Anesthesia in ophthalmic surgery and complications

ANESTHESIA FOR OPHTHALMIC SURGERY AND COMPLICATIONS

SHADAB

INTRODUCTION

Anesthesia for EYE surgery presents many unique challenges.

In addition to possessing technical expertise, the anesthesiologist must have detailed knowledge of ocular anatomy, physiology, and pharmacology.

INTRODUCTION Ocular anatomy Physiology of intraocular pressure and

effect of anesthetic drug on it, Systemic effects of ophthalmic drugs Technique of anaesthesia: advantage

and limitations Pre op evaluation General anaesthesia Complications Oculocardiac reflex and other reflex Specific considerations for eye

surgeries

Ophthalmic SurgeryChallenges for the anaesthesiologist

are Akinesia Analgesia Minimal Bleeding Awareness of drug interactions Regulation of intraocular pressure Prevention of the oculocardiac

reflex Management of oculocardiac reflex Control of intraocular gas

expansion Smooth emergence

Ophthalmic Surgery

Why these patient have a particular challenge to the anesthesiologist?

The combination of a full stomach and an

open-globe injury, both of which

conditions are problematic for the

anesthesiologist.

Any drug or manoeuvre that raises intra-

ocular pressure (lOP) can cause

extrusion of the vitreous humor and loss

of vision.

Ocular Anatomy

APPLIED ANATOMY OF THE ORBIT


The orbit

♦ Four-sided bony pyramid

♦ Base pointing anteriorly

♦ Apex posteromedialiy.

♦ The medial wall of the right and left orbits are parallel to each other

♦ The mean distance from the inferior orbital margin to The apex is 55 mm. (This has important implications when injections are made into the orbit.)


Movement of the globe is controlled by

the six extra-ocular muscles.

The eye is hollow sphere with a rigid

wall.

Intraocular pressure 12—20 mmHg

Ophthalmic surgery can be intraocular

or extraocular procedures, each has

different anaesthetic requirements.


Squeezing and closing of the eyelids

These are controlled by the zygomatic

branch of the facial nerve (VII), which

supplies the motor innervation to the

orbicularis oculi muscle.

The facial nerve also supplies

secretomotor parasympathetic fibres to

the lacrimal glands, and glands of the

nasal and palatine mucosa.


How is aqueous humor formed and eliminated?

a clear fluid that occupies the anterior and posterior chambers of the eye.

Its total volume is 0.3 ml. produced primarily in the posterior chamber circulates through the pupil to the anterior

chamber, passes through the Schlemmn’s canal.

drains into the episcleral veins and finally into the cavernous sinus or jugular venous sinus.

Physiology of IntraocuIar Pressure


The eye is hollow sphere with a rigid wall.

intraocular pressure 12—20 mm Hg

If the contents of the sphere increase, the intraocular pressure rise.



Any anaesthetic event that alters these parameters can affect intraocular pressure

Laryngoscopy Intubation Airway obstruction Coughing Trendelenburg position

Effect of Anesthetic Drugson intraocuIar Pressure

Effect of Anesthetic Drugs

Most anesthetic drugs either lower or have no effect on intraocular pressure

Inhaled Anesthetics

Inhalational anesthetics decrease intraocular pressure in proportion to the depth of anesthesia.

The decrease has multiple causes:

1. A drop in blood pressure reduces choroidal volume

2. Relaxation of the extraocular muscles lowers wall tension

3. pupillary constriction facilitates aqueous outflow.

Intravenous anesthetics

Intravenous anesthetics drugs

decrease intraocular pressure

Exception is ketamine, which usually

raises arterial blood pressure and

does not relax extraocular muscles.

Muscle relaxants

Succinylcholine increases intraocular

pressure by 5—10 mm Hg for 5—10

minutes principally through

prolonged contracture of the

extraocular muscles.

Nondepolarizing muscle relaxants do

not increase intraocular pressure.

The effect of anesthetic agents on intraocular pressure (lOP).

SYSTEMIC EFFECTSOF OPHTHALMIC DRUGS


Topical ophthalmic drugs can be absorbed through the conjunctiva, or they drain through the nasolacrimal duct and be absorbed through the nasal mucosa.

Usage of topical medications can have implications for the anesthesiologist.


Atropine Used to produce mydriasis and

cyclopiegia. 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.


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 15- minute period.

It is contraindicated in closed-angle glaucoma.


Phenylephrine Hydrochloride Phenylephrine hydrochloride is used

to produce capillary decongestion and pupillary dilatation.

