticoagulated patient
B. Less likelihood to puncture globe with myopic patient
C. Reliable motionless field
D. Blocks CN 3-7
A
B
D
C - retrobulbar is better at complete akinesia
For patients who do not tolerate awake eye exams, there are EUA (exams under anesthesia). What type of anesthesia are you most likely to perform?
General anesthesia with a mask. Rarely is there a need for an IV for these exams
Which anesthetic agent DECREASES intraocular pressure?
A. Succinylcholine
B. Inhaled volatile agent
C.Fentanyl
D. Ketamine
B. Inhaled agents