โดย : นพ. ณัฐพงค์ ฉัตรศรีวงศ์ วิสัญญีแพทย์ รพ.เมตตาประชารักษ์ (วัดไร่ขิง)

1. นพ. ณัฐพงค์ ฉัตรศรีวงศ์
วิสัญญีแพทย์ รพ.เมตตาประชารักษ์ (วัดไร่ขง)
ิ

2.  Oculoplastic
 Squint
 Cornea
 Lens
 Glaucoma
 Vitreoretinal
 Neuro-
ophthalmology

3.  Local anesthesia
 Topical anesthesia
 Regional anesthesia
 General anesthesia
 Ophthalmic surgery

4. General
anesthesia
VS
Local
anesthesia

5.  Many benefits
  Physiological disturbance
  PONV
 Economic
 Topical / Regional anesthesia

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

10. What about this choice?

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

17.  Peribulbar block (Pericone)
 Retrobulbar block (Intracone)
 Sub-Tenon’s block

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

24.  Increasing  Decreasing
 External pressure e.g. face   Venous pressure
mask   Arterial pressure
  Venous pressure  Hypocarbia
  Arterial pressure  IV induction agents
 Hypoxia  NDMRD
 Hypercarbia  Aqeous volume
 Succinylcholine, Ketamine (acetazolamide)
 Laryngoscopy  Vitreous volume
 Coughing (mannitol)

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.

28.  Avoid nitrous in vitreoretinal surgery
 Bubbles of sulphurhexafluoride (SF3)
 Emergence without coughing
 Deep extubation
 Lignocaine on cords
 Bolus lignocaine/ propofol beforehand

29. ?
Scoline or not?

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

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).