2. COMPLICATIONS OF
ANAESTHESIA IN
OPTHALMIC SURGERY
PRESENTED BY :-
DEVDUTTA NAYAK

3. Introduction
 Anaesthetic requirements for ophthalmic
surgery :
- Nature of the surgery
- Surgeon’s preference
- Patient’s preference
 Local
 Topical
 Regional
 General

4. Local anaesthesia for eyes
 Non-akinetic and akinetic methods
 Non –akinetic techniques
 Topical ( drops & gel )
 Subconjunctival

5. Topical anaesthesia for eyes
 Non-invasive
 Minimal complications
 Challenging operating conditions
– no akinesia
 Popular for phaco-emulsification cataract surgery
 Careful patient selection
 Co-operative
 Must be able to lie supine & still
 Sedation may be required

6.  Usually, little or no sedation is necessary.
 If necessary, a small dose of midazolam (0.01 mg/kg IV)
is generally sufficient.
 Oversedation, especially in the elderly, can lead to
hypoventilation, hypoxia, and disorientation.
 Usual agents: Proxymetacaine/Proparacaine 0.5% drops
Lignocaine 4% drops & 2% gel
Lignocaine 2% subconj. injection
 2 – 3 drops instilled every 5 mins, 30 mins prior to
surgery; action remains for 30 mins.

7. Akinetic techniques
 Akinetic blocks :
1. Needle techniques
- Intraconal
- Extraconal
- Combined intraconal & extraconal
2. Cannula techniques
- Sub- tenon’s block
 Ophthalmic surgeons prefer immobile eyes
 Friedman et al - patients also prefer akinetic
regional ophthalmic block.
Br J Ophthalmol 2004;88:333-5

8. Regional anaesthesia
 Advantages
 Day cases
 Good akinesia & anaesthesia
 Minimal effect on IOP
 Minimal equipment required
 Low failure rate & high safety profile
 Disadvantages
 Not suitable for all patients
 Complications
 Skill of anaesthetist
 Unsuitable for certain types of surgery

9. Anatomy
 The orbit irregular four-sided pyramid
Apex - pointing posteromedially &
Base - facing anteriorly
 Annulus of Zinn → fibrous ring arising from the superior orbital
fissure, forms the apex
 The surface of cornea, conjunctiva & lids → forms the base
 Globe movements are controlled by -
- Rectus muscles (inferior, lateral, medial &superior)
- Oblique muscles (superior & inferior)
 Rectus muscles → origin - annulus of Zinn
insertion - anterior to the equator of the
globe, Forms an incomplete cone

10. Orbit

11. Cone formed by rectus muscles

12. Nerve supply
 Within the muscle cone :-
- Optic nerve (II)
- Oculomotor nerves (III)
- Abducent nerve (VI nerve),
- Nasociliary nerve (a branch of V nerve),
- Ciliary ganglion and vessels
 ALL3 SO4 LR6
 Trochlear nerve runs outside & above annulus→ superior oblique
(retained activity of this muscle is frequently observed )
.
 Nasociliary nerve → Corneal & perilimbal conjunctival
 Frontal & infraorbital nerves → remainder of the peripheral conjunctival

13. Cont.

14. Tenon’s space anatomy
 Tenon’s capsule → thin membrane enveloping the
globe & separating it from orbital fat
 Inner surface separated from the outer surface of the
sclera by a potential space the sub- tenon’s space
 Sub- tenon’s space → lymphatic space
 Follows the optic nerve & continues with subarachnoid
space

15. Assessment and Preparation
 British Ophthalmic Anesthesia Society :- fasting regimen
 there is difference in clinical practice by different anaesthesist
 Majority do not consider that it is necessary for the pt to be fasted
prior to local anesthesia for eye surgery
( 65 % did not restrict any food or liquid intake )
 Complication rates of starvation or aspiration in ophthalmic
regional anesthesia are unknown
 Pre-op investigations
 Routine investigation of patients for catract surgery is not
essential
 Tests can be done to improve the general health of the patient if
required.
Royal College of Anaesthetists and The Royal College of Ophthalmologists, 2001