Applied to the cornea, it can cause palpitations, nervousness, tachycardia, headache, nausea and vomiting, severe hypertension, reflex bradycardia, and subarachnoid hemorrhage.

Solutions of 2.5%, 5%, and 10% (6.25 mg phenylephrine per drop) are available.


Epinephrine Topical 2% epinephrine will decrease

aqueous secretion, improve outflow, and lower intraocular pressure in open-angie glaucoma.

Side-effects include hypertension, palpitations, fainting, pallor, and tachycardia.

The effects last about 15 minutes. One drop of 2% solution contains 0.5

to 1 mg of epinephrine.


Timolol Maleate (Tinwptic)

Timolol maleate is a beta-blocker used in

the treatment of chronic glaucoma.

Side- effects include light-headedness,

fatigue, disorientation, depressed CNS

function, and exacerbation of asthma.

Bradycardia, bronchospasm, and

potentiation of systemic beta-blockers can

occur.


Acetylcholine

Acetylcholine can be injected

intraoperatively into the anterior

chamber to produce miosis.

Side-effects are due to its

parasympathetic action they include

hypotension, bradycardia, and

bronchospasm.


Echothiophate Iodide (Phosplzolfne Iodide) 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.

Anesthesia for Ophthalamic Surgery

TECHNIQUES OF ANESTHESIA

Facial nerve block

Retrobulbar block

Peribulbar block

Sub Tenon block

Topical anesthesia

General anesthesia

GENERAL VERSUS LOCAL ANESTHESIA

The choice of general versus local anesthesia is made on the basis of the duration of the surgery, the relative risks and benefits of

each technique for the patient, patient preference.

Neither technique has been shown to be safer.

General versus Local AnesthesiaGeneral

Anesthesia:

Patient refusal

Children / movemen

t disorders

Major / lengthy

procedures

Inability to lie still /

flat

Local Anesthesia

:

No Physio-logical distur-bance , PONV

Economic, Day care

Regional Anesthesia

:

Good akinesia

and anaesth

esia

Minimal effect on

IOP

Minimal equipme

nt required

Topical Anesthesia

:

no risk of hemorrhage, brainstem anesthesia, optic nerve damage or

globe perforation

LIMITATIONS…

General Anesthesia:

Eye surgery necessitates

positioning the anesthesiologist away from the

patient’s airway

Patients at extremes of age

Pediatric patients : associated congenital

disorders (eg: rubella syndrome, Down syndrome).Co-morbidity in

elderly: esp. Diabetes,

hypertension and coronary artery

diseaseOphthalmic

drugs

Local Anesthesia:

Complications , Allergy to drug

Skill of anaesthetist

Shortness of breath on

lying down, chronic cough

Parkinson’s disease

Eye Trauma

Topical Anesthesia:

lack of eye

akinesis

treatment of

uncomplicated

cataracts only

PREOPERATIVE EVALUATION Eye surgery patients are a high-risk

group Extremes of Age Other risk factors, such as diabetes,

hypertension, and atherosclerosis The anesthesiologist's goal is to

prepare the patient to present an acceptable risk at surgery.

Acceptable risk is determined by the medical care team with the informed consent of the patient.

HISTORY

Previous hospitalizations and surgical procedures Allergies and drug sensitivities

A current list of medications Patient factors that could

influence anesthetic management include dementia, deafness, language difficulty, restless legs syndrome, obstructive sleep apnea, tremors, dizziness, and claustrophobia.

PHYSICAL EXAMINATIONS

Check for signs of major cardiac or pulmonary decompensation.

Particular attention should be paid to positioning issues, such as severe scoliosis or orthopnea.

CARDIOVASCULAR EVALUATION

The American Heart Association and American College of Cardiology published guidelines for perioperative cardiovascular evaluation for noncardiac surgery.

Ophthalmic procedures such as cataract extraction are specifically identified as low-risk procedures.

For these procedures, evaluation is focused on patients with major clinical predictors of risk.

HYPERTENSION

Severe hypertension may lead to perioperative complications.

It would be prudent to reschedule elective procedures in patients with sustained stage 3 hypertension until after 2 weeks of antihypertensive therapy.

PULMONARY CONSIDERATIONS

Ophthalmic procedures generally require that the patient lie flat comfortably and quietly.

Preoperative risk reduction strategies include cessation of cigarette smoking, treatment of airflow obstruction with bronchodilators or steroids, and administration of antibiotics for respiratory infections.

