OCULAR
ANAESTHESIA
Chairperson:
DR. RUBINA YASMIN
ASSOCIATE PROFESSOR
DEPT. OF ANAESTHESIOLOGY
NIO&H
Moderator:
DR. KANIJUN NAHAR QUADIR
ASSISTANT PROFESSOR
DEPT. OF ANAESTHESIOLOGY
NIO&H
Presenter:
DR. NAFIZ MAHMOOD
DO STUDENT
NIO&H
ANAESTHESIA:
Reversible loss of feeling or sensation, specially the loss of pain
sensation induced to permit to performance of surgery or other
painful procedures.
From the page of History
Karl Koller
Born:
Died:
December 3, 1857
March 21, 1944
Nationality:
Austria
Fields:
Ophthalmology
Cocaine
Known for:
(a south american bush ERYTROXYLUM COCA.)
as a local anaesthetic in 1884
Ophthalmic surgeon work in Vienna
From the page of History
Hermann Jakob Knapp
Born:
Died:
March 17, 1832
April 30, 1911
In 1884 used cocaine for retrobulbar block.
van Lint achieved orbicularis akinesia by local injection
From the page of History
General anaesthesia:
First used by W.T.G Morton of Boston, US
Used – ETHER at Massachusetts General Hospital on 16th
October 1846 to Gilbert Abbott
Types of ocular anaesthesia :
 General anaesthesia
 Local anaesthesia
Topical
Regional
Peribulbar block
Retrofbulbar block
Parabulbar or sub-tenon block
Intracameral block
Facial block
Frontal block
PREFERRED ANAESHETIC TECHNIQUE
LOCAL ANAESTHESIA:
•
•
•
•
•
•
•
•
•
Pterygium
Cataract
Surgery for glaucoma
Minor extra-ocular plastic surgery
Keratoplasty
Dacryocystorhinostomy
Minor anterior segment procedures
Refractive surgey
Vitreo-retinal surgery etc
GENERAL ANAESTHESIA:
•
•
•
•
•
•
Paediatric surgery
Sqint surgery
Major oculoplastic surgery
Orbital trauma repair
Dacryocystorhinostomy
Vitreo-retinal surgery
GENERAL ANAESTHESIA
FOR OCULAR SURGERY
INDICATION:
1.
2.
3.
4.
In children and infant
Anxious & uncooperative patient
Mentally retarded adult
Patient’s preference
OBJECTIVE:
1.
2.
3.
4.
Analgesia
Amnesia
Loss of consciousness
Adequate skeletal muscle relaxation
Advantages:
I.
safe operative environment
II.
Complete akinesia
III. Controlled intra-ocular pressure
IV. For bi-lateral surgery
V.
Avoiding complications of L/A
PRE- ANAESTHETIC CHECKUP
GENERAL:
• Nutritional status
• Retarded growth
• Anaemia
• Jaundice
• Cough
• Temperature
• Oedema
• History of convulsion
RESPIRATORY SYSTEM :
• Cyanosis
• Dyspnoea
• Auscultation of lung field
AIRWAY:
• Mouth opening
• Neck movement
• Dentition
CARDIOVASCULAR SYSTEM :
•
Pulse
•
Blood pressure
•
Heart sound (auscultation)
•
Dependent oedema
INVESTIGATIONS
Full blood count
Urine analysis
Stool R/E
Chest X-ray
Over 40 years
Blood glucose
ECG
Blood urea
 S.Creatinine
Echocardiogram – specially for congenital heart disease
(valvular disease) also for adult – if indicated
OTHER INVESTIGATIONS:
S. electrolytes
Liver function test
Coagulation screening
Procedure of General Anaesthesia
1) Pre-medication for anaesthesia
2) Induction & intubation
3) Maintenance & Monitoring
4) Extubation and Recovery
Drugs used in G/A
1. Pre-medication for anaesthesia with
•
Benzodiazepines (diazepam) –for sedation and reduce
anxiety
•
Anti-emetics – metaclorpramide , ondansetron
•
Atropine - prevent bradycardia
reduce bronchial and salivary secretion
•
Medication for selective patients - hypertensive , diabetic ,
coronary artery disease
2.Induction
Thiopentone ( thiopental sodium) – 5 mg/kg
Propofol – 2.5 mg/kg
3. Maintenance
• Muscle relaxants – suxamethonium, vecuronium etc
• anaesthetic gas – nitrous oxide (N2O) with O2 and
Halothene , isoflurane etc.
