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Anesthesia for
eye surgury
Ali Mohammadian Erdi, MD
Assistant Professor of Anesthesiology &
Fellowship of Pain Medicine
Ardebile University of Medical Sciences
Outline
 Introduction
 Ophthalmic medications
 IntraocuLar Pressure
 Oculocardiac Reflex
 Anesthesia for Eye Surgery
 Specific Ophthalmic Procedures and
anesthetic considerations
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General condition
Surgical procedure is important
 Age groups from infants to the elderly
 preoperative evaluation
 Outpatient setting
 MAC

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Ophthalmic surgury
♦
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Ophthalmic Medications
 Topical : sufficient absorption and may produce
systemic (more rapid than SC administration but slower than
IV administration).
 Topical ophthalmic drugs : Effects on lOP and adverse
reactions
 Ophthalmic drugs, such as glycerol, mannitol, and
acetazolamide given systemically, may produce side
effects
that influence anesthetic management.
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SYSTEMIC EFFECTS OF OPHTHALMIC DRUGS
Atropine
• Used to produce mydriasis and cyclopliegia.
- The 1% solution contains 0.2 to 0.5 mg of atropine
per drop.
- Systemic reactions, include tachycardia, flushing,
thirst, dry skin, and agitation.
- Atropine is contraindicated in closed-angle
glaucoma.
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SYSTEMIC EFFECTS OF OPHTHALMIC DRUGS
Scopolamine
• One drop of the 0.5% solution has 0.2 mg of
scopolamine.
- CNS excitement can be treated with physostigmine,
0.015 mg/kg IV, repeated one or two times in a 15minute period.
- It is contraindicated in closed-angle glaucoma.
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SYSTEMIC EFFECTS OF OPHTHALMIC DRUGS
Phenylephrine Hydrochloride :
• Produce capillary decongestion and pupillary
dilatation.
- Applied to the cornea, it can cause palpitations,
nervousness, tachycardia, headache, nausea ,
vomiting, severe hypertension, reflex
bradycardia, subarachnoid hemorrhage.
- Solutions of 2.5%, 5%, and 10% (6.25 mg
phenylephrine per drop) are available.
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SYSTEMIC EFFECTS OF OPHTHALMIC DRUGS
Timolol Maleate :
- Beta-blocker : treatment of chronic glaucoma.
- Side- effects : light-headedness, fatigue, disorientation,
depressed CNS function ,exacerbation of asthma,
Bradycardia, bronchospasm, and potentiation of
systemic beta-blockers can occur.
Acetyl choline :
- can be injected intraoperatively into the anterior
chamber to produce miosis.
Side-effects : due to its parasympathetic action ,
include hypotension, bradycardia, bronchospasm.
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SYSTEMIC EFFECTS OF OPHTHALMIC DRUGS
Echothiophate :
• A cholinesterase inhibitor, echothiophate iodide is
used as a miotic agent.
 prolong the effect of both succinyicholine and
ester-type local anesthetics.
 Levels of pseudocholinesterase decrease by 80%
after 2 weeks on the drug.
 Succinyicholine and ester-type local anesthetics
should be avoided.
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Ophthalmic Medications :
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IntraocuLar Pressure :
 Anatomy and physiology of the ocular
system, as well as lOP and how it is
influenced by medications (including
anesthetics, disease processes).
 The aqueous humor is formed in the
posterior chamber by the ciliary body in an
active secretory process involving both the
carbonic anhydrase and cytochrome
oxidase systems.
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IOP :
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How is aqueous humor formed and eliminated?
 Aqueous humor is a clear fluid that occupies the
anterior and posterior chambers of the eye.
 Its total volume is 0.3 ml.
 Aqueous humor produced in the posterior
chamber.
 circulates through the pupil to the anterior
chamber, passes through the Schlemmn’s
canal.
 drains into the episcieral veins and finally into
the cavernous sinus or jugular venous.
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Physiology of IntraocuIar Pressure
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IOP :
Any anesthetic event that alters these parameters
can affect IOP:
laryngoscopy
Intubation
airway obstruction
Coughing
Trendelenburg position
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IOP
 The eye is hollow sphere with a rigid wall.
 IOP 12—20 mm Hg .
 If the contents of the sphere increase, the
IOP rise.
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Effect of Anesthetic Drugs on IOP
 Most anesthetic drugs either lower or have no
effect on IOP:
 Inhalational anesthetics decrease IOP in
proportion the depth of anesthesia.
 The decrease has multiple causes:
1- A drop in BP reduces choroidal volume
2 - Relaxation of the extraocular muscles lowers
wall tension
3- pupillary constriction facilitates aqueous
outflow.
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IV anesthetics
- IV anesthetics drugs decrease IOP.
 Exception is ketamine, which usually raises arterial
BP and does not relax extraocular muscles.