16. Cont.
 Enquiry about bleeding disorders & related drugs
 Konstantatos et al –
Patients on anticoagulants to continue their medication.
Clotting results should be within therapeutic range.
Anaesth Intensive Care 2001;29:11-8
 Recommendation for patients receiving antiplatelet agents
- Currently no recomendation
Katz J et al Study - Ophthalmology 2003; 110: 1784-8
- Procedures under topical, subconjunctival, sub- Tenon’s
blocks are recommended
Konstantatos A et al - Anaesth Intensive Care 2001;29:11-8

17.  Chassot et al :-
 Extra occular & anterior chamber surgery can be conducted
during dual antiplatelet theraphy
 Posterior chamber procedures require cessation of
clopidogrel ( but not asprine )
 Only emergency surgery should be performed on full antiplatelet
therapy
 The risk/benefit ratio : preoperative withdrawal of antiplatelet
drugs in order to perform regional block is not justified.
BJA 99 (3):316-28 (2007)

18. Cont.
 Anaesthetic & surgical procedures are explained
 All monitoring and anaesthetic equipments should be functional
 Intravenous line :-
# Anaesthetists and The Royal College of Ophthalmologists, 2001
- IV line must be inserted before embarking on
a needle block
# Kumar CM, Dodds et al -
- Presence of a secure IV line remains good clinical practice
Ophthalmic Anaesthesia. The Netherlands, 2002.

19. Types of regional anaesthesia
 Akinetic Needle Technique
 Peribulbar block (Pericone)
 Retrobulbar block (Intracone, Atkinson’s)
 Sub- Tenon’s block
(parabulbar block, pinpoint anaesthesia,
medial episcleral block)

20. Retrobulbar block –
 The Atkinson’s or classical retrobulbar
block –
- Needle inserted through the skin, at the junction of
medial 2/3rd & lateral 1/3rd of the lower orbital margin
- 2 to 3 mL of local anaesthetic is injected deep into the
orbit behind the globe with the patient looking upwards
& inwards
- A separate 7th nerve block is required.

21. Complications of Facial Block
• subcutaneous hemorrhage
• vocal cord paralysis
• laryngospasm
• dysphagia
• respiratory distress

22. Cont.
 In modern retrobulbar block
- 25-G, 31-mm long needle is inserted through the
conjunctiva or skin in the inferotemporal quadrant as
far laterally as possible below the LR muscle.
- initial direction is tangential to the globe,
once past the equator ,needle goes upwards &
inwards to enter the space behind the globe
 4 to 5 mL of local anaesthetic injected

23. Cont.

25. Peribulbar block : 2 injections
 Inferotemporal injection
 Injection is made outside the cone.
 A 25-G, 31-mm long needle inserted through the
conjunctiva as far laterally as possible in the inferotemporal
quadrant.
 Once the needle is under the globe, it is directed along the
orbital floor.
 5 mL of local anaesthetic agent is injected.

26. Cont.

27. Cont.
Nasal injection
 A medial peribulbar block is performed to
 supplement inferotemporal retrobulbar or peribulbar
injection, particularly when akinesia is not adequate.
Rubin A. Eye blocks. In: Principles and Practice of Regional Anaesthesia :
Churhill Livingstone, 2003
 25 or 27-G needle is inserted just below the supraornital
notch to a depth of 15 to 20 mm
.
 3 to 5 mL of local anaesthetic agent is injected

28. Cont.

29. Needle Selection for Akinetic Block
 Historically → 38 mm long needle
 Chandra M Kumar et al –
 Distance between inferior orbital rim & apex 42 to 54 mm
 Ciliary ganglion lie → 7 mm in front of the apex
( as per study in 120 cadaveric skull )
 Hence ciliary ganglion is 35 mm from the inferior orbital rim
 Patients with shallow orbit are at a ↑ risk with needles ≥ 35 mm
 Vanden Berg et al –
 Shorter (25 mm) needles are recommended
 Some authors claim excellent results with 16-mm needles
Anaesthesia 2004;59:775-80