Patients should be assessed for sleep apnea. Intravenous sedation is often contraindicated in these patients.

ENDOCRINE CONSIDERATIONS

Severe hyperglycemia and hypoglycemia should be avoided.

A fasting blood glucose should be checked preoperatively.

Insulin therapy should be used, if needed, to maintain blood glucose at 150 to 250 mg/dL.

The potential for autonomic neuropathy needs to be considered, especially when elevating the patient from the supine position.

ENDOCRINE CONSIDERATIONS

Patients on long-term steroid therapy generally do not require “stress-dose” steroid treatment for ophthalmic surgery.

The patient should be given his or her normal steroid dose on the day of surgery.

Unexpected hypotension, fatigue, and nausea may be signs of a patient who needs additional steroid

ANTICOAGULATION

Perioperative management of anticoagulants involves weighing the relative risks of thrombotic against possible hemorrhagic complications. That depends on the following: The degree of anticoagulation. The hemorrhagic potential of the

surgical procedure as in orbital and oculoplastic surgery; of intermediate probability in vitreoretinal, glaucoma, and corneal transplant surgery; and least likely in cataract surgery.

INVESTIGATIONS

Electrocardiogram: New chest pain, decreased exercise tolerance, palpitations, near-syncope, fatigue, or dyspnea. Tachycardia, bradycardia, or irregular pulse on examination.

Serum electrolytes: History of severe vomiting or diarrhea, poor oral intake, changes in diuretic management, or arrhythmia. Critical results: Sodium less than 120 mEq/L or greater than 158 mEq/L. Potassium less than 2.8 mEq/L or greater than 6.2 mEq/L.

INVESTIGATIONS

Urea nitrogen: Signs or symptoms of renal decompensation. Critical result: Greater than 104 mg/dL.

Serum glucose: Polydipsia, polyuria, or weight loss. Critical results: Less than 46 mg/dL or greater than 484 mg/dL.

Hematocrit/hemoglobin: History of bleeding, poor oral intake, fatigue, decreased exercise tolerance, or tachycardia. Critical results: Hematocrit less than 18% or greater than 61%. Hemoglobin less than 6.6 mg/dL or greater than 19.9 mg/dL

GENERAL ANESTHESIA

PREMEDICATION

An effective antiemetic should be used

to decrease PONV. Eg- Ondansetron

Opioids are avoided as they contribute

to PONV.

Benzodiazepines are given.

Pretreatment regimens to control the sympathetic response to tracheal intubation:

i.v. lidocaine (1.5 mg/kg) i.v. remifentanil(0.5 to 0.1 µg/kg) i.v. fentanyl (1 to 3 µg/kg) 3 to 5

minutes before induction. i.v alfentanil (20 µg/kg) Oral clonidine (5 µg/kg) 2 hours

before induction

GENERAL ANESTHESIA

INDUCTION The choice of induction technique for

eye surgery usually depends more on

the patient’s medical problems

the patient’s eye disease

the type of surgery contemplated.

GENERAL ANESTHESIA

Intravenous agents: Propofol , Thiopental and Etomidate.

Volatile Agents: can be used, minimal PONV.

Coughing during intubation: avoided by a deep level of anesthesia and profound paralysis.

The IOP response: to laryngoscopy and endotracheal intubation can be blunted.

LMA: can also be used. Less changes in IOP.

AIRWAY MANAGEMENT

For measurement of intraocular pressure (IOP)- maintenance of spontaneous respiration via a facemask should be used, as intubation will raise the intraocular pressure.

Examination under anaesthesia (EUA)-spontaneous respiration through a reinforced laryngeal mask airway (LMA)

It has the advantages of reduced coughing at the end of the surgery and controlled ventilation with the use of muscle relaxants is possible.

AIRWAY MANAGEMENT

Intraocular surgery requires a still eye with low intraocular pressure and the airway is best managed by intubation with paralysis and controlled ventilation.

Access to the airway will be restricted during the surgery so it is important to secure the tracheal tube firmly.

A preformed south facing RAE tube is ideal, but this may be too long in neonates; a reinforced flexible tracheal tube (ETT) may be preferable in this situation.

GENERAL ANESTHESIA

RELAXATION- A nondepolarising muscle relaxant is

used instead of succinylcholine because the latter increases intraocular pressure.

However, the rise in IOP is small by succinylcholine than the fall caused by intravenous induction agent, and also considering risk of aspiration succinylcholine can be used in an emergency case.

