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Anesthesia for Ophthalmic sx edit

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

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Anesthesia for Ophthalmic sx edit

  1. 1. นพ. ณัฐพงค์ ฉัตรศรีวงศ์วิสัญญีแพทย์ รพ.เมตตาประชารักษ์ (วัดไร่ขง) ิ
  2. 2.  Oculoplastic Squint Cornea Lens Glaucoma Vitreoretinal Neuro- ophthalmology
  3. 3.  Local anesthesia  Topical anesthesia  Regional anesthesia General anesthesia Ophthalmic surgery
  4. 4. General anesthesia VS Localanesthesia
  5. 5.  Many benefits   Physiological disturbance   PONV  Economic Topical / Regional anesthesia
  6. 6.  Non-invasive Virtually no complications Challenging operating conditions – no akinesia Increasingly popular for phacoemulsification cataract surgery
  7. 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. 8.  IV access / supplementary O2 Which LA?  Proxymetacaine / amethocaine  Preservative free preferred  ± topical NSAID and mydriatic
  9. 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. 10. What about this choice?
  11. 11.  Advantages  Day cases  Good akinesia and Anesthesia  Minimal effect on IOP  Minimal equipment required
  12. 12.  Disadvantages  Not suitable for all patients  Complications  Skill of Surgeons/Anesthesiologists  Unsuitable for certain types of surgery
  13. 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. 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. 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
  16. 16.  Peribulbar block (Pericone) Retrobulbar block (Intracone) Sub-Tenon’s block
  17. 17.  Comfort Assistant providing reassurance O2 saturation, ECG, BP monitoring Right angled screen providing O2
  18. 18.  Intravascular injection Anaphylaxis Hemorrhage Subconjunctival edema Penetration / perforation of the globe Central spread (sub-arachnoid) Optic nerve atrophy
  19. 19.  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
  20. 20.  Indications:  Patient refusal  Children / learning difficulties / movement disorders  Major / lengthy procedures  Inability to lie still / flat  Claustrophobic
  21. 21.  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
  22. 22.  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
  23. 23.  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)
  24. 24.  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
  25. 25.  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.
  26. 26.  Avoid nitrous in vitreoretinal surgery  Bubbles of sulphurhexafluoride (SF3) Emergence without coughing  Deep extubation  Lignocaine on cords  Bolus lignocaine/ propofol beforehand
  27. 27. ?Scoline or not?
  28. 28.  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
  29. 29.  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
  30. 30. 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★
  31. 31.  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.
  32. 32.  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.
  33. 33.  Cataract Surgery can be performed under Regional Anesthesia without discontinuing anticoagulant therapy (Prothrombin Time 1.5 times control).

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