• Intravenous agent – pethidine , Fentanyl , NSAID
(for pain reduction)
4. Recovery
• Neostigmine
• Atropine
COMPLICATION of G/A
• Hypoxia
• Laryngospasm
• Respiratory depression
• Aspiration pneumonitis
• Cardiac arrythmia
• Hypotension / Hypertension
• Convulsion
• Restlessness
EFFECTS OF ANAESTHETIC AGENTS
ON IOP
DRUGS
INHALED ANAESTHETICS
Volatile agents
Nitrous oxide
Intravenous agents
Barbiturates
Benzodiazepines
Ketamine
Opioids
MUSCLE RELAXENT
Depolarizers (succinylcholine)
Non- depolarizers
EFFECT ON IOP
LOCAL ANAESTHESIA
acts by producing reversible block to the transmission
of peripheral nerve impulses
ADVANTAGES:
 Patient is conscious and alert
 Drugs used in G/A can be avoided
 Systemic complication is less –
Post-operative confusion
Nausea , Vomiting
Urinary retention
Stress response to cardiac patient
DISADVANTAGES:
• Painful
• Difficult in uncooperative patients
NOT SUITABLE FOR:
• Young patient
• Mentally unstable patient
• Patient with physical disabilities that prevent lying
DESIRED PROPERTIES OF L/A
1.
Non-irritating , safe and painless
2. Must be water soluable
3. Rapid onset of action
4. Duration of action appropriate to the operation to be performed
5. Non-toxic
6. No local after effects ( nerve damage , necrosis)
7. Must be effective regardless its application to tissue or mucous
membrane
8. Quickly block motor and sensory nerves
ACTION OF LA
NERVE AXON MEMBRANE
LOCAL ANAESTHESIA
LAH+
(ionised drug)
LA
(free base)
LA
(free base)
Na
channel
LAH+
(ionised drug)
MECHANISM OF ACTION OF L/A
Binds with protein of Na+ channels (at interior side)
Block voltage dependent Na+ conductance ( prevent Na+ influx)
Block depolarization
Initiation and propagation of action potential fails
Afferent impulses can not go to higher center
No pain sensation
Patient preparation for LA
 As for GA
 Optimal health condition
 Friendly rapport
 A suitable vein should always be cannulated in all patient
 Full cardio-pulmonary resuscitation equipment
 Appropriate monitoring
Toxicity of LA:
• Light headedness
• Numbness or tingling of circumoral area
• Anxious
• Drowsy
• Tinnitus
• Convulsion ( To prevent- Diazepam or TPS)
• Coma & apnoea develop subsequently (O2)
• Cardiovascular collapse may result due to myocardial depression &
vasodilatation
HYPOXAEMIA
APNOEA
Types of LA
According to chemical structure
Ester group
Amide group
Procaine
Cocaine
Tetracaine
benzocaine
Lidocaine
Bupivacaine
Ropivacaine
mepivacaine
Esters may cause more allergies
COMMONLY USED L/A
L/A
Oxybuprocaine
Onset of
action
6-20 sec
Duration of
action
15 min
Use
Topical (0.4%)
5-10 min
30-60 min
Infiltration
(concentration)
(1%,2%,4%)
Lignocaine
Bupivacaine
10- 35 sec
15-20 min
Topical (4%)
Moderate
75-90 min
Infiltration (0.25-
0.75%)
OTHERS
L/A
Onset of
action
Duration of
action
Use
(concentration)
Proparacaine
15-30 sec
15-20 min
Topical (0.5%)
Amethocaine
10-25 sec
10-20 min
Topical (0.5-1%)
Ropivacaine
Moderate
1.5-6hrs
Infiltration (1%)
TOPICAL ANAESTHESIA
ADVANTAGES:
 Cost effective
 Immediate visual recovery
 Avoidance of complication - globe rupture , nerve damage
DISADVANTAGES:
 No akinesia
 Not suitable for extended surgery
 Well informed and motivated patient is required
ADVERSE EFFECT OF TOPICAL ANAESTHESIA
• Epithelial and Endothelial toxicity
• Allergy to drug
• Alteration of lacrimation
• Surface keratopathy
USES OF TOPICAL ANAESTHESIA
• Manipulation of superficial cornea and conjunctiva
• Phacoemulsification in cooperative patient
• Prior to regional blocks
PERIBULBAR BLOCK
Most popular now a days
AIM:
Injected into peribulbar space
Spreads to lid and other spaces
Produces globe and orbicularis akinesia and anaesthesia.
