Mod9: Strabismus - Cataract - Retinal Detachment - Open Globe/Penetrating Eye Injuries

Question 1

_{Ophthalmic surgery}

Strabismus

^{Characteristics:}

Answer 1

Poor alignment of visual axis with amblyopia

Surgery (Recession and Resection) most commonly performed with pediatric patients

Very often correction of both “lazy” and “normal” eye is required

Question 2

_{Ophthalmic surgery}

Strabismus

^{Intervention must be done prior to what age for proper stereoscopic development to proceed?}

Answer 2

Prior to 4 months of age

Question 3

_{Ophthalmic surgery}

Strabismus

^{Procedure in older children and adults is primarily:}

Answer 3

Cosmetic*

Question 4

_{Ophthalmic surgery}

Strabismus

^{Anesthesia technique for children:}

Answer 4

General anesthesia

Question 5

_{Ophthalmic surgery}

Strabismus

^{Typical Anesthesia technique for adults:}

Answer 5

Monitored Anesthesia Care

Question 6

_{Ophthalmic surgery}

Strabismus (Recession and Resection)

^{Associated with increased incidence of:}

Answer 6

Occulo-Cardiac Reflex (OCR)

Masseter muscle spasm on induction (3X higher)

^{If present: postpone surgery and consider biopsy}

Malignant Hyperthermia (MH)

Question 7

_{Ophthalmic surgery}

Strabismus (Recession and Resection)

^{Succinylcholine avoided because:}

Answer 7

Association with MH

Interferes with forced duction measurements

^{(increases force requirement for 15 minutes)}

Question 8

_{Ophthalmic surgery - Strabismus (Recession and Resection)}

High incidence of post-operative vomiting

^{Treatment options include:}

Answer 8

Dexamethasone (5-10 mg)

Ondansetron (4-8mg)

May add a 3rd agent

May also avoid INH agents

Or use TIVA

Question 9

_{Ophthalmic surgery - Strabismus}

Muscle Recession Procedure

Answer 9

Muscles are “recessed” to weaken

Muscle is detached from original position and reinserted

Question 10

_{Ophthalmic surgery - Strabismus}

Muscle Resection Procedure

Answer 10

Muscles are “resected” to strengthen

Muscle is disinserted, a portion is removed, then muscle is reattached in original position

Question 11

_{Ophthalmic surgery}

Cataract Procedures

^{Two options:}

Answer 11

Extracapsular Cataract Extraction (ECCE)

Phacoemulsification

Question 12

_{Ophthalmic surgery - Cataract Procedures}

Extracapsular Cataract Extraction (ECCE)

^{Characteristics:}

Answer 12

Typically performed under regional anesthesia

10-12 mm incision

Cloudy lens is removed in one piece and replaced with synthetic lens

Question 13

_{Ophthalmic surgery - Cataract Procedures}

Phacoemulsification

^{Characteristics:}

Answer 13

Most popular cataract procedure

Commonly performed under topical anesthesia

≤ 3 mm microsurgical incision

Cloudy lens is emulsified with ultrasonic vibrations, aspirated, and irrigated

Flexible lens is inserted

Typically a “no stitch” procedure

Question 14

_{Ophthalmic surgery}

Cataract Procedures

^{Anesthesia considerations:}

Answer 14

Position on OR table with slight HOB elevation

Place pillow under knees for comfort

Keep patient warm

Anesthesia provider will be at patient’s side

^{-> Place routine monitors including precordial stethoscope}

^{-> Fresh gas flows of ≥ 10 L/min with decrease accumulation of CO2 under facial drapes}

Non-operative eye may be patched to prevent injury

Question 15

_{Ophthalmic surgery}

Retinal Detachment Procedures

^{Two options:}

Answer 15

Pneumatic Retinopexy (intraocular gas expansion)

Scleral Buckling

Question 16

_{Ophthalmic surgery - Retinal Detachment Procedures}

Pneumatic Retinopexy

^{<strong>(intraocular gas expansion)</strong>}

^{Characteristics:}

Answer 16

Gas bubble is placed inside the vitreous cavity either before or after the retinal hole is treated with cryotherapy or laser

Bubble prevents fluid from entering hole during healing process and tamponades retinal tear

Question 17

_{Ophthalmic surgery - Retinal Detachment Procedures}

Scleral Buckling

^{Characteristics:}

Answer 17

Soft silicone band is placed around the eye

Band relieves vitreous traction on the retinal hole

Question 18

_{Ophthalmic surgery - Retinal Detachment}

Intraocular Gas Expansion

^{Gases used:}

Answer 18

Intravitreal air

Sulfur Hexafluoride (SF6)

Octafluorocyclobutane (C4F8)

Perfluoro propane (C3F8)

