Apex- misc: eyeballs Flashcards by Ashley Frugoli

Identify the statement htat BEST represents the anesthetic considerations of opthalmic surgery:

A. Intraocular perfusion pressure = MAP-CVP
B. Aqueous humor is reabsorbed by the ciliary process
C. Hypocarbia increases IOP
D. N20 is contraindicated for 10 days after a sulfur hexafluoride bubble is placed

Intraoccular perfusion pressure = MAP - IOP
Aqueous humor is PRODUCED by the ciliary process (reabsorbed in the canal of Schlemn)
HYPERCARBIA increaes IOP

How well did you know this?

Not at all

Perfectly

Normal IOP

10-20mmHg

How well did you know this?

Not at all

Perfectly

T/F: increased IOP in a patient with an open globe injury can cause permanent blindness

True

How well did you know this?

Not at all

Perfectly

T/F: Sux is okay to use in a patient with an open eye injury and a full stomach

how much does it increase IOP by and for how long?

what else could you use?

True

5-15mmHg for up to 10 mins

Roc 1.2mg/kg

How well did you know this?

Not at all

Perfectly

What does a chornically elevated IOP that leads to retinal artery compression cause?

Glaucoma

How well did you know this?

Not at all

Perfectly

IOP is reduced by drugs that do one of two things:

reduce aqueous humor production (ciliary)
facilitate aqueous humor drainage

How well did you know this?

Not at all

Perfectly

What kind of surgery corrects the misalignment of the extraocular muscles and re-establishes the visual axis?

2 unique anesthetic considerations for this procedure

Strabismus surgery

PONV and oculocardiac reflex

How well did you know this?

Not at all

Perfectly

Nitrous is contraindicated for how long after SF6 bubble placement?

when it that bubble be used?

7-10 days after

it’s placed over the retina during retinal reattachment, vitrectomy, and macular hole repair

How well did you know this?

Not at all

Perfectly

Aterial supply to the eye

venous supply from the eye

ICA > Opthalmic Artery > Central Retinal artery & Posterior cilliary arteries

Opthalmic veins > cavernous sinus

How well did you know this?

Not at all

Perfectly

Intraocular perfusion pressure =

Map - IOP

10-20mmHg = normal IOP

How well did you know this?

Not at all

Perfectly

Aqueous humor is produced by what (where)

Aqueous humor is reabsorbed by what (where)

Produced by the ciliary process (posterior chamber) (CP/PC)

Reabsorbed by the canal of Schlemm (Anterior Chamber) (anterior - a, ashley schlemm)

How well did you know this?

Not at all

Perfectly

Increase/Decrease/No effect on IOP:

Volatile anesthetics

Decrease

(decrease CVP/MAP)

How well did you know this?

Not at all

Perfectly

Increase/Decrease/No effect on IOP:

Nitrous oxide

decrease - unless in combination with SF6 bubble, than increase

How well did you know this?

Not at all

Perfectly

Increase/Decrease/No effect on IOP:

Hypothermia

decrease

How well did you know this?

Not at all

Perfectly

Increase/Decrease/No effect on IOP:

NDMRs

decrease

How well did you know this?

Not at all

Perfectly

Increase/Decrease/No effect on IOP:

propofol

decrease

Increase/Decrease/No effect on IOP:

Anticholinergics

No effect

Increase/Decrease/No effect on IOP:

LMA placement/removal

minimal effect

Increase/Decrease/No effect on IOP:

Ketamine

special consideration

may or may not

but DOES cause rotary nystamgus and blepharospasm and should be avoided during eye surgery

why should ketamine be avoided during eye surgery

rotary nystagmus and blepharospasm

T/f: the increase in IOP seen with sux can be blocked by a defasciculating dose of NDMR

false - unreliable

Match drug with effect on aqeous humor:

Acetazolamide, echothiopate , Timolol

-decreases aqueous humor production, promotes aqueous humor drainage

Acetazolamide - decreases production (by inhibiting carbonic anhydrase)

Timolol- decreases production

Echothiopate - promotes drainage (via canal of schlmm)

echothiopate can prolong duration of sux and ester-type locals

SF6 bubble

D/C nitrous when
avoid for how long after

D/c 15 mins prior
avoid 7-10 days after

how long to avoid nitrous after silicone oil placed

air bubble?

perfluropropane (C3F8)

0 days

5 days

30 days

2 key considerations for strabismus surgery?

PONV and occulocardiac reflex

T/F: closed angle glaucoma is caused by closure of the posterior chamber

false - anterior chamber ## Footnote just think- posterior chamber has the ciliary process (CP/PC) which produces aqueous humor - if that was closed, no aqueous humor would be produced and there would be a decrease in IOP -anterior chamber has ashley shlemm canal which drains aqueous humor - if thats closed, it builds up and increases IOP

T/F: open angle glaucoma is caused by the closure of the anterior chamber

false- closed angle ## Footnote open angle is caused by sclerosis of hte trabecular meshmork, which impairs drainage of aqueous humor

Why could a retrobulbar block result in apnea? | how long before you see it? ## Footnote what should you assess that would provide an early indication that post-retrobulbar block apnea syndrome is about to happen?

bc injecting LA into the optic sheath is like giving a spinal block in the eye if the LA reaches the brainstem, it can cause apnea | 2-5 mins post injection; usually lasts 15-20 mins but full recovery 1hr ## Footnote assess the contralateral pupil prior to doing the block if the pupil starts small and dilates shortly after the block - be prepared to provide cardiopulmonary support auntil the LA is cleared from the CSF