Anaesthesia for Eye-surgery Dr.Shailendra.V.L. Specialist in Anaesthesia Al Bukariya general hospital Saudi Arabia.

Dr.Shailendra.V.L.

Specialist in Anaesthesia

Al Bukariya general hospital

Saudi Arabia.

Introduction Technological improvements Improved surgical techniques Improved techniques in anaesthesia Better understanding of the physiology

Technological improvements

Improved surgical techniques

Improved techniques in anaesthesia

Better understanding of the physiology

Ophthalmic Surgery Extra ocular surgery- strabismus correction Intra ocular surgery- cataract with IOL Mixed - drainage operations for glaucoma

Extra ocular surgery- strabismus correction

Intra ocular surgery- cataract with IOL

Mixed - drainage operations for glaucoma

Anaesthesia requirements for ophthalmic surgery Immobile eye Uncongested eye  Intra ocular pressure: to minimize the danger of expulsion of intra ocular contents Smooth recovery Avoidance of PONV

Immobile eye

Uncongested eye

 Intra ocular pressure:

to minimize the danger of expulsion of intra ocular contents

Smooth recovery

Avoidance of PONV

Physiology of intra ocular pressure INTRA-OCULAR PRESSURE DETERMINANTS: Factors exerting outward pressure Factors exerting inward pressure

INTRA-OCULAR PRESSURE DETERMINANTS:

Factors exerting outward pressure

Factors exerting inward pressure

Intra-ocular pressure Aqueous humour Vitreous humour Blood within the eye Scleral compliance Extra-ocular muscle tone

Aqueous humour

Vitreous humour

Blood within the eye

Scleral compliance

Extra-ocular muscle tone

Aqueous humour dynamics Ultrafiltration of plasma by ciliary epithelium  Formation of A H in ciliary process  A H circulate around Iris  via pupil Anterior chamber  Canal of Schelmn  Trabecular spaces of Fontana  drains through Episleral venous system

Ultrafiltration of plasma by ciliary epithelium



Formation of A H in ciliary process



A H circulate around Iris

 via pupil

Anterior chamber



Canal of Schelmn



Trabecular spaces of Fontana

 drains through

Episleral venous system

Drugs acting on AH mechanics  production: Acetozolamide (carbonic anhydrase inhibitor) Beta blockers Improve drainage: Miotics (by contracting ciliary muscle) Mydriatics affects drainage

 production:

Acetozolamide (carbonic anhydrase inhibitor)

Beta blockers

Improve drainage:

Miotics (by contracting ciliary muscle)

Mydriatics affects drainage

Choroidal blood volume effecting AH mechanics Systemic blood pressure: Choroidal capillaries auto-regulatory function ↑ in Blood pressure causes transient ↑in IOP Venous pressure: ↑ in CVP causes acute ↑in IOP Coughing/ vomiting/ valsalva/ straining on tube all ↑ IOP ↑ PaCO2 causes ↑ IOP by choroidal vasodilatation

Systemic blood pressure:

Choroidal capillaries auto-regulatory function

↑ in Blood pressure causes transient ↑in IOP

Venous pressure:

↑ in CVP causes acute ↑in IOP

Coughing/ vomiting/ valsalva/ straining on tube all ↑ IOP

↑ PaCO2 causes ↑ IOP by choroidal vasodilatation

Vitreous Humour Fine unstable gel consisting of water & fine supporting structure Volume & pressure reduced by Mannitol which is a dehydrating agent & there by ↓ IOP

Fine unstable gel consisting of water & fine supporting structure

Volume & pressure reduced by Mannitol which is a dehydrating agent & there by ↓ IOP

Extra-ocular muscle tone Tone controlled by the mid-brain GA ↓ muscle tone & there by ↓ IOP Gentle, constant pressure on the eye promotes aqueous humour flow & ↓ IOP

Tone controlled by the mid-brain

GA ↓ muscle tone & there by ↓ IOP

Gentle, constant pressure on the eye promotes aqueous humour flow & ↓ IOP

Pharmacological modifications of IOP Pre anaesthetic Medication: IV diazepam & midazolam ↓ IOP Parental atropine has no effect on IOP Intravenous anaesthetics: Only ketamine ↑ IOP All other agents ↓ IOP

Pre anaesthetic Medication:

IV diazepam & midazolam ↓ IOP

Parental atropine has no effect on IOP

Intravenous anaesthetics:

Only ketamine ↑ IOP

All other agents ↓ IOP

Pharmacological modifications of IOP Inhalational agents effect IOP by: Central action on mid-brain Alteration of aqueous humour ↓ extra-ocular muscle tone Dose dependent reduction in IOP

Inhalational agents effect IOP by:

Central action on mid-brain

Alteration of aqueous humour

↓ extra-ocular muscle tone

Dose dependent reduction in IOP

Pharmacological modifications of IOP Neuro-muscular blockers: Succinylcholine- ↑ IOP by 10 mmHg by 1 minute & lasts for 10 minutes ↑ IOP due to tonic action of drug on Felderstruktur striated extra0ocular muscle Laryngoscopy & Intubation: ↑ IOP

Neuro-muscular blockers:

Succinylcholine- ↑ IOP by 10 mmHg by 1 minute & lasts for 10 minutes

↑ IOP due to tonic action of drug on Felderstruktur striated extra0ocular muscle

Laryngoscopy & Intubation:

↑ IOP

Oculo-cardiac reflex Trigemino-vagal reflex Bradycardia, nodal rhythm, ectopic beats, ventricular fibrillation, asystole Eyeball pressure, traction of extra-ocular muscles, orbital haematoma, ocular trauma & eye pain, eyelid traction Can occur even from enucleated orbit

Trigemino-vagal reflex

Bradycardia, nodal rhythm, ectopic beats, ventricular fibrillation, asystole

Eyeball pressure, traction of extra-ocular muscles, orbital haematoma, ocular trauma & eye pain, eyelid traction

Can occur even from enucleated orbit

Oculo cardiac reflex Afferent pathway Efferent pathway   Short & long ciliary nerves Nucleus of vagus   Ciliary ganglion Cardiac branches via  ophthalmic  division of trigeminal nerve Bradycardia  Trigeminal sensory nucleus

Afferent pathway Efferent pathway

 

Short & long ciliary nerves Nucleus of vagus

 

Ciliary ganglion Cardiac branches

via  ophthalmic 

division of trigeminal nerve Bradycardia



Trigeminal sensory nucleus

Treatment of OCR Ask surgeon to stop all the manipulations Intravenous Atropine 15 micro grams / Kg or intravenous Glycopyrrolate 7.5 micro grams / Kg

Ask surgeon to stop all the manipulations

Intravenous Atropine 15 micro grams / Kg or intravenous Glycopyrrolate 7.5 micro grams / Kg

Systemic effects of ophthalmic medications Eye drops are readily absorbed through hyperemic, incised conjunctiva causing systemic effects Phenyleohrine(2.5%) cause hypertension, arrhythmia and headache Adrenaline(2%) cause hypertension & arrhythmias Timolol (B-blocker) causes bradycardia, hypotension & exacerbation of asthma Phospoline iodide is a lone acting anti-cholinesterase used in glaucoma prolongs suxamethonium induced muscle relaxation

Eye drops are readily absorbed through hyperemic, incised conjunctiva causing systemic effects

Phenyleohrine(2.5%) cause hypertension, arrhythmia and headache

Adrenaline(2%) cause hypertension & arrhythmias

Timolol (B-blocker) causes bradycardia, hypotension & exacerbation of asthma

Phospoline iodide is a lone acting anti-cholinesterase used in glaucoma prolongs suxamethonium induced muscle relaxation

Anaesthetic management of elective intra ocular surgery Goals of general anaesthesia: Immobile eye Stable IOP Minimize bleeding Avoidance of Oculo-cardiac reflex Smooth induction Smooth emergence Minimal post-operative nausea & vomiting

Goals of general anaesthesia:

Immobile eye

Stable IOP

Minimize bleeding

Avoidance of Oculo-cardiac reflex

Smooth induction

Smooth emergence

Minimal post-operative nausea & vomiting

Common Ocular surgeries Cataract surgeries Lid surgeries Conjuctival surgeries Strabismus surgeries Penetrating eye injuries Vitreous surgeries Retinal surgeries Laser surgeries

Cataract surgeries

Lid surgeries

Conjuctival surgeries

Strabismus surgeries

Penetrating eye injuries

Vitreous surgeries

Retinal surgeries

Laser surgeries

Anaesthetic management of elective intra-ocular surgery Pre-medication: use of anxiolytics Induction: Thiopentone + Suxamethonium Intubation: Smooth laryngoscopy & intubation Maintenance: O2 + N20 + Isoflurane/Halothane IPPV with Non-depolarizing muscle relaxant Reversal: Neostigmine + Atropine , extubate in deeper planes Problems encountered: Dark room Face inaccessible