Question 19

_{Ophthalmic surgery - Retinal Detachment - Intraocular Gas Expansion}

Intravitreal air

^{considerations:}

Answer 19

Bubble reabsorbed via diffusion into blood within 5 days

N2O more soluble than N2 in blood

^{→ diffuse into bubble more rapidly than N2 is absorbed by blood}

^{→ ↑bubble size}

^→↑IOP

Avoid using N2O in these introcular procedures

Question 20

_{Ophthalmic surgery - Retinal Detachment - <strong>Intraocular Gas Expansion</strong>}

Sulfur Hexafluoride (SF6)

^{considerations:}

Answer 20

Inert gas

Longer duration action (10 days)

Less soluble than N2

Bubble size doubles within 24hr

^{=> Inhaled N2 from air enters bubble more rapidly than SF6 diffuses into blood}

^{=> Does not raise IOP due to slow expansion}

N20 will rapidly ↑’s bubble size → ↑IOP

Question 21

_{Ophthalmic surgery - Retinal Detachment - Intraocular Gas Expansion}

N₂O

^{To use or not use in these cases?}

Answer 21

N2O diffuses into bubble & increases IOP

If using N2O for anesthesia itself, discontinue use ≥15mins prior to injection of bubble

Avoid further use until bubble absorbed

^{Requires you to know how long these will stay in}

^{=> Air?}

^{=> SF6?}

Question 22

_{Retinal Detachment - Duration of gas bubble in vitreous cavity}

Air

^{How long will Air stay in the vitreous cavity?}

Answer 22

≥ 5days

Question 23

_{Retinal Detachment - Duration of gas bubble in vitreous cavity}

Hexafluoride (SF6)

^{How long will it stay in the vitreous cavity?}

Answer 23

≥ 10 days

Question 24

_{Retinal Detachment - Duration of gas bubble in vitreous cavity}

Octafluorocyclobutane (C4F8)

^{How long will it stay in the vitreous cavity?}

Answer 24

≥ 13 days

Question 25

_{Retinal Detachment - Duration of gas bubble in vitreous cavity}

Perfluoro propane (C3F8)

^{How long will it stay in the vitreous cavity?​}

Answer 25

≥ 30 days

Question 26

_{Ophthalmic surgery - Retinal Detachment - Intraocular Gas Expansion}

Recent Intraocular Gas Expansion

^{For how long should N₂O be contraindicated in these pts?}

Answer 26

Duration of gas bubble

C3F8 => 30 days

C4F8 => 13 days

SF6 => 10 days

Air => 5 days

Question 27

_{Ophthalmic surgery - Retinal Detachment}

Recent Intraocular Gas Expansion

^{These Patients also need to avoid air travel because of:}

Answer 27

Potential for bubble expansion

Question 28

_{Ophthalmic surgery}

Open Globe/Penetrating Eye Injuries

^{When globe is open during surgical procedure or following traumatic injury, Increases in intraocular pressure may result in:}

Answer 28

Drainage of aqueous humor or

Extrusion of vitreous humor through wound

Question 29

_{Ophthalmic surgery}

Open Globe/Penetrating Eye Injuries

^{Loss of vitreous humor can}

Answer 29

seriously worsen vision

Question 30

_{Ophthalmic surgery}

Open Globe/Penetrating Eye Injuries - Aspiration risk

^{Patients with open-globe injuries considered to have}

Answer 30

full stomachs

Question 31

_{Ophthalmic surgery - <strong>Open Globe/Penetrating Eye Injuries</strong>}

Anesthetic Plan

^{Challenging to develop anesthetic plan that is consistent with 2 conflicting objectives}

Answer 31

Prevent further damage to eye by avoiding ↑IOP

Preventing pulmonary aspiration

^{<em>Strategies to achieve these objectives are in conflict mainly because of Sux!!!</em>}

Question 32

_{Ophthalmic surgery - Open Globe/Penetrating Eye Injuries - Anesthetic Plan}

Strategies to Prevent Increases in IOP

^Avoid:

Answer 32

Avoid direct pressure on globe

Avoid increase in CVP

Avoid agents that increase IOP

Question 33

_{Open Globe/Penetrating Eye Injuries - Strategies to Prevent Increases in IOP}

Avoid direct pressure on globe

^How?

Answer 33

Careful facemask technique

No retro/peribulbar blocks

Question 34

_{Open Globe/Penetrating Eye Injuries - Strategies to Prevent Increases in IOP}

Avoid increase in CVP

^How?