MAINTENANCE

Where halothane is used there is an increased risk of dysrhythmias, particularly where eye preparations containing atropine or adrenaline are used, and in the presence of hypercapnia.

Isoflurane or sevoflurane may be preferable.

Total intravenous anaesthesia (TIVA) with propofol has advantages in reducing the risk of postoperative nausea and vomiting (PONV) since propofol has anti-emetic effects.

Remifentanil can reduce volatile requirements.

USE OF NITROUS OXIDE

The use of nitrous oxide in eye surgery is limited by two factors.

Increase the risk of PONV, and in ophthalmic procedures there is a high incidence of PONV

Secondly, nitrous oxide diffuses from the blood into gas filled spaces in the body.

It should be avoided in vitreoretinal detachment surgery where intraocular gas bubbles of sulphur hexachloride or perfluropropane are introduced into the eye to tamponade detached surfaces.

Effect of intraocular gas expansion

If nitrous oxide is used for a patient who has had recent vitreoretinal surgery (the bubble may last several weeks), or if it is commenced mid procedure, it can cause a significant rise in intraocular pressure with resultant ischaemic damage.

Alternatively, if nitrous oxide was used from the start of the anaesthetic, prior to placement of the gas bubble, it will diffuse out of the bubble on completion of the anaesthetic, and the bubble will shrink and risk re-detachment

Intraocular gas expansion

Prevention: discontinue nitrous 15-20 mins

prior to injection. Avoid nitrous oxide 5 days after air

and 10 days after sulfur hexachloride injection.

In case of perfluoropropane avoid nitrous for atleast a month, or until the bubble is resorbed.

GENERAL ANESTHESIA

MONITORING & MAINTENANCE Eye surgery necessitates positioning

the anesthesiologist away from the patient’s airway, making pulse oximetry mandatory for all ophthalmologic procedures.

Continuous monitoring for breathing-circuit disconnections or unintentional extubation is also crucial.

The possibility of kinking and obstruction of the endotracheal tube can be minimised by using a reinforced or preformed right-angle endotracheal tube.

GENERAL ANESTHESIA

MONITORING & MAINTENANCE The possibility of dysrhythmias caused by

the oculocardiac reflex increases the importance of constantly scrutinizing the electrocardiograph.

most pediatric surgery, infant body temperature often rises during ophthalmic surgen’ because of head- to-toe draping and insignificant body-surface exposure.

End-tidal CO2 analysis helps differentiate this from malignant hyperthermia.

GENERAL ANESTHESIA

EXTUBATION & EMERGENCE A smooth emergence from general

anesthesia Deep level of anesthesia. Intravenous lidocaine (1.5 mg/kg)

prior to extubation. Severe postoperative pain is

unusual.

COMPLICATIONS

COMPLICATIONS OF REGIONAL ANAESTHESIA

Retrobulbar hemorrhage

Stimulation of OC reflex

Puncture of posterior globe

IV injection of LA brainstem anesthesia - (delayed

onset LOC and resp. depression)

Optic nerve trauma.

RETROBULBAR HAEMORRHAGE

Venous hemorrhages - spread slower

Arterial hemorrhages - rapid and taut orbital swelling with marked proptosis.

incidence-1% to 3%. Clinical suspicion: stained

conjunctiva and a proptotic globe

RETROBULBAR HAEMORRHAGE

MANAGEMENT Determine IOP Ophthalmoscopy

TREATMENT reduce orbital compartment

pressure, thereby IOP Osmotic diuretics Lateral canthotomy Orbital decompression

OCULOCARDIAC REFLEX

The Oculocardiac Reflex(OCR) is manifested by Bradycardia Bigeminy Ectopics Nodal rhythm Atrioventricular block Cardiac arrest

OCULOCARDIAC REFLEX

Caused By: Traction on the extraocular muscles

(medial rectus) Ocular manipulation Manual pressure on the globe

The OCR is seen during: Eye muscle surgery Detached retina repair Enucleation

OCULOCARDIAC REFLEX

Factors contributing to the incidence of the oculocardiac reflex:

Preoperative anxiety

Hypoxia

Hypercarbia

Increased vagal tone owing to age

OCULOCARDIAC REFLEX

Management stop stimulation by the surgeon

before the arrhythmia progresses to sinus arrest

Atropine (0.01 mg/kg IV) local injection of lidocaine near the

eye muscle

Ensure depth of general anesthesia normocapnia surgical manipulation is gentle.