Pre-medication: use of anxiolytics

Induction: Thiopentone + Suxamethonium

Intubation: Smooth laryngoscopy & intubation

Maintenance: O2 + N20 + Isoflurane/Halothane IPPV with Non-depolarizing muscle relaxant

Reversal: Neostigmine + Atropine , extubate in deeper planes

Problems encountered: Dark room

Face inaccessible

Anaesthesia for perforating eye injury Problems: Full stomach patient Perforated eye Plan: Preoxygenation Induction: Thiopentone + Atracurium Sellick’s maneuver Smooth laryngoscopy & intubation Controlled ventilation Smooth extubation Use of Ondansetron to prevent PONV

Problems: Full stomach patient Perforated eye

Plan: Preoxygenation

Induction: Thiopentone + Atracurium

Sellick’s maneuver

Smooth laryngoscopy & intubation

Controlled ventilation

Smooth extubation

Use of Ondansetron to prevent PONV

Anaesthesia for special ocular surgeries Glaucoma: Anti-cholinesterase eye drops used in treatment can potentiate effects of succinylcholine precipitating bradycardia & arrhythmias To ↓ IOP 20% mannitol is used, hence it is better to catheterize these patients

Glaucoma:

Anti-cholinesterase eye drops used in treatment can potentiate effects of succinylcholine precipitating bradycardia & arrhythmias

To ↓ IOP 20% mannitol is used, hence it is better to catheterize these patients

Anaesthesia for special ocular procedures Retinal detachment surgery: Oculo-cardiac reflex commonly observed Essentially extra-ocular surgery Synthetic silicone strap used to produce scleral indentation

Retinal detachment surgery:

Oculo-cardiac reflex commonly observed

Essentially extra-ocular surgery

Synthetic silicone strap used to produce scleral indentation

Anaesthesia for special ocular surgeries Intra-vitreous gas injection: Intra-vitreous injection of inert gas of low diffusibility such as Sulphar hexafluride (SF6) or Carbon octofluride (C3F6) Gas is absorbed over 10 days and the bubble keeps the sclera intact N20 must be avoided as the bubble size increases upto three times

Intra-vitreous gas injection:

Intra-vitreous injection of inert gas of low diffusibility such as Sulphar hexafluride (SF6) or Carbon octofluride (C3F6)

Gas is absorbed over 10 days and the bubble keeps the sclera intact

N20 must be avoided as the bubble size increases upto three times

Anaesthesia for special ocular procedures Vitrectomy: Closed intra-ocular procedure Surgeon controls IOP manometrically by water tight infusion

Vitrectomy:

Closed intra-ocular procedure

Surgeon controls IOP manometrically by water tight infusion

Ophthalmic procedures in children Naso-lacrimal duct probing / syringing Examination under anaesthesia Intra-ocular pressure measurement Strabismus correction

Naso-lacrimal duct probing / syringing

Examination under anaesthesia

Intra-ocular pressure measurement

Strabismus correction

Naso-lacrimal duct probing Done to open up the duct Trachea to be intubated & throat packed to prevent the fluid entering trachea

Done to open up the duct

Trachea to be intubated & throat packed to prevent the fluid entering trachea

Examination under GA Very common procedure Done to examine in detail the eyes Total intra-venous anaesthesia technique should be used as the procedure is short

Very common procedure

Done to examine in detail the eyes

Total intra-venous anaesthesia technique should be used as the procedure is short

IOP measurement in children General anaesthesia with ketamine must be avoided as IOP will be raised with ketamine General anaesthesia with non-depolarizing relaxants preferred It is advisable to wait for 10 minutes to take measurements after intubation for the IOP to stabilize

General anaesthesia with ketamine must be avoided as IOP will be raised with ketamine

General anaesthesia with non-depolarizing relaxants preferred

It is advisable to wait for 10 minutes to take measurements after intubation for the IOP to stabilize

Strabismus surgery Incidence of OCR very high Careful monitoring Should be anticipated and treated with Atropine / Glycopyrrolate Avoidance of PONV by the use of Ondansetrone

Incidence of OCR very high

Careful monitoring

Should be anticipated and treated with Atropine / Glycopyrrolate

Avoidance of PONV by the use of Ondansetrone

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