30. Complication of agent
 Systemic complication
- Over dose
- Intravascular injection
- Allergic or vasovagal reaction.
- Into CSF within a cuff of dura around
the optic nerve
(confusion, convulsion, unconsiousness, respiratory & cardiac arrest)
- Over dose or intra vascular injection of adrenalin
- Allergic reaction to hyaluronidase

31. Complications of the techniques
 Subconjuctival oedema (chemosis )
 Frequently follow large volume of peribulbar injection
than retrobulbar injection
 Resolves with use of pressure
 No intra or postoperative problem
 Bruising (ecchymosis )
 Disfiguring
 Conjuctival rather than skin injection to prevent
bruising

32. Retrobulbar hemorrhage

33. Retrobulbar hemorrhage
 Incidence = 0.1 -1.7 %
 Predisposing factor : Elderly
Vascular or haematological disease
Pt on steroids, aspirin, NSAIDS, anticoagulant
 Manifest by : Tight eyelids, Proptosis
Subconjuctival or periorbital hemorrhage &
Dramatic increase in IOP
 Central retinal artery pulsation should be monitored. CRAO
reported.
 Impending retinal artery occlusion → Decompressive surgery (Lat.
Canthotomy & Cantholysis)
Anterior chamber paracentesis
 IV Mannitol
 Postpone surgery if unmanageable.

34. Globe perforation
 Both in peribulbar & retrobulbar blocks
 Incidence :- 1 in 874 Gillow et al, Eye 1996;10:533-536
1 in 12,000 Devis et al, J Catract Refract surg;1994:20
1 in 16,224 Manner et al, Eye 1996;10:367-370
 More in long & thin eye
 Globes longer than 26mm are at risk
 Pt who had or presenting for retinal detachment surgery and pt
with myopia have long globes

35.  Hamilton RC et al –
Risk factors that predispose globe penetration
- Presence of a long eye
- Staphyloma or enophthalmos
- Faulty technique
- Lack of appreciation of risk factors
- Uncooperative patient
- Use of unnecessarily long needles
OphthalmolClin North Am 1998;11:99-114.
 Patients with axial myopia have greater risk of globe puncture
 Risk rate is- 1 in 140 needle blocks with an axial length > 26 mm.
Duker et al: Ophthalmology 1991;98:519-26.
 If axial length not known → power of patients spectacles
 In high myopia & in case of pre-existing scleral buckle a classical
peribulbar block or a single medial peribulbar injection is advocated.
Johnson, International Practice of Anaesthesia. 1996 &
Vohra SB ,Br J Anaesth 2000;85:242-5.

36. Cont.
 Diagnosis by- Pain at time of injection
Sudden loss of vision
Hypotonia
Poor red reflex or vitrous haemorage
 When suspected or diagnosed →discuss with the surgeon
 May be avoided by :
- Knowledge of orbital anatomy and length of globe
- Initial tangential niddle insertion
- Not going “up and in “ till niddle tip past the equator
- Aiming for inferior portion of superior orbital fissure
rather than orbital apex

37.  Optic nerve atrophy-
 Direct injury to optic nerve or retinal artery
 Injection into optic nerve sheath or hemorrhage in optic nerve
sheath
 Retrobulbar hemorrhage
May lead to partial or complete visual loss
 Amaurosis
 Mainly with retrobulbar block due to optic nerve block
 Not with peribulbar block
 Pt should be explained
 Occulo cardiac reflex
 Occasionally
 Pt should be monitored

38. Penetration of optic nerve sheath
(Brainstem Anaesthesia)
 Injection into the dural cuff of optic nerve subarachnoid spread
of anaesthetic agent
 Nicoll et al :-
In 6000 retrobulbar block , incidence is 1 in 375 with 1 in 700 life
threatening Anesthesia and analgesia;1987:66
Hamilton et al - incidence is 3 per 1000
Canadian journal of anaesthesia;1988: 35
 All injection should be made with the globe in primary gaze position
 Symptoms usually appear within 8 min
( immediately or upto 40 min after block)

39.  Sign & symptoms :- Drowsiness , vomiting
Convulsions
Respiratory depression or arrest
Neurological deficit
Cardiac arrest
 Myotoxicity
- Most frequently affect the inferior rectus muscle
- Usually recover but sometimes requires corrective surgery.
- Rainin etal
Highest concentration of local anesthetic should not be
used as they are found to be myotoxic.
Archives of Opthalmology 1985;103
Direct injection into the muscle should be avoided.