L/A agent :
o Lignocaine 2%
o Bupivacaine 0.75%
Along with
o Hyaluronidase 5-7.5 IU/ml
o Adranaline 1: 200,000
VOLUME :
8-10 ml (approximately)
INSERTION POINT:
• 1st - Junction of medial 2/3rd and lateral 1/3rd of lower lid adjacent
& Parallel to orbital floor
• 2nd - Just infero-medial to supra orbital notch or just medial to
medial canthus
POSITION OF PATIENT:
Supine and in primary gaze
USE OF PERIBULBAR BLOCK
1. Cataract
2. Glaucoma
3. Keratoplasty
4. Vitreoretinal surgery
5. Strabismus surgery
ADVANTAGES:
• Less chance of globe injury
• Less chance of optic nerve damage
DISADVANTAGES:
• Pain
• Conjunctival chemosis
• Less akinesia than retrobulbar block
RETROBULBAR BLOCK
AIM:
Injected in muscle cone to block
• Cilliar nerve and ganglion
• 3rd , 4th & 6th cranial nerves
• provides - akinesia and
anaesthesia of the globe.
POSITION OF PATIENT :
Supine and in primary gaze
SITE OF INJECTION :
In the lower lid margin just above a point between medial
2/3rd & lateral 1/3rd of lower orbital margin
DIRECTION OF NEEDLE :
backward , upwards and medially towards apex of orbit
VOLUME:
2 – 4 ml usually
ADVANTAGES:
• Complete akinesia
• Dilatation of pupil
• Adequate and quicker anaesthesia
• Minimal amount of agent required
Complications :
 Retrobulbar haemorrhage
 Globe penetration
 Optic nerve sheath injury
 Optic nerve atrophy
 Decrease visual acuity
 Retinal vascular occlusion
Cont…
 Brain stem anaesthesia
 Frank convulsion
 Extra ocular muscle palsy
 Trigeminal nerve block
 Oculo-cardiac reflex
 Respiratory arrest
Contraindication :
• Bleeding disorder ( risk of retrobulbar haemorrhage)
• Extreme myopia ( globe perforation)
• An open eye injury (may cause expulsion of intraocular contents)
• Posterior staphyloma
PARABULBAR OR SUB-TENON BLOCK
DRUG : LIGNOCAINE
Conjunctival incision 2-3 mm
Halfway between inf. limbus & fornix
to open sub-tenon space
Blunt canulla or needle is inserted to post. Sub-tenon space
Bathing the nerves & muscles within the cone
Infiltration
Dissection
ADVANTAGES:
• Avoid vascular and optic nerve injury
• Requires lower volume of anaesthetics
• Better anaesthesia to iris and ant.segment
DISADVANTAGES:
• Subconjunctival haemorrhage
• More post-operative morbidity
FRONTAL BLOCK
AIM: to block supra-orbital and supra-trochlear nerve
supplying the upper lid.
USE:
ptosis surgery
SITE OF INSERTION: just below mid-point of supra- orbital
margin transcutaneously
directed towards roof of orbit
VOLUME: about 2 mlw
INTRACAMERAL ANAESTHESIA
AGENT:
lignocain 1%
(without preservative or adrenaline)
USE:
used for phacoemulsification
FACIAL BLOCK
AIM:
blocking the action
of orbicularis oculi.