OCULORESPIRATORY REFLEX

may cause shallow breathing, reduced respiratory rate and even full respiratory arrest.

Trigemino vagal reflex- connection exists between the trigeminal sensory nucleus and the pneumotactic centre in the pons and medullary respiratory centre.

Commonly seen in strabismus surgery

Atropine has no effect.

OCULOEMETIC REFLEX

It is likely responsible for the high

incidence of vomiting after squint surgery (60-90%).

Trigemino-vagal reflex with traction on the extraocular muscles stimulating the afferent arc.

Antiemetics may reduce the incidence, a regional block technique provides the best prophylaxis

BRAINSTEM ANAESTHESIA Amaurosis

Gaze Palsy (Ductional Defects),

Apnea Shivering Tachycardia and

Hypertension Dysphagia Loss Of

Consciousness Cardiac Arrest

BRAINSTEM ANAESTHESIA The onset of symptoms -delayed 2

to 40 minutes after injection.

Management: Early and prompt treatment 100% oxygen maintenance of vital signs tracheal intubation and controlled

ventilation

OCULAR PENETRATION AND PERFORATION

most common in the myopic, elongated globes.

Myopics with staphyloma. associated with the use of large,

dull needles. a sensation of "poking through

”during the placement of the needle.

sudden appearance of hypotony, vitreous hemorrhage or a diminished red reflex

OCULAR PENETRATION AND PERFORATION

Diagnosis -Indirect fundoscopy

The most common sequelae- Retinal detachment

Appropriate retinal surgery-to prevent the loss of vision.

FACIAL NERVE BLOCK COMPLICATIONS

Blocked at several points after exiting from the base of the skull from the stylomastoid foramen

Nadbath block, O'Brien procedure, Atkinson procedure

Disturbances of swallowing and respiratory difficulties

Horner's syndrome permanent facial nerve paralysis-longer

needles and hyaluronidase use of a single injection of a large

volume of LA

COMPLICATIONS ASSOCIATED WITH GENERAL ANAESTHESIA

PONV

Increase in IOP-extrusion of intraocular contents

Intraocular gas expansion

Pulmonary embolism

POST OPERATIVE NAUSEA AND VOMITING

Most common complication associated with outpatiet

The incidence in patients undergoing strabismus surgery -85%.

MANAGEMENT Metoclopromide i.v (10 mg) 5HT3 antagonists Dexamethasone i.v

Pulmonary Embolus

chief cause of postoperative ophthalmic surgery death

particularly a problem with long procedures (retinal and oculoplastic surgery) in the elderly.

from a leg deep venous thrombosis

Pneumatic leg compression devices

INTRAOCULAR GAS EXPANSION

Intravitreal air/SF6 injection: to flatten a detached retina and allow anatomically correct healing

Nitrous oxide:expansion of air bubble and rise in IOP

Prevention: discontinue nitrous 15-20 mins prior to injection

CONTROL OF INTRAOCULAR PRESSURE

Management of anesthesia for ophthalmic surgery requires control of IOP before, during, and after the procedure

Any anesthetic event that alters the following parameters can affect intraocular pressure laryngoscopy Intubation airway obstruction Coughing Trendelenburg position

Strategies to Prevent Increases in Intraocular PressureAvoid direct pressure on the globe

Patch eye with Fox shield

No retrobulbar or peribulbar injections

Avoid increases in central venous pressure

Prevent coughing during induction and intubation

deep level of anesthesia and relaxation

Avoid head-down positions

Extubate deeply asleep

Avoid pharmacological agents that increase IOP

Succinylcholine

Ketamine (?)

Specific Clinical Situations and Complications

Penetrating Eye Injuries

Balancing the need to prevent aspiration of gastric contents…

and prevention of sudden significant increases in IOP.

Penetrating Eye Injuries

Strategies to Prevent Increases in Intraocular Pressure (IOP). Avoid direct pressure on the globe No retrobulbar or peribulbar injections Careful face mask technique Prevent coughing during induction and

intubation Avoid head-down positions Avoid pharmacological agents that

increase IOP - Succinylcholine, Ketamine (?)

PENETRATING EYE INJURIES

Strategies to Prevent Aspiration Pneumonia.