 SCH increases IOP by 5—10 mmHg for 5—10
minutes( contracture of the extraocular muscles).
 Nondepolarizing M.R do not increase IOP.
 Pretreatment with a NDMRD or lidocaine
,acetazolamide, propranolol may attenuate SCH
induced increases in lOP.
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The effect of anesthetic agents on lOP
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Oculocardiac Reflex (OCR)
 Triggered by multiple stimuli :
1 - external pressure on the globe
2 - traction on the extraocular muscles
3 - traction on the conjunctiva,
4 - placement of a retrobulbar block.
- Trigeminal afferent and a vagal efferent pathway.
 Bradycardia is the most common clinical manifestation .
 Cardiac dysrhythmias (junctional rhythm, ectopic atrial rhythm, A-V
blockade, ventricular bigeminy, multifocal PVC, wandering pacemaker,
idioventricular rhythm, V. tachycardia, asystole) may occur.
 This reflex is not suppressed by GA, and may be augmented by
arterial hypoxemia and hypercapnia.
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What factors contribute to the incidence of the OCR?
 Preoperative anxiety
 light general anesthesia
 Hypoxia
 Hypercarbia
 Increased vagal tone owing to age
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How do you diagnose and treat the OCR?
 Monitor the ECG intraoperatively and during any
eye manipulation.
• Stop the surgical stimulus immediately.
• Ensure that ventilation is adequate.
• Ensure sufficient anesthetic depth.
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PREVENTION AND TREATMENT
 In children: prophylactic IV anticholinergic drug
(atropine, glycopyrrolate) shortly before the
stimulus may be recommended.
 IM atropine for prophylactic treatment in adults
has not been found to be effective.
 Treatment :
1 - Removal of the surgical stimulus.
2 - If the reflex persists , administration of
atropine (10 to 20 micro/kg IV)or alternatively,
glycopyrrolate is a consideration.
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Anesthesia for Eye Surgery
 Preoperative evaluation is very important ( medications ).
 GA is necessary in infants and children
 In adults, most eye procedures can be achieved with
MAC + Regional block (retrobulbar or peri bulbar block)
 Most anesthetic induction drugs and NDMRD may be
used.
 SCH can be used if it is recognized that this drug
transiently increases lOP.
- When GA is selected avoid :
coughing, nausea, vomiting on emergence and in the
postoperative period.
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Goals in Management of Anesthesia for
Ophthalmic Surgery
 Control of IOP.
 Intense analgesia
 Akinesia (motionless eye)
 Avoidance of the OCR
 Awareness of possible drug interactions
 Awakening without coughing, nausea, or
vomiting
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RETROBULBAR OR PERIBULBARBLOCK
 Surgery : cornea, anterior chamber, and lens
can be accomplished with a retrobulbar or peri
bulbar block
 Procedure does not last more than 2 hours and
the patient is able to cooperate.
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RETROBULBAR OR PERIBULBARBLOCK
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 Retrobulbar hemorrhage
 Stimulation of the OCR
 Puncture of the posterior of the globe
 IV injection of L.A solution
 Intraocular injection
Complications
of
Retrobulbar
Block :
 Central retinal artery occlusion
 Subdural injection
 Spread of L.A to the brainstem : delayed
onset loss of consciousness because of
respiratory depression (post-retrobulbar apnea
syndrome)
 Blindness
 Penetration of the optic nerve
 L.A spread to the midbrain resulting in
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paralysis of the contralateral extraocular
muscles.
Characteristics of a Peribulbar Block :
 Nerves Blocked :
 Lacrimal
 Complications :
 Frontal
 Spread of L.A solution to
 Trochlear
 Oculomotor
 Nasociliary
 Abducens
 Infraorbital
 Zygomatic
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the contralateral eye
 Periorbital ecchymoses
 Transient blindness
TRAUMATIC INJURIES TO THE EYE
 Eye injuries : Penetrating or blunt trauma,
Emergency GA for a patient with a full stomach.
 Avoid any sudden increases in Iop, extrusion of
the ocular contents and loss of vision.
 H2 receptor antagonist + metoclopramide
respectively.
 Awake tracheal intubation is not usually
feasible.
 Placement of a retrobulbar block is ill advised.
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TRAUMATIC INJURIES TO THE EYE
 RSI or modified RSI is recommended.
 Precautions that blunt the cardiovascular and
lOP responses to laryngoscopy and tracheal
intubation should be considered.
 The choice of SCH (after pretreatment with a
NDMRD) may offer the advantage of RSI of
anesthesia and tracheal intubation with
minimal change in lOP.
