6. Non-invasive
Virtually no complications
Challenging operating conditions
– no akinesia
Increasingly popular for
phacoemulsification cataract surgery
7. Careful patient selection
Co-operative
Not distressed
Straightforward surgery
Must be able to lie supine and still
Not claustrophobic
Sedation (Anesthesiologist stand-by)
8. IV access / supplementary O2
Which LA?
Proxymetacaine / amethocaine
Preservative free preferred
± topical NSAID and mydriatic
9. 20-30 min before surgery
Two to three drops every 5 minutes
Cornea is avascular – once absorbed LA
remains for about 30 min
Supplemented by incremental injection
11. Advantages
Day cases
Good akinesia and Anesthesia
Minimal effect on IOP
Minimal equipment required
12. Disadvantages
Not suitable for all patients
Complications
Skill of Surgeons/Anesthesiologists
Unsuitable for certain types of surgery
13. Orbit – shape of
irregular pyramid
Base at front
Axis points posterio-
medially towards skull
Globe lies in anterior
part of orbit
- sits high and lateral
14. Four rectus muscles
arise from the back of
orbit
Insert into the globe
just forward of
equator
Form a cone
- boundary between
two compartments
CENTRAL PERIPHERAL
(retrobulbar) (peribulbar)
15. Within the cone
Optic nerve
Opthalmic artery & vein
Ciliary ganglion
Oculomotor nerves
Sensory supply to orbit
from opthalmic division Trigeminal nerve
enters the orbit through superior orbital fissure
18. Comfort
Assistant providing
reassurance
O2 saturation, ECG,
BP monitoring
Right angled screen
providing O2
19. Intravascular injection
Anaphylaxis
Hemorrhage
Subconjunctival edema
Penetration / perforation of the globe
Central spread (sub-arachnoid)
Optic nerve atrophy
20. 2001Guidelines (RCA & College Of
Ophthalmologists)
Trained staff
Surgeons – topical / sub-conjunctival / sub-Tenon
– without Anesthesiologist
Anesthesiologist & iv access when retrobulbar /
peribulbar
Anesthesiologist in charge when sedation used
21. Indications:
Patient refusal
Children / learning difficulties / movement
disorders
Major / lengthy procedures
Inability to lie still / flat
Claustrophobic
22. Patients at extreme age
Old – medication, confused, deaf, blind, with
co-morbid like DM, CAD, HTN, COPD
Young – congenital anomalies, temp. & fluid
balance
Opthalmic drugs
Timolol – B-Blocker
Phospholine iodide – anti-cholinesterase
23. Normally 10-20 mmHg
Must be controlled when operating within the globe
IOP impaired op. conditions
expulsion of intra-ocular contents
Mild IOP improved op. conditions
25. Careful with face mask
No ketamine
Laryngoscopy after completely paralyzed
4% Xylocaine topical anesthesia at vocal cord
Head up tilt
Monitoring: ECG, oximeter, capnograph and
peripheral nerve stimulator if available
26. Continue volatile agent until spontaneous
respiration is resumed after reversal
Anti-emetic may be administered
No food/drink for 3 hours to reduce the
possibility of aspiration of gastric contents
★
If no muscle relaxants and patient breathes
spontaneously, the depth of anesthesia must
be increased to prevent coughing or straining
against the tube.
27.
28. Avoid nitrous in vitreoretinal surgery
Bubbles of sulphurhexafluoride (SF3)
Emergence without coughing
Deep extubation
Lignocaine on cords
Bolus lignocaine/ propofol beforehand
32. Traction on EOM may cause sudden and
profound bradycardia via oculocardiac reflex
mediated by CN X
Occasionally seen during other forms of eye
surgery e.g. retinal detachment
33.
34.
35. Prevention
Moderated by LA (abolish afferent arc)
Avoid hypoxia/hypercapnia (sensitizes the reflex)
Prophylactic anticholinergic ★ esp in children
Management
STOP stimuli at once
Ensure adequate ventilation
Ensure sufficient anesthetic depth
If needed, atropine 0.02 mg/kg IV
36. Is atropine useful?
Controversial
0.4 mg IM as a premedicant has no vagolytic
effect after 60 min and is of no value in
preventing or treating OCR
0.4 mg IV is effective for 30 minutes in
preventing bradycardia associated with the
OCR
Doses >0.5 mg IV can cause tachycardia★
37. Examination in children can often be provided
satisfactorily via a face mask
If the naso-lacrimal duct is to be irrigated
Intubation or
Positioning the patient with a pillow under the
shoulders
Ketamine can also be used but pre-medication with
atropine is essential to prevent laryngospasm caused
by excessive secretions.
38. If sedation is required Midazolam (0.5 -1 mg) with
Fentanyl 25 – 50 mg or Propofol 20 mg.
Peribulbar block is advisable when axial length is
less than 26mm and patient can lie flat & still.
Haelan (Sodium Hyaluronate) is injected at the time
of incision to maintain the shape of anterior
chamber and controls the vitreous bulge.
39. Cataract Surgery can be performed under Regional
Anesthesia without discontinuing anticoagulant
therapy (Prothrombin Time 1.5 times control).