Brief discussion on Anesthesia in ophthalmic surgery

1. ANESTHESIA FOR
OPHTHALMIC
SURGERY
Dr Md Ferdous Islam
CMH,Dhaka

2. 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.

3.  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
 Specific considerations for eye surgeries

4. Challenges 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

5. TECHNIQUES OF ANAESTHESIA
 GENERAL ANESTHESIA
 LOCAL ANESTHESIA
a. Topical anesthesia
b. Infiltration anesthesia
Retrobulbar block
Peribulbar block
Sub Tenon block
Sub conjunctival block
c. Nerve block
d. Intra cameral

6. AGENTS

8.  Adjuvants:
Inj.Adrenaline( 1 in 100000)
It reduces systemic absorption by local vasoconstriction.It also
reduces chance of bleeding, prolongs the duration of action. It
is contraindicated in HTN and Heart diseases.
Inj Hyaluronidase
It enhances diffusion of agents through tissue by breaking
down extracellular matrix. It is used 15 unints/ ml of anesthetic
solution

9. GA Vs LA
 The choice is made on the basis of
the duration of the surgery,
the relative risks and benefits of each
technique for the patient,
patient preference.

10. Indication of GA
In children
 EUA
 Probbing of NLD
 Surgeries
 Cataract
 Glaucoma
 Enucleation in Retinoblastoma
 Injury Repair
 Squint
 DCR

11. In adults
 Repair of perforating injury
 Mentally retarded pt
 Non co operative Pt
 Too nervous and apprehensive pt
 Eneucleation, evisceration, Exenteratin
surgery
 Major Occuloplastic surgery
 Surgeon’s preference

12. General versus Local
Anesthesia
General
Anesthesia:
Patient
refusal
Children /
movement
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
anaesthe
sia
Minimal
effect on
IOP
Minimal
equipme
nt
required
Topical
Anesthesia:
no risk of
hemorrhage,
brainstem
anesthesia,
optic nerve
damage or
globe
perforation

13. 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
disease
Ophthalmic 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
uncomplica
ted
cataracts
only

14. PREOPERATIVE
EVALUATION
 Eye surgery patients are a high-risk group
 Age
 diabetes, hypertension, and
atherosclerosis
 informed consent of the patient.

15. HISTORY
 Allergies and drug sensitivities
 A current list of medications
 Patient factors incl dementia, deafness,
language difficulty, restless legs
syndrome, obstructive sleep apnea,
tremors, dizziness, and claustrophobia.

16. 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, Tremor.

17. CARDIOVASCULAR
EVALUATION
 The AHA 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.

18. 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.

19. PULMONARY
CONSIDERATIONS
Preoperative risk reduction strategies incl
 cessation of cigarette smoking,
 treatment of airflow obstruction
 administration of antibiotics for respiratory
infections.
 Patients should be assessed for sleep apnea.
Intravenous sedation is often contraindicated in
these patients.

20. ENDOCRINE
CONSIDERATIONS
 Severe hyperglycemia and hypoglycemia
should be avoided.
 A FBS should be checked preoperatively.
 Insulin therapy should be used, if needed,
to maintain blood glucose at 150 to
250 mg/dL.

21. ANTICOAGULATION
 Perioperative management of anticoagulants 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; least
likely in cataract surgery.

22. INVESTIGATIONS
 ECG: New chest pain, decreased exercise
tolerance, palpitations, near-syncope,
fatigue, or dyspnea. Tachycardia,
bradycardia, or irregular pulse on
examination.
 Serum electrolytes: H/O severe vomiting or
diarrhea, poor oral intake, changes in
diuretic management, or arrhythmia.
Critical results: Na less than 120 mEq/L or
greater than 158 mEq/L.
K less than 2.8 mEq/L or greater than
6.2 mEq/L.

23. INVESTIGATIONS
 Urea nitrogen: renal decompensation. Critical
result: Greater than 104 mg/dL.
 RBS: 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

24. 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.

25. GENERAL ANESTHESIA
 Intravenous agents: Propofol , Thiopental
and Etomidate.
 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.

