Week 1 Anesthesia for Eye Surgery

Question 1

The eye resides in the _________ bony structure.

Answer 1

pyramidal

Question 2

What are the three layers of the eye?

Answer 2

• Sclera
• Uveal tract (middle layer)
• Retina

Question 3

Where does the eye get most of its focusing power?

Answer 3

Curvature of the cornea

Question 4

Name the three layers of the uveal tract (middle layer)?

Answer 4

• Choroid
• Ciliary body
• Iris

Question 5

What are the features of the choroid layer in the eye? (Uveal layer)

Answer 5

• Layer of blood vessels

- Located posterior

Question 6

What are the features of the ciliary body of the eye? (Uveal Layer)

Answer 6

• Resides behind the iris
• produces the aqueous humor
• adjust the focus on the lens by reducing the tension on suspension fibers or zonules of the lens

Question 7

What are the feature of the Iris? (Uveal layer)

Answer 7

• Pigmented

- Controls the light entry

Question 8

What occurs within the iris during sympathetic response in the eye?

Answer 8

-Iris DILATOR muscle contracts

dilitation or MYDRIASIS

Question 9

What occurs within the iris during a parasympathetic response in the eye?

Answer 9

-iris SPINCTER muscles contracts

pupillary constriction or MYIOSIS

Question 10

The retina ends __ mm behind the iris.

Answer 10

4

Question 11

Where is the Pars plana located?

Answer 11

-Area between limbus (edge) of cornea and end of retina

Question 12

T/F: The Pars plana is the safe entry point for vitectomy procedures?

Answer 12

TRUE

Question 13

How does ocular cardiac reflex (OCR) manifest?

Answer 13

• bradycardia
• AV block
• ventricular ectopy
• asystole (rarely)

Question 14

Ocular cardiac reflex is seen especially with traction on this muscle?

Answer 14

Medial rectus

Question 15

What nerve is primarily responsible for the ocular cardiac reflex?

Answer 15

-Trigeminovagal

Question 16

T/F: The ocular cardiac reflex will improve with hypoxemia and hypercarbia.

Answer 16

FALSE

Question 17

How would ocular cardiac reflex be treated?

Answer 17

• Ask surgeon to stop
• Assess ventilation
• Lidocaine localization or deepen anesthetic
• Atropine

Question 18

T/F: Ocular cardiac response fatigues with repeated stimulation.

Answer 18

TRUE

Question 19

What regulate the intraocular pressure (IOP)?

Answer 19

• aqueous fluid

- blood volume

Question 20

What is normal intraocular pressure (IOP)?

Answer 20

10 to 22 mmHg

Question 21

If intraocular pressure rises above __ mmHg it is considered _______.

Answer 21

> 22

-pathological

Question 22

Aqueous fluid production is constant and facilitated by _________.

Answer 22

carbonic anhydrase

Question 23

Increase intraocular pressure leads to ocular HTN and structural changes causing?

Answer 23

• atrophy of optic disc
• atrophy of nerve fibers
• optic artery occlusion

Question 24

Decreased intraocular pressure leads to:

Answer 24

-fluid accumulation in the eye

Question 25

An increase to CVP increases intraocular pressure more than the increase of ___________.

Answer 25

blood pressure

Question 26

How much could coughing increase intraocular pressure?

Answer 26

40 mmHg

Question 27

What will occur to intraocular pressure if PaCO2 drops suddenly?

Answer 27

-FAST drop in IOP due to choroidial vasoconstriction

Question 28

What will occur to intraocular pressure if PaCO2 increases?

Answer 28

-SLOW increase in IOP

Question 29

Metabolic acidosis _______ the choroid vessel volume and therefore IOP.

Answer 29

Decreases

Question 30

Metabolic alkalosis ________ the choroid volume and the IOP.

Answer 30

increases

Question 31

What will most anesthetic drugs do to the IOP.

Answer 31

Decrease the IOP

Question 32

What two anesthetic drugs would be avoided if elevated IOP was a concern

Answer 32

- Etomidate | - Ketamine

Question 33

Non depolarizing NMR do not alter IOP with exception of curare which ______ it.

Answer 33

decrease

Question 34

Azetazolamide (Diamox) is used to ________ aqueous production by carbonic anhydrase inhibitor.

Answer 34

Decrease

Question 35

Osmotic diuretic will ______ IOP and will have a max effect at 30 to 45 minutes and return to normal after ____.

Answer 35

- decrease | - 5-6 hours

Question 36

Echothipate opth. is used to treat glaucoma and is a ___________ drug. This could prolong muscle paralysis after __________.

Answer 36

- anticholinesterase | - succinylcholine

Question 37

Flomax ( Tamsulosin) is selective alpha antagonistic. It binds to the dilator muscle causing dilation and complicates cataract surgery. This could last for up to ______ off therapy.

Answer 37

7 - 28 days

Question 38

Facial nerve block causes what block to the eye muscle?

Answer 38

orbicular oculi muscle

Question 39

What are the three facial nerve blocks?

Answer 39

- Van Lint. - Atkinson - O'Brian

Question 40

What is the major complication of a facial nerve block?

Answer 40

subcutaneous hemorrhage

Question 41

What will the Nadbath Rehman block and effect.

Answer 41

BLOCK -Entire tunk of facial nerve EFFECT - lower facial droop postop for several hour - vocal cord paralysis,laryngospasm, dysphasia and respiratory distress (close to the vagus and glossopharyngeal nerve)

Question 42

What muscle may not be blocked by a retrobulbar block?

Answer 42

-Superior rectus muscle

Question 43

Retrobulbar hemorrhage is the most common complication of the block and observation of _____ must be monitored.

Answer 43

ocular cardiac reflex (OCR)

Question 44

Injection of the block in the optic sheath could cause what complications?

Answer 44

- contralateral amaurosis (lack of vision) - obtundation - respiratory arrest (within 20 minute and last for up to an hour) - vascular collapse form depressant effect on the medulla (total spinal)

Question 45

If sulfur hexaflouride is used as an air bubble in eye surgery then N2O should be d/c'd __ minutes before placement of bubble and avoided ______ days after surgery.

Answer 45

- 15 | - 7 to 15

Question 46

If Perfluoropropane is used as the air bubble in eye surgery then avoid N2O for up to ___ month after instillation.

Answer 46

1

Question 47

Ketamine in eye surgery is usually avoided due to __________.

Answer 47

nystagmus