40. OCR (Oculo-Cardiac Reflex)
a trigeminal-vagal reflex response that is manifested as cardiac
arrhythmias and hypotension and may be elicited by pain,
pressure, or manipulation of the eyeball
afferent pathway:
long and short ciliary nerves ciliary ganglion gasserian
ganglion along the ophthalmic division of the trigeminal nerve
(the fifth cranial nerve)main trigeminal sensory nucleus in
the floor of the fourth ventricle.
efferent pathway:
starts in the vagal cardiac depressor nerve  negative inotropic
and conduction effects

41. OCR
Occurs:
 most often during strabismus surgery in children
 occasionally during retinal surgery & because of
retrobulbar block
 during nonophthalmic surgery if pressure is placed on
the eyeball.
The more acute the onset and the stronger and more
sustained the traction, the more likely OCR is to occur
Hypoventilation and increased arterial carbon dioxide
partial pressure significantly increase the incidence of
bradycardia during strabismus surgery

42. OCR
To reduce the incidence and severity of OCR:
 Intramuscular (?) administration of atropine
 gentle manipulation of the extraocular muscles
 control of ventilation to maintain normocapnia
 surgeon and anesthesiologist communication
treating OCR:
 The first step in is to stop stimulation by the surgeon before
the arrhythmia progresses to sinus arrest
 atropine (0.007 mg/kg IV)
 local injection of lidocaine near the eye muscle
 ensure that the depth of general anesthesia is adequate, the
patient is normocapnic, and surgical manipulation is gentle.

43. Sub Tenon’s Anaesthesia
 Original idea of Turnbull (1884 )
 Modified & popularised by Mein and
Woodcock, Hansen, Stevens, Greenbaum & others
 Also known as : Parabulbar block
Pinpoint anesthesia
Episcleral block

44. Anatomy of sub- tenon’s space

45. Sub- Tenon’s block
 Standard technique
 Obtaining surface anaesthesia
 Access to the sub-Tenon’s space
 Insertion of a cannula
 Administration of local anaesthetic agent

46.  Inferonasal quadrant is the most common site of access
(can be accessed from all 4 quadrants )
 Stevens JD et al -
Inferonasal quadrant allows good fluid distribution superiorly
while avoiding area of surgery & damage to the vortex veins
Br J Ophthalmol 1992; 76: 670–674
 With the patient - looking upwards & outwards
 Conjunctiva & Tenon’s capsule are gripped with non-toothed
forceps (Moorfield forceps) ,5 to 10 mm away from the limbus
 A small incision is made with scissors ( Westcott scissors) to
expose the sclera & the cannula is inserted following the globe

47. Cont.

48. Cannulae for Sub-Tenon’s Block
 Metal or plastic
 Commonly used cannula is → metal, 19-G, 2.54-cm long &
curved with a blunt end
 Others Southampton cannula
Mid sub- Tenon cannula
Anterior cannula
Ultrashort cannula
 Volume of LA varies from 1.5 -11 mL
( 3 to 5 mL is commonly used)
 Smaller volumes →provide globe anesthesia
Larger volumes → if akinesia is desirable

