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

1
Q

Ophthalmic surgery

Strabismus

Characteristics:

A

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

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2
Q

Ophthalmic surgery

Strabismus

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

A

Prior to 4 months of age

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3
Q

Ophthalmic surgery

Strabismus

Procedure in older children and adults is primarily:

A

Cosmetic*

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4
Q

Ophthalmic surgery

Strabismus

Anesthesia technique for children:

A

General anesthesia

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5
Q

Ophthalmic surgery

Strabismus

Typical Anesthesia technique for adults:

A

Monitored Anesthesia Care

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6
Q

Ophthalmic surgery

Strabismus (Recession and Resection)

Associated with increased incidence of:

A

Occulo-Cardiac Reflex (OCR)

Masseter muscle spasm on induction (3X higher)

If present: postpone surgery and consider biopsy

Malignant Hyperthermia (MH)

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7
Q

Ophthalmic surgery

Strabismus (Recession and Resection)

Succinylcholine avoided because:

A

Association with MH

Interferes with forced duction measurements

(increases force requirement for 15 minutes)

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8
Q

Ophthalmic surgery - Strabismus (Recession and Resection)

High incidence of post-operative vomiting

Treatment options include:

A

Dexamethasone (5-10 mg)

Ondansetron (4-8mg)

May add a 3rd agent

May also avoid INH agents

Or use TIVA

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9
Q

Ophthalmic surgery - Strabismus

Muscle Recession Procedure

A

Muscles are “recessed” to weaken

Muscle is detached from original position and reinserted

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10
Q

Ophthalmic surgery - Strabismus

Muscle Resection Procedure

A

Muscles are “resected” to strengthen

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

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11
Q

Ophthalmic surgery

Cataract Procedures

Two options:

A

Extracapsular Cataract Extraction (ECCE)

Phacoemulsification

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12
Q

Ophthalmic surgery - Cataract Procedures

Extracapsular Cataract Extraction (ECCE)

Characteristics:

A

Typically performed under regional anesthesia

10-12 mm incision

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

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13
Q

Ophthalmic surgery - Cataract Procedures

Phacoemulsification

Characteristics:

A

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

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14
Q

Ophthalmic surgery

Cataract Procedures

Anesthesia considerations:

A

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

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15
Q

Ophthalmic surgery

Retinal Detachment Procedures

Two options:

A

Pneumatic Retinopexy (intraocular gas expansion)

Scleral Buckling

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16
Q

Ophthalmic surgery - Retinal Detachment Procedures

Pneumatic Retinopexy

<strong>(intraocular gas expansion)</strong>

Characteristics:

A

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

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17
Q

Ophthalmic surgery - Retinal Detachment Procedures

Scleral Buckling

Characteristics:

A

Soft silicone band is placed around the eye

Band relieves vitreous traction on the retinal hole

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18
Q

Ophthalmic surgery - Retinal Detachment

Intraocular Gas Expansion

Gases used:

A

Intravitreal air

Sulfur Hexafluoride (SF6)

Octafluorocyclobutane (C4F8)

Perfluoro propane (C3F8)

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19
Q

Ophthalmic surgery - Retinal Detachment - Intraocular Gas Expansion

Intravitreal air

considerations:

A

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

20
Q

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

Sulfur Hexafluoride (SF6)

considerations:

A

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

21
Q

Ophthalmic surgery - Retinal Detachment - Intraocular Gas Expansion

N2O

To use or not use in these cases?

A

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?

22
Q

Retinal Detachment - Duration of gas bubble in vitreous cavity

Air

How long will Air stay in the vitreous cavity?

23
Q

Retinal Detachment - Duration of gas bubble in vitreous cavity

Hexafluoride (SF6)

How long will it stay in the vitreous cavity?

A

≥ 10 days

24
Q

Retinal Detachment - Duration of gas bubble in vitreous cavity

Octafluorocyclobutane (C4F8)

How long will it stay in the vitreous cavity?