Answer 34

Prevent coughing/bucking during induction & intubation

Ensure deep level anesthesia & relaxation prior to DL

Avoid head-down positions

Extubate deep

Question 35

_{Open Globe/Penetrating Eye Injuries - Strategies to Prevent Increases in IOP}

Avoid agents that increase IOP

^{These are:}

Answer 35

Succinylcholine

Ketamine

Etomidate

Question 36

_{Ophthalmic surgery - Open Globe/Penetrating Eye Injuries - Anesthetic Plan}

Strategies to Prevent Aspiration Pneumonia

^Including:

Answer 36

Regional anesthesia with minimal sedation

Premedication

^{Metoclopramide - Nonparticulate acid - H2-antagonists}

Evacuation of gastric contents

^{NGT; whic is contraindicated in OGI}

RSI with CCP

^{Rapid acting induction agent (Propofol/STP) - Avoid Sux/<strong>Roc preferred</strong> - Avoid PPV- Intubation ASAP}

Extubate awake with RSI

^{(vs <u>Deep in open globe </u>to prent inc CVP)}

Question 37

_{Ophthalmic surgery}

Open Globe/Penetrating Eye Injuries

^{What preop medications should be considered?}

Answer 37

Anxiety

Analgesia

Aspiration prophylaxis

^{H2-antagonits - 5HT - Reglan - Bacitra}

Question 38

_{Ophthalmic surgery}

Open Globe/Penetrating Eye Injuries

^{What induction agents are recommended?}

Answer 38

Propofol (preferred)

Avoid Ketamine, Etomidate (d/t inc IOP)

Question 39

_{Ophthalmic surgery}

Open Globe/Penetrating Eye Injuries

^{Which muscle relaxants should be used?}

Answer 39

Succinylcholine? => Avoid

NDMR? => Roc preferred @ 1.2 mg/kg for RSI

Question 40

_{Ophthalmic surgery - Open Globe/Penetrating Eye Injuries}

Induction

^{Interventions:}

Answer 40

Control IOP with smooth induction/laryngoscopy

^{Achieve deep level anesthesia}

^{Lidocaine 1-1.5 mg/kg IV}

^{Thiopental, up to 6 mg/kg IV, <u>or</u>}

^{Propofol, up to 2.5 mg/kg IV}

Profound muscle relaxation?

^{Most avoid succinylcholine}

^{Use NDMR}

Concern: Patients with open-globe injuries considered to have full stomachs

RSI vs. MRSI vs. AFOI

Question 41

_{Ophthalmic surgery - Open Globe/Penetrating Eye Injuries - Induction}

Profound muscle relaxation

^How?

Answer 41

Most avoid succinylcholine

Use NDMR

Question 42

_{Ophthalmic surgery - Open Globe/Penetrating Eye Injuries - Induction}

Aspiration Concerns at induction

Answer 42

Patients with open-globe injuries considered to have

“full stomachs”

RSI vs. MRSI vs. AFOI

RSI: Strict non-ventilatory efforts after preoxygenation and once the pt is induced

MRSI: Gently, with low PP, ventilate the pt while cricoid pressure is applied

AFOI: Option of last resort

Question 43

_{Ophthalmic surgery - Open Globe/Penetrating Eye Injuries}

Rapid Sequence Induction Techniques

^{w/ Succinylcholine}

Answer 43

Preoxygenate

Pretreat (NDMR)

Lidocaine: 1.5-2.0 mg/kg IV

Cricoid pressure

Propofol 2 mg/kg

Succinylcholine: 2 mg/kg

Deepen anesthetic rapidly

Question 44

_{Ophthalmic surgery - Open Globe/Penetrating Eye Injuries}

Rapid Sequence Induction Techniques

^{w/ NDMR}

Answer 44

Preoxygenate

Lidocaine: 1.5-2.0 mg/kg IV

Cricoid pressure

Administer NDMR

^{(If giving any other NDMR other than ROC, because most take longer to work, some providers will give this before propofol - However, this is not common practice)}

Propofol 2 mg/kg

^{(If using the RSI dose of Roc, give after Propofol because it works at about the same time as Sux)}

Intubate when PNS confirms paralysis

Deepen anesthetic rapidly

Question 45

_{Ophthalmic surgery - Open Globe/Penetrating Eye Injuries}

Maintenance

^{Avoid coughing or “bucking” through use of​:}

Answer 45

Deep neuromuscular blockade

Question 46

_{Ophthalmic surgery - Open Globe/Penetrating Eye Injuries}

Emergence

^{Avoid coughing or “bucking” through use of​:}

Answer 46

Lidocaine 1-1.5 mg/kg IV

Small narcotic boluses

Antiemetics

Question 47

_{Open Globe/Penetrating Eye Injuries - Maintenance & Emergence}

Anesthetic plan must also consider prevention of aspiration

^{How is this achieved?}

Answer 47

Preoperative metoclopramide and ranitidine

Intraoperative decompression of stomach

Intraoperative or postoperative antiemetics