USE :
as an adjunct to
retrobulbar block.
TYPES:
1.
Van lint
2.
O’Brien
3.
Nadbath & Rehman
4.
Atkinson
Major sight and life-threatening complications
A. Retrobulbar orbital haemorrhage
SIGNS & SYMPTOMS
• rapid intraorbital and intraocular pressure elevation
• increasing proptosis
• marked pain
• ecchymoses in the eyelids
• Chemosis
• vision down to poor perception or no perception of light
MANAGEMENT:
Evaluation:
Indirect ophthalmoscopy - for evidence of central retinal artery
perfusion compromise.
Immediate medical treatment:
intravenous osmotic agents such as –
• acetazolamide
• mannitol
Surgery:
Surgical decompression such as -
• Canthotomy,
• Cantholysis
• Orbital decompression
B. Globe perforation:
(Exceptionally soft eye ; myopic eye is more prone)
• Occurred with retrobulbar and peribulbar anaesthesia
• suspected if –
 marked pain during the delivery of local an aesthesia
 hypotony with inability to secure a stable globe - intraoperative signs of
perforation
 reduced red reflex due to vitreous haemorrhage
 Serious sight threatening vitreoretinal complications may result
**** seek the advice of a specialist vitreoretinal surgeon
C. Nerve Injury
Optic nerve may be damaged by:
●● direct trauma by needle
●● ischaemic damage from intrasheath injection or haemorrhage
●● pressure from retrobulbar haemorrhage
●● pressure from excess local anaesthetic injection into the
retrobulbar space
●● excessive applied external pressure.
NEED TO CARE :
• avoiding deep injections into the orbit and
• injecting with the eye in the primary position
D. Brain stem anaesthesia
Due to spread of local anaesthetic along the optic nerve sheath
SYMPTOMS & SIGNS:
• drowsiness
• light-headedness
• confusion
• loss of verbal contact
• cranial nerve palsies
• convulsions
• respiratory depression or respiratory arrest
• cardiac arrest
ONSET OF SYMPTOMS:
within 10-20 mins of LA injection
SYMPTOMS LASTS FOR:
Hours
E. Muscle palsy
Diplopia and ptosis are common for 24–48 hours post-operatively
when large volumes of long-acting local anaesthetics are used.
If this persists or fails to recover, it may be due to muscle damage
as a result of :
• intramuscular injection of local anaesthetics
• local anaesthetic myotoxicity
• ischaemic contracture following haemorrhage/trauma
F. Oculocardiac Reflex (Trigeminovagal reflex)
Trigeminal nerve – afferent and vagal efferent pathway
CAUSES:
• Traction on extra-ocular muscle
• Pressure on globe
RESULT:
 Bradycardia
 Ventricular ectopy
 Ventricular fibrilation
AFFERENT PATHWAY
Impulses
Long & short cilliary nerve
Cilliary ganglion
Trigeminal gasserian ganglion
main trigeminal sensory nucleus
in the floor of the 4th ventricle
EFFERENT PATHWAY
Cardiovascular center of medulla
afferent
LCN
Vagus nerve
Heart
SCN
CG
TGG
VN
efferent
Treatment
• Stop the surgical stimulus immediately.
• Ensure adequate ventilation .
• Ensure sufficient anesthetic depth.
Atropine / Glycopyrrolate (anti-cholinergic):
often helpful immediately or prior surgery
TAKE HOME MESSAGES
• All local anaesthetic agents are myotoxic
• Direct injection into a muscle should be avoided
• No LA technique is entirely free of severe systemic adverse events
• short, fine needle should be used
• the eye in the primary gaze position (looking straight ahead)
• Gentle aspiration after insertion of needle should be done to
alleviate possible entry to blood vessel.
• Bevel of the needle facing the globe and tangenital to sclera.
• All occular surgery with LA should be treated as GA.