 Alternatively, the use of a large (modified RSI)
dose of NDMRD reduce lOP and facilitate
tracheal intubation
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Strabismus Surgery
 Special considerations :
1 - increased risk for the development of malignant
Hyperthermia
2 - A high incidence of postoperative
nausea and vomiting
3 - Risk for OCR
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Strabismus Surgery
 Incidence of isolated masseter spasm after halothane
and SCH is 4 times higher in these.
 Avoiding drugs that are known to trigger MH.
 PONV: The incidence in children after surgery varies
from 48% to 85%.
 The high incidence of PONV caused by extraocular
muscle manipulation or pain that induces an OCR,
vagal response.
- Limiting the dose of opioids and substituting propofol
for inhaled anesthetics, together with the use of a
selective 5-hydroxy tryptamine type 3 receptor
antagonist, have been shown to be highly effective .
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Glaucoma
 Elevated lOP that compresses capillaries and
subsequent blood flow to the optic nerve and
ultimately by ischemic damage to the optic nerve
and blindness.
 OPEN-ANGLE GLAUCOMA :
 Most common type , Sclerosis of trabecular tissue
results in impaired aqueous filtration and drainage.
 Chronically elevated lOP slowly, but progressively
damages the optic nerves.
 Treatment : lowering lOP with medications that
produce miosis and trabecular stretching.
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GLAUCOMA
 CLOSED-ANGLE GLAUCOMA :
 A narrow angle between the iris and cornea.
 Can be caused by swelling of the crystalline lens or
by trauma or displacement of the lens.
 Surgical intervention may be necessary.
TREATMENT: Trabeculectomy
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MANAGEMENT OF ANESTHESIA
1 - Continuation of drugs that induce miosis
2 - Avoidance of venous congestion, which could
increase lOP.
3 - Interaction between antiglaucoma drugs and
anesthetic drugs.
4 - As with strabismus surgery, avoidance of
coughing, nausea, and vomiting is essential.
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PNEUMATIC RETINOPEXY
Can be performed to repair a
straightforward retinal detachment.
 Injecting a gas bubble into the middle part
of the eye.
 Anesthesia : GA or RA

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INTRAOCULAR GAS EXPANSION
 A gas bubble injected into the posterior
chamber during vitreous surgery.
 Intravitreal air injection will tend to flatten
a detached retina and allow anatomically
correct healing.
 The air bubble is absorbed within 5 days
by gradual diffusion through adjacent
tissue and into the blood stream.
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INTRAOCULAR GAS EXPANSION
 GA : Movement and prevention of reaction to the
tracheal tube during emergence are important.
 N2O may expand a hexafluoride gas bubble because
N2O is 117 times more diffusible than SF6 and rapidly
enters the gas bubble.
 N2O should be discontinued at least 20 minutes before
intravitreal injection of gas (washout of nitrous oxide
from the lungs is 90% complete within 10 minutes).
 The gas bubble may remain in the eye for 10 to 28
days, depending on what gas is used.
 GA with N2O should be avoided during this period.
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INTRAOCULAR GAS EXPANSION
 If the patient is breathing nitrous oxide, the bubble
will increase in size.
 because N2O is 35 times more soluble than
nitrogen in blood
 N2O tends to diffuse into an air bubble more
rapidly than nitrogen is absorbed by the
bloodstream.
 If the bubble expands after the eye is closed, IOP
will rise.
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INTRAOCULAR GAS EXPANSION
Sulfur hexafluoride (SF6) :
 it is less soluble in blood than is nitrogen and
much less soluble than nitrous oxide.
 Its longer duration of action (up to 10 days)
compared with an air bubble can provide an
advantage to the ophthalmologist.
 Bubble size doubles within 24 hours after
injection because nitrogen from inhaled air
enters the bubble more rapidly than the sulfur
hexafluoride diffuses into the bloodstream.
 Even so, unless high volumes of pure sulfur
hexafluoride are injected, the slow bubble
expansion does not usually raise IOP.
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Injury to the Eye during Anesthesia
 CORNEAL ABRASION
 Corneal abrasion produces the sensation of the
presence of a foreign body in the eye, tearing,
conjunctivitis, and photophobia. The pain is made
worse by blinking.
 Applying nonionic petroleum-based ophthalmic
ointment to the eye, securely taping the eyelids
shut during anesthesia,
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ACUTE GLAUCOMA
 Caused by the use of drugs that induce mydriasis
will be manifested as dull periorbital pain in the
early postoperative period.
 Administration of mannitol and acetazolamide will
reduce the acutely increased lOP and associated
pain.
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ISCHEMIC EYE INJURY
 Unrecognized external pressure on the globe -
prone position.
 If external pressure on the globe > venous
pressure, the veins may collapse, arterial inflow
may continue, and arterial hemorrhage is likely.
- If external pressure > arterial pressure ischemia of the retina.
 prevention : Appropriate headrests - The
patient's eyes should be checked throughout
the operation to confirm that the position on
the headrest has not changed.
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