49. One inch curved metal posterior sub-
Tenon’s cannula

50. Plastic anterior sub-Tenon’s cannula.

51. Plastic mid-sub-Tenon’s cannula

52. Cont.
 Behndig A et al –
Prolonged anesthesia & analgesia are obtained
by inserting a catheter in the sub-Tenon’s space.
J Cataract Refract Surg 1998;24:1307-9
 Sub-Tenon’s block used primarily for cataract surgery
Also effective for →Vitreoretinal surgery
Panretinal photocoagulation
Trabeculectomy
Strabismus surgery
Delivery of drugs
 Sub-Tenon’s block favoured→ in patients on anticoagulants, aspirin
& NSAIDs
Konstantatos A et al - Anaesth Intensive Care 2001;29:11-8

53. Passage of local anaesthetic agent
during sub-Tenon’s injection
 Ultrasound & MRI studies shows –
injected anesthetic agent opens the sub-Tenon’s
space giving a characteristic ‘T-sign’
 Local anaesthetic agent diffuses into intraconal &
extraconal areas resulting in anesthesia & akinesia of
the globe & eyelids
 Intense analgesia is produced by blockade of the short
ciliary nerves as they pass through the Tenon capsule

54. characteristic ‘T-sign’.

55. Complications of Sub-Tenon’s Block
 Minor complications → pain during
injection, chemosis, conjunctival hemorrhage & leakage of local
anaesthetic
 Major complications → orbital & retrobulbar
hemorrhage, rectus muscle paresis & trauma, globe
perforation, central spread of local anesthetic, orbital cellulitis etc.
 Most of these complications occurs following use of 2.54- cm
metal cannula.
Kumar CM et al - Eur J Anaesthesiol 2005;22:567-77.
 Smaller or flexible cannulae appear to be safer but the incidence
of minor complications increases.
Kumar CM & Dodds C et al - An Br J Anaesth 2001;87:631.

56. Pain during injection
 Multifactorial
 Incidence with posterior metal cannula ≈ up to 44%
 Pain scores on a VAS have been reported as high as 5
Stevens JD - Br J Ophthalmol 1992; 76: 670–674
 Smaller cannulae appear to offer a marginal benefit
Kumar CM, & Dodds et al - Eye 2004; 18: 873–876
 Guise PA et al -
Premedication or sedation during sub-Tenon’s injection
does not add any benefit Anesthesiology 2003; 98: 964–968
 Preoperative → explanation of the procedure, good surface
anesthesia, gentle technique, slow injection of warm local
anaesthetic agent & reassurance are considered good practice

57.  Chemosis-
 Incidence ≈ 25 to 60% with a posterior cannula &
100% with shorter cannulae
 Resolves with application of digital pressure
 Minor conjunctival hemorrhage
 Incidence ≈ 20 to 100% & depends on the cannula used
 Anaesthesia and akinesia
 Akinesia is volume dependent
(large proportion develop akinesia with 4-5 ml of LA )
 Superior oblique muscle & lid movements may remain active in a
significant number of patients


58. Pharmacological Considerations
during Ophthalmic Regional Block
 Local Anaesthetic Agent
All the modern LA are suitable & studies have shown little
difference in the quality of anesthesia, analgesia & akinesia
 Adjuvant
Vasoconstrictors :-
- Increases the intensity and duration of block & minimize
bleeding from small vessels
pH Alteration :-
- Alkalization decreases onset time and prolong the
duration of effect after needle block
. Zahl K et al - Anesthesiology 1990;72:230
- No such benefit is seen during sub-Tenon’s block.
Moharib et al - Reg Anesth Pain Med 2000;25:514-7

59. Hyaluronidase :-
 Improves the effectiveness & quality of needle & sub- Tenon’s
block
 use remains controversial
 The amount of hyaluronidase used - 5 to150 IU / mL
 Orbital swelling - allergic actions or excessive doses & orbital
pseudotumour have been reported
Others :-
 Muscle relaxants & clonidine are known to increase the onset &
potency of orbital block
 use is neither routine nor recommended.