26. AIRWAY MANAGEMENT
 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)

27. 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.

28. 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.

29. 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.

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

31. Topical anesthesia
 Relieve pain and itching caused by conditions
such as sunburn or other minor burns, insect
bites, minor cuts and scratches.
 Fluorescence dye examination for corneal ulcer.
 Gonioscopy
 Corneal scrapping for bacteriological study
 Paracentesis
 Perform a contact /applanation tonometry.
 Cataract, pterygium and glaucoma surgery
 Removal of small foreign objects from the
uppermost layer of the cornea or conjunctiva.

32. Retrobulbar Block
A long needle is introduced at junction of
middle third and lateral third of inferior orbital
margin and then directed backwards and
medially towards the apex of the orbit.
Effects are Anaesthesia, akinesia, Hypotony
proptosis
65

33. Peribulbar Blocks
• At superior and inferior parts of
peripheral space of orbit.
• The superior injection.
• The Inferior Inj
• An Intermittent Pr.
• Advantages
66

35. Sub-Tenon’s Block
• Sensory block
• Short-ciliary nerves pass
through Tenon’s capsule to
globe
• Akinesia
• Direct blockade of ant.
nerve fibres as they enter
extra-ocular muscles
68

36. FACIAL NERVE BLOCK
 Blocked at several points after exiting from the
base of the skull from the stylomastoid foram
 Van Lint block A needle is introduced about 1
cm below and behind the lareral canthus. About
4ml sol along the supero lateral and inferolateral
orbital margin in a V shape manner.
 O'Brien’s procedure About 4 ml sol is infiltrated
at the neck of the mandible just infront of the
tragus.

38. Other Nerve Block
 Intratrochlear nerve block
 Supraorbital nerve block
 Lacrimal nerve block
 Infraorbital and Zygomatic nerve block

39. Intra Cameral Anaesthesia
Injecting 1% Lidocaine inj into ant
chamber by side port incision or
paracentsis.
Anaesthetises Iris and the Ciliary
Body
Reduces pain and IOP
The drug must be washed properly

40. COMPLICATIONS

41. COMPLICATIONS OF
REGIONAL ANAESTHESIA
 Retrobulbar hemorrhage
 CRAO
 Stimulation of OC reflex
 Puncture of posterior globe
 IV injection of LA
 brainstem anesthesia - (delayed onset
LOC and resp. depression)
 Optic nerve trauma.

42. 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

43. RETROBULBAR
HAEMORRHAGE
MANAGEMENT
 Determine IOP
 Ophthalmoscopy
TREATMENT
 reduce orbital compartment pressure,
thereby IOP
 Osmotic diuretics
 Lateral canthotomy
 Orbital decompression

44. OCULOCARDIAC REFLEX
The Oculocardiac Reflex(OCR) is manifested
by
 Bradycardia
 Ectopics
 Nodal rhythm
 Atrioventricular block
 Cardiac arrest

45. 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

46. OCULOCARDIAC REFLEX
 Factors contributing to the incidence of
the oculocardiac reflex:
Preoperative anxiety
Hypoxia
Increased vagal tone owing to age

47. 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.

48. 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

49. 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

50. 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

51. BRAINSTEM
ANAESTHESIA Amaurosis
 Gaze Palsy
(Ductional Defects),
 Apnea
 Shivering
 Tachycardia and
Hypertension
 Dysphagia
 Loss Of
Consciousness
 Cardiac Arrest

52. 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

53. 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

54. OCULAR PENETRATION
AND PERFORATION
 Diagnosis -Indirect fundoscopy
 The most common sequelae- Retinal
detachment
 Appropriate retinal surgery-to prevent the
loss of vision.

55. COMPLICATIONS ASSOCIATED
WITH GENERAL ANAESTHESIA
 PONV
 Increase in IOP-extrusion of
intraocular contents
 Intraocular gas expansion
 Pulmonary embolism

56. 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

57. 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

58. 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

59. Ref
 American Academy of Ophthalmology
 Alexander J.E. Foss,Essential Ophthalmic Surgery