Premedication by Metoclopramide and Histamine H2-receptor antagonists

Nonparticulate antacids

Evacuation of gastric contents by Nasogastric tube1

Rapid-sequence induction

Cricoid pressure

A rapid-acting induction agent like Succinylcholine,1rocuronium

Avoidance of positive-pressure ventilation

Intubation as soon as possible

Extubation awake

Pediatric Eye Injuries

Regional eye anesthesia- not suitable

Topical anesthetic cream:to start an intravenous line OR

Rapid, gentle induction of anesthesia by mask (with 7% to 8% sevoflurane).

Pediatric Eye Injuries

stomach decompression-during surgery

To facilitate tolerance of the endotracheal tube and minimize bucking

1.narcotic: 10 to 20 minutes before the end of surgery

2.lidocaine (1.5 mg/kg) 5 minutes before extubation

Syringing and probing of nasolacrimal ducts

Anaesthetic considerations:

The surgical team may require placement of a topical vasoconstrictor onto the child’s nasal mucosa.

Hypotensive anaesthesia may be required to reduce bleeding.

The airway should be protected from blood, ideally with a throat pack, and the nasopharynx should be adequately suctioned out before extubation.

Opioids may be required for analgesia for this procedure.

The use of antimicrobial prophylaxis for those at risk of infective endocarditis is no longer routinely recommended for this procedure

STRABISMUS SURGERY

Problem the possible increased risk of malignant

hyperthermia the high incidence (PONV) the likelihood of an OCR

Solution avoid succinylcholine and halothane i.v lidocaine (1.5 mg/kg) low-dose ondansetron (50 µg/kg) dexamethasone (150 µg/kg) regimen

STRABISMUS SURGERY

Induction technique, method of airway control and choice of ventilation according to the preference of the anaesthetist.

Maintenance of anaesthesia is usually achieved with a volatile anaesthetic agent and air;

The use of total intravenous anaesthesia (TIVA) has been shown to reduce PONV.

Consider atropine 20mcg/kg IV or glycopyrolate 10mcg/kg IV as high incidence of oculocardiac reflex.

STRABISMUS SURGERY PONV is common postoperatively, up

to 50 – 75%. Giving two anti-emetic agents such

as ondansetron 0.1 mg/kg IV and dexamethasone 0.1-0.2 mg/kg IV can reduce this to 10%.

Ideally extubate in deep plane. Analgesia should include topical

tetracaine or oxybuprocaine, NSAIDS such as ibuprofen or diclofenac and paracetamol, unless contraindicated.

STRABISMUS SURGERY

Intraoperative opioids should be avoided due to the high incidence of PONV, but where necessary, consider the use of fentanyl.

A peribulbar block is effective for analgesic requirements and reduces PONV, possibly by blocking the ophthalmic division of the trigeminal nerve that passes to the vomiting centre in the medulla.

A sub-Tenon block performed intraoperatively by the surgeon can be very effective for analgesia.

VITREORETINAL SURGERY

Avoid nitrous oxide if an intraocular gas bubble is used.

Avoid nitrous oxide in patients who have had an intraocular bubble placed for several weeks after the procedure.

Controlled ventilation and paralysis should be considered for maintaining a still eye and avoiding raised IOP during the procedure.

VITREORETINAL SURGERY

This procedure is painful and analgesia including opioids should be considered.

Anti-emesis should be used routinely

Avoid raised IOP during extubation – extubate deep.

CONCLUSION

Anesthesia for eye surgery posses unique challenges.

Knowledge of ocular anatomy is important to prevent retrobulbar hemorrhage and other complications.

With intraocular procedures, profound akinesia and meticulous control of IOP are requisite.

However, with extraocular surgery, the significance of IOP fades, whereas concern about elicitation of the oculocardiac reflex assumes prominence.

CONCLUSION

Intraocular pressure are affected by physiological factors, anaesthetic drugs and technique. The regulation of IOP is important as increase in it can cause extrusion of the vitreous humor and loss of vision.

Ophthalmic drugs may significantly alter the patient’s reaction to anesthesia.

Regardless of the technique, ventilation and oxygenation must be monitored, and equipment to provide positive pressure ventilation must be immediately available .

CONCLUSION Goal of general anaesthesia is to

provide: Smooth intubation, Stable IOP, Avoidance of severe oculocardiac reflexes, A motionless field and Smooth emergence

The complications of ophthalmic anesthesia are rare and can be both vision- and life-threatening.

Complications involving the intraocular expansion of gas bubbles can be avoided by discontinuing nitrous oxide at least 15 min prior to the injection of air or SF6, or by avoiding the use of nitrous oxide entirely .

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Anesthesia in ophthalmic surgery and complications

Health & Medicine