A

≥ 13 days

25
Retinal Detachment - Duration of gas bubble in vitreous cavity **Perfluoro propane (C3F8)** How long will it stay in the vitreous cavity?​
≥ 30 days
26
Ophthalmic surgery - Retinal Detachment - Intraocular Gas Expansion **Recent Intraocular Gas Expansion** For how long should N2O be contraindicated in these pts?
Duration of gas bubble C3F8 =\> 30 days C4F8 =\> 13 days SF6 =\> 10 days Air =\> 5 days
27
Ophthalmic surgery - Retinal Detachment **Recent Intraocular Gas Expansion** These Patients also need to avoid air travel because of:
Potential for bubble expansion
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:
**Drainage** of aqueous humor or **Extrusion** of vitreous humor through wound
29
Ophthalmic surgery **Open Globe/Penetrating Eye Injuries** Loss of vitreous humor can
seriously worsen vision
30
Ophthalmic surgery **Open Globe/Penetrating Eye Injuries - Aspiration risk** Patients with open-globe injuries considered to have
full stomachs
31
Ophthalmic surgery - Open Globe/Penetrating Eye Injuries **Anesthetic Plan** Challenging to develop anesthetic plan that is consistent with 2 conflicting objectives
Prevent further damage to eye by avoiding ↑IOP Preventing pulmonary aspiration Strategies to achieve these objectives are in conflict mainly because of Sux!!!
32
Ophthalmic surgery - Open Globe/Penetrating Eye Injuries - Anesthetic Plan **Strategies to Prevent Increases in IOP** Avoid:
Avoid direct pressure on globe Avoid increase in CVP Avoid agents that increase IOP
33
Open Globe/Penetrating Eye Injuries - Strategies to Prevent Increases in IOP **Avoid direct pressure on globe** How?
Careful facemask technique No retro/peribulbar blocks
34
Open Globe/Penetrating Eye Injuries - Strategies to Prevent Increases in IOP **Avoid increase in CVP** How?
Prevent coughing/bucking during induction & intubation Ensure deep level anesthesia & relaxation prior to DL Avoid head-down positions **Extubate deep**
35
Open Globe/Penetrating Eye Injuries - Strategies to Prevent Increases in IOP **Avoid agents that increase IOP** These are:
Succinylcholine Ketamine Etomidate
36
Ophthalmic surgery - Open Globe/Penetrating Eye Injuries - Anesthetic Plan **Strategies to Prevent Aspiration Pneumonia** Including:
**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/Roc preferred - Avoid PPV- Intubation ASAP **Extubate awake** with RSI (vs Deep in open globe to prent inc CVP)
37
Ophthalmic surgery **Open Globe/Penetrating Eye Injuries** What preop medications should be considered?
Anxiety Analgesia Aspiration prophylaxis H2-antagonits - 5HT - Reglan - Bacitra
38
Ophthalmic surgery **Open Globe/Penetrating Eye Injuries** What induction agents are recommended?
Propofol (preferred) ## Footnote *Avoid Ketamine, Etomidate (d/t inc IOP)*
39
Ophthalmic surgery **Open Globe/Penetrating Eye Injuries** Which muscle relaxants should be used?
Succinylcholine? =\> Avoid NDMR? =\> **Roc** preferred @ 1.2 mg/kg for RSI
40
Ophthalmic surgery - Open Globe/Penetrating Eye Injuries **Induction** Interventions:
**Control IOP with smooth induction/laryngoscopy** Achieve deep level anesthesia Lidocaine 1-1.5 mg/kg IV Thiopental, up to 6 mg/kg IV, or _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**
41
Ophthalmic surgery - Open Globe/Penetrating Eye Injuries - Induction **Profound muscle relaxation** How?
Most avoid succinylcholine Use NDMR
42
Ophthalmic surgery - Open Globe/Penetrating Eye Injuries - Induction ## Footnote **Aspiration Concerns at induction**
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
43
Ophthalmic surgery - Open Globe/Penetrating Eye Injuries **Rapid Sequence Induction Techniques** w/ Succinylcholine
Preoxygenate Pretreat (NDMR) Lidocaine: 1.5-2.0 mg/kg IV Cricoid pressure **Propofol 2 mg/kg** **Succinylcholine: 2 mg/kg** Deepen anesthetic rapidly
44
Ophthalmic surgery - Open Globe/Penetrating Eye Injuries **Rapid Sequence Induction Techniques** w/ NDMR
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
45
Ophthalmic surgery - Open Globe/Penetrating Eye Injuries **Maintenance** Avoid coughing or “bucking” through use of​:
Deep neuromuscular blockade
46
Ophthalmic surgery - Open Globe/Penetrating Eye Injuries **Emergence** Avoid coughing or “bucking” through use of​:
Lidocaine 1-1.5 mg/kg IV Small narcotic boluses Antiemetics
47
Open Globe/Penetrating Eye Injuries - Maintenance & Emergence **Anesthetic plan must also consider prevention of aspiration** How is this achieved?
Preoperative metoclopramide and ranitidine Intraoperative decompression of stomach Intraoperative or postoperative antiemetics