60. Sedation and Ophthalmic Regional
Blocks
 commonly used during topical anesthesia
 patients, in whom explanation & reassurance have no benefit
 opioids & small doses of IV anesthetic induction agents are used
 The Royal College of Anesthetists and The Royal
College of Ophthalmologists, 2001
 The routine use of sedation is discouraged
 A means of providing supplemental O2 should be available
 Sedation should only be used to allay anxiety & not to cover
inadequate block

61. Intraocular Pressure (IOP) and
Ophthalmic Regional Blocks
 Changes in IOP after retrobulbar & peribulbar injections
are controversial
 IOP is generally reported to increase immediately after
injection
Bowman R et al - Br J Ophthalmol 1996;80:394-7.
Palay DA et al - Ophthalmic Surg 1990;21:503-7.
Watkins R et al - Br J Ophthalmol 2001;85:796-8.
 IOP is not seen to increase after sub-Tenon’s block
Ling R etal - J Cataract Refract Surg 2002;28:113-7.
Vallance etal - J Cataract Refract Surg 2004;30:433-6.
Alwitry etal - Eye 2001;15:733-5.

62. Retained Visual Sensations During
Ophthalmic Regional Blocks
 Many patients experience intraoperative visual sensations
 This include light, colours, movements & instruments during
all forms of local ophthalmic anesthesia
 During sub- Tenon’s block
 (16%) found the experience to be unpleasant or frightening
Wickremasinghe et al - Eye 2003; 17: 501–-505
 Patients receiving orbital blocks should receive preoperative
advice as this may alleviate an unpleasant experience

63. Intraoperative Care and Monitoring
 Patient should be comfortable with soft padding over
pressure areas
 The Royal College of Anaesthetists and The Royal College of
Ophthalmologists
All patients undergoing major eye surgery under local anesthesia
should be monitored with
 pO2
 ECG
 Maintenance of verbal contact

64. Choice of Technique
 Preference for anaesthetic technique by surgeons & patients varies
 Friedman et al -
72% patients preferred block anesthesia to topical anesthesia
Br J Ophthalmol 2004;88:333-5.
 Ruschen et al supports this view -
Patients have higher satisfaction scores with sub- Tenon’s block
over topical anesthesia alone.
Br J Ophthalmol 2005;89:291-3
 The choice of technique depend on a balance between
- patient’s wishes
- operative needs of the surgeon
- skills of the anesthetist &
- place where such surgery is being performed

65. The Rules
 2001 Guidelines (RCA & Coll. of
Ophthalmologists)
 Trained staff
 Surgeons – topical /sub- conjunctival / sub- Tenon
( without anaesthetist )
 Anaesthetist & iv access with retrobulbar &
peribulbar blocks
 Anaesthetist in charge when sedation is used

66. General anaesthesia for ophthalmic
surgery
 Indications:
 Patient refusal
 Children / learning difficulties / movement
disorders
 Major / lengthy procedures
 Inability to lie still / flat
 Penetrating Eye Injuries

67. Specific Complications:
 IOP rise : ? Ketamine
Succynil choline
 Intraocular Gas Expansion : N2O

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

69. 70
GENERAL ANESTHESIA
 Respiratory complications
 Laryngoscope & intubation
 Respiratory obstruction & spasm (isoflurane)
 Hypoxemia (N2O)
 Hypercapnia / Hypocapnia
 Hypoventilation
 Aspiration pneumonia
 Chest infections

70. 71
 Cardiovascular complications
 Hypertension
 Hypotension
 Cardiac arrhythmias
 Death (halothane)
 Neurological complications
 Headache
 Delayed recovery
 Perioperative neuropathy
 Hallucinations & unpleasant dreams (ketamine)

71. 72
 Postoperative nausea & vomiting (propofol, etomidate)
 Temperature changes
 Hypothermia
 Hyperthermia (atropine, halothane)
 Allergic drug reactions
 Itching
 Anaphylaxis
 Hypotension, arrhythmia, tachycardia
 Bronchospasm, cough, dyspnea

72. 73
 Complications of positioning
 Air embolism
 Nerve palsies
 Brachial plexus, Radial nerve, Ulnar nerve
 Skin necrosis
 Miscellaneous
 Renal dysfunction (enflurane)
 Muscle pain (succinylcholine)

73. THANK YOU